Vitamin D deficiency rickets (VDDR) is a disorder biochemically characterized by elevated serum alkaline phosphatase (ALP) activity, normal or decreased serum calcium (Ca) and inorganic phosphate concentrations, secondary hyperparathyroidism and decreased serum 25−hydroxyvitamin D (25(OH)D) levels. In stage 1 VDDR, urinary amino acid and phosphate excretion are normal with minimal or no findings of rickets on radiographs. Pseudohypoparathyroidism (PHP) is an inherited disorder characterized by end−organ resistance to parathormone (PTH). VDDR occasionally resembles PHP type 2 in clinical presentation and biochemical features, creating difficulties in the differential diagnosis of these two entities. Here we report an infant diagnosed with VDDR. In addition to inadequate vitamin D intake, usage of antiepileptic drugs (AED) may have led to the worsening of the vitamin D deficiency. The patient presented with a history of febrile convulsions, for which he received phenobarbital treatment. The initial findings of hypocalcemia, hyperphosphatemia and normal tubular reabsorption of phosphate, mimicking PHP 2, responded well to vitamin D and oral Ca treatment with normalization of serum Ca, phosphorus (P), ALP and PTH levels
Conflict of interest:None declared.
Vitamin D deficiency rickets; Pseudohypoparathyroidism; antiepileptic drugs
Objective: Serum alkaline phosphatase (ALP) levels show great variation with age and sex in children and adolescents. Additionally, different buffers used even in the same method cause variable results. This detail is not usually taken into account in the evaluation. We aimed to study pediatric age- and sex-specific reference ranges for ALP by colorimetric assay using p-nitrophenyl phosphate as substrate and diethanolamine as buffer and also to compare the ALP levels in patients with different types of rickets.
Methods: 1741 healthy children and adolescents (904 girls) were included in the study for normative data. 77 different ALP measurements from 38 nutritional rickets (NR), 7 vitamin D-dependent rickets (VDDR) and 8 hypophosphatemic rickets (HR) patients were included.
Results: Reference values for ALP were constructed. ALP levels demonstrated a tetraphasic course with two peaks at infancy and puberty. There was no difference in ALP levels between boys and girls until puberty. However, higher ALP levels were noted at 10-11 years in girls (p=0.02) and at 12-13, 14-15, 16-17 years in boys (p<0.001). ALP levels start to decline after age 12 and 14 in girls and boys, respectively. Serum ALP levels were highest in the VDDR group and lowest in the HR group (median z-score values in HR, VDDR and NR were 3.6, 10.4 and 6.5, respectively; p<0.001). Similarly, plasma parathormone(PTH) levels ranged from highest to lowest in the VDDR, NR and HR groups (median values: 525, 237 and 98 pg/mL, respectively; p<0.001).
Conclusions: This normative data will provide a basis for better evaluation of ALP levels determined by the described method. Furthermore, use of z-scores gives a more precise assessment of changes in ALP levels in rickets and other bone disorders.
Conflict of interest:None declared.
Alkaline phosphatase; children; reference values; rickets
A 12-week-old domestic cat presented at a local veterinary clinic with hypocalcemia and skeletal abnormalities suggestive of rickets. Osteomalacia (rickets) is a disease caused by impaired bone mineralization leading to an increased prevalence of fractures and deformity. Described in a variety of species, rickets is most commonly caused by vitamin D or calcium deficiencies owing to both environmental and or genetic abnormalities. Vitamin D-dependent rickets type 1A (VDDR-1A) is a result of the enzymatic pathway defect caused by mutations in the 25-hydroxyvitamin D3-1-alpha-hydroxylase gene [cytochrome P27 B1 (CYP27B1)]. Calcitriol, the active form of vitamin D3, regulates calcium homeostasis, which requires sufficient dietary calcium availability and correct hormonal function for proper bone growth and maintenance. Patient calcitriol concentrations were low while calcidiol levels were normal suggestive of VDDR-1A. The entire DNA coding sequencing of CYP27B1 was evaluated. The affected cat was wild type for previously identified VDDR-1A causative mutations. However, six novel mutations were identified, one of which was a nonsense mutation at G637T in exon 4. The exon 4 G637T nonsense mutation results in a premature protein truncation, changing a glutamic acid to a stop codon, E213X, likely causing the clinical presentation of rickets. The previously documented genetic mutation resulting in feline VDDR-1A rickets, as well as the case presented in this research, result from novel exon 4 CYP27B1 mutations, thus exon 4 should be the initial focus of future sequencing efforts.
Vitamin D is present in two forms, ergocalciferol (vitamin D2) produced by plants and cholecalciferol (vitamin D3) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D], plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of 1,25(OH)2D from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the 1α-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D 1α-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of 1,25(OH)2D despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human 1α-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and 1α-hydroxylase mutations with clinical findings.
Vitamin D; Rickets; 1α-hydroxylase
Objective: Insulin-like growth factor binding protein-4 (IGFBP-4), inhibits IGF actions under a variety of experimental conditions. Parathyroid hormone (PTH), 1.25-hydroxy(OH)vitamin D, IGF-I, IGF-II and transforming growth factor (TGF)-b are the major regulators of IGFBP-4 production in vitro. However, little is known about the in vivo regulation of circulating IGFBP-4 in humans.
Methods: We measured serum concentrations of calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), PTH, vitamin D, IGF-I, IGFBP-3, and IGFBP-4 in infants (n=22) with nutritional rickets before and after treatment of rickets with vitamin D (300 000 U single dose po).
Results: The mean±SD age of the patients was 1.3±1.6 years (range 0.2-3). Serum Ca and P increased, whereas ALP and PTH decreased after treatment (Ca from 6.6±1.4 to 9.5±1.6 mg/dL, P from 3.9±1.4 to 5.4±0.8 mg/dL, ALP from 2590±2630 to 1072±776 IU/mL and PTH from 407±248 to 27.4±20.8 ng/dL, respectively). Vitamin D levels were low (7.8±2.5 ng/mL) and increased after treatment (18.1±4.0 ng/mL, p<0.001). Serum IGF-I and IGFBP-3 levels both increased after treatment (IGF-I: 13.5±12.2 vs. 23.7±14.2 ng/mL, p<0.001 and IGFBP-3: 1108±544 vs. 1652±424 ng/mL, p<0.001). However, serum IGFBP-4 levels did not change significantly after treatment (18.8±8.0 vs. 21.5±4.8 ng/mL). No correlation between PTH and IGF-I, IGFBP-3 or IGFBP-4 was detected. Significant correlations were observed between PTH and ALP (r=0.53, p<0.05), and between IGF-I and IGFBP-3 (r=0.46, p<0.05).
Conclusion: The results demonstrate that contrary to in vivo studies, circulating IGFBP-4 levels are not influenced by secondary hyperparathyroidism in vitamin D deficiency rickets since IGFBP-4 levels did not change after normalization of PTH with vitamin D treatment.
Conflict of interest:None declared.
Vitamin D; rickets; IGF-I; IGFBP-3; IGFBP-4; PTH; Bone
There are two types of vitamin D dependent rickets (VDDR) that cause rickets in children. VDDR type 1 (VDDR-I) is caused by an inborn error of vitamin D metabolism, which interferes with renal conversion of calcidiol (25OHD) to calcitriol (1,25(OH)2D) by the enzyme 1-α-hydroxylase. Patients with VDDR-I have mutations of chromosome 12 that affect the gene for the enzyme 1-α-hydroxylase, resulting in decreased levels of 1,25(OH) vitamin D. Clinical features include growth failure, hypotonia, weakness, rachitic rosary, convulsions, tetany, open fontanels and pathologic fractures. We report a case of VDDR-I in 14-month-old male child. Establishing an early diagnosis of these genetic forms of rickets is challenging, especially in developing countries where nutritional rickets is the most common variety of the disease where genetic diagnosis is not always possible because of financial constraints. A prompt diagnosis is necessary to initiate adequate treatment, resolve biochemical features and prevent complications, such as severe deformities that may require surgical intervention.
Vitamin D dependent rickets type I; seizure; 1,25(OH) vitamin D
Lower vitamin D status has been reported in diabetic patients. Serum 25-hydroxyvitamin D and adiponectin were inversely associated with type 2 diabetes and insulin resistance. Vitamin D may involve in regulation of the adiponectin levels, which is directly related to insulin sensitivity.
The aim of this study was to investigate the effect of therapeutic dose of vitamin D on serum adiponectin and insulin resistance in vitamin D-insufficient or deficient type 2 diabetic patients.
Materials and Methods:
This double-blind, randomized, clinical trial was conducted on 81 type 2 diabetic patients with vitamin D level of 10-30 ng/mL. Intervention was 50000 IU vitamin D or placebo once a week for 8 weeks. At the beginning and end of the study, blood samples were collected after 12 hours of fasting and serum glucose, insulin, 25-hydroxyvitamin D, and adiponectin were measured. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR).
After 8-week intervention, serum 25-hydroxyvitamin D significantly increased and reached the normal levels in patients receiving vitamin D (P < 0.001) and the levels of fasting serum glucose, insulin, and HOMA-IR were significantly decreased (P = 0.04, 0.02 and 0.007, respectively). No significant changes were observed in these levels in the placebo group. Significant differences were observed in mean changes in the above-mentioned variables between the two groups (P = 0.01, 0.04 and 0.006, respectively). No significant changes were found in serum adiponectin in the vitamin D and placebo groups (P = 0.83).
Therapeutic dose of vitamin D can improve vitamin D status and glycemic indicators. But it seems that an 8-week intervention period was not sufficient to reveal the possible effects of vitamin D on serum adiponectin levels.
Diabetes Mellitus; Vitamin D; Insulin Resistance; Adiponectin
We investigated whether the anti-atherosclerosis of adiponectin (APN) relates to the reduction of oxidative stress. We observed the overexpression of adiponectin gene with different titers on atherosclerosis (AS) models of high-fat apolipoprotein E-deficient (ApoE−/−) mice.
We divided 48 male ApoE−/− mice into 4 groups: control group, high-fat diet group, low adiponectin group, and high adiponectin group. The low and high adiponectin group mice were treated with recombinant adenovirus expressing mice adiponectin (Ad-APN) with low-dose adiponectin 1.0×108 p.f.u. and high-dose adiponectin 5.0×108 p.f.u. via the tail every 2 weeks and given a high-fat diet for the last 8 weeks. On the 14th day after injection, blood samples were obtained from the vena cava.
Along with increased serum adiponectin, serum superoxide dismutase (SOD) activity increased (P<0.05) and concentration of malondialdehyde (MDA) was decreased (P<0.05). Levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) were decreased, especially TC and LDL-C (P<0.05). A real-time fluorescent quantitative polymerase chain reaction test was used to analyze levels of mRNA expression for endothelial nitric oxide synthase (eNOS) and adiponectin in the aorta. Along with increased adiponectin, the mRNA expression of eNOS in the aorta was increased significantly (P<0.05). The lesion formation in the aortic sinus was inhibited by 25% and 31% in the low-APN group and high-APN group, respectively (P<0.05). Along with the increase of adiponectin doses, the damage of atherosclerosis gradually eased. However, the differences between the low-APN group and high-APN group had no statistical significance.
Adiponectin may protect the aorta from atherosclerosis injury by reducing oxidative stress, reducing lesion formation size in the aortic root and reducing TC, TG, and LDL-C in serum. The molecular mechanism may involve preservation of SOD, reducing MDA in serum, and increasing eNOS and adiponectin mRNA expression in the aorta.
Adiponectin; Atherosclerosis; Nitric Oxide Synthase Type III; Oxidative Stress; Superoxide Dismutase
Rickets is softening of bones due to defective mineralization of cartilage in the epiphyseal growth plate, leading to widening of ends of long bones, growth retardation, and skeletal deformities in children. The predominant cause is deficiency or impaired metabolism of vitamin D. The observation that some forms of rickets could not be cured by regular doses of vitamin D, led to the discovery of rare inherited abnormalities of vitamin D metabolism or vitamin D receptor. Vitamin D dependent rickets (VDDR) is of two types: Type I is due to defective renal tubular 25-hydroxyvitamin D 1-α hydroxylase and type II is due to end-organ resistance to active metabolite of vitamin D. Typical signs are observed from the first month of life. The patient with rickets described below had markedly increased serum alkaline phosphatase and 1,25-dihydroxyvitamin D. We attribute these abnormalities to impaired end-organ responsiveness to 1,25-dihydroxyvitamin D.
End-organ resistance; rickets; vitamin D; vitamin D dependent rickets; 1,25-dihydroxyvitamin D
Rickets/osteomalacia is an important problem in a tropical country. Many cases are due to poor vitamin D intake or calcium deficient diets and can be corrected by administration of calcium and vitamin D. However, some cases are refractory to vitamin D therapy and are related to renal defects. These include rickets of renal tubular acidosis (RTA), hypophosphatemic rickets, and vitamin D dependent rickets (VDDR). The latter is due to impaired action of 1α-hydroxylase in renal tubule. These varieties need proper diagnosis and specific treatment.
Hypophosphatemic rickets; osteomalacia; renal rickets; rickets; renal tubular acidosis; vitamin D rickets
Several endocrine factors, including sex-steroid hormones are known to influence adiponectin secretion. Our purpose was to evaluate the influence of testosterone and of the synthetic non-aromatizable/non-5α reducible androgen 17β-hydroxyestra-4,9,11-trien-3-one (trenbolone) on circulating adiponectin and adiponectin protein expression within visceral fat. Young male and female F344 rats underwent sham surgery (SHAM), gonadectomy (GX), or GX plus supraphysiologic testosterone-enanthate (TE) administration. Total circulating adiponectin was 39% higher in intact SHAM females than SHAM males (p<0.05). GX increased total adiponectin by 29–34% in both sexes (p<0.05), while TE reduced adiponectin to concentrations that were 46–53% below respective SHAMs (p≤0.001) and ablated the difference in adiponectin between sexes. No differences in high molecular weight (HMW) adiponectin were observed between sexes or treatments. Adiponectin concentrations were highly and negatively associated with serum testosterone (males: r = −0.746 and females: r = −0.742, p≤0.001); however, no association was present between adiponectin and estradiol. In separate experiments, trenbolone-enanthate (TREN) prevented the GX-induced increase in serum adiponectin (p≤0.001) in young animals, with Low-dose TREN restoring adiponectin to the level of SHAMs and higher doses of TREN reducing adiponectin to below SHAM concentrations (p≤0.001). Similarly, TREN reduced adiponectin protein expression within visceral fat (p<0.05). In adult GX males, Low-dose TREN also reduced total adiponectin and visceral fat mass to a similar magnitude as TE, while increasing serum HMW adiponectin above SHAM and GX animals (p<0.05). Serum adiponectin was positively associated with visceral fat mass in young (r = 0.596, p≤0.001) and adult animals (r = 0.657, p≤0.001). Our results indicate that androgens reduce circulating total adiponectin concentrations in a dose-dependent manner, while maintaining HMW adiponectin. This change is directionally similar to the androgen-induced lipolytic effects on visceral adiposity and equal in magnitude between TE and TREN, suggesting that neither the aromatization nor the 5α reduction of androgens is required for this effect.
Adiponectin is a cytokine mainly secreted from the adipose tissue, which has insulin-sensitizing effects, antiatherosclerotic actions, and antiinflammatory properties. There are a few studies that have demonstrated that adiponectin is reduced in patients with psoriasis suggesting that this adipocytokine may have a role in the pathogenesis of psoriasis. There have been no studies so far on adiponectin in relation to psoriasis and metabolic syndrome (MetS).
This study was performed to analyze serum adiponectin and insulin levels in psoriasis patients with and without MetS and in controls with and without MetS.
Materials and Methods:
We performed a case control study on 60 psoriasis patients, 29 with MetS and 31 without MetS and 40 controls, 20 with and 20 without MetS, matched for age, sex, and body mass index (BMI). Fasting serum insulin and adiponectin levels were measured in all groups.
The overall serum adiponectin levels were significantly reduced in psoriasis patients when compared with controls (P = 0.000). A significant reduction was also observed in psoriasis patients with MetS than those without MetS in the same group (P = 0.000). Similar decrease was observed between those with MetS in the psoriasis and control groups (P = 0.001). The lowest mean value of serum adiponectin (6387.9 ng/ml) was observed in psoriasis with MetS group and highest value (12146.3 ng/ml) in controls without MetS.
Adiponectin levels are decreased in psoriasis patients irrespective of MetS thus indicating a role in its pathogenesis. This study prompts future trials on drugs increasing adiponectin levels in patients with psoriasis.
Psoriasis; metabolic syndrome; serum adiponectin
Adiponectin, an adipocyte-derived protein, modulates a number of metabolic processes. Methadone maintenance treatment (MMT) changes the level of hormones produced by adipose tissue in addicts. However, current data remains contradictory.
The aim of this study was to evaluate the effect of MMT on serum adiponectin levels in drug addicts.
Materials and Methods:
Twenty-five drug abusers with a mean age of 37.4 ± 8.7 years were referred to the Baharan Hospital, Zahedan, and 22 healthy age-matched control subjects with a mean age of 35 ± 9.5 years were enrolled in the study. Addicts were treated with methadone at (40 to 120 mg/d) for six months. Measurement of anthropometric parameters, serum adiponectin, and biochemical parameter levels, were assessed in the addicts, before and after six months of MMT, but only once in the healthy controls.
The mean basal serum adiponectin level was not significantly lower in the drug abuser group compared to the healthy subjects (P > 0.05). After six months of MMT, the mean serum adiponectin level of the drug addicts was not significantly different from their mean baseline level or that of the healthy subjects (P > 0.05). However, the mean baseline serum adiponectin level was significantly lower in overweight/obese addicts when compared to underweight patients and healthy individuals (P < 0.001). After six months of MMT, the mean level of serum adiponectin increased significantly in the underweight subjects compared to the normal weight and overweight/obese subjects (P < 0.0001) and the control group (P < 0.001). Adiponectin concentration was correlated inversely with body mass index and positively correlated with waist circumference and serum high-density lipoprotein levels.
This study showed that MMT did not markedly alter the concentration of serum adiponectin in drug abusers. However, in regard to the variations in the serum lipid profiles and anthropometric parameters, the findings indicated that low concentrations of serum adiponectin might play a role in the pathogenesis of obesity and other metabolic abnormalities. Thus, more long-term studies with larger sample sizes are recommended.
Adiponectin; Drug Users; Methadone
Chronic obstructive pulmonary disease (COPD) is the only cause of mortality and morbidity with an increasing incidence. Adiponectin has recently gained the spotlight for its possible association with COPD or its exacerbation. This study evaluated the association of serum and alveolar adiponectin levels with COPD-related variables.
Materials and Methods
This analytical cross-sectional study was carried out on 45 COPD patients. Number of cigarettes smoked (packs), years of smoking, number of disease exacerbations per year and BMI were all recorded. Patients underwent spirometry and their disease severity was determined based on BODE index. Venous blood sample was obtained to measure the adiponectin serum level, ESR and CRP. Bronchoscopy and BAL were performed as well and alveolar secretions were collected to assess the alveolar fluid level of adiponectin.
The mean serum level of adiponectin in COPD patients was significantly higher than the upper limit of normal range in healthy individuals (P = 0.000). Level of alveolar adiponectin in smoker patients was significantly higher than non-smokers (P = 0.043) but serum adiponectin was not significantly different between them. Serum adiponectin level had a significant reverse correlation with BMI and a direct correlation with number of exacerbations per year and CRP. Level of alveolar adiponectin had a direct association with number of exacerbations per year and number of smoked cigarettes.
Based on the obtained results, smoking cessation is very important in COPD and more emphasis should be placed on patient's weight control especially those with low BMI as well as rehabilitation programs for these patients.
Alveolar adiponectin; Serum adiponectin; Chronic Obstructive Pulmonary Disease (COPD)
Adiponectin plays a protective role in the development of obesity-linked disorders. We demonstrated that adiponectin exerts beneficial actions on acute ischemic injury in mice hearts. However, the effects of adiponectin treatment in large animals and its feasibility in clinical practice have not been investigated. This study investigated the effects of intracoronary administration of adiponectin on myocardial ischemia-reperfusion (I/R) injury in pigs.
Methods and Results
The left anterior descending coronary artery was occluded in pigs for 45 minutes and then reperfused for 24 hours. Recombinant adiponectin protein was given as a bolus intracoronary injection during ischemia. Cardiac functional parameters were measured by a manometer-tipped catheter. Apoptosis was evaluated by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling staining. Tumor necrosis factor-α and interleukin-10 transcripts were analyzed by real-time polymerase chain reaction. Serum levels of derivatives of reactive oxygen metabolites and biological antioxidant potential were measured. Adiponectin protein was determined by immunohistochemical and Western blot analyses. Intracoronary administration of adiponectin protein led to a reduction in myocardial infarct size and improvement of left ventricular function in pigs after I/R. Injected adiponectin protein accumulated in the I/R-injured heart. Adiponectin treatment resulted in decreased tumor necrosis factor-α and increased interleukin-10 mRNA levels in the myocardium after I/R. Adiponectin-treated pigs had reduced apoptotic activity in the I/R-injured heart and showed increased biological antioxidant potential levels and decreased derivatives of reactive oxygen metabolite levels in the blood stream after I/R.
These data suggest that adiponectin protects against I/R injury in a preclinical pig model through its ability to suppress inflammation, apoptosis, and oxidative stress. Administration of intracoronary adiponectin could be a useful adjunctive therapy for acute myocardial infarction.
adiponectin; myocardial infarction; reperfusion
These studies have shown that the bones of guinea pigs given daily injections of parathormone from the age of 2 to 7 days to the age of 110 to 120 days, show relatively very little effect after receiving 20 units daily during the last 65 to 87 days of treatment. But it is probable that their bones underwent decalcification early in the treatment and that subsequently the parathormone, continued at the same dosage, did not maintain the effects on the bones. Healing finally occurred despite it. The bones of guinea pigs treated with intermittent injections of large doses of parathormone from the time they were 1 week old to the age of 95 to 145 days also showed relatively few changes at the end of the treatment. The injections were given at intervals of 7 to 11 days, and were stepped up from 60 units to 140 units. From our previous experience (1) we infer that the earlier injections of parathormone produced very extensive bone changes which healed in the intervals between the injections. As the guinea pigs became older the injections of parathormone did not produce as severe effects. We have found in our studies of experimental hyperparathyroidism that the bone changes after a single large dose of parathormone in young guinea pigs are soon healed. The study of a series of animals shows that healing begins at about the 48th hour after injection, and proceeds rapidly. Between the 8th and 14 days, callus may be observed at the costochondral junctions, where fractures had occurred. Now the endosteum may be lined by osteoblasts and the vessel canals by new formed bone. In adult guinea pigs extremely large single doses had little effect on the bones in 48 hours, even though the dose killed the animal. It was only when three doses pyramided over a period of 48 hours and totaling 2580 units of parathormone were given, that moderately severe bone resorption could be demonstrated in the adult. The elevation of serum calcium may be considered as one of the indices of calcium mobilization in experimental hyperparathyroidism. When the rate of calcium excretion exceeds the rate of its mobilization, or when the animal is on a low calcium diet, hypercalcemia may be absent. It is possible to raise the serum calcium of adult guinea pigs by large single doses of parathormone, but the resulting rise is not as great as in the young (2). This is confirmatory evidence of the fact that calcium is mobilized much less rapidly from the bones of old animals than from those of young ones. Collip pointed out that young normal dogs are more susceptible to parathormone (6). This observation was corroborated by Morgan and Garrison (7). We found that the same difference held also in experimental hyperparathyroidism produced in dogs by repeated doses of parathormone (8). In man, clinical experience likewise indicates the necessity of using relatively large doses of parathormone to raise the serum calcium of adults. The serum calcium of middle-aged or old adults does not rise significantly unless as much as 100 units or more of parathormone are given daily for a number of days. Charts VI and VII, in a recent paper by Merritt and Bauer (9), support our findings of the relative difficulty of obtaining a significant elevation of serum calcium in adults. If adult guinea pigs are given daily injections of parathormone which are rapidly stepped up, the animals may be killed by the ensuing acute hyperparathyroidism, only slight bone changes being produced. However, a careful avoidance of the induction of acute hyperparathyroidism by gradual stepping up of the parathormone dose permits the employment of doses continued over a long period of time that could not possibly have been tolerated otherwise. Furthermore, healing of the lesions thus produced may occur, in spite of the continuance of parathormone at this level. It seems likely that the difference in response of young and old guinea pigs to single doses of parathormone, as indicated by the bone changes, as well as by the serum calcium and phosphorus, is related to the more rapid rate of mineral metabolism in the young, actively growing animals. The calcium mobilizing effect of parathormone is most prominent in actively growing young animals, the calcium being withdrawn from the most readily available stores—the regions of most active new bone formation and most active bone reconstruction (10). In the adult animal the calcium reserves (in the formed bone) are less susceptible to the calcium mobilizing effect of parathormone. The adult guinea pig will show relatively slight bone changes even as a result of extremely large, fatal doses of parathormone. Repeated doses, as is well known, will produce, by pyramiding, greater effects than the entire amount administered at one time. In this type of experiment the young again show greater susceptibility of the bone than the adult. In time, however, some compensation takes place, and the effects of the same doses are decreased until finally healing may occur in spite of the continued treatment. Increase of the dose, however, again elicits the parathormone effects upon the bone, as well as upon the serum calcium and phosphorus, without toxic changes (1, 8). It would seem that some compensation sets in which may be overcome by increasing the dose. This compensation is especially evident in the experiments in which the parathormone doses were stepped up gradually from small amounts. In addition to the compensation observed in young and adult animals as a result of repeated injections of parathormone, we must also consider the possibility that there is a compensating mechanism in adult animals more effective than in the young. That compensation occurs is unquestionable but its nature is not clear. Apparently it is less effective during pregnancy, doses of parathormone which produce only slight bone changes in ordinary adults causing very severe lesions in advanced pregnancy (11). Parathormone has been shown to produce only one primary effect on bone, and that is decalcification. This may come about as the result of a change in the circulating tissue fluids, the salts being dissolved out of the organic matrix, and the latter disappearing secondarily. The process is most rapid in the vicinity of most active bone formation. The osteoblasts disappear from the surfaces of bone where dissolution is occurring, and at the same time the marrow connective tissue proliferates. Fusion of cells produces osteoclasts (12), which then proceed to remove the decalcified organic matrix, with the production of the deep lacunae of Howship. Frequently leucocytes are also observed actively phagocyting the decalcified organic matrix, and often leucocytes are observed within the osteoclasts (12). Healing is associated with the complete reversal of the process. The osteoclasts disappear, the connective tissue diminishes, osteoblasts reappear, and bone formation is resumed. As we have previously stated (13), parathormone produces a more continuous effect than experimental acidosis and greater changes than are seen in experimental osteoporosis. A pronounced decalcification results from it which, with its sequelae, simulates von Recklinghausen's disease. The emphasis which the older pathologists laid on osteoclasts as a special feature of ostitis fibrosa cystica is justified, for in the experimental condition the appearance of great numbers of osteoclasts is a constant feature, whenever decalcification occurs (13). There seems to be no doubt that the giant cell tumors found in ostitis fibrosa cystica are expressions of the same pathological response. The other features of the bone changes of hyperparathyroidism—marrow hemorrhage, cysts, fractures, and osteoid proliferation—are secondary to the primary decalcification. Progress of the pathological changes leads to circulatory stasis and cyst formation. Stresses and strains exerted on the progressively weakening bone may result in microscopical or gross fractures. Osteoid tissue is, as we have previously pointed out (13), merely reparative in nature, being laid down as support to the weakened or fractured bone, or as a part of healing. Osteoid borders appear on bone surfaces 48 hours after one large dose of parathormone. The mosaic picture which we have observed in the bones of some of our animals is produced by short and irregularly disposed cement lines resulting from rapid bone transformation. Schmorl (14) recently emphasized the mosaic-like appearance of the newly formed lamellar bone in Paget's disease (ostitis fibrosa deformans). The mosaic-like appearance of bone has also been described in local bone conditions, as e.g. syphilitic periostitis, and in bone in the vicinity of cysts and giant cell tumors in von Recklinghausen's disease (ostitis fibrosa cystica). However, Schmorl claims that in no disease is the mosaic appearance so constant and the arrangement of the cement lines so irregular as in Paget's disease. In chronic experimental hyperparathyroidism (von Recklinghausen's disease), the mosaic structure is not a prominent feature because of the progressive decalcification. But the bones of our young guinea pigs which received intermittent injections showed a mosaic-like appearance indicative of the periodic decalcifications and restorations which they had undergone.
Adiponectin is a predominantly adipocyte-derived hormone which influences insulin sensitivity and energy homeostasis through at least two receptors, AdipoR1 and AdipoR2. In animal models, adiponectin may regulate ovarian steroidogenesis, folliculogenesis, and ovulation. The receptors AdipoR1 and AdipoR2 are present in the human ovary, but their regulation is unknown. In these studies, we determined the effects of LH receptor activation on the expression and function of the two adiponectin receptors in human granulosa cells.
Granulosa cells were obtained at the time of oocyte retrieval in women undergoing in vitro fertilization (IVF). Cells were isolated and cultured for 48 h in DMEM/F12 medium with 5 % FBS and 50 ug/ml gentamicin. Medium was changed to low serum for 12 h and cells were treated with hCG (100 ng/ml), forskolin (30 μMol/L), or FSH (1 IU/ml) for 24 h for mRNA experiments. mRNA was isolated and RT PCR was performed using Taqman assays and quantification with the delta delta CT method. For immunocytochemistry, cells were grown on chamber slides and treated with hCG for 1 to 24 h and fixed with acetone. ICC was performed with polyclonal rabbit primary antibodies followed by alexa fluor goat anti-rabbit antibody and imaging with a fluorescence microscope and Zeiss software analysis. 3β-hydroxysteroid dehydrogenase (3βHSD) enzyme activity was determined by measuring the progesterone produced when cells were provided with an excess of 22-hydroxy-cholesterol as substrate following an incubation with hCG (1 IU/ml) and/or adiponectin (10 ng/ml). Progesterone content in the media was determined by ELISA.
Messenger RNA for the two Adiponectin receptors is differentially regulated by activation of LHR with hCG treatment. AdipoR2 was increased nearly 4-fold (p < 0.05), whereas AdipoR1 expression was not changed by hCG treatment. Treatment with either FSH or forskolin (an activator of cAMP) had similar effects. Basal AdipoR2 protein was fairly low in granulosa cells in culture however treatment of cells with hCG resulted in a discernible increase in immunodetectable cytoplasmic protein as early as 6 h after treatment and was maintained for at least 24 h. The number of cells positive for AdipoR2 at 6 h increased from a basal of 20 % to almost 60 % (p < 0.05). Adiponectin treatment of hCG-primed cells resulted in increased 3βHSD activity by approximately 60 % over hCG alone and more than 3-fold over basal levels.
AdipoR2 is regulated by the LH receptor function via a cAMP dependant mechanism. Increased expression of adipoR2 prior to and following ovulation may contribute to enhanced 3βHSD activity and increased progesterone secretion by the corpus luteum of the ovary. Dysregulation of adiponectin that may occur with PCOS may impair normal progesterone production.
Ovary; Granulosa; Adiponectin; Adiponectin receptor; PCOS; Progesterone
Key circulating molecules that link vitamin D (VD) to pediatric obesity and its co-morbidities remain unclear. Using a proteomic approach, our objective was to identify key molecules in obese children dichotomized according to 25OH-vitamin D (25OHD) levels. A total of 42 obese children (M/F = 18/24) were divided according to their 25OHD3 levels into 25OHD3 deficient (VDD; n = 18; 25OHD<15 ng/ml) or normal subjects (NVD; n = 24; >30 ng/ml). Plasma proteomic analyses by two dimensional (2D)-electrophoresis were performed at baseline in all subjects. VDD subjects underwent a 12mo treatment with 3000 IU vitamin D3 once a week to confirm the proteomic analyses. The proteomic analyses identified 53 “spots” that differed between VDD and NVD (p<0.05), amongst which adiponectin was identified. Adiponectin was selected for confirmational studies due to its tight association with obesity and diabetes mellitus. Western Immunoblot (WIB) analyses of 2D-gels demonstrated a downregulation of adiponectin in VDD subjects, which was confirmed in the plasma from VDD with respect to NVD subjects (p<0.035) and increased following 12mo vitamin D3 supplementation in VDD subjects (p<0.02). High molecular weight (HMW) adiponectin, a surrogate indicator of insulin sensitivity, was significantly lower in VDD subjects (p<0.02) and improved with vitamin D3 supplementation (p<0.042). A direct effect in vitro of 1α,25-(OH)2D3 on adipocyte adiponectin synthesis was demonstrated, with adiponectin and its multimeric forms upregulated, even at low pharmacological doses (10−9 M) of 1α,25-(OH)2D3. This upregulation was paralleled by the adiponectin interactive protein, DsbA-L, suggesting that the VD regulation of adiponectin involves post-transciptional events. Using a proteomic approach, multimeric adiponectin has been identified as a key plasma protein that links VDD to pediatric obesity.
Background: Low vitamin D and adiponectin levels are both associated with obesity and cardiovascular disease. Previous studies have indicated that vitamin D levels are directly associated with adiponectin, and that this association varies across body mass index (BMI) categories; stronger with increasing BMI. Few studies examined this association in African-Americans (AA), known to have lower levels of vitamin D and adiponectin, and in whites.
Methods: We assessed whether serum vitamin D is associated with serum adiponectin in a biracial population-based sample. Cross-sectional analyses were performed on 426 non-diabetic participants (218 whites and 208 AA) from the META-Health Study, a random sample from the metro Atlanta. Age-adjusted correlations and multivariable linear regression were used for analyses. We investigated the effect modification of the BMI categories of lean, overweight, and obese as defined by standard cut-points (25 and 30 kg/m2).
Results: The mean (SD) age of our study sample was 50.5 (9) years. The mean (SD) levels of vitamin D were 27.4 (9.8) ng/mL in white women, 25.5 (9.3) ng/mL in white men, 16.9 (7.3) ng/mL in AA women, and 18.8 (7.3) ng/mL in AA men. The mean (SD) levels of adiponectin were 17.0 (17.1) μg/mL in white women, 9.9 (11.3) μg/mL in white men, 6.6 (4.8) μg/mL in AA women, and 9.4 (11.6) μg/mL in AA men. Among lean white women (n = 63), there was a significant direct association between vitamin D and adiponectin (β = 0.02, p = 0.04) after adjustment for age, systolic blood pressure, HDL-cholesterol, triglycerides, income, and season of blood drawing. On the contrary, in lean AA women (n = 23), there was a significant inverse association (β = −0.06, p = 0.01).
Conclusion: The association of vitamin D and adiponectin is dependent on race, gender, and BMI category. Among lean white women, there was a significant direct association, whereas in lean AA women the association was inverse. No association was present among obese individuals.
vitamin D; adiponectin; obesity; minorities; African-Americans; obesity
Primary hyperparathyroidism (PHPT) is extremely uncommon among children and is more likely to be associated with genetic syndromes, multiglandular involvement, and more severe symptoms. Rickets can very rarely be the presenting feature of PHPT in children. Rickets was diagnosed in a 12-year-old girl presenting with short stature, genu valgum, eversion deformity at the ankle joints, and flat feet. Radiograms showed generalized osteopenia, widening of the distal ends of the long bones along with splaying, cupping and fraying. Biochemical evaluation revealed low serum calcium (7.8 mg/dL), low phosphorus (1.4 mg/dL), vitamin-D deficiency [25-hydroxy-vitamin-D (25(OH)D): 8.7 ng/mL], and elevated intact parathyroid hormone (PTH, 811 pg/mL). Re-evaluation due to lack of clinical improvement following vitamin-D and calcium supplementation revealed hypercalcemia 11.9 mg/dL, normal 25(OH)D 41 ng/mL, persistence of elevated PTH 632 pg/mL. A 99mTc-sestamibi scan showed increased uptake at the lower pole of the right lobe of the thyroid. A right inferior parathyroidectomy was performed. Histopathology revealed chief cell type parathyroid adenoma. Last evaluated 4 months after surgery, the bone pains and proximal weakness had resolved, with significant improvement in the patient’s quality of life. Rickets in the setting of PHPT often masks the classical phenotype of PHPT. In a child with rickets, lack of improvement following vitamin-D supplementation, hypercalcemia at presentation or following vitamin-D supplementation are warning signs which necessitate further evaluation to rule out PHPT.
Conflict of interest:None declared.
primary hyperparathyroidism; rickets; Parathyroid adenoma
Adiponectin may regulate ovarian steroidogenesis, folliculogenesis and ovulation. The alterations in the distribution of adiponectin multimers in follicular fluid (FF) and the relationship between adiponectin multimers and folliculogenesis in women with polycystic ovary syndrome (PCOS) remain unclear. In this study, we aimed to investigate the association between the levels of total and high molecular weight (HMW) adiponectin in serum and FF and folliculogenesis in women undergoing in vitro fertilisation (IVF).
This prospective study included ten Chinese women with PCOS and ten controls undergoing IVF. The levels of the total and HMW adiponectin in serum and FF were determined by ELISA. Insulin resistance (IR) was estimated using the homeostasis model assessment insulin resistance index (HOMA-IR).
After controlling for the body mass index (BMI), the levels of the total, and the HMW adiponectin in the serum and FF were significantly lower in the women with PCOS compared with the normovulatory women undergoing IVF (P < 0.05). The levels of the HMW adiponectin were significantly lower in the FF than in the serum (P < 0.01). No significant differences were found in the total adiponectin levels in the serum and in the FF (P > 0.05). Decreased HMW adiponectin in the FF was associated with an increased number of follicles and decreased follicular diameters in the normovulatory and PCOS women, and this association was independent of the overall adiposity. A strong positive linear correlation was observed between the number of the follicles and the IR estimated by HOMA-IR (r = 0.784, P < 0.0001). We found that the larger follicular diameters had a negative relationship with the IR estimated by HOMA-IR (r = −0.445, P < 0.05). A strong negative linear correlation was observed between HOMA-IR and the HMW adiponectin levels (r = −0.726, P < 0.001) and the total adiponectin levels (r = −0.759, P < 0.001) in the FF.
The levels of the total adiponectin and the HMW adiponectin in the FF and serum were decreased in the Chinese women with PCOS compared with the normovulatory women undergoing IVF, and the differences persisted after controlling for the BMI. Ovarian HMW adiponectin is negatively correlated to folliculogenesis.
Polycystic ovary syndrome; Adiponectin multimers; Follicular fluid; In vitro fertilisation; Folliculogenesis
The effects of 25-hydroxycholecalciferol were studied in 4 children with deficiency rickets and 22 children with D-resistant rickets, including patients with hereditary hypophosphatemic D-resistant rickets, “pseudo-deficiency” rickets, and rickets secondary to cystinosis or to tyrosinosis. Three protocols were used. (a) 8 days after a single oral dose of 16,000 IU of 25-hydroxycholecalciferol, normalization of all biological parameters was observed in all cases of deficiency rickets. A complete lack of response was observed in the different types of resistant rickets. (b) Under prolonged administration of 2,640 IU/day for 2 months, clinical-biological symptoms and X-ray lesions disappeared, and a catch-up growth pattern was observed in deficiency rickets; no relapse of rickets occurred up to 5 months after therapy was stopped. The same dose had no significant effect in 10 patients with hereditary hypophosphatemic D-resistant rickets. A bone biopsy performed in one case showed the persistence of characteristic lesions. (c) With increasing doses of 25-hydroxycholecalciferol varying from 6,000 to 30,000 IU/day and a follow-up of 6 months up to 2 yr duration, clinical-biological-radiologic recovery and catch-up growht was obtained in all cases of “pseudo-deficiency” rickets. In hypophosphatemic hereditary D-resistant rickets, 5 out of 13 patients' serum concentration of phosphorus reached at least 30 mg/liter, but a catch-up growth pattern was not observed. These results indicate that (a) 25-hydroxycholecalciferol is highly active in deficiency rickets; (b) a defect in the conversion of vitamin D3 to its active 25-hydroxy metabolite is probably not the metabolic defect in any of the different types of vitamin D-resistant rickets studied.
Objective: This study aimed (a) to investigate the relationship between the degree of obesity and serum adiponectin, tumor necrosis factor (TNF)−α, leptin, insulin levels and the lipid profile; (b) to clarify the relationship between insulin resistance/glucose tolerance and adipocytokine levels; and (c) to investigate the value of adipocytokine levels as a marker of metabolic syndrome (MS).
Methods: We studied 151 obese children and adolescents (86 boys and 65 girls; mean age was 12.3±2.4 years). We defined obesity as a body−mass index (BMI) z−score more than 2 SD above the mean for age and sex. The control group consisted of 100 children (48 boys, 52 girls, mean age 12.4±2.5 years). Fasting glucose, insulin levels and lipid profiles were measured in all cases and controls after a 12−hour fast. Adiponectin, TNF−α, and leptin levels were measured in the subjects who participated in the adipocytokine branch of the study. An oral glucose tolerance test (OGTT) was also performed in all obese patients. Obese patients were grouped into three subgroups according to their glucose tolerance and insulin sensitivity assessment, and also according to whether they were grouped as MS or not.
Results: Serum levels of total cholesterol, LDL and VLDL cholesterol, log triglyceride, insulin, leptin and TNF−α were higher, whereas HDL and square root adiponectin levels were lower in the obese group when compared with controls. Multiple regression analysis among BMI−z score, LDL, triglyceride, HOMA−IR, leptin and TNF−α as determinants of adiponectin revealed that BMI−z score was the only determinant for adiponectin (r:−0.45, p<0.0001). Adiponectin levels in hyperinsulinemic and impaired glucose tolerance groups (IGT) tended to be lower than in normoinsulinemic obese children, however, the difference was not significant. There was a weak negative correlation between adiponectin levels and increasing severity of insulin resistance (r=−0.23, p=0.005) in the groups of obese subjects. Mean serum adiponectin level in subjects with MS was lower than in subjects without MS (p=0.008).
Conflict of interest:None declared.
children; obesity; Adiponectin; metabolic syndrome
Children with calcium-deficiency rickets may have increased vitamin D requirements and respond differently to vitamin D2 and vitamin D3. Our objective was to compare the metabolism of vitamins D2 and D3 in rachitic and control children. We administered an oral single dose of vitamin D2 or D3 of 1.25 mg to 49 Nigerian children—28 with active rickets and 21 healthy controls. The primary outcome measure was the incremental change in vitamin D metabolites. Baseline serum 25-hydroxyvitamin D [25(OH)D] concentrations ranged from 7 to 24 and 15 to 34 ng/mL in rachitic and control children, respectively (p < .001), whereas baseline 1,25-dihydroxyvitamin D [1,25(OH)2D] values (mean ± SD) were 224 ± 72 and 121 ± 34 pg/mL, respectively (p < .001), and baseline 24,25-dihydroxyvitamin D [24,25(OH)2D] values were 1.13 ± 0.59 and 4.03 ± 1.33 ng/mL, respectively (p < .001). The peak increment in 25(OH)D was on day 3 and was similar with vitamins D2 and D3 in children with rickets (29 ± 17 and 25 ± 11 ng/mL, respectively) and in control children (33 ± 13 and 31 ± 16 ng/mL, respectively). 1,25(OH)2D rose significantly (p < .001) and similarly (p = .18) on day 3 by 166 ± 80 and 209 ± 83 pg/mL after vitamin D2 and D3 administration, respectively, in children with rickets. By contrast, control children had no significant increase in 1,25(OH)2D (19 ± 28 and 16 ± 38 pg/mL after vitamin D2 and D3 administration, respectively). We conclude that in the short term, vitamins D2 and D3 similarly increase serum 25(OH)D concentrations in rachitic and healthy children. A marked increase in 1,25(OH)2D in response to vitamin D distinguishes children with putative dietary calcium-deficiency rickets from healthy children, consistent with increased vitamin D requirements in children with calcium-deficiency rickets. © 2010 American Society for Bone and Mineral Research.
metabolic bone; vitamin D; calcium; pediatric; nutrition
Chronic ethanol feeding sensitizes Kupffer cells to activation by lipopolysac-charide (LPS), leading to increased production of tumor necrosis factor-α (TNF-α). Adiponectin treatment protects mice from ethanol-induced liver injury. Because adiponectin has anti-inflammatory effects on macrophages, we hypothesized that adiponectin would normalize chronic ethanol-induced sensitization of Kupffer cells to LPS-mediated signals. Serum adiponectin concentrations were decreased by 45% in rats fed an ethanol-containing diet for 4 wk compared with pair-fed rats. Adiponectin dose dependently inhibited LPS-stimulated accumulation of TNF-α mRNA and peptide in Kupffer cells from both pair- and ethanol-fed rats. Kupffer cells from ethanol-fed rats were more sensitive to both globular (gAcrp) and full-length adiponectin (flAcrp) than Kupffer cells from pair-fed controls with suppression at 10 ng/ml adiponectin after chronic ethanol feeding. Kupffer cells expressed both adiponectin receptors 1 and 2; chronic ethanol feeding did not change the expression of adiponectin receptor mRNA or protein. gAcrp suppressed LPS-stimulated ERK1/2 and p38 phosphorylation as well as IκB degradation at 100–1,000 ng/ml in Kupffer cells from both pair- and ethanol-fed rats. However, only LPS-stimulated ERK1/2 phosphorylation was sensitive to 10 ng/ml gAcrp. gAcrp also normalized LPS-stimulated DNA binding activity of early growth response-1 with greater sensitivity in Kupffer cells from rats fed chronic ethanol. In conclusion, these results demonstrate that Kupffer cells from ethanol-fed rats are more sensitive to the anti-inflammatory effects of both gAcrp and flAcrp. Suppression of LPS-stimulated ERK1/2 signaling by low concentrations of gAcrp was associated with normalization of TNF-α production by Kupffer cells after chronic ethanol exposure.
macrophage; Toll-like receptor 4; inflammation; mitogen-activated protein kinase; early growth response-1; lipopolysaccharide; tumor necrosis factor-α