The objective of this study was to develop a cell culture system for fetal baboon hepatocytes and to test the hypotheses that (1) expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase-1 (PEPCK-1) is upregulated in hepatocytes isolated from fetuses of nutrient-restricted mothers (MNR) compared to ad libitum-fed controls (CTR) and (2) glucocorticoids stimulate PEPCK-1 expression.
Hepatocytes from 0.9G CTR and MNR fetuses were isolated and cultured. PEPCK-1 protein and mRNA levels in hepatocytes were determined by western blot and quantitative PCR, respectively.
Fetuses of MNR mothers were intrauterine growth restricted (IUGR). Feasibility of culturing 0.9G fetal baboon hepatocytes was demonstrated. PEPCK-1 protein levels were increased in hepatocytes isolated from IUGR fetuses and PEPCK-1 mRNA expression was stimulated by glucocorticoids in fetal hepatocytes.
Cultured fetal baboon hepatocytes that retain their in vivo phenotype provide powerful in vitro tools to investigate mechanisms that regulate normal and programmed hepatic function.
Liver; dexamethasone; diabetes nonhuman primate
To enhance learning (knowledge, attitudes and practices) about the importance of family health history (FHH) information and familial risks.
A pre–post design with one group was employed in this study. Five learning sessions were conducted with a community-based sample (n = 75) recruited from five counties in Texas, USA. Each learning session included: a short online video; enactive instructions on how to use the online Surgeon General FHH tool; and a presentation on how to assess familial risks. Participants completed the pre–post knowledge, attitudes and practices questionnaires and the study's satisfaction survey, and participated in a short focus group interview.
Participants’ average age was 48.1 ± 13.3 years. Over half of the participants (79%) were female, and 55% described themselves as non-Hispanic White. Our findings showed significant changes (p < 0.05) in participants’ specific knowledge about factors that affect their familial risks. Similarly, significant changes (p < 0.05) in participants’ attitudes toward familial risks assessment for common disease complications and confidence in controlling these risks have been documented. Participants’ reported a high level of satisfaction in using online FHH tools, yet no significant change (p > 0.05) was detected in their reported practices regarding sharing FHH information with their providers or relatives. Focus group interviews revealed that participants were uncertain about providers’ or relatives’ reactions to sharing FHH information.
Using different learning styles may have a significant impact on improving knowledge and attitudes about familial risks.
familial risks assessment; family health history tool; genomics; learning; online Surgeon General
Naturally occurring type-2 diabetes has been found in a colony of baboons. Ongoing characterization of the baboon colony maintained at the Southwest National Primate Research Center has revealed a significant range of glucose sensitivity with some animals clearly diabetic. Seven baboons, 4 with diabetes and 3 without diabetes underwent histopathological investigation. Three diabetic animals were diagnosed using fasting blood glucose, hemoglobin A1C and intravenous glucose tolerance test, and a fourth one was known to have hyperglycemia. One control baboon and 3 baboons with diabetes had microalbuminuria. On kidney biopsy, diabetic baboons had thickening of the glomerular basement membrane and mesangial matrix expansion compared to controls. Immunohistochemistry showed the diabetic animals had increased mesangial expression of cellular fibronectin ED-A. Two diabetic animals with microalbuminuria had evidence of mesangiolysis with formation of an early nodule. One diabetic animal had a Kimmestiel-Wilson nodule. We conclude that the baboon represents a useful primate model of diabetes and nephropathy that resembles the nephropathy associated with type-2 diabetes in humans.
Glomerular basement membrane; mesangium; diabetic nephropathy; baboon; renal morphology
To describe the development and implementation process and assess the effect on self-reported clinical practice changes of a multidisciplinary, collaborative, interactive continuing medical education (CME)/continuing education (CE) program on chronic obstructive pulmonary disease (COPD).
Multidisciplinary subject matter experts and education specialists used a systematic instructional design approach and collaborated with the American College of Chest Physicians and American Academy of Nurse Practitioners to develop, deliver, and reproduce a 1-day interactive COPD CME/CE program for 351 primary care clinicians in 20 US cities from September 23, 2009, through November 13, 2010.
We recorded responses to demographic, self-confidence, and knowledge/comprehension questions by using an audience response system. Before the program, 173 of 320 participants (54.1%) had never used the Global Initiative for Chronic Obstructive Lung Disease recommendations for COPD. After the program, clinician self-confidence improved in all areas measured. In addition, participant knowledge and comprehension significantly improved (mean score, 77.1%-94.7%; P<.001). We implemented the commitment-to-change strategy in courses 6 through 20. A total of 271 of 313 participants (86.6%) completed 971 commitment-to-change statements, and 132 of 271 (48.7%) completed the follow-up survey. Of the follow-up survey respondents, 92 of 132 (69.7%) reported completely implementing at least one clinical practice change, and only 8 of 132 (6.1%) reported inability to make any clinical practice change after the program.
A carefully designed, interactive, flexible, dynamic, and reproducible COPD CME/CE program tailored to clinicians' needs that involves diverse instructional strategies and media can have short-term and long-term improvements in clinician self-confidence, knowledge/comprehension, and clinical practice.
AANP, American Academy of Nurse Practitioners; ACCP, American College of Chest Physicians; ADDIE, Analysis, Design, Development, Implementation, and Evaluation; APN, advanced practice nurse; CE, continuing education; CI, confidence interval; CME, continuing medical education; COPD, chronic obstructive pulmonary disease; DO, doctor of osteopathy; GOLD, Global Initiative for Chronic Obstructive Lung Disease; MD, medical doctor; PA, physician assistant; SME, subject matter expert
Since 1996, aging studies using several strains of long-lived mutant mice have been conducted. Among these studies, Ames dwarf mice have been extensively examined to seek clues regarding the role of the growth hormone/insulin-like growth factor-1 axis in the aging process. Interestingly, these projects demonstrate that Ames dwarf mice have physiological characteristics that are similar to those seen with calorie restriction, which has been the most effective experimental manipulation capable of extending lifespan in various species. However, this introduces the question of whether Ames dwarf and calorie-restricted (CR) mice have an extended lifespan through common or independent pathways. To answer this question, we compared the disease profiles of Ames dwarf mice to their normal siblings fed either ad libitum (AL) or a CR diet. Our findings show that the changes in age-related diseases between AL-fed Ames dwarf mice and CR wild-type siblings were similar but not identical. Moreover, the effects of CR on age-related pathology showed similarities and differences between Ames dwarf mice and their normal siblings, indicating that calorie restriction and Ames dwarf mice exhibit their anti-aging effects through both independent and common mechanisms.
age-related pathology; Ames dwarf mice; calorie restriction; neoplastic disease; aging
We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)+/0]. The Tg(TRX1)+/0 mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)+/0 mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)+/0 mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)+/0 mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)+/0 mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice.
Thioredoxin; Transgenic mouse; Oxidative stress; Protein carbonylation; Aging
The Free Radical or Oxidative Stress Theory of Aging is one of the most popular theories in aging research and has been extensively studied over the past several decades. However, recent evidence using transgenic/knockout mice that overexpress or down-regulate antioxidant enzymes challenge the veracity of this theory since the animals show no increase or decrease in lifespan. These results seriously call into question the role of oxidative damage/stress in the aging process in mammals. Therefore, the theory requires significant modifications if we are to understand the relationship between aging and the regulation of oxidative stress. Our laboratory has been examining the impacts of thioredoxins (Trxs), in the cytosol and mitochondria, on aging and age-related diseases. Our data from mice that are either up-regulating or down-regulating Trx in different cellular compartments, that is, the cytosol or mitochondria, could shed some light on the role of oxidative stress and its pathophysiological effects. The results generated from our lab and others may indicate that: 1) changes in oxidative stress and the redox state in the cytosol, mitochondria or nucleus might play different roles in the aging process; 2) the role of oxidative stress and redox state could have different pathophysiological consequences in different tissues/cells, for example, mitotic vs. post-mitotic; 3) oxidative stress could have different pathophysiological impacts in young and old animals; and 4) the pathophysiological roles of oxidative stress and redox state could be controlled through changes in redox-sensitive signaling, which could have more diverse effects on pathophysiology than the accumulation of oxidative damage to various molecules. To critically test the role of oxidative stress on aging and age-related diseases, further study is required using animal models that regulate oxidative stress levels differently in each cellular compartment, each tissue/organ, and/or at different stages of life (young, middle and old) to change redox sensitive signaling pathways.
Thioredoxin; Transgenic mouse; Knockout mouse; Oxidative stress; Cancer; aging
The primary purpose of the present set of studies was to provide a direct comparison of the effects of the angiotensin-converting enzyme inhibitor enalapril and the angiotensin receptor blocker losartan on body composition, physical performance, and muscle quality when administered late in life to aged rats. Overall, enalapril treatment consistently attenuated age-related increases in adiposity relative to both placebo and losartan. The maximal effect was achieved after 3 months of treatment (between 24 and 27 months of age), at a dose of 40 mg/kg and was observed in the absence of any changes in physical activity, body temperature, or food intake. In addition, the reduction in fat mass was not due to changes in pathology given that enalapril attenuated age-related increases in tumor development relative to placebo- and losartan-treated animals. Both enalapril and losartan attenuated age-related decreases in grip strength, suggesting that changes in body composition appear dissociated from improvements in physical function and may reflect a differential impact of enalapril and losartan on muscle quality. To link changes in adiposity to improvements in skeletal muscle quality, we performed gene array analyses to generate hypotheses regarding cell signaling pathways altered with enalapril treatment. Based on these results, our primary follow-up pathway was mitochondria-mediated apoptosis of myocytes. Relative to losartan- and placebo-treated rats, only enalapril decreased DNA fragmentation and caspase-dependent apoptotic signaling. These data suggest that attenuation of the severity of skeletal muscle apoptosis promoted by enalapril may represent a distinct mechanism through which this compound improves muscle strength/quality.
Age-related adiposity; Body composition; Sarcopenia; Renin–angiotensin system; Physical function; Muscle quality
The anti-tumor effects of calorie restriction (CR) and the possible underlying mechanisms were investigated using ethylnitrosourea (ENU)-induced glioma in rats. ENU was given transplacentally at gestational day 15, and male offspring were used in this experiment. The brain from 4-, 6-, and 8-month-old rats fed either ad libitum (AL) or calorie-restricted diets (40% restriction of total calories compared to AL rats) was studied. Tumor burden was assessed by comparing the number and size of gliomas present in sections of the brain. Immunohistochemical analysis was used to document lipid peroxidation [4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA)], protein oxidation (nitrotyrosine), glycation and AGE formation [methylglyoxal (MG) and carboxymethyllysine (CML)], cell proliferation activity [proliferating cell nuclear antigen (PCNA)], cell death [single-stranded DNA (ssDNA)], presence of thioredoxin 1 (Trx1), and presence of heme oxygenase-1 (HO-1) associated with the development of gliomas. The results showed that the number of gliomas did not change with age in the AL groups; however, the average size of the gliomas was significantly larger in the 8-month-old group compared to that of the younger groups. Immunopositivity was observed mainly in tumor cells and reactive astrocytes in all histological types of ENU-induced glioma. Immunopositive areas for HNE, MDA, nitrotyrosine, MG, CML, HO-1, and Trx1 increased with the growth of gliomas. The CR group showed both reduced number and size of gliomas, and tumors exhibited less accumulation of oxidative damage, decreased formation of glycated end products, and a decreased presence of HO-1 and Trx1 compared to the AL group. Furthermore, gliomas of the CR group showed less PCNA positive and more ssDNA positive cells, which are correlated to the retarded growth of tumors. Interestingly, we also discovered that the anti-tumor effects of CR were associated with decreased hypoxia-inducible factor-1α (HIF-1α) levels in normal brain tissue. Our results are very exciting because they not only demonstrate the anti-tumor effects of CR in gliomas, but also indicate the possible underlying mechanisms, i.e. anti-tumor effects of CR observed in this investigation are associated with reduced accumulation of oxidative damage, decreased formation of glycated end products, decreased presence of HO-1 and Trx1, reduced cell proliferation and increased apoptosis, and decreased levels of HIF-1α.
calorie restriction; ethylnitrosourea; glioma; oxidative stress; HIF-1α
Although studies of Ames and Snell dwarf mice have suggested possible important roles of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in aging and age-related diseases, the results cannot rule out the possibility of other hormonal changes playing an important role in the life extension exhibited by these dwarf mice. Therefore, growth hormone receptor/binding protein (GHR/BP) knockout (KO) mice would be valuable animals to directly assess the roles of somatotropic axis in aging and age-related diseases because the primary hormonal change is due to GH/IGF-1 deficiency. Our pathological findings showed GHR/BP KO mice to have a lower incidence and delayed occurrence of fatal neoplastic lesions compared with their wild-type littermates. These changes of fatal neoplasms are similar to the effects observed with calorie restriction and therefore could possibly be a major contributing factor to the extended life span observed in the GHR/BP KO mice.
Growth hormone receptor/binding protein; Knockout mouse; Neoplastic disease; Aging
Rodent models are an invaluable resource for studying the mechanism of mammalian aging. In recent years, the availability of transgenic and knockout mouse models has facilitated the study of potential mechanisms of aging. Since 1996, aging studies with several long-lived mutant mice have been conducted. Studies with the long-lived mutant mice, Ames and Snell dwarf, and growth hormone receptor/binding protein knockout mice, are currently providing important clues regarding the role of the growth hormone/insulin like growth factor-1 axis in the aging process. Interestingly, these studies demonstrate that these long-lived mutant mice have physiological characteristics that are similar to the effects of calorie restriction, which has been the most effective experimental manipulation capable of extending lifespan in various species. However, a question remains to be answered: do these long-lived mutant and calorie-restricted mice extend their lifespan through a common underlying mechanism?
aging; growth hormone receptor/binding protein; knockout mouse; neoplastic disease