Induction of premature senescence and a less-fibrogenic phenotype by programmed cell death 4 knockdown in the human hepatic stellate cell line Lieming Xu-2.

Although programmed cell death 4 (PDCD4) was initially reported as a tumor suppressor and has been shown to inhibit cancer cell growth and metastasis, recent studies have demonstrated that loss of PDCD4 expression also induces growth inhibition by inducing apoptosis and/or cellular senescence. At present, the roles of PDCD4 in the activation and profibrogenic properties of myofibroblasts, which are critically involved in organ fibrosis, such as that in the liver, are unclear. We, therefore, investigated the roles of PDCD4 in myofibroblasts using human hepatic stellate cell line Lieming Xu-2 (LX-2). PDCD4 knockdown inhibited LX-2 proliferation and induced a senescent phenotype with increased ß-galactosidase staining and p21 expression in a p53-independent manner together with downregulation of the notch signaling mediator RBJ-κ/CSL. During PDCD4 knockdown, alpha smooth muscle actin (α-SMA; an activation marker of myofibroblasts), matrix metalloproteinases MMP-1 and MMP-9, and collagen IV were upregulated, but the expression of collagen1α1 and collagen III was markedly downregulated without any marked change in the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1). These results demonstrated that knockdown of PDCD4 induced the cellular senescence phenotype and activated myofibroblasts while suppressing the profibrogenic phenotype, suggesting roles of PDCD4 in cellular senescence and fibrogenesis in the liver.

HSPA8 Single-Nucleotide Polymorphism Is Associated with Serum HSC70 Concentration and Carotid Artery Atherosclerosis in Nonalcoholic Fatty Liver Disease.

There is an association between nonalcoholic fatty liver disease (NAFLD) and atherosclerosis, but the genetic risk of atherosclerosis in NAFLD remains unclear. Here, a single-nucleotide polymorphism (SNP) of the heat shock 70 kDa protein 8 (HSPA8) gene was analyzed in 123 NAFLD patients who had been diagnosed using a liver biopsy, and the NAFLD phenotype including the maximum intima-media thickness (Max-IMT) of the carotid artery was investigated. Patients with the minor allele (A/G or G/G) of rs2236659 showed a lower serum heat shock cognate 71 kDa protein concentration than those with the major A/A allele. Compared with the patients with the major allele, those with the minor allele showed a higher prevalence of hypertension and higher Max-IMT in men. No significant associations between the HSPA8 genotype and hepatic pathological findings were identified. In decision-tree analysis, age, sex, liver fibrosis, and HSPA8 genotype were individually associated with severe carotid artery atherosclerosis (Max-IMT ≥ 1.5 mm). Noncirrhotic men aged ≥ 65 years were most significantly affected by the minor allele of HSPA8. To predict the risk of atherosclerosis and cardiovascular disease, HSPA8 SNP genotyping might be useful, particularly for older male NAFLD patients.

Degradation of the Tumor Suppressor PDCD4 Is Impaired by the Suppression of p62/SQSTM1 and Autophagy.

PDCD4 (programmed cell death 4) is a tumor suppressor that plays a crucial role in multiple cellular functions, such as the control of protein synthesis and transcriptional control of some genes, the inhibition of cancer invasion and metastasis. The expression of this protein is controlled by synthesis, such as via transcription and translation, and degradation by the ubiquitin-proteasome system. The mitogens, known as tumor promotors, EGF (epidermal growth factor) and TPA (12-O-tetradecanoylphorbol-13-acetate) stimulate the degradation of PDCD4 protein. However, the whole picture of PDCD4 degradation mechanisms is still unclear, we therefore investigated the relationship between PDCD4 and autophagy. The proteasome inhibitor MG132 and the autophagy inhibitor bafilomycin A1 were found to upregulate the PDCD4 levels. PDCD4 protein levels increased synergistically in the presence of both inhibitors. Knockdown of p62/SQSTM1 (sequestosome-1), a polyubiquitin binding partner, also upregulated the PDCD4 levels. P62 and LC3 (microtubule-associated protein 1A/1B-light chain 3)-II were co-immunoprecipitated by an anti-PDCD4 antibody. Colocalization particles of PDCD4, p62 and the autophagosome marker LC3 were observed and the colocalization areas increased in the presence of autophagy and/or proteasome inhibitor(s) in Huh7 cells. In ATG (autophagy related) 5-deficient Huh7 cells in which autophagy was impaired, the PDCD4 levels were increased at the basal levels and upregulated in the presence of autophagy inhibitors. Based on the above findings, we concluded that after phosphorylation in the degron and ubiquitination, PDCD4 is degraded by both the proteasome and autophagy systems.

Ameliorative effects of ethanolic constituents of Bangladeshi propolis against tetracycline-induced hepatic and renal toxicity in rats.

The study reports the phenolic composition of propolis from Bangladesh and its ameliorative effects against tetracycline-induced hepatonephrotoxicity in rats. Male Wistar Albino rats (n = 18) were randomly divided into three following groups: (1) normal control, (2) tetracycline-treatment (200 mg kg-1  rat-1 ), and (3) tetracycline (200 mg kg-1  rat-1 ) + propolis (100 mg kg-1  rat-1 ) treatments. The ethanolic extract of propolis contained major phenolic acids as well as a flavonoid, rutin. Oral exposure to tetracycline caused severe hepatic and renal damage as indicated by significant alterations in liver marker enzymes in rat serum: bilirubin and protein concentrations, lipid profile, and markers of kidney function when compared with controls. The observed biochemical perturbations were accompanied by histopathological changes. Co-administration with propolis extract, however, prevented the changes in biochemical parameters, as revealed by maintenance of cell membrane integrity and regulation of lipid profile and the conservation of the histoarchitecture. PRACTICAL APPLICATIONS: Propolis is a resinous honeybee product which is becoming increasingly popular due to its potential contributions to human health. The phenolic compounds identified in propolis from Bangladesh were effective against tetracycline-induced hepatic and renal toxicity. Propolis may be a promising natural product in reducing the effects of chronic liver and kidney damage.

Relationship between serum uric acid and hypertension: a cross-sectional study in Bangladeshi adults.

Experimental evidence suggests a causal role of serum uric acid (SUA) in hypertension development. Currently, there are few data available on the association between SUA and hypertension; data from Bangladeshi adults are not available yet. This study evaluated the association of SUA with hypertension among Bangladeshi adults. Blood samples were obtained from 140 males and 115 females and analyzed for SUA and lipid levels. Hypertension was defined as SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg. All participants were divided into four quartiles based on SUA concentrations. Association of SUA with hypertension was evaluated by logistic regression models. The prevalence of hypertension and prehypertension was significantly higher in male (15.4 and 47.6%, respectively) than in the female (5.6 and 33.4%, respectively) subjects (p < 0.01). Males had a higher mean level of SUA (310.7 ± 67.9 µmol/L) than in the females (255.3 ± 69.3 µmol/L) (p < 0.001). Hyperuricemia was prevalent 9.1% in males and 10.3% in females. An increasing trend for hypertension and prehypertension was found in both genders with increasing SUA levels in the quartiles (p < 0.01). SUA levels in the quartiles were positively correlated with blood pressure (p < 0.01). After adjusting for baseline covariates, SUA levels were significantly associated with hypertension (p < 0.01). Findings of this study indicate the significance of maintaining normal SUA level to prevent hypertension.

Prevalence of hyperuricemia and the relationship between serum uric acid and obesity: A study on Bangladeshi adults.

BACKGROUND AND OBJECTIVES: Recent studies have shown that hyperuricemia is commonly associated with dyslipidemia, cardiovascular diseases, hypertension and metabolic syndrome. Elevated serum uric acid has been demonstrated to be associated with obesity in the adult population in many countries; however, there is still a lack of evidence for the Bangladeshi population. The aims of this study were to evaluate the prevalence of hyperuricemia and determine the relationship between serum uric acid (SUA) and obesity among the Bangladeshi adults. METHODS: In this cross-sectional study, blood samples were collected from 260 adults (142 males and 118 females) and analyzed for SUA and lipid profile. All participants were categorized as underweight (n = 11), normal (n = 66), overweight (n = 120) and obese (n = 63) according to the body mass index (BMI) scale for the Asian population. Based on SUA concentration the participants were stratified into four quartiles (Q1: < 232 µmol/L, Q2: 232-291 µmol/L, Q3: 292-345 µmol/L and Q4: > 345 µmol/L). RESULTS: The mean age and BMI of the participants were 32.5 ± 13.3 years and 24.9 ± 3.8 kg/m2, respectively. The average level of SUA was 294 ± 90 µmol/L with a significant difference between males and females (p < 0.001). Overall, the estimated prevalence of hyperuricemia was 9.3% with 8.4% in male and 10.2% in female participants. There were significant increases in the prevalence of obesity (17.4%, 22.2%, 28.6% and 31.8%, respectively, p < 0.01 for trend) across the SUA quartiles. A multiple logistic regression analysis revealed that SUA quartiles were independently associated with the presence of obesity (p < 0.01). CONCLUSION: Present study indicates a significant positive relationship between SUA and obesity among the Bangladeshi adults. Therefore, routine measurement of SUA is recommended in obese individuals to prevent hyperuricemia and its related complications.

Hypertension prevalence and influence of basal metabolic rate on blood pressure among adult students in Bangladesh.

BACKGROUND: Hypertension is a global health issue and is currently increasing at rapid pace in South Asian countries including Bangladesh. Although, some studies on hypertension have been conducted in Bangladesh, there is a lack of scientific evidence in the adult student population that was missing from the previous and recent national cross-sectional studies. Moreover, the specific risk factors of hypertension in the Bangladeshi adults still need to be investigated. This study was conducted to estimate hypertension prevalence among adult students in Bangladesh and to test the hypothesis of Luke et al. (Hypertension 43:555-560, 2004) that basal metabolic rate (BMR) and blood pressure are positively associated independent of body size. METHOD: The data was collected on 184 adult university students (118 female and 66 male) in Dhaka, Bangladesh. Anthropometric, BMR details and an average of at least two blood pressure measurements were obtained. Hypertension was defined by a systolic blood pressure (SBP) ≥ 140 mmHg and/or, diastolic blood pressure (DBP) ≥ 90 mmHg. RESULTS: Overall, 6.5% of participants had hypertension with significantly (p < 0.001) higher prevalence in male (12.1%) than in the female (3.4%) students. Age and BMI showed positive and significant correlation with hypertension among the students. When adjusted for body mass index (BMI), as well as other potentially confounding variables such as age, sex, smoking status and degree of urbanization, BMR was positively correlated with SBP and DBP (p < 0.001). Thus, higher BMR is associated with SBP and DBP; this is opposite the well documented inverse relationship between physical activity and blood pressure. If the influence of BMR on blood pressure is confirmed, the systematically elevated BMR might be an important predictor that can explain relatively high blood pressure and hypertension in humans. CONCLUSION: This study reports the prevalence and associated risk factors of hypertension in the Bangladeshi adult students. The study also showed a positive association between BMR and blood pressure among the participants. A large scale longitudinal study across the country is needed to find out the underlying causes of hypertension in the Bangladeshi adults. In addition, comprehensive and integrated intervention programs focusing on modifiable risk factors are recommended to make awareness and prevent hypertension.

Vitamin D and Parathyroid Hormone Status in Female Garment Workers: A Case-Control Study in Bangladesh.

Despite the abundant sunlight, vitamin D deficiency is prevalent in South Asian countries including Bangladesh. Information on vitamin D level is insufficient in adults particularly in female garment workers in Bangladesh. This study was designed to evaluate the status of vitamin D, parathormone (PTH), calcium, and alkaline phosphatase (ALP) among the female garment workers in Bangladesh. Blood samples were collected from female garment workers (n = 40, case group) and general female workers (n = 40, control group) in Dhaka. Serum vitamin D, PTH, calcium, and ALP were measured by chemiluminescence microparticle immunoassay. The mean level of vitamin D was significantly (p < 0.001) lower in case (14.2 ± 2.6 ng/mL) than in the control (22.4 ± 2.4 ng/mL) group. No significant difference was found at mean of PTH and calcium between case (33.9 ± 17.2 pg/mL; 9.1 ± 0.6 mg/dL, resp.) and control (35.9 ± 16.3 pg/mL; 9.3 ± 0.6 mg/dL, resp.) group. The mean ALP in case (117.2 ± 14.4 U/L) group was significantly (p < 0.001) higher than the control group (80.5 ± 30.6 U/L). Overall, PTH level did not show significant correlation with vitamin D. However, calcium and ALP levels showed a significant positive (p < 0.05) and negative (p < 0.001) correlation with vitamin D, respectively. This study indicates a high prevalence of vitamin D deficiency in the female garment workers in Bangladesh.

Biomonitoring of ochratoxin A in blood plasma and exposure assessment of adult students in Bangladesh.

SCOPE: Ochratoxin A (OTA), a mycotoxin known for its nephrotoxic, immunotoxic, and carcinogenic effects in animals, deserves attention due to its widespread occurrence as food and feed contaminant. Studies in many countries report the presence of OTA in human blood plasma or serum at variable levels. However, no biomonitoring study has been carried out in so far, and also food analysis data are insufficient to assess OTA exposure. METHODS AND RESULTS: Therefore, 64 blood samples were collected from healthy university students (32 female, 32 male) in Bangladesh for biomarker analysis. OTA and its metabolite ochratoxin alpha were determined in the plasma samples by a validated method using HPLC-fluorescence analysis. After liquid-liquid extraction, OTA was detected in all plasma samples (100%) at a range of 0.20-6.63 ng/mL and ochratoxin alpha was detected in 95% of the samples at 0.10-0.79 ng/mL. The OTA mean level in plasma of males (0.92 ± 1.09 ng/mL) and females (0.78 ± 1.02) were not significantly different. Statistical analysis of food consumption data for the participants, provided in a food frequency questionnaire, did not reveal a significant association between OTA level in plasma and their intake of typical staple foods (rice, wheat, maize, and lentil). CONCLUSION: The dietary intake of OTA (mean 11.7, max 91.7 ng/kg b.w./wk) calculated on the basis of plasma concentration in Bangladeshi students was lower than the tolerable weekly OTA intake (120 ng/kg b.w./wk) set by EFSA. Nonetheless, further biomonitoring is recommended in cohorts from other parts of the country that may have higher mycotoxin exposure than the present group.