Association of tumor necrosis factor (TNF) promoter polymorphisms with plasma TNF-α levels and susceptibility to diabetic nephropathy in North Indian population

Investigations of associations between TNF-α promoter polymorphisms and genetic susceptibility to type 2 diabetes mellitus: A cross-sectional study in Chinese Han population

Type 2 diabetes (T2DM) is characterised by insulin resistance and a relative shortage of insulin secretion. Tumour necrosis factor-α (TNF-α) plays an important role in insulin resistance by impairing insulin signal transduction. The variants of the TNF-α promoter region are considered to influence its transcription and are associated with the TNF-α level. Therefore, it is worth detecting the association of the variants in the TNF-α gene with the development of T2DM. The aim of this study was to investigate the association of five variants (rs1799964, rs1800630, rs1799724, rs1800629 and rs361525) in the TNF-α gene promoter region with T2DM in a Chinese Han population. A total of 713 subjects with T2DM and 751 nondiabetic subjects were genotyped using the TaqMan method. The associations of the five variants with the development of T2DM were evaluated. The associations of the five variant genotypes with metabolic traits in nondiabetic subjects were analysed. Our data showed that the A allele of rs1800629 could increase the risk of developing T2DM (p = .002, OR = 1.563; 95% CI: 1.18-2.08). According to inheritance mode analysis, compared with the G/G genotype, the G/A+2A/A genotype of rs1800629 showed a risk effect on T2DM in the log-additive mode (p = .002, OR = 1.56; 95% CI: 1.17-2.07). The haplotypes analysis identified that the rs1799724-rs1800629CA was associated with high risk of the development of T2DM (p = .002, OR = 1.559, 95% CI: 1.173-2.072). Conversely, the rs1799724-rs1800629CG was a protective haplotype of T2DM (p = .001, OR = 0.732, 95% CI: 0.607-0.884). Moreover, compared with the rs1799964 (T/T+C/T) genotype, the rs1799964 C/C genotype was associated with higher glycosylated haemoglobin (HbA1c) levels in nondiabetic subjects (p = .017). Our results revealed that the rs1800629 in the TNF-α gene promoter region was associated with T2DM in a Chinese Han population.

Association between polymorphisms of cytokine genes and diabetic nephropathy: A comprehensive systematic review and meta-analysis

AIM

Diabetic nephropathy (DN) is one of the microvascular complications of diabetes, leading to renal failure. In this study, we sought to systematically investigate the cytokine gene polymorphisms association with DN.

METHODS

A structured bibliographic search on PubMed, Scopus, and EMBASE databases has been performed to identify related papers. The odds ratio and corresponding 95% confidence intervals (CIs) were calculated to estimate the association.

RESULTS

Overall, the pooled results showed that the dominant models of TNF-α rs1800629, IL-1β rs16944, IL-8 rs4073, and IL-10 rs1800896 were associated with increased susceptibility to DN. Also, the pooled analyses of the mutant allele vs wild allele of TNF-α rs1800629, rs1799964, IL-1β rs16944, and IL-8 rs4073 were associated with increased susceptibility to DN. Rs1800629, rs16944, rs4073, and rs1800896 polymorphisms were significantly associated with DN susceptibility, suggesting its potential use as a genetic risk marker in the population.

The Relationship between Metabolic Syndrome and Plasma Metals Modified by EGFR and TNF-α Gene Polymorphisms

With the escalating global prevalence of metabolic syndrome (MetS), it is crucial to detect the high-risk population early and to prevent chronic diseases. Exposure to various metals has been indicated to promote MetS, but the findings were controversial, and the effect of genetic modification was not considered. Epidermal growth factor receptor (EGFR) was proposed to be involved in the pathway of metabolic disorders, and tumor necrotic factor-α (TNF-α) was regarded as an early inflammatory biomarker for MetS. This research aimed to analyze the impact of EGFR and TNF-α gene polymorphisms on the prevalence of MetS under environmental or occupational exposure to metals. We gathered data from 376 metal industrial workers and 639 non-metal workers, including physical parameters, biochemical data, and plasma concentrations of six metals. According to the genomic database of Taiwan Biobank, 23 single nucleotide polymorphisms (SNPs) on EGFR gene and 6 SNPs on TNF-α gene were incorporated in our research. We applied multivariable logistic regression to analyze the probability of MetS with various SNPs and metals. Our study revealed some susceptible and protective EGFR and TNF-α genotypes under excessive exposure to cobalt, zinc, selenium, and lead. Thus, we remind the high-risk population of taking measures to prevent MetS.

Cytokine Polymorphisms and Predisposition to Diabetic Nephropathy: A Meta-Analysis

BACKGROUND

Cytokine polymorphismsmight influence the predisposition to diabetic nephropathy (DN), but the results of already published related studies are still controversial and ambiguous.

OBJECTIVES

The authors designed this meta-analysis to more precisely estimate relationships between TNF-α/IL-1/IL-4/IL-8/IL-18polymorphisms and DN by pooling the results of already published related studies.

METHODS

The authors searched Pubmed, Embase, Web of Science and CNKI for already published studies. Thirty already published studies were pooled and analyzed in this meta-analysis.

RESULTS

The overall pooled meta-analysis results showed that distributions of TNF-α -238 G/A, TNF-α -308 G/A, TNF-α -1031 C/T, IL-1A -889 C/T, IL-1B -511 C/Tand IL-18 -137 G/C polymorphisms among patients and controls differed significantly. Additionally, we also found that distributions of TNF-α -308 G/A, IL-1B -511 C/T and IL-18 -137 G/C polymorphisms among patients and controls from Asians differed significantly, and the distribution of the IL-1B -511 C/T polymorphism among patients and controls from Caucasians also differed significantly.

CONCLUSION

The meta-analysis results demonstrated that TNF-α -238 G/A, TNF-α -308 G/A, TNF-α -1031 C/T, IL-1A -889 C/T, IL-1B -511 C/Tand IL-18 -137 G/Cpolymorphisms might influence predisposition to DN in the overall pooled population. Moreover, TNF-α -308 G/A, IL-1B -511 C/T and IL-18 -137 G/C polymorphisms might influence predisposition to DN in Asians, whereas the IL-1B -511 C/T polymorphism might also influence predisposition to DN in Caucasians.

Study the Association of Tumor Necrosis Factor Promoter Polymorphism with Type 2 Diabetic Nephropathy

Type 2 Diabetes Mellitus (T2DM) is well known to include an inflammatory component that has been considered to be related to diabetic complications. Diabetic nephropathy (DN) is one of the significant complications as it constitutes the most frequent cause of end-stage renal disease. Tumor Necrosis Factor-α (TNF-α) is known as a multifunctional proinflammatory cytokine which is associated with some pathological processes such as immunoregulation, proliferation, inflammation, and apoptosis. The aim was to explore the association between the TNF-α promoter -1031T/C single nucleotide polymorphism (SNP) and the serum TNF-α level in addition to nephropathy among type 2 diabetic patients. The study included 38 T2DM subjects without nephropathy (DM group), 40 subjects with DN, and 20 controls. Identification of TNF-α promoter gene polymorphism -1031T/C was done by PCR-RFLP, and genotyping was confirmed by direct sequencing. The serum TNF-α level was assessed by ELISA. Correlations were tested by Pearson's correlation analysis. Logistic regression was used to detect the most independent factor for development of DN. The serum level of TNF-α in the DM group was significantly higher than controls (p < 0.001); also, the DN group was considerably higher than controls and DM without nephropathy (p < 0.001). Also, there was a significant positive correlation between serum levels of TNF-α with FBG (fasting blood glucose), creatinine, total cholesterol, LDL-C, HbA1c, and microalbumin/creatinine ratio (ACR) among the DN group (p = 0.042, <0.001, <0.001, <0.001, 0.027, and 0.043, respectively). Mutant homozygous CC and heterozygous TC genotypes were higher in DN than in DM and controls. C allele was more represented in DN than in DM and controls (p = 0.003) while T allele was higher in controls than in DM and DN patients. The levels of TNF-α were higher in subjects who had mutant CC than the wild TT genotype among DN (p < 0.001). C allele was more risky for DN than T allele between DN and controls by 5.4-fold (CI: 1.75-16.68) as well as between DN and DM by 2.25-fold (CI: 1.1-4.59). Conclusion. Serum levels of TNF-α were higher in individuals with mutant CC genotype of -1031T/C TNF-α gene, and C allele could be associated with increased risk for nephropathy among patients with T2DM.

Association between TNF-alpha polymorphism and the age of first suicide attempt in chronic patients with schizophrenia

Patients with schizophrenia (SCZ) exhibit higher suicide rates than the general population. However, the molecular mechanism remains poorly understood. Tumor necrosis factor (TNF)-alpha polymorphisms have been repeatedly indicated to play a pathogenetic role in various mental disorders, but none of these studies focused on the susceptibility to suicidal behavior in SCZ. We recruited 1087 chronic inpatients with SCZ and 576 controls to assess the psychopathological symptoms of SCZ using the Positive and Negative Syndrome Scale scales. We selected 2 polymorphisms (-308G>A and -1031C>T) in the TNF-alpha gene and analyzed their associations with SCZ and suicide. Our results showed that TNF-alpha -308G>A and -1031C>T were not related to SCZ and suicide. However, we found that suicide attempters with the C allele carriers exhibited suicidal behaviors significantly later than those with TT genotype in the SCZ patients. The haplotype containing the T allele of the -1031 was significantly associated with the age of suicide initiation. Further logistic regression analysis showed that -1031C>T interacted with psychopathological symptoms and drinking, age of smoking, and related to the initiation age of suicide attempts. Our study demonstrated that the TNF-alpha variants may affect the age at which suicide attempts started among SCZ suicide attempters.

Association of TNF-α gene alterations (c.-238G>A, c.-308G>A, c.-857C>T, c.-863C>A) with primary glaucoma in north Indian cohort

BACKGROUND

Tumor Necrosis Factor-alpha (TNF-α) a pleuripotent pro-inflammatory cytokine, is involved in retinal ganglion cells apoptosis in glaucoma. Thus present study aimed to analyze the association of TNF-α promoter region alterations (c.-238G>A (rs361525), c.-308G>A (rs1800629), c.-857C>T (rs1799724) and c.-863C>A (rs1800630)) with glaucoma in north Indian cohort.

METHODS

Present hospital based case control study involved 286 glaucoma patients (Primary Open Angle Glaucoma [POAG], Primary Angle Closure Glaucoma [PACG], Primary Congenital Glaucoma [PCG]) and 300 controls. TNF-α gene alteration (c.-238G>A (also referred as c.-418G>A; NM_000594.3)), c.-308G>A (c.-488G>A; NM_000594.3), c.-857C>T (c.-1037C>T; NM_000594.3) and c.-863C>A (c.-1043C>A; NM_000594.3) harboring regions were PCR amplified and sequenced by Sanger sequencing. Allele frequency and genotype distribution in glaucoma cases and controls were compared using chi-square test and genetic association tested using different genetic models.

RESULTS

Statistically significant genotype and allelic association was observed between glaucoma cases and controls for c.-308G>A and c.-863C>A alterations (p = 0.001, p = 0.001; p = 0.001, p = 0.001 respectively). AA genotype of c.-308G>A conferred ~7 fold increased risk towards glaucoma (OR = 6.82, 95% CI = 2.82-16.53, p = 0.001). c.-863C>A alteration under dominant, recessive and co-dominant genetic models conferred ~2 fold increased risk for glaucoma. However, no association for c.-238G>A and c.-857C>T variants with glaucoma was observed. Further, three haplotypes (GGCA, GACC and GACA) (OR = 0.48, 95% CI = 0.35-0.67, p = 0.001; OR = 0.58, 95% CI = 0.36-0.91, p = 0.019 and OR = 0.16, 95% CI = 0.05-0.51, p = 0.002, respectively) conferred protective role towards glaucoma.

CONCLUSIONS

Present study is the first to indicate significant association of c.-308G>A and c.-863C>A alterations with glaucoma in cases from north Indian cohort. Also it is the first study from India to analyze the association and interaction of four promoter region alterations (c.-238G>A, c.-308G>A, c.-857C>T and c.-863C>A) in TNF-α resulting in three protective haplotypes.

Tumor necrosis factor-alpha -1031T/C polymorphism is associated with cognitive deficits in chronic schizophrenia patients versus healthy controls

Recent compelling research has demonstrated a pathophysiologic role for proinflammatory cytokines of microglial origin in decreasing neurocognitive function. Psychiatric diseases are already known to have reduced cognitive function and are also associated with increased inflammation. To elaborate on these data, our study aims to investigate how a particular polymorphism of the tumor necrosis factor gene, TNF-α -1031T/C, affects neurocognitive performance in patients with schizophrenia. We recruited 905 patients with schizophrenia and 571 healthy control subjects. We employed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to test for neurocognitive function and the positive and negative syndrome scale to evaluate schizophrenia severity. The -1031T/C polymorphism was genotyped in both healthy controls and schizophrenic patients. Our results demonstrate that patients with the C allele (either T/C or C/C) possessed increased immediate memory index, visuospatial/constructional index, and RBANS total scores as compared to patients without it (p < .05). In healthy controls, there was no significant difference across genotypes (p > .05). Our findings demonstrate that the TNF-α -1031T/C polymorphism may not play a role in the susceptibility of schizophrenia itself, but may be involved in the cognitive deficits of schizophrenia. This suggests an important role for cytokine signaling in mediating the severity of cognitive dysfunction in schizophrenia.

Genetic variations in key inflammatory cytokines exacerbates the risk of diabetic nephropathy by influencing the gene expression

BACKGROUND

Diabetic nephropathy is the single strongest predictor of mortality in patients with diabetes. The development of overt nephropathy involves important inter-individual variations, even after adjusting for potential confounding influences of modifiable and non-modifiable risk factors. Genome-wide transcriptome studies have reported the activation of inflammatory signaling pathways and there is mounting indication of the role of genetic factors.

METHODS

We screened nine genetic variations in three cytokine genes (TNF-α, IL-6 and IL-β) in 1326 unrelated subjects comprising of healthy controls (n = 464), type 2 diabetics with nephropathy (DN, n = 448) and type 2 diabetes without nephropathy (T2D, n = 414) by sequence-specific amplification. Functional implication of SNPs was elucidated by correlation studies and relative gene expression using Realtime-Quantitative PCR (RT-qPCR).

RESULTS

Individual SNP analysis showed highest association of IL-1β rs16944-TT genotype (OR = 3.51, 95%CI = 2.36-5.21, P = 0.001) and TNF-α rs1800629-AA genotype (OR = 2.75, 95% CI = 1.64-4.59, P = 0.001) with T2D and DN respectively. The haplotype frequency showed significant risk of seven combinations among T2D and four combinations among DN subjects. The highest risk of T2D and DN was associated with GGTGAGTTT (OR = 4.25, 95%CI = 3.3-14.20, P = 0.0016) and GACGACCTT (OR = 21.3, 95%CI = 15.1-28.33, P = 0.026) haplotypes respectively. Relative expression by RT-qPCR showed increased cytokine expression in cases as compared to controls. TNF-α expression was increased by more than four-folds (n-fold = 4.43 ± 1.11) in DN. TNF-α, IL-6 and IL-1β transcript levels were significantly modulated by promoter region SNPs.

CONCLUSIONS

The present study implicates a strong association between cytokine TNF-α, IL-6 and IL-1β gene promoter polymorphisms and modulation of transcript levels with susceptibility to nephropathy in diabetes subjects.

Effect of AMP-activated protein kinase subunit alpha 2 (PRKAA2) genetic polymorphisms on susceptibility to type 2 diabetes mellitus and diabetic nephropathy in a Chinese population

BACKGROUND

It is well known that AMP-activated protein kinase (AMPK) is a key factor affecting the development of type 2 diabetes mellitus (T2DM). The single nucleotide polymorphism (SNP) rs2746342 in the AMPK alpha 2 subunit gene (PRKAA2) has been found to be associated with susceptibility to T2DM in the Chinese Han population. The present study further investigates the association of PRKAA2 genotypes with susceptibility to T2DM and its complication, diabetic nephropathy.

METHODS

The PRKAA2 genotypes of 406 T2DM patients and 214 controls from the Chinese Han population were determined with regard to SNPs rs10789038, rs2796498 and rs2746342. The association between these SNPs and susceptibility to T2DM and diabetic nephropathy was evaluated. The clinical characteristics differed significantly between T2DM patients and controls.

RESULTS

After adjustment for age, sex and body mass index, there was an obvious relationship between T2DM and both rs10789038 (odds ratio [OR] 1.634; P = 0.015) and rs2796498 (OR 0.656; P = 0.030), but not rs2746342. There was haplotype association of PRKAA2 rs10789038-rs2796498-rs2746342 with T2DM susceptibility. In addition, rs2796498 was found to be related to the susceptibility to diabetic nephropathy.

CONCLUSIONS

Polymorphisms in rs10789038 and rs2796498 are associated with the susceptibility to T2DM, and rs2796498 may be related to diabetic nephropathy.

Clinical Efficacy of Alprostadil Combined with α-lipoic Acid in the Treatment of Elderly Patients with Diabetic Nephropathy

Objective

To evaluate the effect and toxicity of alprostadil combined with thioctic acid injection in the treatment of patients with diabetic nephropathy (DN).

Methods

Sixty two patients with DN were included in this study and randomly divided into control group (n=32) and experiment group (n=30). Patients in the control group were given alprostadil 20ug+NS 100ml ivgtt, qd and patients in the experiment group were given alprostadil 20ug+NS 100ml ivgtt combined with thioctic acid injection of 0.45g+100ml ivgtt, qd for 14 days. After treatment, the renal function and serum level of CRP, IL-6 and TNF-α were compared between the two groups.

Results

After two weeks of treatment, the serum level of CysC and UAER significant decreased for both control and experiment group with statistical difference of p<0.05. After treatment, the serum level of CysC were 1.40 ±0.46 mg/L and 1.02±0.33 for control and experiment group respectively (p<0.05). The post-treatment UAER in experiment group was significantly lower than those of control group with statistical difference (81.02±0.33 vs112.45±20.32, p<0.05) ug/min. The serum level of CRP, IL-6 and TNF-α were significantly decreased after treatment for both control and experiment group (p<0.05). And the post-treatment serum CRP, IL-6 and TNF-α in experiment group were significantly lower than those of control group with statistical difference (p<0.05). No significant side effects were found for the two groupsin the course of treatment.

Conclusion

Alprostadil combined with α-lipoic acid may improve renal function in patients with diabetic nephropathy by decreasing the levels of serum inflammatory factors.

SOCS3 overexpression inhibits advanced glycation end product-induced EMT in proximal tubule epithelial cells

Diabetic nephropathy (DN) is among the most severe complications of diabetes mellitus, and may lead to end-stage renal disease. Sustained exposure to advanced glycation end products (AGEs) typically causes renal tubular epithelial cells (TECs) to suffer from an epithelial-to-mesenchymal transition (EMT). However, there remains no consensus regarding the mechanism underlying the cause of EMT in TECs as induced by AGEs. In the present study, we investigated the promotion of EMT in TECs by AGEs, and the activation of Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling. In addition, we constructed a recombinant adenovirus (Ad) that overexpressed suppressor of cytokine signaling 3 (SOCS3), and examined the regulatory role of SOCS3 in the activation of JAK/STAT signaling and the promotion of EMT in TECs. The results demonstrated that AGE-bovine serum albumin (BSA) treatment significantly promoted the expression of EMT-associated proteins, while reducing the expression of the epithelial cell marker, E-cadherin. Furthermore, the Ad-mediated SOCS3 overexpression markedly inhibited the AGE-BSA-induced JAK2/STAT3 activation; phosphorylated JAK2 and phosphorylated STAT3 expression levels were reduced by the Ad-SOCS3 infection, compared with the control Ad (Ad-con) infection, in HK-2 cells subject to AGE-BSA. Moreover, the overexpression of SOCS3 markedly inhibited the AGE-BSA-promoted EMT in HK-2 cells. AGE-BSA-promoted EMT-associated proteins, such as α-smooth muscle actin and collagen I, were reduced by the Ad-SOCS3 virus infection, in contrast to the Ad-con virus infection. Furthermore, reduced E-cadherin expression was reversed by the Ad-SOCS3 virus infection, in contrast to the Ad-con virus infection, in epithelial HK-2 cells. In conclusion, the present study confirmed the inhibitory role of SOCS3 in the AGE-induced EMT in renal TECs, implying the protective role of SOCS3 in DN.

Association of NFKB1 gene polymorphism (rs28362491) with levels of inflammatory biomarkers and susceptibility to diabetic nephropathy in Asian Indians

AIM

To investigate the association of NFKB1 gene -94 ATTG insertion/deletion (rs28362491) polymorphism with inflammatory markers and risk of diabetic nephropathy in Asian Indians.

METHODS

A total of 300 subjects were recruited (100 each), normoglycemic, (NG); type 2 diabetes mellitus (T2DM) without any complications (DM) and T2DM with diabetic nephropathy [DM-chronic renal disease (CRD)]. Analysis was carried out by polymerase chain reaction-restriction fragment length polymorphism and ELISA. Pearson’s correlation, analysis of variance and logistic regression were used for statistical analysis.

RESULTS

The allelic frequencies of -94 ATTG insertion/deletion were 0.655/0.345 (NG), 0.62/0.38 (DM) and 0.775/0.225 (DM-CRD). The -94 ATTG ins allele was associated with significantly increased levels of urinary monocyte chemoattractant protein-1 (uMCP-1); uMCP-1 (P = 0.026) and plasma tumor necrosis factor-alpha (TNF-α); TNF-α (P = 0.030) and almost doubled the risk of diabetic nephropathy (OR = 1.91, 95%CI: 1.080-3.386, P = 0.025).

CONCLUSION

-94 ATTG ins/ins polymorphism might be associated with increased risk of developing nephropathy in Asian Indian subjects with diabetes mellitus.

Diabetes mellitus: The linkage between oxidative stress, inflammation, hypercoagulability and vascular complications

BACKGROUND

Vascular complications are the leading cause of morbidity and mortality among patients with type 1 and type 2 diabetes mellitus. These vascular abnormalities result of a chronic hyperglycemic state, which leads to an increase in oxidative stress and inflammatory responses.

AIM

This review addresses the relationships among endothelial dysfunction, hypercoagulability and inflammation and their biomarkers in the development of vascular complications in type 1 and type 2 diabetes.

RESULTS

Inflammation, endothelial dysfunction, and hypercoagulability are correlated to each other, playing an important role in the development of vascular complications in diabetic patients. Moreover, it has been observed that several endothelial, inflammatory and pro-coagulant biomarkers, such as VWF, IL-6, TNF-α, D-dimer and PAI-1, are increased in diabetic patients who have microvascular and macrovascular complications, including nephropathy or cardiovascular disease.

CONCLUSION

It is promising the clinical and laboratory use of endothelial, inflammatory and pro-coagulant biomarkers for predicting the risk of cardiovascular and renal complications in diabetic patients and for monitoring these patients.