Polymorphism of stress protein HSP70-2 gene in Tunisians: susceptibility implications in type 2 diabetes and obesity

The role of heat shock proteins (HSPs) in type 2 diabetes mellitus pathophysiology

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by sustained hyperglycemia caused by impaired insulin signaling and secretion. Metabolic stress, caused by an inappropriate diet, is one of the major hallmarks provoking inflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Heat shock proteins (HSPs) are a group of highly conserved proteins that have a crucial role in chaperoning damaged and misfolded proteins to avoid disruption of cellular homeostasis under stress conditions. To do this, HSPs interact with diverse intra-and extracellular pathways among which are the insulin signaling, insulin secretion, and apoptosis pathways. Therefore, HSP dysfunction, e.g. HSP70, may lead to disruption of the pathways responsible for insulin secretion and uptake. Consistently, the altered expression of other HSPs and genetic polymorphisms in HSP-producing genes in diabetic subjects has made HSPs hot research in T2DM. This paper provides a comprehensive overview of the role of different HSPs in T2DM pathogenesis, affected cellular pathways, and the potential therapeutic strategies targeting HSPs in T2DM.

Emerging role of heat shock proteins in cardiovascular diseases

Heat Shock Proteins (HSPs) are evolutionarily conserved proteins from prokaryotes to eukaryotes. They are ubiquitous proteins involved in key physiological and cellular pathways (viz. inflammation, immunity and apoptosis). Indeed, the survivability of the cells under various stressful conditions depends on appropriate levels of HSP expression. There is a growing line of evidence for the role of HSPs in regulating cardiovascular diseases (CVDs) (viz. hypertension, atherosclerosis, atrial fibrillation, cardiomyopathy and heart failure). Furthermore, studies indicate that a higher concentration of circulatory HSP antibodies correlate to CVDs; some are even potential markers for CVDs. The multifaceted roles of HSPs in regulating cellular signaling necessitate unraveling their links to pathophysiology of CVDs. This review aims to consolidate our understanding of transcriptional (via multiple transcription factors including HSF-1, NF-κB, CREB and STAT3) and post-transcriptional (via microRNAs including miR-1, miR-21 and miR-24) regulation of HSPs. The cytoprotective nature of HSPs catapults them to the limelight as modulators of cell survival. Yet another attractive prospect is the development of new therapeutic strategies against cardiovascular diseases (from hypertension to heart failure) by targeting the regulation of HSPs. Moreover, this review provides insights into how genetic variation of HSPs can contribute to the manifestation of CVDs. It would also offer a bird's eye view of the evolving role of different HSPs in the modulation and manifestation of cardiovascular disease.

Interaction of HSP70-2 gene polymorphism with body mass index and alcohol consumption on the prognosis of Uyghur patients with ischemic heart failure

OBJECTIVES

To investigate the interaction of HSP70-2 gene polymorphism with body mass index (BMI) and alcohol consumption on the prognosis of Uyghur patients with ischemic heart failure (IHF).

METHODS

A total of 205 Uyghur patients with IHF admitted in Urumqi Friendship Hospital from June 2014 to June 2017 were enrolled; 200 age and sex-matched healthy Uyghur physical examiners in the hospital were enrolled as healthy controls. The HSP70-2 gene +1267 polymorphism was detected by PCR. Multivariate unconditional logistic regression was used to analyze the risk factors associated with prognosis in patients with IHF, and the relative excess risk of interaction (RERI) was calculated by crossover analysis to determine the interaction of HSP70-2 gene polymorphism with BMI and alcohol consumption.

RESULTS

Patients were followed up for 3 years, there were 56 cases with poor prognosis (27.32%) and 149 cases with good prognosis (72.68%). Compared with the healthy control group and the good prognosis group, the poor prognosis group had a significantly higher proportion of subjects with alcohol consumption, abnormal alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels as well as lower BMI and left ventricular ejection fraction (all P<0.05). There were significant differences in distributions of HSP70-2 genotype AA/AG/GG and A/G allele between the good prognosis group and the poor prognosis group (both P<0.05). There were significant differences in the distribution of HSP70-2 genotype (χ2=45.42, P<0.01) and A/G allele among IHF patients with different NYHA cardiac function class; the frequency of A allele of HSP70-2 gene increased, and G allele decreased with the increase of cardiac function class (χ2=19.14, P<0.01). Multivariate logistic regression analysis showed that alcohol consumption as well as abnormal ALT and AST were risk factors for poor prognosis in patients with IHF, while BMI and GG type of HSP70-2 gene (compared with AA type) were protective factors (all P<0.05). Crossover analysis showed a significant additive interaction between BMI and HSP70-2 gene polymorphism (RERI=1.15, 95%CI: 0.54-1.76, P<0.01), and for patients carrying HSP70-2 gene type AA/AG, BMI<26.5 kg/m2 increased the risk of poor prognosis (OR=7.47, 95%CI: 2.51-22.22, P<0.01); there was no significant additive interaction between alcohol consumption and HSP70-2 gene polymorphism (RERI=0.56, 95%CI: －6.07-7.20, P>0.05).

CONCLUSIONS

The HSP70-2 gene polymorphism interacts with BMI in Uyghur IHF patients, and BMI<26.5 kg/m2 increases the risk of poor prognosis in IHF patients carrying the HSP70-2 AA/AG genotype.

Sleeve gastrectomy improves lipid dysmetabolism by downregulating the USP20-HSPA2 axis in diet-induced obese mice

INTRODUCTION

Obesity is a metabolic disease accompanied by abnormalities in lipid metabolism that can cause hyperlipidemia, non-alcoholic fatty liver disease, and artery atherosclerosis. Sleeve gastrectomy (SG) is a type of bariatric surgery that can effectively treat obesity and improve lipid metabolism. However, its specific underlying mechanism remains elusive.

METHODS

We performed SG, and sham surgery on two groups of diet-induced obese mice. Histology and lipid analysis were used to evaluate operation effect. Immunohistochemistry, immunoblotting, real-time quantitative PCR, immunoprecipitation, immunofluorescence and mass spectrometry were used to reveal the potential mechanisms of SG.

RESULTS

Compared to the sham group, the SG group displayed a downregulation of deubiquitinase ubiquitin-specific peptidase 20 (USP20). Moreover, USP20 could promote lipid accumulation in vitro. Co-immunoprecipitation and mass spectrometry analyses showed that heat-shock protein family A member 2 (HSPA2) potentially acts as a substrate of USP20. HSPA2 was also downregulated in the SG group and could promote lipid accumulation in vitro. Further research showed that USP20 targeted and stabilized HSPA2 via the ubiquitin-proteasome pathway.

CONCLUSION

The downregulation of the USP20-HSPA2 axis in diet-induced obese mice following SG improved lipid dysmetabolism, indicating that USP20-HSPA2 axis was a noninvasive therapeutic target to be investigated in the future.

Response to oxidative stress of peripheral blood mononuclear cells from multiple sclerosis patients and healthy controls

The complex scenario of multiple sclerosis (MS) pathology involves several mechanisms, including oxidative stress response. The heat shock proteins (HSPs) are important for the protection of the cells; however, their role in MS is not clear. The present research is focused on the response of peripheral blood mononuclear cells (PBMCs) to oxidative stress and to the involvement of HSP70-2 (a protein coded by the HSPA1B gene, located in the MHC class III). To this aim, we challenged PBMCs from MS patients and healthy controls with hydrogen peroxide. Specifically, PBMCs mitochondrial activity, HSP70-2 protein expression and the production of intracellular reactive oxygen species were assessed. These parameters were also related to the HSP70-2 rs1061581 polymorphism, which is linked to the risk of developing MS. Moreover, mitochondrial activity and HSP70-2 protein levels were also related to disease severity. Overall, our results indicate that PBMCs, from both MS patients and healthy controls, may display a similar response towards an oxidative insult; within this context, HSP70-2 does not seem to be central in the protection of PBMCs. Nevertheless, the HSP70-2 rs1061581 polymorphism is related to ROS levels and appears to have a role in the different expression of HSP70-2 under oxidative stimulus.

The association of TNF-α -308G/A and -238G/A polymorphisms with type 2 diabetes mellitus: a meta-analysis

Tumor necrosis factor-α (TNF-α) is involved in insulin resistance and has long been a candidate gene implicated in type 2 diabetes mellitus (T2DM), however the association between TNF-α polymorphisms -308G/A and -238G/A and T2DM remains controversial. The present study sought to verify associations between these polymorphisms and T2DM susceptibility using a meta-analysis approach. A total of 49 case-control studies were selected up to October 2018. Statistical analyses were performed by STATA 15.0 software. The odds ratios (ORs) and 95% confidence intervals were calculated to estimate associations. Meta-analyses revealed significant associations between TNF-α -308G/A and T2DM in the allele model (P=0.000); the dominant model (P=0.000); the recessive model (P=0.001); the overdominant model (P=0.008) and the codominant model (P=0.000). Subgroup analyses also showed associations in the allele model (P=0.006); the dominant model (P=0.004) and the overdominant model (P=0.005) in the Caucasian and in the allele model (P=0.007); the dominant model (P=0.014); the recessive model (P=0.000) and the codominant model (P=0.000) in the Asian. There were no associations between TNF-α -238G/A and T2DM in the overall and subgroup populations. Meta-regression, sensitivity analysis and publication bias analysis confirmed that results and data were statistically robust. Our meta-analysis suggests that TNF-α -308G/A is a risk factor for T2DM in Caucasian and Asian populations. It also indicates that TNF-α -238G/A may not be a risk factor for T2DM. More comprehensive studies will be required to confirm these associations.

Heat Shock Protein 70 and The Risk of Multiple Sclerosis in The Iranian Population

Multiple sclerosis (MS) is a chronic disease of the central nervous system and one of the most common causes of neurological disability among those aged 20-40 years, particularly in women. Major histocompatibility complex (MHC) Class II genes are known to be involved in the development of MS. One of the important groups of this complex is the HSP gene family, especially HSP70, which is induced under stress conditions. The aim of the present case-control study was to determine the association between the heat shock protein 70 (HSP70) and risk of MS in Iranian patients by genotyping the rs1061581 gene polymorphism. A total of 50 relapsing-remitting MS (RRMS) patients and 50 healthy control subjects were considered for this study. Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR- RFLP) method. PCR-RFLP results of twenty-five randomly selected samples were confirmed by DNA sequencing. Genotypic and allelic distributions were compared between the case and control groups. We observed no significant difference in the distribution of rs1061581 genotype and allele frequencies between RRMS patients and controls. In addition, there was no association between the HSP70 gene polymorphism and the clinical variables in the case group. Our data indicate that HSP70, in particular rs1061581, is unlikely to be involved in the susceptibility to or the severity of RRMS in Iranian patients. Further large prospective studies are required to confirm these findings.

Association of A1538G and C2437T single nucleotide polymorphisms in heat shock protein-70 genes with diabetic nephropathy among South Indian population

Diabetic Nephropathy (DN) is the leading cause of end-stage renal disease, characterized by progressive albuminuria and conferring additional risk of cardiovascular disease (CVD) and mortality. The crucial role of heat-shock proteins (HSPs) on renal function in patients with DN has been well documented. The present study was aimed to understand the association of HSP-70 gene variants on the susceptibility of Type 2 Diabetes Mellitus (T2DM) and DN. A total of 946 subjects (549 Males; 397 Females) were recruited and divided into four groups according to the levels of urinary albumin excretion (UAE): those with normoalbuminuria (UAE <30 mg/24 h; n=230), those with microalbuminuria (30≤ UAE ≤300 mg/24 h; n=230), and those with macroalbuminuria (UAE> 300 mg/24 h; n=230). The control group randomly enrolled a consecutive population of 256 healthy subjects who had a routine medical check-up in our hospital. Those subjects had no history or clinical symptoms of diabetes. Subjects were genotyped for HSP70-2 (+1538 A/G; rs2763979) and HSP70-hom (+2437 C/T; rs2227956) by PCR-restriction fragment length polymorphism (RFLP). The ‘G’ allele of HSP70-2 (+1538 A/G) single nucleotide polymorphism (SNP) showed relative risk for normoalbuminuria, microalbuminuria and macroalbuminuria subjects whereas the ‘T’ allele of HSP70-hom (+2437 C/T) SNP showed significant protection against macroalbuminuria subjects. In conclusion, our results indicate that the HSP70-2 (+1538 A/G) and HSP70-hom (+2437 C/T) SNPs are highly associated with renal complications in T2DM among the South Indian population.

Genetic risk of type 2 diabetes in populations of the African continent: A systematic review and meta-analyses

BACKGROUND

Type 2 diabetes (T2D) is growing faster in Africa than anywhere else, driven by the dual effects of genetic and environmental factors. We conducted a systematic review and meta-analyses of published studies on genetic markers of T2D in populations within Africa.

METHODS

Multiple databases were searched for studies of genetic variants associated with T2D in populations living in Africa. Studies reporting on the association of a genetic marker with T2D or indicators of glycaemia were included. Data were extracted on study design and characteristics, genetic determinants, effect estimates of associations with T2D.

FINDINGS

Overall, 100 polymorphisms in 57 genes have been investigated in relation with T2D in populations within Africa, in 60 studies. Almost all studies used the candidate gene approach, with >88% published during 2006-2014 and 70% (42/60) originating from Tunisia and Egypt. Polymorphisms in ACE, AGRP, eNOS, GSTP1, HSP70-2, MC4R, MTHFR, PHLPP, POL1, TCF7L2, and TNF-α gene were found to be associated with T2D, with overlapping effect on various cardiometabolic traits. The polymorphisms investigated in multiple studies mostly had consistent effects across studies, with only modest or no statistical heterogeneity. Effect sizes were modestly significant [e.g., odd ratio 1.49 (95%CI 1.33-1.66) for TCF7L2 (rs7903146)]. Underpowered genome-wide studies revealed no diabetes risk loci specific to African populations.

INTERPRETATION

Current evidence on the genetic markers of T2D in African populations mostly originate from North African countries, is overall scanty and largely insufficient to reliably inform the genetic architecture of T2D across Africa.

Relationship between HSP70-2 A+1267G Polymorphism and Cardiovascular Events of Chinese Peritoneal Dialysis Patients

BACKGROUND

Heat shock proteins (HSPs) are expressed by cells in response to various environmental stresses. A single-nucleotide polymorphism A+1267G of the HSPA1B gene affects the expression of HSP70-2, with the A allele being protective against inflammatory conditions. We investigated the relation between the HSP A+1267G polymorphism and the clinical outcomes of Chinese peritoneal dialysis (PD) patients.

METHODS

We studied 347 new PD cases (181 males, age 56.6 ± 13.7 years). Genotyping was done by standard methods. Patients were followed for 40.5 ± 20.7 months for survival analysis.

RESULTS

For the entire cohort, there was no difference in the 5-year survival between genotype groups. However, there was a significant interaction between HSP polymorphism and diabetic status on the cardiovascular event-free survival. In patients without pre-existing diabetes, 5-year cardiovascular event-free survival of the GG/AG genotype group was significantly better than that of the AA genotype group (57.2 vs. 32.1%, p = 0.011).

CONCLUSION

The G allele of the HSP70-2 A+1267G polymorphism confers survival advantages in non-diabetic PD patients. The role of HSP in the pathogenesis of cardiovascular disease in renal failure patients needs further investigation.

Mild Electrical Stimulation with Heat Shock Reduces Visceral Adiposity and Improves Metabolic Abnormalities in Subjects with Metabolic Syndrome or Type 2 Diabetes: Randomized Crossover Trials

Background

The induction of heat shock protein (HSP) 72 by mild electrical stimulation with heat shock (MES + HS), which improves visceral adiposity and insulin resistance in mice, may be beneficial in treating metabolic syndrome (MS) or type 2 diabetes mellitus (T2DM).

Methods

Using open-label crossover trials, 40 subjects with MS or T2DM were randomly assigned using computer-generated random numbers to 12 weeks of therapeutic MES + HS followed by 12 weeks of no treatment, or vice versa. During the intervention period, physical and biochemical markers were measured.

Findings

Compared to no treatment, MES + HS treatment was associated with a significant decrease in visceral adiposity (− 7.54 cm² (− 8.61%), 95% CI − 8.55 to − 6.53 (p = 0.037) in MS, − 19.73 cm² (− 10.89%), 95% CI − 20.97 to − 18.49 (p = 0.003) in T2DM). Fasting plasma glucose levels were decreased by 3.74 mg/dL (− 5.28%: 95% CI − 4.37 to − 3.09 mg/dL, p = 0.029) in MS and by 14.97 mg/dL (10.40%: 95% CI − 15.79 to 14.15 mg/dL, p < 0.001) in T2DM, and insulin levels were also reduced by 10.39% and 25.93%, respectively. HbA1c levels showed a trend toward reduction (− 0.06%) in MS, and was significantly declined by − 0.43% (95% CI − 0.55 to − 0.31%, p = 0.009) in T2DM. HbA1c level of less than 7.0% was achieved in 52.5% of the MES + HS-treated T2DM patients in contrast to 15% of the non-treated period. Several insulin resistance indices, inflammatory cytokines or adipokines, including C-reactive protein, adiponectin, and tumor necrosis factor-α, were all improved in both groups. In isolated monocytes, HSP72 expression was increased and cytokine expression was reduced following MES + HS treatment. Glucose excursions on meal tolerance test were lower after using MES + HS in T2DM.

Interpretation

This combination therapy has beneficial impacts on body composition, metabolic abnormalities, and inflammation in subjects with MS or T2DM. Activation of the heat shock response by MES + HS may provide a novel approach for the treatment of lifestyle-related diseases.

Funding

Funding for this research was provided by MEXT KAKENHI (Grants-in-Aid for Scientific Research from Ministry of Education, Culture, Sports, Science and Technology, Japan).

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We report the use of mild electrical stimulation with heat shock (MES + HS) in treating metabolic syndrome or type 2 diabetes.

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The treatment improves visceral adiposity, glucose homeostasis, insulin resistance and chronic inflammatory status.

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Our findings suggest that MES + HS might be a valuable therapeutic option for patients with these lifestyle-related diseases.

Are Hsp70 protein expression and genetic polymorphism implicated in multiple sclerosis inflammation?

Genetic and environmental factors contribute to disease Multiple Sclerosis (MS) susceptibility, the most prevalent neurological pathology affecting young individuals in Western countries. We focused our attention on HSP70-2, an inducible chaperon induced under stress conditions. Genotype analysis of HSP70-2 (+1267 A/G) polymorphism revealed a significant association between the minor allele G and presence of MS (OR:1.31, 95% CI: 1.02-1.69, P = 0.039). In addition, Hsp70-2 protein content in vitro from PBMC was significantly lower in MS patients with GG genotype compared to AA genotype, indicating an implication of the G allele of HSP70-2 gene polymorphism in the development of MS.

Crohn's disease and polymorphism of heat shock protein gene HSP70-2 in the Chinese population

BACKGROUND AND AIMS

Crohn's disease (CD) is a multifactorial disorder with a pivotal role of the genetic component. A single nucleotide polymorphism in heat shock protein 70-2 (HSP70-2) has been shown to be associated with a severe clinical course in CD. The purpose of this study was to identify associations between the HSP70-2 polymorphism and the clinical courses of CD in the Chinese population.

METHODS

One hundred patients with CD and 190 healthy individuals were genotyped for the HSP70-2 PstI polymorphism by restriction fragment length polymorphism analysis.

RESULTS

The genotype frequency of the PstI polymorphism did not differ between patients and controls. The A allele was higher in CD patients than in controls (61% vs 52%, P = 0.047, odds ratio [OR] = 1.423, 95% confidence interval [CI]: 1.004-2.015). Furthermore, this polymorphism was higher in the penetrating or fistula surgery of CD patients than in controls (63% vs 52%, P = 0.049, OR = 1.530, 95% CI: 1.001-2.337; Table ). But there was no significant difference between the penetrating or fistula surgery patients and no surgery patients (P = 0.673, OR = 0.883, 95% CI: 0.495-1.574). We used multivariate analysis to determine the effects of genotypes on sex, disease behavior, disease location, and so on. No significant difference was observed between these parameters and genotype.

CONCLUSION

This study reported that the allele A of PstI polymorphism was the association between CD and HSP70-2 gene in the Chinese population. It was also association between penetrating or fistula surgery of CD and HSP70-2 gene in the Chinese population.

Hsp70-2 gene polymorphism: susceptibility implication in Tunisian patients with coronary artery disease

Abstract

Coronary artery disease (CAD) is a multifactorial disease where genetic and environmental factors interact in complex ways to cause the disease. Heat shock protein genes are involved in the progress of CAD. This implies that genetic variants of Hsp70–2 genes might contribute to the development of the CAD.

Aim of study

The aim of this study was to characterize statistical correlation of linkage between lipid profiles, polymorphism PstI site of Hsp70–2 gene and CAD.

Patients and methods

This study was carried out on Tunisian patients with CAD recruited from Hospital of Fattouma Bourguiba of Monastir-Tunisia. Polymerase chain reaction and restriction enzymes were used to determine the genotypic distributions in 252 unrelated patients and 151 healthy control subjects. Further, ApoA-I and ApoB as well as the serum total of cholesterol, HDL, triglyceride, and hs-CRP levels were measured.

Results

We showed a decreased level of ApoA-I, whereas the levels of each of ApoB and hs-CRP were increased in patients with CAD compared with control group. In addition our studies of a polymorphic PstI site of Hsp70-2 gene at position 1267 of the Hsp70–2 gene have revealed that the allelic frequency of P2 was significantly more frequent in CAD patients than controls group (p=0.007, OR=1.495). The genotypic distribution showed a high incidence of P2/P2 genotype in CAD patients (0.190) compared to healthy control (0.009) with reach significant difference (p=0.006). The P2 carriers showed a significantly increased of Total-Cholesterol (CT) and C-reactive protein (hs-CRP) levels in CAD patients (p=0.008 and p=0.018, respectively).

Conclusion

The high incidence of P2-Hsp70-2 genotype in CAD patients and the significantly association of P2/P2 genotype with elevated Total Cholesterol and hs-CRP levels, supported that P2–Hsp70–2 genotype has susceptibility implication in CAD and could increased the risk of CAD in Tunisian population.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1118340895703689

Genetic polymorphisms in adipokine genes and the risk of obesity: a systematic review and meta-analysis

Polymorphisms in adipokine genes, such as leptin (LEP), leptin receptor (LEPR), resistin (RETN), adiponectin (ADIPOQ), interleukin-1β (IL-1β), IL-6 (IL-6), and tumor necrosis factor-α (TNF-α) may be involved in the development of obesity. We conducted a systematic review of published evidence on the association between different adipokine genes and the risk of obesity. Librarian-designed searches of PubMed and HuGeNet, review of reference lists from published reviews and content expert advice identified potentially eligible studies. The genotyping information and polymorphisms of different adipokine genes, numbers of genotyped cases and controls and frequencies of genotypes were extracted from 48 eligible studies included in this review. Twenty-one polymorphisms each associated with obesity in at least one study were identified. Polymorphisms in the adipokine genes, LEP, LEPR, and RETN were not associated with obesity susceptibility, whereas ADIPOQ G276T (T vs. G: odds ratio (OR), 1.59; 95% confidence interval (CI), 1.39-1.81), IL-1β C3953T (CC vs. CT+TT: OR, 1.61; 95% CI, 1.18-2.20), and TNF-α G308A (GG vs. GA+AA: OR, 1.19; 95% CI, 1.02-1.39) polymorphisms were associated with an increased risk of obesity. The IL-6 G174C polymorphism was also associated obesity when using allelic comparisons, the recessive genetic model and the dominant genetic model with OR (95% CI) of 1.95 (1.37-2.77), 1.44 (1.15-1.80), and 1.36 (1.16-1.59), respectively. No significant evidence of publication bias was present. However, these "null" results were underpowered due to a small pooled sample size, and analysis of additional case-control studies with larger sample sizes should provide further clarifications.

Increased serum HSP70 levels are associated with the duration of diabetes

The evolutionary conserved family of heat shock proteins (HSP) is responsible for protecting cells against different types of stress, including oxidative stress. Although the levels of HSPs can be readily measured in blood serum, the levels of HSP70 in patients with different durations of diabetes have not been studied before. We quantified serum HSP70 levels in a healthy control group (n = 36) and two groups of type 2 diabetic patients, defined as newly diagnosed diabetes (n = 36) and patients with diabetes duration of more than 5 years (n = 37). The clinical characteristics and biochemical parameters were evaluated in the studied population. We found that serum HSP70 levels were significantly higher in patients with diabetes when compared with controls (p < 0.001) and it was higher in patients with disease for more than 5 years than in newly diagnosed patients (p < 0.001). Serum HSP70 was inversely correlated with fasting blood sugar in patients with diabetes for more than 5 years (r = -0.500, p = 0.002), positively correlated with the history of hypertension in newly diagnosed patients (p < 0.001), and positively correlated with age in patients with diabetes (r = 0.531, p = 0.001). Serum level of HSP70 is significantly higher in patients with diabetes and correlates with the duration of disease. Higher HSP70 in prolonged diabetes versus newly diagnosed diabetes may be an indicator of metabolic derangement in the course of diabetes.

Study of TNFalpha -308G/A and IL6 -174G/C polymorphisms in type 2 diabetes and obesity risk in the Tunisian population

OBJECTIVES

We investigated two genetic markers in pro inflammatory molecules : TNFalpha -308G/A and IL6 -174G/C in order to assess their effect on type 2 diabetes (T2D) and obesity in the Tunisian population.

DESIGN AND METHODS

The study sample includes 228 patients with T2D and 300 healthy controls. Genotyping of IL6 -174G/C (rs1800795) was performed using Automated Dye Terminator Sequencing and of TNFalpha -308G/A (rs1800629) using the LightTyper technology.

RESULTS

SNPs IL6 -174G/C and TNFalpha -308G/A are associated neither with T2D (p=0.89, p=0.34 respectively) nor with risk for overweight (p=0.86, p=0.12 respectively) in Tunisian population. Bonferroni correction showed that the founded association of IL6 -174G/C SNP with T2D susceptibility restricted to overweight patients (p(nominal)=0.03, p(corrected)=0.0033) is likely to be a random result.

CONCLUSION

SNPs IL6 -174G/C and TNFalpha -308G/A are not major contributors to T2D or obesity risk in our Tunisian population.

Heat-shock protein gene polymorphisms and the risk of nephropathy in patients with Type 2 diabetes

HSPs (heat-shock proteins) are molecular chaperones synthesized under stress conditions, and are involved in renal cell survival and matrix remodelling in acute and chronic renal diseases. In the present study, we investigated whether the HSP70 gene polymorphisms affect susceptibility to DN (diabetic nephropathy) in patients with T2DM (Type 2 diabetes mellitus). The study group consisted of 452 patients with nephropathy. Two control subgroups involved 340 healthy individuals and 132 patients with T2DM lasting > or =10 years who were free of nephropathy. Subjects were genotyped for the HSP70-1 +190 G/C and -110 A/C, HSP70-2 +1267 A/G and HSP70-hom +2437 T/C polymorphisms by PCR, followed by digestion with restriction endonucleases. There were no statistically significant differences in genotype distribution between patients with T2DM with DN and controls for the HSP70-hom polymorphism. Significant differences were observed for HSP70-1 and HSP70-2 polymorphisms. CC homozygotes of the -110 and +190 HSP70-1 polymorphisms were more frequent in patients with T2DM with DN compared with healthy controls (22 compared with 6% and 15 compared with 6.5% respectively; P<0.01). The OR (odds ratio) for the risk allele was 2.17 [95% CI (confidence interval), 1.73-2.72] for the -110 A/C and 1.74 (95% CI, 1.40-2.15) for +190 G/C polymorphisms. A strong association with DN was found for the +1267 HSP70-2 polymorphism. The GG genotype and the G allele were associated with DN, with the OR for the G allele being 4.77 (95% CI, 3.81-5.96). All GG homozygotes in the patient group had higher LDL (low-density lipoprotein)-cholesterol levels than AA homozygotes (P<0.01), suggesting that the observed effect might be associated with this cardiovascular risk factor. These patients progressed faster to end-stage renal failure than those with other genotypes. In conclusion, our results indicate that the HSP70-1 and HSP70-2 polymorphisms are associated with renal complications in T2DM and may be useful in identifying patients with increased risk of DN.

Regular thermal therapy may promote insulin sensitivity while boosting expression of endothelial nitric oxide synthase--effects comparable to those of exercise training

Regular thermal therapy, using saunas or hot baths, has the potential to improve impaired insulin sensitivity and boost endothelial expression of the "constitutive" isoform of nitric oxide synthase--effects, analogous to those of aerobic training that should promote vascular health. Previous clinical reports suggest that hot tubs may be beneficial for diabetic control, and that sauna therapy can decrease blood pressure in essential hypertension and provide symptomatic benefit in congestive heart failure. For those who lack ready access to a sauna or communal hot tub, regular hot baths at home may suffice as practical thermal therapy. Thermal therapy might be viewed as an alternative to exercise training in patients too physically impaired for significant aerobic activity.

Crohn's disease and polymorphism of heat shock protein gene HSP70-2 in the Tunisian population

BACKGROUND AND AIMS

Crohn's disease is a multifactorial disorder with a pivotal role of the genetic component. HSP70-2 gene, located in IBD3 region, has a PstI polymorphic site associated recently with Crohn's disease especially with a perforating form. In this study, we sought to determine whether this polymorphism was associated with Crohn's disease in the Tunisian population and its correlation with clinical manifestation of the disease.

METHODS

In all, 148 patients with Crohn's disease and 81 healthy individuals were genotyped for the HSP70-2 PstI polymorphism by restriction fragment length polymorphism analysis.

RESULTS

The allele and genotype frequency of the PstI polymorphism did not differ between patients and controls. Furthermore, this polymorphism was not associated with specific disease behavior.

CONCLUSION

This study reported the absence of association between Crohn's disease and HSP70-2 gene in the Tunisian population. The allele A of PstI polymorphism was not associated with phenotype of the disease.

Screening of 134 single nucleotide polymorphisms (SNPs) previously associated with type 2 diabetes replicates association with 12 SNPs in nine genes

More than 120 published reports have described associations between single nucleotide polymorphisms (SNPs) and type 2 diabetes. However, multiple studies of the same variant have often been discordant. From a literature search, we identified previously reported type 2 diabetes-associated SNPs. We initially genotyped 134 SNPs on 786 index case subjects from type 2 diabetes families and 617 control subjects with normal glucose tolerance from Finland and excluded from analysis 20 SNPs in strong linkage disequilibrium (r(2) > 0.8) with another typed SNP. Of the 114 SNPs examined, we followed up the 20 most significant SNPs (P < 0.10) on an additional 384 case subjects and 366 control subjects from a population-based study in Finland. In the combined data, we replicated association (P < 0.05) for 12 SNPs: PPARG Pro12Ala and His447, KCNJ11 Glu23Lys and rs5210, TNF -857, SLC2A2 Ile110Thr, HNF1A/TCF1 rs2701175 and GE117881_360, PCK1 -232, NEUROD1 Thr45Ala, IL6 -598, and ENPP1 Lys121Gln. The replication of 12 SNPs of 114 tested was significantly greater than expected by chance under the null hypothesis of no association (P = 0.012). We observed that SNPs from genes that had three or more previous reports of association were significantly more likely to be replicated in our sample (P = 0.03), although we also replicated 4 of 58 SNPs from genes that had only one previous report of association.

A comparison of major histocompatibility complex SNPs in Han Chinese residing in Taiwan and Caucasians

Genetic dissection of complex diseases is both important and challenging. The human major histocompatibility complex is involved in many human diseases and genetic mechanisms. This highly polymorphic chromosome region has been extensively studied in Caucasians but not as well in Asians. Thus, we compared genotypic distributions, linkage disequilibria and haplotype blocks between Caucasian and Taiwan's Han Chinese populations. Moreover, we investigated the population admixture and phylogenetic system in Han Chinese residing in Taiwan. The results show that Taiwan's Han Chinese differ drastically in genotypic information compared with Caucasians but are relatively homogeneous among the three major ethnic subgroups, Minnan, Hakka and Mainlanders. Differences in allele frequency (AF) between Taiwanese and Caucasians in some disease-associated loci may reveal clues to differences in disease prevalence. The results of ethnic heterogeneity imply that public databases should be used with caution in cases where the study population(s) differs from the population characterized in the database. The high homogeneity we observed among the Taiwanese subpopulations mitigates the possibility of spurious association caused by ignoring population stratification in Taiwanese disease gene association studies. These results are useful for understanding our genetic background and designing future disease gene mapping studies.

Proteomic Analysis of Primary Cultures of Human Adipose-derived Stem Cells

Adipogenesis plays a critical role in energy metabolism and is a contributing factor to the obesity epidemic. This study examined the proteome of primary cultures of human adipose-derived adult stem (ADAS) cells as an in vitro model of adipogenesis. Protein lysates obtained from four individual donors were compared before and after adipocyte differentiation by two-dimensional gel electrophoresis and tandem mass spectroscopy. Over 170 individual protein features in the undifferentiated adipose-derived adult stem cells were identified. Following adipogenesis, over 40 proteins were up-regulated by > or = 2-fold, whereas 13 showed a > or = 3-fold reduction. The majority of the modulated proteins belonged to the following functional categories: cytoskeleton, metabolic, redox, protein degradation, and heat shock protein/chaperones. Additional immunoblot analysis documented the induction of four individual heat shock proteins and confirmed the presence of the heat shock protein 27 phosphoserine 82 isoform, as predicted by the proteomic analysis, as well as the crystallin alpha phosphorylated isoforms. These findings suggest that the heat shock protein family proteome warrants further investigation with respect to the etiology of obesity and type 2 diabetes.

1267 HSP70-2 polymorphism as a risk factor for carotid plaque rupture and cerebral ischaemia in old type 2 diabetes-atherosclerotic patients

Patients with type 2 diabetes mellitus (NIDDM) are at risk for macrovascular disease complications, such as myocardial infarction (MI) or stroke from plaque rupture. Cytokines play a key role in plaque vulnerability. IFN-gamma inhibits collagen synthesis thereby affecting plaque stability. High IL-6, TNF-alpha, and dyslipidemia are risk factors for thrombosis. Abnormal increments of HSP70 in atherosclerotic plaques might lead to plaque instability and rupture caused by chronic inflammation, which up-regulates the expression of pro-inflammatory cytokines (IL-6 and TNF-alpha) in human monocytes. Studies of a polymorphic PstI site lying in the coding region at position 1267 of the HSP70-2 gene have shown that the BB genotype is associated with NIDDM. We screened 60 old NIDDM patients with carotid stenosis and 107 old healthy controls for 1267 HSP70-2 polymorphism in order to establish if an association with plaque frailty exists. Different genotypic distributions were observed between patients and healthy controls. An increased relative risk was associated with the B allele (p = 0.0107; odds ratio = 1.861). HSP70-2, IL-6, IFN-gamma, TNF-alpha gene expressions within the plaques and serum levels of triglyceride, total cholesterol and LDL cholesterol were tested from patients stratified according to their B+ (AB and BB) and B- (AA) genotypes. Plaque morphology (soft or fibrous-calcified) and the incidence of cerebral ischaemia were also assessed. B+ patients showed increased HSP70-2, IL-6, IFN-gamma, TNF-alpha and dyslipidemia as compared to B- carriers. The frequency of soft plaques increased in B+ in comparison to B- patients (67% versus 13%; odds ratio 13.0, p = 0.0006). A higher frequency of cerebral ischaemia (ictus or transient ischaemic attack (TIA)) was present in B+ than in B- genotype (53% versus 20%; odds ratio 4.57, p < 0.05) Hence, 1267 HSP70-2 polymorphism may be of use in identifying B+ NIDDM patients at risk for carotid plaque rupture and cerebral ischaemia.