Effect of genetic polymorphism +294T/C in peroxisome proliferator-activated receptor delta on the risk of ischemic stroke in a Tunisian population

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of type 2 diabetes mellitus and dyslipidemia, but not coronary artery disease in a Chinese Han population

Background

Relationships of the polymorphisms in fat mass and obesity-associated gene (FTO) and peroxisome proliferator-activated receptor delta gene (PPARD) with metabolic-related diseases remain to be clarified.

Methods

One thousand three hundred and eighty-one subjects were enrolled. Metabolic-related diseases including obesity, dyslipidemia, hyperhomocysteinemia, hyperuricemia, hypertension, type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) were defined based on diagnostic criteria. FTO rs9939609 and rs17817449, and PPARD rs2016520 and rs2267668 polymorphisms were genotyped by using polymerase chain reaction-restricted fragment length polymorphism method.

Results

Patients with T2DM or dyslipidemia had a higher frequency of AA, AT or AA + AT genotypes as well as A allele of FTO rs9939609 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.04 for all). Patients with T2DM or dyslipidemia had a higher frequency of GG, GT or GG + GT genotypes as well as G allele of FTO rs17817449 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.03 for all). Multivariate logistic regression analyses showed that FTO rs9939609 and rs17817449 polymorphisms were independently associated with T2DM as well as dyslipidemia after adjustment for age, sex, smoking and other metabolic diseases. FTO rs9939609 and rs17817449 polymorphisms were not associated with obesity, hyperhomocysteinemia, hyperuricemia, hypertension and CAD. Obese or T2DM carriers of the AA or AT genotype of the FTO rs9939609 polymorphism had a higher prevalence of dyslipidemia compared to non-obese or non-T2DM carriers of the AA or AT genotype (P = 0.03 for both). Among the carriers of GG or GT genotype of the FTO rs17817449 polymorphism, the prevalence of dyslipidemia in obese patients was higher than that in non-obese subjects (P < 0.01). PPARD rs2016520 and rs2267668 polymorphisms were not correlated with any of the metabolic-related diseases in the study population.

Conclusion

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of T2DM and dyslipidemia, and the risk is further increased among obese individuals. PPARD rs2016520 and rs2267668 polymorphisms are not associated with metabolic-related diseases.

C Allele of the PPARδ+294T>C Polymorphism Confers a Higher Risk of Hypercholesterolemia, but not Obesity and Insulin Resistance: A Systematic Review and Meta-Analysis

The relationships of the PPARα Leu162Val and PPARδ+294 T>C polymorphisms with metabolic indexes have been reported to be inconsistent and even contradictory. The meta-analysis was conducted to clarify the relationships between the two variants and the indexes of obesity, insulin resistance, and blood lipids. PubMed, Google Scholar, Embase, and Cochrane Library were searched for eligible studies. Standardized mean difference with 95% confidence interval was calculated to estimate the differences in the metabolic indexes between the genotypes of the Leu162Val and+294 T>C polymorphisms. Heterogeneity among studies was assessed by Cochran's x2-based Q-statistic test. Publication bias was identified by using Begg's test. Forty-one studies (44 585 subjects) and 33 studies (23 018 subjects) were identified in the analyses for the Leu162Val and+294 T>C polymorphisms, respectively. C allele carriers of the+294 T>C polymorphism had significantly higher levels of total cholesterol and low-density lipoprotein cholesterol than TT homozygotes in the whole population. Notably, C allele carriers of the+294 T>C polymorphism had significantly higher levels of triglycerides and total cholesterol in East Asians, but lower levels of triglycerides in West Asians than TT homozygotes. Regarding the Leu162Val polymorphism, it was found that Val allele carriers had significantly higher levels of blood glucose than Leu/Leu homozygotes only in European Caucasians. The meta-analysis demonstrates that C allele of the+294 T>C polymorphism in PPARδ gene confers a higher risk of hypercholesterolemia, which may partly explain the relationship between this variant and coronary artery disease.

Stroke in Africa: profile, progress, prospects and priorities

Stroke is a leading cause of disability, dementia and death worldwide. Approximately 70% of deaths from stroke and 87% of stroke-related disability occur in low-income and middle-income countries. At the turn of the century, the most common diseases in Africa were communicable diseases, whereas non-communicable diseases, including stroke, were considered rare, particularly in sub-Saharan Africa. However, evidence indicates that, today, Africa could have up to 2-3-fold greater rates of stroke incidence and higher stroke prevalence than western Europe and the USA. In Africa, data published within the past decade show that stroke has an annual incidence rate of up to 316 per 100,000, a prevalence of up to 1,460 per 100,000 and a 3-year fatality rate greater than 80%. Moreover, many Africans have a stroke within the fourth to sixth decades of life, with serious implications for the individual, their family and society. This age profile is particularly important as strokes in younger people tend to result in a greater loss of self-worth and socioeconomic productivity than in older individuals. Emerging insights from research into stroke epidemiology, genetics, prevention, care and outcomes offer great prospects for tackling the growing burden of stroke on the continent. In this article, we review the unique profile of stroke in Africa and summarize current knowledge on stroke epidemiology, genetics, prevention, acute care, rehabilitation, outcomes, cost of care and awareness. We also discuss knowledge gaps, emerging priorities and future directions of stroke medicine for the more than 1 billion people who live in Africa.

Role of peroxisome proliferator-activated receptors in stroke prevention and therapy-The best is yet to come?

Role of peroxisome proliferator-activated receptors (PPARs) in the pathophysiology of stroke and protective effects of PPAR ligands have been widely investigated in the last 20 years. Activation of all three PPAR isoforms, but especially PPAR-γ, was documented to limit postischemic injury in the numerous in vivo, as well as in in vitro studies. PPARs have been demonstrated to act on multiple mechanisms and were shown to activate multiple protective pathways related to inflammation, apoptosis, BBB protection, neurogenesis, and oxidative stress. The aim of this review was to summarize two decades of PPAR research in stroke with emphasis on in vivo animal studies. We focus on each PPAR receptor separately and detail their implication in stroke. This review also discusses recent clinical efforts in the field and the epidemiological data with regard to role of PPAR polymorphisms in susceptibility to stroke, and tries to draw conclusions and describe future perspectives.

Genetic polymorphisms of PPAR genes and human cancers: evidence for gene-environment interactions

Peroxisome proliferator-activated receptors (PPARs) are nuclear transcription factors that play a role in lipid metabolism, cell proliferation, terminal differentiation, apoptosis, and inflammation. Although several cancer models have been suggested to explain PPARs' involvement in tumorigenesis, however, their role is still unclear. In this review, we examined associations of the different PPARs, polymorphisms and various types of cancer with a focus on gene-environment interactions. Reviewed evidence suggests that functional genetic variants of the different PPARs may modulate the relationship between environmental exposure and cancer risk. In addition, this report unveils the scarcity of reliable quantitative environmental exposure data when examining these interactions, and the current gaps in studying gene-environment interactions in many types of cancer, particularly colorectal, prostate, and bladder cancers.

PPARD rs2016520 polymorphism and circulating lipid levels connect with brain diseases in Han Chinese and suggest sex-dependent effects

The PPARD polymorphisms were shown to be associated with circulating lipoprotein metabolism in various diseases. We aimed to check the contribution of PPARD rs2016520 and lipid concentration to the risk of intracerebral hemorrhages (ICH) and brain tumors (BT) in Han Chinese. A total of 864 participants were included in the case-control study. The melting temperature shift (Tm-shift) method was used for rs2016520 genotyping. Under the recessive model, PPARD rs2016520 was shown to be associated with the risk of ICH (P=0.029, odds ratio (OR)=2.72), specifically in males (P=0.045, OR=3.98). Additionally, we also found that the levels of TC and LDL-C were significantly higher in participants with brain diseases than in the controls (TC: P<0.0001; LDL-C: P<0.0001). Significantly higher HDL-C and lower ApoA-I levels were observed in the male patients with brain diseases (HDL-C: P<0.0001; ApoA-I: P=0.008), in contrast of a higher TG level in female ICH (P=0.023). Subsequent interaction analysis between PPARD rs2016520 and lipoprotein metabolism showed that the LDL-C level was positively correlated with ICH in the rs2016520-AA carriers (P<0.0001), but not in the other genotype carriers (AG or GG, P=0.300). Our results showed that PPARD rs2016520 displayed a strong relationship with ICH risk in the male Han Chinese. The TC and LDL-C levels were positively higher in the patients with brain diseases than in the controls. The levels of TG, HDL-C and ApoA-I were shown to affect brain disease in a gender-dependent model. The genotype rs2016520-AA showed significant interaction with the circulating LDL-C levels in ICH.

PPAR-alpha and PPAR-beta expression changes in the hippocampus of rats undergoing global cerebral ischemia/reperfusion due to PPAR-gamma status

Background

Peroxisome proliferator-activated receptors (PPARs, including alpha, beta and gamma subtypes) and their agonists have a protective role in treatment of central nervous system (CNS) diseases. The present study was designed to investigate the expression changes of PPAR-alpha, -beta, -gamma and NF-kappa B in the hippocampus of rats with global cerebral ischemia/reperfusion injury (GCIRI) after treatment with agonists or antagonists of PPAR-gamma.

Methods

A rat GCIRI model was established by occlusion of bilateral common carotid arteries and cervical vena retransfusion. GW9662 (5 μg), a selective PPAR- gamma antagonist, was intraventricularly injected at 0.5 h before GCIR; Rosiglitazone (0.8, 2.4 and 7.2 mg/kg), a selective PPAR- gamma agonist, was injected intraperitoneally at 1 h before GCIRI. The expression changes of PPAR-alpha, -beta and -gamma at mRNA and protein levels were detected by RT-PCR and western blotting. The changes of spatial learning and memory (SLM) functions were assessed by using a Morris water maze; the pathohistological changes of hippocampal neurons were evaluated by hematoxylin-eosin (HE) staining; the contents of IL-1, IL-6, IL-10 and TNF-alpha, and the NF- kappa B expression were measured by enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were also detected.

Results

The SLM function and hippocampal neurons were significantly impaired after the occurrence of GCIRI. The MDA, IL-1, IL-6, IL-10, TNF-alpha content and expression of PPARs increased significantly, but the SOD activity and NF-kappa B expression were weakened in the hippocampus. Rosiglitazone treatment significantly protected rats from SLM function impairment and neuron death, and resulted in higher expressions of SOD activity and NF-kappa B, but lower contents of MDA and inflammatory factors. After treatment with rosiglitazone or GW9662, no significant change in PPAR-alpha or -beta expression was detected.

Conclusions

Rosiglitazone, a PPAR-gamma agonist, plays a protective role in hippocampal neuron damage of GCIRI rats by inhibiting the oxidative stress response and inflammation. The activation or antagonism of PPAR-gamma did not affect the expression of PPAR-alpha or -beta, indicating that the three subtypes of PPARs act in independent pathways in the CNS.

Polymorphisms in PPAR Genes (PPARD, PPARG, and PPARGC1A) and the Risk of Chronic Kidney Disease in Japanese: Cross-Sectional Data from the J-MICC Study

Chronic kidney disease (CKD) is well known as a strong risk factor for both end stage renal disease and cardiovascular disease. To clarify the association of polymorphisms in the PPAR genes (PPARD, PPARG, and PPARGC1A) with the risk of CKD in Japanese, we examined this association among the Japanese subjects using the cross-sectional data of J-MICC (Japan Multi-Institutional Collaborative Cohort) Study. The subjects for this analysis were 3,285 men and women, aged 35–69 years, selected from J-MICC Study participants; genotyping was conducted by multiplex polymerase chain reaction-based Invader assay. The prevalence of CKD was determined for CKD stages 3–5 (defined as eGFR < 60 ml/min/1.73 m²). Participants with CKD accounted for 17.3% of the study population. When those with PPARD T-842C T/T were defined as reference, those with PPARD T-842C T/C and C/C demonstrated the OR for CKD of 1.26 (95%CI 1.04–1.53) and 1.31 (95%CI 0.83–2.06), respectively. There were no significant associations between the polymorphisms in other PPAR genes and the risk of CKD. The present study found a significantly increased risk of CKD in those with the C allele of PPARD T-842C, which may suggest the possibility of personalized risk estimation of this life-limiting disease in the near future.