Different DNA aberrations processes can cause colorectal cancer (CRC). Herein, we conducted a comprehensive molecular characterization of 27 CRCs from Iranian patients.
Materials and Methods
Array CGH was performed. The MSI phenotype and the methylation status of 15 genes was established using MSP. The CGH data was compared to two established lists of 41 and 68 cancer genes, respectively, and to CGH data from African Americans. A maximum parsimony cladogram based on global aberrations was established.
The number of aberrations seem to depend on the MSI status. MSI-H tumors displayed the lowest number of aberrations. MSP revealed that most markers were methylated, except RNF182 gene. P16 and MLH1 genes were primarily methylated in MSI-H tumors. Seven markers with moderate to high frequency of methylation (SYNE1, MMP2, CD109, EVL, RET, LGR and PTPRD) had very low levels of chromosomal aberrations. All chromosomes were targeted by aberrations with deletions more frequent than amplifications. The most amplified markers were CD248, ERCC6, ERGIC3, GNAS, MMP2, NF1, P2RX7, SFRS6, SLC29A1 and TBX22. Most deletions were noted for ADAM29, CHL1, CSMD3, FBXW7, GALNS, MMP2, NF1, PRKD1, SMAD4 and TP53. Aberrations targeting chromosome X were primarily amplifications in male patients and deletions in female patients. A finding similar to what we reported for African American CRC patients.
This first comprehensive analysis of CRC Iranian tumors reveals a high MSI rate. The MSI tumors displayed the lowest level of chromosomal aberrations but high frequency of methylation. The MSI-L were predominantly targeted with chromosomal instability in a way similar to the MSS tumors. The global chromosomal aberration profiles showed many similarities with other populations but also differences that might allow a better understanding of CRC's clinico-pathological specifics in this population.
In Chuvash polycythemia, a homozygous 598C>T mutation in the von Hippel-Lindau gene (VHL) leads to an R200W substitution in VHL protein, impaired degradation of α-subunits of hypoxia inducible factor (HIF)-1 and HIF-2, and augmented hypoxic responses during normoxia. Chronic hypoxia of high altitude is associated with decreased serum glucose and insulin concentrations. Other investigators reported that HIF-1 promotes cellular glucose uptake by increased expression of GLUT1 and increased glycolysis by increased expression of enzymes such as PDK. On the other hand, inactivation of Vhl in murine liver leads to hypoglycemia associated with a HIF-2-related decrease in the expression of the gluconeogenic enzymes genes Pepck, G6pc, and Glut2. We therefore hypothesized that glucose concentrations are decreased in individuals with Chuvash polycythemia. We found that 88 Chuvash VHLR200W homozygotes had lower random glucose and glycosylated hemoglobin A1c levels than 52 Chuvash subjects with wildtype VHL alleles. Serum metabolomics revealed higher glycerol and citrate levels in the VHLR200W homozygotes. We expanded these observations in VHLR200W homozygote mice and found that they had lower fasting glucose values and lower glucose excursions than wild-type control mice but no change in fasting insulin concentrations. Hepatic expression of Glut2 and G6pc but not Pdk2 was decreased and skeletal muscle expression of Glut1, Pdk1 and Pdk4 was increased. These results suggest that both decreased hepatic gluconeogenesis and increased skeletal uptake and glycolysis contribute to the decreased glucose concentrations. Further study is needed to determine whether pharmacologically manipulating HIF expression might be beneficial for treatment of diabetic patients.
VHL; hypoxia inducible factors; glucose; insulin; glycolysis; gluconeogenesis
Some studies suggest that HIV infection progresses slowly in patients with sickle cell disease (SCD). The authors aimed to determine the relationships between SCD and HIV infection.
National Hospital Discharge Survey data from adult Africane–Americans in the period of 1997–2009 were analysed. The comorbidities of SCD with HIV infections in hospital discharges were analysed. Multiple logistic regression was used to test the association between SCD and HIV. For comparative purposes, the relationships of SCD with hepatitis B virus (HBV) and hepatitis C virus (HCV) were also assessed.
423 431 records were divided into two time periods 1997–2003 (53% of records) and 2004–2009 (47% of records). The frequency of HIV diagnosis was lower in patients with SCD (1.5% vs 3.3% in patients without SCD). In logistic regression, SCD diagnosis was associated with an OR of 0.24 (95% CI 0.18 to 0.32) for HIV diagnosis in the first period and with an OR of 0.31 (95% CI 0.22 to 0.42) in the second period. In contrast, SCD was associated with higher risk of HCV (OR=2.01, 95% CI 1.56 to 2.59 in the first period and OR=2.12, 95% CI 1.71 to 2.63 in the second period). SCD was also associated with a higher risk of HBV (OR=1.15, 95% CI 0.72 to 1.83 in the first period and OR=1.82, 95% CI 1.24 to 2.68 in the second period).
The lower risk of HIV comorbidity, but not HCV and HBV, with SCD is consistent with the possibility that SCD has a unique effect in altering the risk of HIV infection or progression. Investigation of how the haemolytic and immunological changes of SCD influence HIV might lead to new therapeutic or preventive approaches.
Background and Aim
Negative association has been reported between presence of Helicobacter pylori and developing gastroesophageal reflux disease (GERD) and its complications. The aim of this study was to determine whether H. pylori (HP) can be protective against GERD in an African American (AA) population.
From 2004 to 2007, we studied 2,020 cases; esophagitis (58), gastritis (1,558), both esophagitis and gastritis (363) and a normal control group (41). We collected their pathology and endoscopy unit reports. HP status was determined based on staining of gastric biopsy.
HP data was available for 79 % (1,611) of the cases. The frequency of HP positivity in gastritis patients was 40 % (506), in esophagitis patients 4 % and in normal controls 34 % (11), while HP was positive in 34 % of the patients with both esophagitis and gastritis. After adjusting for effects of age and sex, odds ratio of HP was 0.06 (95 % CI 0.01–0.59; P value = 0.01) for the esophagitis group versus the normal group.
Our results show H. pylori has a significant negative association with esophagitis in AAs which may point to a protective role of H. pylori in the pathogenesis of esophagitis. In addition, H. pylori may be the reason for the low GERD complications in AAs.
H. pylori; Reflux esophagitis; African Americans
Background & Aims
Among the ethnic groups age standardized incidence rate of colorectal cancer (CRC) is highest among African-Americans. The majority of CRC arise from preexisting adenoma. It is shown that 30% of the US adult population has adenomas. The potential risk of malignant transformation in adenomas differs by specific pathologic and clinical characteristics that we aimed to study in AAs.
Material and Methods
All pathologic reports (150,000) in Howard University Hospital from 1959 to 2006 were reviewed manually. Those pathology reports compatible with the colorectal polyps were carefully reviewed and selected by a GI pathologist. All cases with cancer then excluded from the list. Data then were entered into excel and checked for missing data and duplications. Differences in right side and left side polyps for sex, histology, clinical symptoms were assessed by chi-2 test.
A total number of 5013 colorectal polyps were diagnosed in this period that include 47% male, with mean age (SD) of 63 (12). Half of cases were diagnosed in 2001–2006. Tubular adenoma was the most frequent pathology (73%). The highest frequency of right sided polyps was observed in 1990’s (56%). Left sided polyps were younger (P<0.000), more hyperplasic (23% vs. 5%; P<0.000) and more frequent in female (56% vs. 52%; P=0.02) compared to right sided. The frequency of right sided adenoma significantly increases from 18% in 60’s to 51% in the period of 2001–2006 (P<0.000). The most frequent symptom in both sides was GI bleeding (21%).
There was a ratio of 9:1 for neoplastic to hyperplastic polyps in our study which is more than what has been reported in Caucasians (7:1). Our data shows a shift in polyps from the left side to the right side of the colon in recent years. This data is consistent with the lack of a reduction in the incidence of colon cancer in African Americans. Screening is thus very important in AA to reduce the incidence of colon cancer.
Colon; polyp; African American
African Americans have disproportionately higher incidence and death rates of colorectal cancer among all ethnic groups in the United States. Several lifestyle factors (e.g. diet, physical activity and alcohol intake) have been suggested as risk factors for colorectal cancer. Stressful life events have also been identified as risk factors for colorectal cancer. The association between stressful life events and colon polyps, which are precursors of colorectal cancer, has yet to be determined.
We aimed to evaluate the relationship between stressful life events and the presence of colon polyps and adenomas in African American men and women.
In this cross-sectional study, 110 participants were recruited from a colon cancer screening program at Howard University Hospital. Participants completed an 82-item Life Events Questionnaire (Norbeck 1984), assessing major events that have occurred in the participants’ life within the past 12 months. Participants also reported whether the event had a positive or negative impact. Three scores were derived (total, positive, and negative).
Total life events scores were higher (Median [M] = 29 and Interquartile range [IQR] = 18-43) in patients with one or more polyps compared to patients without polyps (M, IQR = 21,13-38; P = 0.029). Total, positive or negative Life Events scores did not differ significantly between normal and adenoma patients. Total, negative and positive Life Events scores did not differ between patients who underwent diagnostic colonoscopy (symptomatic) and patients who underwent colonoscopy for colon cancer screening (asymptomatic) and patients for surveillance colonoscopies due to a personal history of colon polyps. Linear regression analysis indicated that male gender is associated with 9.0 unit lower total Life Events score (P = 0.025).
This study suggests that patients who experienced total life events may be at higher risk of having colon polyps and adenomas which indicates an association between stress and the development of colorectal polyps.
Stress; Life events; Colon adenoma; African Americans
Platelets are activated in sickle cell disease (SCD), and particularly during vaso-occlusive episodes (VOE). Thrombospondin-1 (TSP1), a major secretory product of activated platelets, is increased in the circulation in VOE and binds to sickle red blood cells (RBC) promoting vascular adhesion. Thus, we hypothesized that TSP1 may represent a plasma biomarker of disease severity in SCD. We tested the plasma collected from patients in steady state (n = 27) and VOE (n = 14), as well as healthy controls (n = 17) at the University of Pittsburgh Medical Center (UPMC), and from patients in steady state enrolled in the walk-PHaSST clinical trial (n = 483). We found that TSP1 levels were increased in VOE in the UPMC cohort. Among steady-state patients at UPMC, TSP1 values correlated positively with lifetime history of acute chest syndrome (r = 0.72, P < 0.0001) and hemoglobin concentration (r = 0.49, P = 0.01), and negatively with markers of hemolysis, such as LDH (r = −0.50, P = 0.009). Analysis of the walk-PHaSST cohort also showed a positive association between TSP1 levels and hydroxyurea use (r = 0.14, P = 0.003), and confirmed the negative associations with the severity of hemolysis. Our results suggest that TSP1 levels are associated with more VOE, hydroxyurea use and lower rates of hemolysis. High TSP1 concentrations may indicate higher risk of the viscosity/vaso-occlusion phenotype of SCD.
To identify factors associated with frequent severe vaso-occlusive pain crises in a contemporary pediatric cohort of sickle cell anemia (SCA)enrolled in a prospective study of pulmonary hypertension and the hypoxic response in sickle cell disease (SCD).
Clinical and laboratory characteristics of children with SCA who had ≥3 severe pain crises requiring health care in the preceding year were compared with subjects with <3 such episodes.
Seventy-five children (20%) reported ≥3 severe pain episodes in the preceding year, and 232 (61%) had none. Frequent pain episodes were associated with older age (OR 1.2; 95% CI 1.1–1.3; P<0.0001), α-thalassemia trait (OR 3.5; 1.6–6.7; P=0.002), higher median hemoglobin (OR 1.7; 95% CI: 1.2–2.4; P<0.003) and lower lactate dehydrogenase (LDH) concentration (OR 1.82; 95% CI: 1.07–3.11; P = 0.027). Children with high pain frequency also had an increased iron burden (serum ferritin 480 vs. 198 μg/L; P=0.006) and higher median tricuspid regurgitation jet velocity (2.41 vs. 2.31 m/s; P=0.001). Neither hydroxy urea use nor fetal hemoglobin levels were significantly different according to severe pain history.
In our cohort of children with SCA increasing age was associated with higher frequency of severe pain episodes as were α-thalassemia, iron overload, higher hemoglobin and lower LDH concentration and higher tricuspid regurgitation velocity.
Sickle cell anemia; vaso-occlusive crisis; pain
Non-invasively assessed pulmonary pressure elevations and left ventricular diastolic dysfunction (LVDD) are associated with increased mortality in adults with sickle cell disease (SCD), but their relationship to exercise intolerance has not been evaluated prospectively.
Methods and Results
Echocardiography, six-minute walk distance, hemolytic rate, and serum concentrations of ferritin and erythropoietin were evaluated in a cohort of 483 subjects with homozygous hemoglobin S in the US and UK Walk-PHaSST study. Tricuspid regurgitation velocity (TRV), which reflects systolic pulmonary artery pressure, was 2.7 to <3.0 m/sec (mean±SD 2.8±0.1) in 26% of the subjects and ≥3.0 m/sec (3.4±0.4) in 11%. LV lateral E/e′ ratio, which has been shown to reflect LV filling pressure in other conditions but has not been studied in SCD, was significantly higher in the groups with TRV ≥2.7 m/sec. Increased hemolysis (P<0.0001), LV lateral E/e′ ratio (P=0.0001), BUN (P=0.0002) and erythropoietin (P=0.002) were independently associated with an increased TRV. Further, female gender (P<0.0001), older age (P<0.0001), LV lateral E/e′ ratio (P=0.014), and TRV (P=0.019) were independent predictors of a shorter six-minute walk distance.
Echocardiography-estimated elevated pulmonary artery systolic pressure and LV lateral E/e′ ratio were independently associated with poor exercise capacity in a large cohort of patients with sickle cell anemia. Controlled trials investigating whether strategies to prevent or delay pulmonary hypertension and/or LVDD will improve exercise capacity and long-term outcomes in sickle cell anemia should be considered.
sickle cell anemia; pulmonary hypertension; left ventricular diastolic dysfunction; echocardiography; six-minute walk
Alcohol consumption is associated with increased iron stores. In sub-Saharan Africa, high dietary ionic iron and the ferroportin Q248H allele have also been implicated in iron accumulation. We examined the associations of ferroportin Q248H, alcohol and dietary iron with serum ferritin, aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT) concentrations in African Americans.
Inner-city African Americans (103 men, 40 women) were recruited from the community according to reported ingestion of >4 alcoholic drinks per day or <2 per week. Typical daily heme iron, non-heme iron and alcohol were estimated using University of Hawaii’s multiethnic dietary questionnaire. Based on dietary questionnaire estimates we established categories of < versus ≥56 g alcohol per day, equivalent to 4 alcoholic drinks per day assuming 14 g alcohol per drink.
Among 143 participants, 77% drank <56 g alcohol/day and 23% ≥56 g/d as estimated by the questionnaire. The prevalence of ferroportin Q248H was 23.3% with alcohol >56 g/d versus 7.5% with lower amounts (P=0.012). Among subjects with no history of HIV disease, serum ferritin concentration had positive relationships with male gender (P=0.041), alcohol consumption (P=0.021) and ALT concentration (P=0.0001) but not with dietary iron intake or ferroportin Q248H. Serum AST and ALT concentrations had significant positive associations with male gender and hepatitis C seropositivity but not with alcohol or dietary iron intake or ferroportin Q248H.
Our findings suggest a higher prevalence of ferroportin Q248H with greater alcohol consumption, and this higher prevalence raises the possibility that the allele might ameliorate the toxicity of alcohol. Our results suggest that alcohol but not dietary iron contributes to higher body iron stores in African Americans. Studies with larger numbers of participants are needed to further clarify the relationship of ferroportin Q248H with the toxicity of alcohol consumption.
Esophageal cancer accounts for a considerable proportion of carcinomas of the upper gastrointestinal tract in African Americans. Our aim was to describe the epidemiology of esophageal squamous cell cancer (ESCC) and esophageal adenocarcinoma (EA) among African Americans in the last five decades.
A total of 601 records of patients with documented esophageal cancer between 1959 and 2007 at Howard University Hospital were reviewed. Demographic characteristics, risk factors, clinical stage and histological findings were reviewed. The change in prevalence of the disease and the interaction between main risk factors with tumor stage of the patients were assessed over the years of this study.
A total of 552 patients (91.8%) had ESCC while 49 patients (8.2%) had EA. The mean age at diagnosis was 60.1 and 60.6 years for ESCC and EA, respectively (P = 0.8). The peak incidence was in the 1980–1989 decade. Out of 136 ESCC patients with TNM staging information, 130 (95.6%) were diagnosed in stage 2 and above. The majority (73%) of the ESCC were in the mid- and upper third of the esophagus and associated with smoking and alcohol exposure. The majority (81%) of the EA were in the mid- and lower third. The most common presenting symptoms were dysphagia (77.7%), and weight loss (31.9%).
ESCC is the predominant esophageal cancer in African Americans and diagnosed in late stages, and its diagnosis in our institution has decreased since 1990. A combination of genetic factors, environmental influences (e.g., those related to diet), and the deleterious changes associated with smoking and alcohol consumption, and differences in tumor histology, are the obvious parameters that should be the focus of future studies, and early diagnosis at an earlier stage should be considered among blacks.
African American; Esophageal cancer; Esophageal squamous cell carcinoma; Esophageal adenocarcinoma
SEL1L gene product is implicated in the endoplasmic reticulum (ER)-associated protein degradation and Unfolded Protein Response pathways. This gene and associated miRNAs have been indicated as predictive and prognostic markers of pancreatic cancer.
Explore the role of SEL1L in colorectal cancer (CRC) progression.
SEL1L expression was analysed immunohistochemically in 153 adenomas and 71 CRCs from African American and North Italian patients. The distribution of stained cells was determined by computing median and inter quartile range. The receiver operating characteristics plot was used as discriminate power of SEL1L expression, CRC diagnosis and the effects on patient survival.
SEL1L was low in normal mucosa and confined to few scattered cells at the base crypt of the villi and in the foveolar glandular compartment. The highest levels were in Paneth cells within the lysosomes. The enterocytic progenitor cells and mature enterocytes showed less cytoplasmic staining. In CRCs, SEL1L expression significantly correlated with the progression from adenoma to carcinoma (P = 0.0001) being stronger in well-to-moderately differentiated cancers. No correlation was found with other clinicopathological characteristics or ethnicity.
SEL1L expression is a potential CRC tissue biomarker since its expression is significantly higher in adenoma cells with respect to normal mucosa. The levels of expression decrease sensibly in undifferentiated CRC cancers. Interestingly, Paneth cells contain high levels of SEL1L protein that could indicate pre-neoplastic mucosa undergoing neoplastic transformation. Since SEL1L’s major function lies within ER stress and active ERAD response, it may identify CRCs with differentiated secretory phenotype and acute cellular stress.
SEL1L expression; Colorectal cancers; Paneth’s cells
Control selection is a major challenge in epidemiologic case-control studies. The aim of our study was to evaluate using hospital versus neighborhood control groups in studying risk factors of esophageal squamous cell carcinoma (ESCC).
We compared the results of two different case-control studies of ESCC conducted in the same region by a single research group. Case definition and enrollment were the same in the two studies, but control selection differed. In the first study, we selected two age- and sex-matched controls from inpatient subjects in hospitals, while for the second we selected two age- and sex-matched controls from each subject's neighborhood of residence. We used the test of heterogeneity to compare the results of the two studies. We found no significant differences in exposure data for tobacco-related variables such as cigarette smoking, chewing Nass (a tobacco product) and hookah (water pipe) usage, but the frequency of opium usage was significantly different between hospital and neighborhood controls. Consequently, the inference drawn for the association between ESCC and tobacco use did not differ between the studies, but it did for opium use. In the study using neighborhood controls, opium use was associated with a significantly increased risk of ESCC (adjusted OR 1.77, 95% CI 1.17–2.68), while in the study using hospital controls, this was not the case (OR 1.09, 95% CI 0.63–1.87). Comparing the prevalence of opium consumption in the two control groups and a cohort enrolled from the same geographic area suggested that the neighborhood controls were more representative of the study base population for this exposure.
Hospital and neighborhood controls did not lead us to the same conclusion for a major hypothesized risk factor for ESCC in this population. Our results show that control group selection is critical in drawing appropriate conclusions in observational studies.
Background. The mechanisms of severe malarial anemia and cerebral malaria, which are extreme manifestations of Plasmodium falciparum malaria, are not fully understood.
Methods. Children aged <6 years from southern Zambia presenting to the hospital with severe malarial anemia (n = 72), cerebral malaria (n = 28), or uncomplicated malaria (n = 66) were studied prospectively. Children with overlapping severe anemia and cerebral malaria were excluded.
Results. Low interleukin 10 concentrations had the strongest association with severe anemia (standard β = .61; P < .001) followed by high tumor necrosis factor α and sFas concentrations, low weight-for-age z scores, presence of stool parasites, and splenomegaly (standard β = .15–.25; P ≤ .031); most of these factors were also associated with lower reticulocytes. Greater parasitemia was associated with higher interleukin 10 and tumor necrosis factor α concentrations, whereas sulfadoxizole/pyrimethamine therapy and lower weight-for-age z scores were associated with lower interleukin 10 levels. Thrombocytopenia and elevated tissue plasminogen activator inhibitor 1 levels had the strongest associations with cerebral malaria (standard β = .37 or .36; P < .0001), followed by exposure to traditional herbal medicine and hemoglobinuria (standard β = .21–.31; P ≤ .006).
Conclusions. Predictors of severe malarial anemia (altered immune responses, poor nutrition, intestinal parasites, and impaired erythropoiesis) differed from those of cerebral malaria (thrombocytopenia, herbal medicine, and intravascular hemolysis). Improved preventive and therapeutic measures may need to consider these differences.
Pulmonary hypertension (PH) is associated with adverse outcomes in adults with sickle cell disease (SCD) but its importance in children is less clear. We define the incidence and etiologies of PH in pediatric patients with SCD. Children with SCD (n = 310) and matched controls (n = 54) were prospectively enrolled under basal conditions. Participants underwent echocardiography, pulse oximetry, 6-minute walk, and hematologic testing. Echocardiographic measures were compared between SCD and control subjects before and after adjusting for hemoglobin. Correlation of echocardiographic and clinical parameters was performed. Tricuspid regurgitation velocity (TRV) was elevated compared to controls (2.28 vs. 2.10 m/s, p <0.0001). Increased TRV was associated with left ventricular diastolic diameter, hemoglobin, and estimated left atrial pressure. TRV remained elevated when controlled for left ventricular diameter and left atrial pressure. An echocardiography-derived pulmonary resistance was not significantly different between SCD and control patients, although it was elevated in the SCD subgroup with elevated TRV. When controlled for hemoglobin, TRV was no longer statistically different, but pulmonary insufficiency velocity, septal wall thickness and estimated pulmonary resistance were statistically higher. TRV, pulmonary insufficiency end diastolic velocity, and markers of increased cardiac output correlated with indicators of adverse functional status including history of acute chest syndrome, stroke, transfusions, and 6-minute walk. In conclusion, children with SCD have mildly increased TRV that correlated with increased cardiac output and left ventricular filling pressures. Hemoglobin adjusted analysis also suggests contribution of primary vascular changes.
Pulmonary hypertension; Tricuspid regurgitation; Pulmonary vascular resistance; Sickle cell
There are sparse data on genetic, epigenetic and vitamin D exposure in African Americans (AA) with colon polyp. Consequently, we evaluated serum 25(OH) D levels, vitamin D receptor (VDR) polymorphisms and the methylation status of the tumor suppressor gene dickkopf homolog 1 (DKK1) as risk factors for colon polyp in this population.
The case-control study consisted of 93 patients with colon polyp (cases) and 187 healthy individuals (controls) at Howard University Hospital. Serum levels of 25(OH)D (including D3, D2, and total) were measured by liquid chromatography-mass spectrometry. DNA analysis focused on 49 single nucleotide polymorphisms (SNPs) in the VDR gene. Promoter methylation analysis of DKK1 was also performed. The resulting data were processed in unadjusted and multivariable logistic regression analyses.
Cases and controls differed in vitamin D status (D3<50 nmol/L: Median of 35.5 in cases vs. 36.8 in controls nmol/L; P = 0.05). Low levels of 25(OH)D3 (<50 nmol/L) were observed in 86% of cases and 68% of controls and it was associated with higher risks of colon polyp (odds ratio of 2.7, 95% confidence interval 1.3–3.4). The SNP analysis showed no association between 46 VDR polymorphisms and colon polyp. The promoter of the DKK1 gene was unmethylated in 96% of the samples.
We found an inverse association between serum 25(OH)D3 and colon polyp in AAs. VDR SNPs and DKK1 methylation were not associated with colon polyp. Vitamin D levels may in part explain the higher incidence of polyp in AAs.
The genetic bases of the highly variable degrees of anaemia and haemolysis in persons with Hb SS are not fully known, but several studies have indicated that G6PD deficiency is not a factor. The G6PD202A and G6PD376G alleles and α-thalassaemia were determined by molecular genetic testing in 261 children and adolescents with Hb SS in a multicentre study. G6PD202A,376G (G6PD A-) was defined as hemizygosity for both alleles in males and homozygosity in females. Among the participants 41% were receiving hydroxycarbamide.
The prevalence of G6PD202A,376G was 13.6% in males and 3.3% in females with an overall prevalence of 8.7%. G6PD202A,376G was associated with a 10 g/l decrease in haemoglobin concentration (P=0.008) but not with increased haemolysis as measured by lactate dehydrogenase, bilirubin, aspartate-aminotransferase, reticulocyte count or a haemolytic component derived from these markers (P>0.09). Similar results were found within a sub-group of children who were not receiving hydroxycarbamide. By comparison, single and double α-globin deletions were associated with progressively higher haemoglobin concentrations (P=0.005 for trend), progressively lower values for haemolytic component (P=0.007), and increased severe pain episodes (P<0.001).
In conclusion, G6PD202A,376G may be associated with lower haemoglobin concentration in sickle cell anaemia by a mechanism other than increased haemolysis.
sickle cell anaemia; G6PD; haemolysis; alpha-thalassaemia; haemoglobin concentration
N-terminal (NT) pro-brain natriuretic peptide (proBNP) ≥160 ng/l has a 78% positive predictive value for pulmonary hypertension and is associated with increased mortality in US sickle cell disease patients, but the importance in sickle cell disease patients in Africa is not known. In a cross-sectional study at Ahmadu Bello University Teaching Hospital, Shika-Zaria, Nigeria, we studied 133 hydroxycarbamide-naïve Nigerian sickle cell anaemia patients aged 18-52 years at steady-state and 65 healthy controls. Twenty-six percent of patients versus 5% of controls had NT-proBNP ≥160 ng/l (P=0.0006). By logistic regression among the patients, human immunodeficiency virus seropositivity, higher serum ferritin and lower haemoglobin or higher lactate dehydrogenase independently predicted elevated NT-proBNP. After adjustment for haemoglobin concentration, elevated NT-proBNP concentration was associated with an estimated 7.8-fold increase in the odds of severe functional impairment, defined as an inability to walk more than 300 m in six min (95% confidence interval 1.5-32.6; P=0.005). Similarly, elevated tricuspid regurgitation velocity was associated with an estimated 5.6-fold increase in the odds of functional impairment (95% confidence interval 1.5-21.0; P=0.011). In conclusion, NT-proBNP elevation is common and is associated with markers of anaemia, inflammation and iron status and with severe functional impairment among sickle cell anaemia patients in Nigeria.
sickle cell disease; N-terminal pro-brain natriuretic peptide; six-minute walk; haemolysis; Africa
Colon cancer is one of the leading causes of cancer related deaths. Its impact on African Americans (AAs) is higher than in the general population both in the incidence and mortality from the disease. Colon cancer aggressiveness in AAs as well as non-frequent check-ups and follow up in this population have been proposed as ways to explain the observed discrepancies. These facts made the detection of early carcinogenesis markers in this population a priority.
Materials and Methods
Here, we analyzed 50 colon adenomas from AA patients for both microsatellite instability (MSI) and the methylation status of SLC5A8 gene. This gene's product is involved in the transport of butyrate that has anti-proliferative properties through its effects on histone acetylation and gene expression. A proteomic analysis to check the expressed histones in adenoma and normal tissues was also performed.
The analyzed samples displayed 82% (n = 41) methylation level of SLC5A8 gene in adenomas. The MSI-H (high) adenoma were about 18% (n = 9) while the rest were mostly MSS (microsatellite stable) with few MSI-L (Low). No association was found between SLC5A8 methylation and the MSI status. Also, there was no association between SLC5A8 methylation and the sex and age of the patients. However, there were more right sided adenomas with SLC5A8 methylation than the left sided ones. The proteomic analysis revealed distinct histone expression profiles between normal and adenoma tissues.
SLC5A8 is highly methylated in AA colon adenomas which points to its potential use as a marker for early detection. The MSI rate is similar to that found in colon cancer tumors in AAs. These findings suggest that both processes stem from the same epigenetic and genetic events occurring at an early stage in colon carcinogenesis in AAs.
Hepatitis C virus (HCV) infection may be associated with thrombocytopenia and increased iron stores in patients receiving medical care. We aimed to determine how often changes in hematologic, iron metabolic and inflammatory markers occur in individuals with undiagnosed HCV in the community.
Inner-city African Americans (n=143) were recruited from the community according to reported ingestion of alcohol. They were divided broadly into those who drank more or less than 56 g alcohol/day as assessed by dietary questionnaire. HCV serology was determined and laboratory values were compared according to HCV seropositivity in analyses that adjusted for alcohol consumption.
The prevalence of HCV seropositivity was 23% among men and 29% among women. Levels of hepatocellular enzymes were higher with HCV seropositivity (P <0.0001) but hemoglobin concentrations, white blood cell and platelet counts and serum ferritin concentrations did not differ. The globulin fraction of the serum protein concentration (P=0.002) was increased with HCV seropositivity as expected with chronic inflammation. However, erythrocyte sedimentation rate and serum iron and haptoglobin levels did not differ significantly according to HCV status. Furthermore, multivariate analysis revealed that C-reactive protein was decreased and transferrin concentration was increased with both HCV and alcohol consumption (P<0.014).
Previously undiagnosed HCV seropositivity has little effect on the complete blood count and body iron stores but appears to perturb the response to an inflammatory stimulus, causing reduced rather than increased circulating CRP concentrations and increased rather than decreased transferrin concentrations.
HCV infection; African American; CRP; Iron metabolism
Chromatin remodeling and activation of transcription are important aspects of gene regulation, but these often go awry in disease progression, including during colon cancer development. We investigated the status of global histone acetylation (by measuring H3, H4 acetylation of lysine residues, which also occur over large regions of chromatin including coding regions and non-promoter sequences) and expression of histone deacetylase 2 (HDAC2) in colorectal cancer (CRC) tissue microarrays using immunohistochemical staining. Specifically, HDAC2 and the acetylation of histones H4K12 and H3K18 were evaluated in 134 colonic adenomas, 55 moderate to well differentiated carcinomas, and 4 poorly differentiated carcinomas compared to matched normal tissue. In addition, the correlation between expression of these epigenetic biomarkers and various clinicopathological factors including, age, location, and stage of the disease were analyzed. HDAC2 nuclear expression was detected at high levels in 81.9%, 62.1%, and 53.1% of CRC, adenomas, and normal tissue, respectively (P = 0.002). The corresponding nuclear global expression levels in moderate to well differentiated tumors for H4K12 and H3K18 acetylation were increased while these levels were decreased in poorly differentiated tumors (P = 0.02). HDAC2 expression was correlated significantly with progression of adenoma to carcinoma (P = 0.002), with a discriminative power of 0.74, when comparing cancer and non-cancer cases. These results suggest HDAC2 expression is significantly associated with CRC progression.
Global histone acetylation; HDAC2; Colon cancer
Verbal autopsy (VA) is one method to obtain valid estimates of causes of death in the absence of valid medical records. We tested the reliability and validity of a VA questionnaire developed for a cohort study in Golestan Province in northeastern Iran.
A modified version of the WHO adult verbal autopsy was used to assess the cause of death in the first 219 Golestan Cohort Study (GCS) subjects who died. The GCS cause of death was determined by two internists who independently reviewed all available medical records. Two other internists (“reviewers”) independently reviewed only the VA answers and classified the cause of death into one of nine general categories; they repeated this evaluation one month later. The reliability of the VA was measured by calculating intra-reviewer and inter-reviewer kappa statistics. The validity of the VA was measured using the GCS cause of death as the gold standard.
VA showed both good validity (sensitivity, specificity, PPV, and NPV all above 0.81) and reliability (kappa>0.75) in determining the general cause of death independent of sex and place of residence. The overall multi-rater agreement across four reviews was 0.84 (95%CI: 0.78–0.89). The results for identifying specific cancer deaths were also promising, especially for upper GI cancers (kappa = 0.95). The multi-rater agreement in cancer subgroup was 0.93 (95%CI: 0.85–0.99).
VA seems to have good reliability and validity for determining the cause of death in a large-scale adult follow up study in a predominantly rural area of a middle-income country.
Chuvash polycythemia results from a homozygous 598C>T mutation in exon 3 of the von Hippel-Lindau (VHL) gene. This disrupts the normoxia pathway for degrading hypoxia inducible factor (HIF)-1α and HIF-2α causing altered expression of HIF-1 and HIF-2 inducible genes. As hypoxia induces expression of proinflammatory cytokines, we hypothesized that there might be an elevation of Th1 cytokines in the setting of Chuvash polycythemia. We analyzed plasma concentrations of Th1 (interleukins-2 and 12, interferon-γ, granulocyte-monocyte colony-stimulating factor, tumor necrosis factor-α) and Th2 cytokines (interleukins-4, 5, 10, and 13) using the Bio-Plex multiplex suspension array system in 34 VHL598C>T homozygotes and 32 VHL wild-type participants from Chuvashia. Concentrations of all the Th1 and Th2 cytokines measured were elevated in the VHL598C>T homozygotes compared with the control wild-type participants, but the ratios of Th1 to Th2 cytokines did not differ by genotype. In parallel, peripheral blood concentrations of CD4 positive T-helper cells and CD4/CD8 ratio were lower in the VHL598C>T homozygotes. In conclusion, the up-regulated hypoxic response in Chuvash polycythemia is associated with increased plasma products of both the Th1 and Th2 pathways, but the balance between the two pathways seems to be preserved.
Colorectal cancer develops through genetic, epigenetic, and environmental events that result in uncontrolled cell proliferation. Colorectal cancer incidence and mortality is higher in African Americans (AA) than in the general population. Here, we carried out a molecular analysis of sporadic colorectal cancer tumors from AAs to investigate possible explanations for the observed disparities.
A total of 222 AA colorectal cancer tumors were analyzed for micro-satellite instability (MSI) for protein expression of two DNA mismatch repair genes, MLH1 and MSH2, by immunohistochemistry; for the methylation silencing of MLH1, p16, APC, and APC2 promoters by methylation-specific PCR; and for point mutations in two oncogenes, KRAS and BRAF, by sequencing.
In our sample, 19.8% of the AAs colorectal cancer tumors were MSI high (MSI-H) and did not associate with any of the clinicopathologic features, except tumor differentiation. Higher levels of inactive DNA mismatch repair proteins MLH1 (41%) and MSH2 (33%) were found by immunohistochemistry. Methylation-specific PCR analysis revealed a high level of methylation for MLH1 (66%), APC (53%), and APC2 (90%), but not for p16 (26%). BRAF mutations were only within the MSI-H tumors, whereas most (64%) of KRAS mutations were found within the non – MSI-H group.
MLH1, MSH2, and BRAF alterations are significantly associated with MSI-H phenotype, unlike APC, APC2 and KRAS alterations. The prominent role of DNA mismatch repair gene suppression in MSI-H and a distinctive role of BRAF and KRAS mutations with respect to MSI status are supported by this study
Pulmonary hypertension and left ventricular diastolic dysfunction are complications of sickle cell disease. Pulmonary hypertension is associated with hemolysis and hypoxia, but other unidentified factors are likely involved in pathogenesis as well.
Design and Methods
Plasma concentrations of three angiogenic markers (fibroblast growth factor, platelet derived growth factor–BB [PDGF-BB], vascular endothelial growth factor [VEGF]) and seven inflammatory markers implicated in pulmonary hypertension in other settings were determined by Bio-Plex suspension array in 237 children and adolescents with sickle cell disease at steady state and 43 controls. Tricuspid regurgitation velocity (which reflects systolic pulmonary artery pressure), mitral valve E/Edti ratio (which reflects left ventricular diastolic dysfunction), and a hemolytic component derived from four markers of hemolysis and hemoglobin oxygen saturation were also determined.
Plasma concentrations of interleukin-8, interleukin-10 and VEGF were elevated in the patients with sickle cell disease compared to controls (P≤0.003). By logistic regression, greater values for PDGF-BB (P = 0.009), interleukin-6 (P = 0.019) and the hemolytic component (P = 0.026) were independently associated with increased odds of elevated tricuspid regurgitation velocity while higher VEGF concentrations were associated with decreased odds (P = 0.005) among the patients with sickle cell disease. These findings, which are consistent with reports that PDGF-BB stimulates and VEGF inhibits vascular smooth muscle cell proliferation, did not apply to E/Etdi.
Circulating concentrations of angiogenic and pro-Inflammatory markers are altered in sickle cell disease children and adolescents with elevated tricuspid regurgitation velocity, a subgroup that may be at risk for developing worsening pulmonary hypertension. Further studies to understand the molecular changes in these children are indicated.