Association of tumor necrosis factor alpha, interferon gamma and interleukin 10 gene polymorphisms with peripheral neuropathy in South Indian patients with type 2 diabetes. Cytokine. 2009;47:173-177. [PMID: 19608431 DOI: 10.1016/j.cyto.2009.06.007]

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.

Association between diabetic retinopathy and polymorphisms of cytokine genes: a systematic review and meta-analysis

INTRODUCTION

Diabetic retinopathy (DR) is a medical condition caused by damage to the blood vessels of retina tissue due to diabetes mellitus. DR leads to injury in neural and vascular structures and is reported to be significantly influenced by inflammation and inflammatory mediators like cytokines. In this study, a systematic review and meta-analysis were performed to analyze the association between cytokine gene polymorphisms and DR.

METHODS

We identified relevant studies from Scopus, PubMed, and Google scholar databases. Allele and genotype frequencies were pooled. Heterogeneity and publication bias were explored. The odds ratio (OR) and corresponding 95% confidence intervals (CIs) were calculated to estimate the relation.

RESULTS

A total of 3337 cases and 4945 controls in 19 eligible studies were included in the meta-analysis. Overall, results indicated the negative association between the cytokine gene polymorphisms and DR susceptibility in the allelic model (IFN-γ (rs2430561): OR 0.64, [CI]: 0.5 to 0.82; and TGF-β (rs1800471): [OR] = 0.15, [CI]: 0.03 to 0.79); and also, in the dominant model (IFN-γ (rs2430561): OR = 0.4, [CI]: 0.22 to 0.75; and TGF-β (rs1800471): OR = 0.14, [CI]: 0.05 to 0.4).

CONCLUSION

The present study suggests that IFN-γ (rs2430561) and TGF-β (rs1800471) polymorphisms are associated with decreased susceptibility to DR.

The Relationship between the IFNG (rs2430561) Polymorphism and Metabolic Syndrome in Perimenopausal Women

Background and Objectives: Metabolic syndrome (MetS) is a multiple risk factor for atherosclerosis, cardiovascular disease, type 2 diabetes and strokes. One-third of middle-age women are at risk of MetS, which predisposes them to type 2 diabetes and cardiovascular disease. Changes in the regulation of anti-inflammatory cytokines―which play an important role in pathologic processes―may contribute to inflammatory disorders. Cytokine polymorphisms are known to have an impact on gene expression. The purpose of this study was to search for the relationship between the IFNG polymorphisms and the levels of proinflammatory cytokines. Materials and Methods: This study, conducted in West Pomeranian Voivodeship, Poland, involved 416 women. Of these women, 33.6% of them had primary education, 44.8% lived in cities with a population of over 100,000, and 82.7% were married. Of the participants, 28.4% met the criteria for MetS. The study involved: interview performed to collect sociodemographic and medical data, anthropometric measurements, as well as venous blood collection for biochemical analysis, genetic testing and the measurement of inflammatory markers. Results: The link between the IFNG (rs2430561) polymorphism and serum PIC (proinflammatory cytokines) levels was tested with regard to MetS. In the MetS+ subgroup, the T/T and A/T genotypes of the IFNG gene were accompanied by higher IL-6 levels than in the MetS− subgroup. Conclusion: Our study has not confirmed a direct link between the IFNG polymorphisms and the levels of inflammatory biomarkers. Nevertheless, the T/T and A/T genotypes of the IFNG gene may predispose to elevated IL-6 levels.

Association Analysis of Tumor Necrosis Factor Alpha Promoter Polymorphisms and Vitiligo Susceptibility in South Indian Tamils

Tumor necrosis factor alpha (TNF-α) has been associated with the pathogenesis of several autoimmune diseases. Also, various studies in different ethnics showed an association between TNF-α gene polymorphisms and susceptibility to vitiligo. The paucity of genetic data led us to undertake this study to evaluate the association of five TNF-α SNPs (rs1799964, rs1800630, rs1799724, rs1800629, and rs361525) with the development of vitiligo in South Indian Tamils. A total of 264 vitiligo patients and 264 healthy controls were recruited and TNF-α genotyping was performed using amplification-refractory mutation system polymerase chain reaction and TaqMan allele discrimination assay. Circulatory TNF-α levels were measured by enzyme-linked immunosorbent assay. We observed that a single polymorphic allele A in the promoter region -308 (rs1800629) conferred significant risk to develop vitiligo (p = 0.0002, OR = 1.70, 95% CI = 1.28-2.25), whereas the other polymorphisms failed to contribute to disease risk (p > 0.05). From the constructed haplotypes, TCCAG was found to be a significant risk factor for vitiligo (p < 0.05). Also, a strong linkage disequilibrium was observed between the following SNPs: (1) rs1799964 and rs1800629 (2) rs1800630 and rs1799724 (D' = 0.90). Analysis of the influence of genotype on phenotypes revealed that the A allele of rs361525 was a risk factor for vitiligo in females (p = 0.04, OR = 0.45, 95% CI = 0.21-0.95), whilst the rs1800629 allele conferred protection against early disease onset (p < 0.05). A statistically significant difference in plasma TNF-α levels was found between cases and controls (p < 0.05). The TNF-α -308A allele and TCCAG haplotype were identified as genetic risk factors for vitiligo susceptibility in South Indian Tamils.

IFN-γ/mTORC1 decreased Rab11 in Schwann cells of diabetic peripheral neuropathy, inhibiting cell proliferation via GLUT1 downregulation

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes mellitus. Rab11 is conserved gene-regulating vesicle traffic and reported to be involved in the pathogenesis of diabetes mellitus by affecting insulin sensitivity. We aimed to investigate the role of Rab11 in the pathogenesis of DPN. In this study, Rab11 expression decreased in the sciatic nerves of diabetic mice with impaired conduction function versus those of normal mice. In vitro experiment revealed interferon-γ (IFN-γ), not high glucose and interleukin 1β was the main factor to lead to Rab11 downregulation in RSC96 cells. Again, both Rab11 knockdown and IFN-γ treatment caused cell viability inhibition and the decrease in BrdU-positive cells. In contrast, overexpression of Rab11 reversed IFN-γ-reduced cell proliferation. Furthermore, mTORC1 not mTORC2 was proven to be suppressed by IFN-γ treatment in RSC96 cells, indicated in decreased phospho-p70S6K. Inhibition of the mTORC1 pathway resulted in Rab11 expression downregulation in RSC96 cells. Activation of the mTORC1 pathway effectively prevented IFN-γ-reduced Rab11 expression in RSC96 cells. Also, glucose transporter 1 (GLUT1) was found to be downregulated in RSC96 cells with Rab11 silence and overexpression of GLUT1 reversed Rab11 blocking-caused proliferation inhibition. Taken together, our findings suggest that IFN-γ decreases Rab11 expression via the inhibition of the mTORC1 signaling pathway, causing reduced cell proliferation in Schwann cells of DPN by GLUT1 downregulation.

Probucol-poly(meth)acrylate-bile acid nanoparticles increase IL-10, and primary bile acids in prediabetic mice

Aim: Common features in insulin-resistance diabetes include inflammation and liver damage due to bile acid accumulation. Results & methodology: This study aimed to test in vivo pharmacological effects of combining two drugs, ursodeoxycholic acid that has bile acid regulatory effects, and probucol (PB) that has potent anti-oxidative stress effects, using a new poly(meth)acrylate nano-targeting formulation on prediabetic mice. Mice were made diabetic and were fed daily with either PB, nanoencapsulated PB or nanoencapsulated PB-ursodeoxycholic acid before blood, tissues, urine and feces were collected for inflammation and bile acid measurements. The nanoencapsulated PB-ursodeoxycholic acid formulation increased plasma IL-10, and increased the concentration of primary bile acids in the liver and heart. Conclusion: Results suggest potential applications in regulating IL-10 in insulin-resistance prediabetes.

Diabetic neuropathy in children and adolescents with type 1 diabetes mellitus: Diagnosis, pathogenesis, and associated genetic markers

Diabetic neuropathy (DN) is a common long-term complication of type 1 (T1D) and type 2 (T2D) diabetes mellitus, with significant morbidity and mortality. DN is defined as impaired function of the autonomic and/or peripheral nervous system, often subclinical, particularly in children and adolescents with T1D. Nerve conduction studies (NCS) and skin biopsies are considered gold-standard methods in the assessment of DN. Multiple environmental and genetic factors are involved in the pathogenesis of DN. Specifically, the role of metabolic control and glycemic variability is of paramount importance. A number of recently identified genes, including the AKR1B1, VEGF, MTHFR, APOE, and ACE genes, contribute significantly in the pathogenesis of DN. These genes may serve as biomarkers to predict future DN development or treatment response. In addition, they may serve as the basis for the development of new medications or gene therapy. In this review, the diagnostic evaluation, pathogenesis, and associated genetic markers of DN in children and adolescents with T1D are presented and discussed.

Genetics of diabetic neuropathy: Systematic review, meta-analysis and trial sequential analysis

OBJECTIVE

Diabetic neuropathy (DN) is one of the most common complications of diabetes that occurs in more than 67% of individuals with diabetes. Genetic polymorphisms may play an important role in DN development. However, until now, the association between genetic polymorphisms and DN risk has remained unknown. We performed a systematic review, meta-analysis, and trial sequential analysis (TSA) of the association between all genetic polymorphisms and DN risk.

METHODS

Relevant published studies examining the relationship between all genetic polymorphisms and DN were obtained based on a designed search strategy up to 28 February 2019. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess overall pooled effects of genetic models as well as in subgroup analyses. Sensitive analysis and publication bias were applied to evaluate the reliability of the study. Moreover, TSA was conducted to estimate the robustness of the results.

RESULTS

We conducted a systematic review of a total of 1256 articles, and then 106 publications reporting on 136 polymorphisms of 76 genes were extracted. We performed 107 meta-analyses on 36 studies involving 12,221 subjects to derive pooled effect estimates for eight polymorphisms. We identified that ACE I>D, MTHFR 1298A/C, GPx-1 rs1050450, and CAT -262C/T were associated with DN, while MTHFR C677T, GSTM1, GSTT1, and IL-10 -1082G/A were not. Sensitivity analysis, funnel plot, and Egger's test displayed robust results. Furthermore, the results of TSA indicated sufficient sample size in studies of ACE, GPx-1, GSTM1, and IL-10 polymorphisms.

INTERPRETATION

Our study assessed the association between ACE I>D, MTHFR C677T, MTHFR 1298A/C, GPx-1 rs1050450, CAT -262C/T, GSTM1, GSTT1, and IL-10 -1082G/A polymorphisms and DN risk. We hope that the data in our research study are used to study DN genetics.

Searching for the Role of the IFNγ rs2430561 Polymorphism in Inducible Inflammation: Contribution to Metabolic Syndrome in 45 to 60-Year-Old Women

Metabolic syndrome (MetS) is a cluster of conditions, increasing the risk of developing diseases that can lead to premature death. Interferon γ-inducible (the production of which is dependent on the IFNγ rs2430561 polymorphism) tryptophan-kynurenine inflammatory cascade helps to understand the increased association between inflammatory process and MetS, which is why we seek the relationship between the IFNγ gene polymorphisms and serum levels of markers of interferon-gamma (IFNγ)-inducible inflammatory cascade. The study sample consisted of 416 women, including 118 (28.4%) with MetS. The research procedure involved interview, anthropometric measurements, and blood collection. Kynurenine levels were significantly higher in the group of women with MetS. In the group with MetS, the A/T genotype of the IFNγ gene was accompanied by higher kynurenine levels. A direct relationship between the IFNγ gene polymorphisms and the rest of the markers of IFNγ-inducible inflammatory cascade was not confirmed with regard to MetS in 45 to 60-year-old women. A disparity in the kynurenine level, as well as the relationship between the presence of the A/T genotype of the IFNγ gene and a higher level of kynurenine in the group of women with MetS, may indicate an association between inflammation, metabolic disorders and tryptophan-kynurenine inflammatory cascade.

TNF-α (-308) Gene Polymorphism and Type 2 Diabetes Mellitus in Ethiopian Diabetes Patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a metabolic disorder resulting from insulin insufficiency or function. Predisposing factors for T2DM are mainly genetic and environmental. Genetic polymorphism of cytokines like tumor necrosis factor-alpha (TNF-α) is suggestive of interference with insulin-sensitive glucose uptake and induces insulin resistance that ultimately could lead to T2DM. In this study, we assessed the effect of TNF-α (-308) G/A gene polymorphism and its association with the development of T2DM in an Ethiopian population.

METHODS

An institutional-based cross-sectional study was conducted on study subjects with T2DM and non-diabetic healthy controls. DNA was extracted and genotyping was carried out by using amplification refractory mutation system polymerase chain reaction. A genetic-polymorphism on TNF-α (-308) G/A with T2DM was evaluated by logistic regression and Student's t-test. A P-value <0.05 was considered as statistically significant.

RESULTS

In the present study, we observed a significant association between T2DM and TNF-α (-308) gene polymorphism's GG genotype [χ2 test P = 0.005, OR (95% CI) =2.667 (1.309-5.45d8)]. In contrast, no statistically significant differences were observed in the frequencies of genotypes AA and AG (χ2 test P=0.132 and 0.067, respectively). Moreover, T2DM individuals had higher concentrations of lipid profiles for those carrying the TNF-α (-308) GG genotype as compared to the control group.

CONCLUSION

TNF-α (-308) genetic polymorphism may be implicated in the genetic susceptibility for, as well as the development of T2DM and lipid metabolism in the Ethiopian population. Therefore, a large-scale study and early screening of TNF-α (-308) genetic polymorphism may help in early management and control of diabetes and related outcomes.

Ethnic variation of IL-4 intron 3 VNTR gene polymorphism; its association with type 2 diabetes mellitus and its complication (neuropathy) in Egyptian subjects

Type 2 diabetes mellitus (T2DM) has multigenetic and environmental interactive factors. Although diabetic neuropathies (DPN) are the most common, but at the same time, the least recognized and understood long-term complication of diabetes. This study aimed to investigate the association of IL-4 VNTR gene polymorphism with T2DM complicated with neuropathy in Egyptian subjects. This is a case control study including 102 T2DM Egyptian patients, plus 188 unrelated healthy individuals as controls. They were evaluated for variable number tandem repeat (VNTR); 70 base pair repeats located in the intron 3; of IL-4 gene using the PCR technique. Homozygote frequency of the three-repeat allele (A1/A1) genotype of IL-4 VNTR was nearly equal among diabetic cases and controls (60.8% vs. 62.2%, respectively). Heterozygous frequency of (A1/A2) genotype was higher among controls compared to cases (33.5% vs. 19.6%, respectively) but not statistically significant. The (A2) allele had a significantly higher frequency in diabetic cases compared to controls (29.3% vs. 21.0%, respectively) while the (A1) allele had lower frequency but not significant one (70.7% vs. 79.0%, respectively). Comparing cases complicated with diabetic neuropathy vs. noncomplicated cases regarding their polymorphic IL-4 (VNTR) genotypes revealed a nonsignificant lower frequency of (A1A1) genotype (57.1% vs. 65.1%, respectively, p = .57) with a higher combined (A2A2 + A1/A2) genotype frequency (42.9% vs. 34.9%, respectively). Only two haplotypes (A1) & (A2) of IL-4 (VNTR) gene were recognized among Egyptian population; (A2) allele may influence in diabetes but not its complication (neuropathy) among Egyptian diabetic patients.

Interleukin-10 -1082A > G (rs1800896) polymorphism is associated with diabetic retinopathy in type 2 diabetes

AIM

To investigate whether the -1082A > G polymorphism (rs1800896) in the interleukin-10 (IL10) gene is associated with diabetic retinopathy (DR) in Brazilians with type 2 diabetes mellitus.

METHODS

This case-control study included 847 outpatients with type 2 diabetes and 145 healthy blood donors. Four hundred and two patients had no DR, 253 had non-proliferative DR (NPDR), and 192 had proliferative DR (PDR). Genotyping was done by real-time PCR.

RESULTS

Genotype and allele frequencies were similar in patients and blood donors. In relation to the presence and severity of DR, the AA genotype was overrepresented among patients with NPDR, whereas the GG genotype was more frequent among patients with PDR. Multiple logistic regression analysis showed that the AA genotype was independently associated with increased risk of NPDR, after controlling for duration of diabetes, body mass index, and insulin use (adjusted OR = 1.50; 95% CI = 1.04-2.17). The GG genotype, however, did not remain associated with increased risk of PDR (adjusted OR = 1.49; 95% CI = 0.78-2.86).

CONCLUSIONS

This study identified, for the first time, an independent association of the -1082A > G polymorphism in the IL10 gene with NPDR in type 2 diabetes. This finding provides additional evidence supporting that genetic variants of IL10 are involved in the pathogenesis of DR.

Association Between Interleukin-10 Gene (-1082g/A) Polymorphism and Type 2 Diabetes, Diabetes-Related Traits, and Microvascular Complications in the Croatian Population

Interleukin (IL)-10 is an anti-inflammatory cytokine, and a decrease in its secretion is associated with obesity, metabolic syndrome and type 2 diabetes. However, it has not been established whether the intensity of the immune response during diabetes-associated chronic inflammation affects the development and/or progression of type 2 diabetes and its microvascular complications. The aim of this study was to investigate the role of single nucleotide polymorphism (SNP)-1082G/A for IL-10 gene in development of diabetes type 2 and its complications. DNA was extracted from blood cells of 240 overweight/obese subjects for IL-10 genotyping. Based on the presence of diabetes type 2, patients were divided in two groups: experimental group of 144 patients with diabetes type 2 and control group of 96 age- and gender-matched subjects without diabetes. Compared to control group, diabetic group had higher levels of leukocytes (p=0.012), fibrinogen (p=0.049) and plasminogen activator inhibitor-1 (PAI-1) (p=0.009), and lower levels of albumin (p=0.001). There were no differences in the frequency of SNP-1082G/A for IL-10 gene between the two groups (p=0.654). When considering diabetes related traits in all subjects in relation to specific genotype, a group with homozygous (AA) genotype had higher values of the mean fasting glucose (p<0.000001), HbA1c (p<0.000001) and HOMA-IR (p=0.003632), while the mean HOMA-B value (p=0.000178) was lower when compared to the groups with GG and GA genotypes. There was no difference in devel-opment of diabetic nephropathy, retinopathy and polyneuropathy between the IL-10 polymorphism genotypes. In conclusion, obese diabetes type 2 patients had an increased inflammation activity com-pared to obese non-diabetic individuals. There was no association of the investigated polymorphisms and development of type 2 diabetes and its microvascular complications. However, diabetes related traits clearly depended on the presence of specific IL-10 genotype.

Neuropathy-specific alterations in a Mexican population of diabetic patients

Background

Neuropathy is one of the major complications of type 2 diabetes mellitus. Our first aim was to determine the clinical characteristics of a population of diabetic patients with different types of neuropathy. Our next goal was to characterize the cytokine profile (IL-6 and IL-10), nerve growth factor (NGF) and circulating cell-adhesion molecules in these patients. Finally, we aimed to compare the renal function among the groups of neuropathic patients.

Methods

In a cross-sectional study, we included 217 diabetic patients classified in three groups: sensory polyneuropathy with hypoesthesia (DS_hP) or hyperesthesia (DS_HP), and motor neuropathy (DMN). Two control groups were included: one of 26 diabetic non-neuropathic patients (DNN), and the other of 375 non-diabetic (ND) healthy subjects. The participants were attending to the Mexican Institute of Social Security.

Results

The circulating levels of NGF were significantly lower in diabetic patients, compared to healthy subjects. The range of IL-6 and IL-10 levels in neuropathic patients was higher than the control groups; however, several samples yielded null measurements. Neuropathic patients also showed increased circulating levels of the adhesion molecules ICAM, VCAM, and E-Selectin, compared to the ND group. Moreover, neuropathic patients showed reduced glomerular filtration rates compared to healthy subjects (82–103 ml/min per 1.73 m², data as range from 25th–75th percentiles), especially in the group with DMN (45–76 ml/min per 1.73 m²).

Conclusions

Some particular alterations in neuropathic patients included -but were not limited to- changes in circulating NGF, cell adhesion molecules, inflammation, and the worsening of the renal function. This study supports the need for further clinical surveillance and interventions considering a neuropathy-related basis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-017-0939-6) contains supplementary material, which is available to authorized users.

Recent advances in exploring the genetic susceptibility to diabetic neuropathy

Diabetic polyneuropathy and cardiovascular autonomic neuropathy are common and disabling complications of diabetes. Although glycaemic control and cardiovascular risk factors are major contributory elements in its development, diabetic neuropathy recognizes a multifactorial influence and a multiplicity of pathogenetic mechanisms. Thus genetic and environmental factors may contribute to its susceptibility, each with a modest contribution, by targeting various metabolic and microvascular pathways whose alterations intervene in diabetic neuropathy pathogenesis. This review is aimed at describing major data from the available literature regarding genetic susceptibility to diabetic neuropathies. It provides an overview of the genes reported as associated with the development or progression of these complications, i.e. ACE, MTHFR, GST, GLO1, APOE, TCF7L2, VEGF, IL-4, GPX1, eNOS, ADRA2B, GFRA2, MIR146A, MIR128A. The identification of genetic susceptibility can help in both expanding the comprehension of the pathogenetic mechanisms of diabetic nerve damage and identifying biomarkers of risk prediction and response to therapeutic intervention.

Association of TNFα-308, IFNγ+874, and IL10-1082 gene polymorphisms and the risk of non-small cell lung cancer in the population of the South Indian state of Telangana

BACKGROUND

Cytokine-mediated inflammation is important in the pathogenesis of non-small cell lung cancer (NSCLC). Genetic polymorphisms in cytokine genes and their association with lung cancer in the Indian population have not been reported.

METHODS

For the first time, we analyzed genetic polymorphisms of TNFα ^-308, IFNγ ⁺⁸⁷⁴, and IL10 ^-1082 genes in 246 NSCLC patients and 250 healthy controls in the South Indian population from Telangana using ARMS PCR.

RESULTS

IFNγ⁺⁸⁷⁴ A/T and IL10^-1082 G/G gene polymorphisms were found to be significantly associated with NSCLC with 1.56- and 1.68-fold disease risk, respectively. There was no association between the risk of NSCLC and TNFα^-308 polymorphism. Gene polymorphisms stratified according to smoking revealed that IFNγ⁺⁸⁷⁴ A/T polymorphisms in smokers increased the disease risk by 2.91 fold. IL10^-1082 G/G polymorphisms showed 2-fold increased risk among patients who were smokers when compared to the controls. However, there was no association between TNFα^-308, IFNγ⁺⁸⁷⁴, and IL10^-1082 gene polymorphism and the stage of the NSCLC patients. The overall risk associated with the combination of these polymorphisms indicated that the TNFα^-308 G/A + IFNγ⁺⁸⁷⁴ A/T + IL10^-1082 G/G genotype increased the risk by 1.5 fold.

CONCLUSIONS

The results of our study indicate an association between cytokine gene polymorphisms and the risk of NSCLC in an Indian population.

African vs. Caucasian and Asian difference for the association of interleukin-10 promotor polymorphisms with type 2 diabetes mellitus (a meta-analysis study)

Background

Interleukin-10 (IL-10) is a multifunctional regulatory cytokine that might be associated with increased risk of type 2 diabetes mellitus (T2DM). IL-10 gene polymorphisms have been reported to be associated with T2DM in several ethnic populations with controversial results.

Objectives

This work is an updated meta-analysis aiming at the evaluation of the association between IL-10 gene polymorphisms: rs1800872 (− 592 C > A), rs1800896 (− 1082 A > G) and rs1800871 (− 819 C > T) with the risk of T2DM.

Methods

All available full text studies published up to July 2015 were included in this meta-analysis. Mainly Pubmed and Science Direct databases were searched for all eligible studies pertinent to testing the association between IL-10 gene polymorphisms with the susceptibility to T2DM. Further analyses of the pooled and stratified data in terms of individual polymorphic types and subject ethnicity were done and assessed using varied genetic models.

Results

Fifteen case-control studies with a total of 26 comparisons (10 for IL-10 − 592 C > A rs1800872, 11 for IL-10 − 1082 A > G rs1800896 and 5 for IL-10 − 819 C > T rs1800871 polymorphisms) met our inclusion criteria. IL-10 − 1082 A > G polymorphism was the only one to show an association with T2DM in all pooled sample particularly among Asian and European (high frequency of the G allele) ethnic groups. On the other hand, IL-10 − 592 C > A and − 819 C > T were significantly associated with T2DM only among African subjects.

Conclusions

This meta-analysis demonstrated that IL-10 − 1082 A > G polymorphism was associated with increased risk of development of T2DM in total subjects no matter was their ethnic background, while both IL-10 − 592 C > A and − 819 C > T polymorphisms were associated with that risk only among African subjects.

Association of tumor necrosis factor-alpha and interferon gamma gene polymorphisms and their plasma levels in leprosy, HIV and other peripheral neuropathies

OBJECTIVE

Mycobacterium leprae and Human Immunodeficiency Virus (HIV) are causative agents known to be involved in nerve damage in leprosy and HIV-peripheral neuropathy (HIV-PN) respectively. Among other peripheral neuropathies the most common is diabetic neuropathy, which is metabolically induced. The proinflammatory cytokines TNF-α and IFN-γ have been implicated in the pathogenesis of peripheral neuropathy. The association between the plasma levels of these cytokines and their single nucleotide polymorphisms (SNPs) were investigated in leprosy neuropathy (LN), HIV-PN and other peripheral neuropathies (OPN).

METHODS

Eighty-eight individuals with LN (PB=36; MB=52), 39 with HIV-PN, 52 patients with OPN, 101 HIV positive individuals without neuropathy (HIV) and 113 healthy subjects (HS) were included in the study. Plasma cytokine levels were measured by sandwich ELISA and one way ANOVA was carried out among the groups. SNPs of TNF-α- 308 G/A, -238 G/A and IFN-γ +874 T/A were investigated by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Their frequencies were compared between groups by Pearson's chi squared test.

RESULTS

Plasma TNF-α and IFN-γ was significantly increased in LN (p<0.05), HIV-PN (p<0.05) and OPN (p<0.05) as compared to HS. A significant association was found between IFN-γ +874 A/A genotype in LN (p<0.05; OR=7.9), HIV-PN (p<0.05; OR=8.9) and OPN (p<0.05; OR=8.9) as compared to HS.

CONCLUSION

Elevated levels of plasma TNF-α and IFN-γ and the association of IFN-γ +874 A/A genotype SNP in LN, HIV-PN and OPN suggests a common involvement of these cytokines in susceptibility/pathogenesis of peripheral neuropathy.

Association of adiponectin gene polymorphisms with an elevated risk of diabetic peripheral neuropathy in type 2 diabetes patients

OBJECTIVE

In this study, we examined the association between two adiponectin (ADPN) gene polymorphisms, +45T/G and +276G/T, and susceptibility to diabetic peripheral neuropathy (DPN) in type 2 diabetes mellitus (T2DM) patients.

METHODS

A total of 180 T2DM patients were enrolled in this study and assigned to two groups: DPN group (n=90) and non-DPN (NDPN) group (n=90). In addition, 90 healthy subjects were chosen as healthy normal control (NC). The plasma level of ADPN was quantified by ELISA method and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotype analysis of the two ADPN polymorphisms, +45T/G (rs2241766) and +276G/T (rs1501299), in all the study subjects. Statistical analysis of data was performed with SPSS version 20.0 software.

RESULTS

Serum levels of ADPN were markedly reduced in the DPN group compared to NDPN and NC groups (all P<0.05). The frequencies of TT, TG and GG genotypes and the T and G alleles of T45G and G276T polymorphisms in DPN group were significantly different than the NDPN group (all P<0.05). Notably, T45G and G276T polymorphisms were associated with significantly reduced plasma levels of ADPN in DPN and NDPN groups, compared to the NC group (P<0.001). Significant difference in ADPN plasma levels were also observed between TT, TG and GG genotypes of T45G and G276T polymorphisms. Our results indicate that the T allele in +45T/G and +276G/T polymorphisms is correlated with an elevated risk of DPN in T2DM patients. Haplotype analysis showed that GG and GT haplotypes showed a negative relationship with DPN, while TG haplotype positively correlated with risk of DPN in T2DM patients (all P<0.05).

CONCLUSION

Our results show that T45G and G276T polymorphisms of ADPN are associated with a significantly elevated risk of DPN in T2DM patients, likely by down-regulating ADPN serum level.

Identifying Common Genetic Risk Factors of Diabetic Neuropathies

Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.

Association of a Large Panel of Cytokine Gene Polymorphisms with Complications and Comorbidities in Type 2 Diabetes Patients

AIMS

The polymorphisms of pro- and anti-inflammatory cytokines may be involved in type 2 diabetes (T2D) pathogenesis and its complications.

METHODS

We investigated in 102 T2D patients the association of the cytokine polymorphisms in the TNF-α, IL-10, IL-6, TGF-β1, and IFN-γ genes with the T2D microvascular complications and comorbidities (hypertension, dyslipidemia, and obesity). Cytokine genotypes were determined by PCR using Cytokine Genotyping Tray kit.

RESULTS

Diabetic retinopathy was associated with GG genotype and G allele in TGF-β1 codon 25C/G polymorphism (p = 0.004 and p = 0.018) and the nephropathy was associated the lower frequency of GG genotype in IL-10 -1082G/A polymorphism (p = 0.049). Hypertension was associated with the CC genotype and C allele for IL-10 -592C/A polymorphism (p = 0.013 and p = 0.009) and higher frequencies of T (p = 0.047) and C (p = 0.033) alleles of the TGF-β1 codon 10T/C and IL-10 -819T/C polymorphisms, respectively. The TGF-β1 codon 10T/C polymorphism was associated with the BMI groups (p = 0.026): the CC genotype was more frequent in the group with BMI < 25 Kg/m(2), while the TC genotype was more frequent in the group with BMI = 30 Kg/m(2).

CONCLUSIONS

Our findings suggest that TGF-β1 and IL-10 polymorphisms are involved in complications and comorbidities in T2D patients.

Genetic polymorphisms of cytokine genes in type 2 diabetes mellitus

Diabetes mellitus is a combined metabolic disorder which includes hyperglycemia, dyslipidemia, stroke and several other complications. Various groups all over the world are relentlessly working out the possible role of a vast number of genes associated with type 2 diabetes (T2DM). Inflammation is an important outcome of any kind of imbalance in the body and is therefore an indicator of several diseases, including T2DM. Various ethnic populations around the world show different levels of variations in single nucleotide polymorphisms (SNPs). The present review was undertaken to explore the association of cytokine gene polymorphisms with T2DM in populations of different ethnicities. This will lead to the understanding of the role of cytokine genes in T2DM risk and development. Association studies of genotypes of SNPs present in cytokine genes will help to identify risk haplotype(s) for disease susceptibility by developing prognostic markers and alter treatment strategies for T2DM and related complications. This will enable individuals at risk to take prior precautionary measures and avoid or delay the onset of the disease. Future challenges will be to understand the genotypic interactions between SNPs in one cytokine gene or several genes at different loci and study their association with T2DM.

Association between interleukin 10 gene polymorphisms and risk of type 2 diabetes mellitus in a Chinese population

Objective

To investigate the relationship between the interleukin 10 ( IL10) gene single nucleotide polymorphisms (SNP) −1082 G/A (rs1800896), −819 T/C (rs1800871) and −592 A/C (rs1800872) and risk of type 2 diabetes mellitus in a Chinese population.

Methods

This case–control study recruited patients with type 2 diabetes mellitus and healthy control subjects. Genotyping of the −1082 G/A (rs1800896), −819 T/C (rs1800871) and −592 A/C (rs1800872) SNPs was conducted and genotype frequencies were compared between the two groups.

Results

The study recruited 364 patients with type 2 diabetes mellitus and 677 healthy controls. Patients carrying the −1082 GG genotype had a significantly increased risk of type 2 diabetes mellitus (adjusted odds ratio [OR] 1.57, 95% confidence interval [CI] 1.03, 2.68), as did those patients carrying the −592 AA genotype (adjusted OR 1.63, 95% CI 1.06, 2.53). Subjects carrying both the −1082 GA + GG and −592 AC + AA genotypes had a significantly increased risk of type 2 diabetes mellitus (adjusted OR 2.03, 95% CI 1.24, 3.15).

Conclusions

The SNPs −1082G/A and −592 A/C increased the risk for type 2 diabetes mellitus, and could be potential targets for screening for the early detection of the risk of type 2 diabetes mellitus.

Association of IL-6, TNF-α and IL-10 gene polymorphisms with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a metabolic pro-inflammatory disorder characterized by chronic hyperglycemia and increased levels of circulating cytokines suggesting a causal role of inflammation in its etiology. Polymorphism of cytokine genes including interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were studied in T2DM patients as well as in normal healthy controls. Genomic DNA was isolated from both T2DM patients and controls followed by quantification and genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using suitable primers. The genotypic, allelic and carriage rate frequency distribution in patients and controls were analyzed by SPSS (version 15.0). Odd ratios with 95 % confidence interval was determined to describe the strength of association by logistic regression model. Double and triple combinations of genotypes were analyzed by χ(2) test. Gene-gene interaction and linkage disequilibrium tests were performed using SHEsis software. Individually, IL-6, TNF-α and IL-10 did not show any association. In double combination, IL-6 -597 GA and TNF-α -308 GG genotypes increased the risk up to 21 times and in triple combination IL-6 -597 AA, TNF-α -308 GG and IL-10 -592 CA increased the risk of T2DM up to 314 times. In gene-gene interaction allele 'A' of all studied polymorphisms increased the risk of T2DM up to 1.41 times. Our results suggest that individuals having a haplotype combination of AA, GG and CA for IL-6, TNF-α and IL-10 gene polymorphisms will have higher susceptibility and be at greater risk of developing T2DM.

Inflammation: therapeutic targets for diabetic neuropathy

There are still no approved treatments for the prevention or of cure of diabetic neuropathy, and only symptomatic pain therapies of variable efficacy are available. Inflammation is a cardinal pathogenic mechanism of diabetic neuropathy. The relationships between inflammation and the development of diabetic neuropathy involve complex molecular networks and processes. Herein, we review the key inflammatory molecules (inflammatory cytokines, adhesion molecules, chemokines) and pathways (nuclear factor kappa B, JUN N-terminal kinase) implicated in the development and progression of diabetic neuropathy. Advances in the understanding of the roles of these key inflammatory molecules and pathways in diabetic neuropathy will facilitate the discovery of the potential of anti-inflammatory approaches for the inhibition of the development of neuropathy. Specifically, many anti-inflammatory drugs significantly inhibit the development of different aspects of diabetic neuropathy in animal models and clinical trials.

Interleukin-10 -592C/A, -819C/T and -1082A/G Polymorphisms with Risk of Type 2 Diabetes Mellitus: A HuGE Review and Meta-analysis

Background

Several studies have been conducted in recent years to evaluate the risk of type 2 diabetes mellitus (T2DM) and polymorphisms of interleukin (IL)-10. However, the results remain conflicting rather than conclusive. This meta-analysis aimed to summarize the current evidence from case-control studies that evaluated this association.

Methods

We carried out a search in Medline, EMBASE, and the Chinese National Knowledge Infrastructure (CNKI) database for relevant studies. Data were extracted using a standardized form and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association.

Results

10 studies were included in our meta-analysis and systemic review. Our meta-analysis indicated that IL-10 −1082A/G polymorphism was associated with the risk of T2DM (GA vs. AA: OR = 1.21, 95% CI = 1.03–1.14; GA/GG vs. AA: OR = 1.22, 95% CI = 1.05–1.41), whereas there was no association between IL-10 −592C/A (CC/CA vs. AA: OR = 1.07, 95% CI = 0.59–1.93) or -819C/T (CC/CT vs. TT: OR = 0.93, 95% CI = 0.49–1.75) polymorphism and T2DM risk was found in our study.

Conclusions

This meta-analysis provides strong evidence that IL-10 −1082A/G polymorphism associated with risk of T2DM. However, no association of the IL-10 −592C/A or −819C/T polymorphism with T2DM risk was found. Additional well-designed large studies were required for the validation of our results.

High association of IL-4 gene intron 3 VNTR polymorphism with diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is a common disease. It is one of the late complications of diabetes mellitus. DPN can lower the quality of life by causing severe painful clinic symptoms. The aim of this study is to evaluate interleukin (IL)-4 gene variable number of tandem repeat (VNTR) polymorphism on DPN in Turkish population. Two hundred and twenty-seven DPN patients and 241 controls were enrolled in this study. Genomic DNA was isolated and genotyped using polymerase chain reaction analyses for the IL-4 gene intron 3 VNTR polymorphism. The distribution of genotype frequencies of IL-4 gene intron 3 VNTR polymorphism was statistically different between DPN patients and control group (p = 0.001). The frequency of P1 and P2 alleles was statistically different between DPN patients and control group (p = 0.00009). The results of this study suggested that intron 3 VNTR polymorphism of the IL-4 gene plays an important role in the occurrence of DPN in the Turkish population.

Association between interleukin 10 gene -1082 A/G polymorphism and the risk of type 2 diabetes mellitus: a meta-analysis of 4250 subjects

Increasing evidence suggests that interleukin 10 (IL 10) gene -1082 A/G (rsl800896) polymorphism may be associated with an increased risk of type 2 diabetes mellitus (T2DM). However, the results are inconsistent. The aim of this study is to analyze the association between this variant and the T2DM risk by meta-analysis. PubMed, Embase, Web of Science, and Google Scholar were searched from January 1, 1989 to February 17, 2012, as well as hand searching of the references of identified articles were performed. All the statistical tests were performed using Stata 11.0. Seven case-control studies were identified, covering a total of 1879 T2DM cases and 2371 controls. The results showed evidence of significant association between IL 10 gene -1082 A/G polymorphism and T2DM risk (for G/G+G/A vs. A/A: OR=1.21, 95% CI=1.05-1.40, p=0.010, p=0.040 after Bonferroni testing). In the subgroup analysis by ethnicity, no significant association was found between IL 10 gene -1082 A/G polymorphism and T2DM risk in Europeans. In summary, results from this meta-analysis provide evidence that IL 10 gene -1082 G allele is associated with increased risk of T2DM.

The linkage between inflammation and Type 2 diabetes mellitus

The Type 2 diabetes mellitus (DM2) is considered nowadays as one of the most important chronic disturbances because of the significant number of people with diabetes and its severe complications, responsible for elevated indexes of morbidity and mortality. DM2 is characterized by several degrees of insulin resistance and relative deficiency in its secretion. Genetic and environmental factors have been described as of major importance in the DM2 development as obesity, which is directly correlated with development of resistance in peripheral tissues and inflammatory state in metabolic activated adipose tissue. Inflammatory responses may have a dual role in DM2, since it may have either a causal relationship leading to resistance to insulin or may be intensified by the hyperglycemic state, resulting in DM2 complications. In this review, we discuss the association of polymorphisms in genes encoding inflammatory cytokines and the increased level of these pro-inflammatory markers, associated to chronic pathologic conditions in DM2.

Interleukin (IL)-10 gene polymorphisms are associated with type 2 diabetes with and without nephropathy: a study of patients from the southeast region of Iran

The impact of several environmental and genetic factors on diabetes and its complications is well documented. It has also been established that cytokines play a key role in the regulation of immune responses which have been shown to be important in the pathogenesis of diabetes. Studies showed that single-nucleotide polymorphisms within the -592 region of interleukin-10 (IL-10) are associated with the regulation of its expression. In this study, we aimed to find polymorphisms of this region that may be associated to type 2 diabetic (T2D) patients with and without nephropathy. In this study, peripheral blood samples were collected from 100 T2D patients without nephropathy, 100 T2D patients with nephropathy, and 100 healthy controls. DNA was extracted, and a polymerase chain reaction-restriction fragment length polymorphism technique was performed to examine the polymorphisms within the -592 region of the IL-10 gene. Our results showed a significant difference between the genotypes and alleles of the -592 region of IL-10 in nephropathic and non-nephropathic patients in comparison to the healthy controls. The differences between the two patient groups in relation to genotypes and alleles were not significant. Results of this study suggest that the functional gene polymorphism of IL-10 reported here may play an important role in the pathogenesis of diabetes, but it seems that these polymorphisms do not have an effect on the nephropathic complications of the disease.

Angiotensin-converting enzyme gene single polymorphism as a genetic biomarker of diabetic peripheral neuropathy: longitudinal prospective study

BACKGROUND

Identifying patients at risk of developing diabetic peripheral neuropathy (DPN) is of paramount importance in those with type 2 diabetes mellitus (T2DM) to provide and anticipate secondary prevention measures as well as intensify action on risk factors, particularly so in primary care. Noteworthy, the incidence of DPN remains unknown in our environment.

AIMS

(i) To analyze a single angiotensin-converting enzyme (ACE) gene polymorphism (D/I) as a genetic marker of risk of developing DPN, and (ii) to determine the incidence of DPN in our environment.

RESEARCH DESIGN AND METHODS

Longitudinal study with annual follow-up for 3years involving a group of T2DM (N=283) randomly selected. ACE gene polymorphism distribution (I=insertion; D=deletion) was determined. DPN was diagnosed using clinical and neurophysiology evaluation.

RESULTS

Baseline DPN prevalence was 28.97% (95% CI, 23.65-34.20). ACE polymorphism heterozygous genotype D/I presence was 60.77% (95% CI, 55.05-66.5) and was independently associated with a decreased risk of DPN (RR, 0.51; 95% CI, 0.30-0.86). DPN correlated with age (P<0.001) but not with gender (P=0.466) or time of evolution of T2DM (P=0.555). Regarding end point, DPN prevalence was 36.4% (95% CI, 30.76-42.04), and accumulated incidence was 10.4% 3years thereafter. In the final Poisson regression analysis, the presence of heterozygous genotype remained independently associated with a decreased risk of DPN (RR, 0.71; (95% CI, 0.53-0.96). DPN presence remained correlated with age (P=0.002), but not with gender (P=0.490) or time of evolution (P=0.630).

CONCLUSIONS

In our series, heterozygous ACE polymorphism (D/I) stands as a protective factor for DPN development. Accumulated incidence of DPN was relevant. Further prospective studies are warranted.

Can immune-related genotypes illuminate the immunopathogenesis of cytomegalovirus disease in human immunodeficiency virus-infected patients?

Most human immunodeficiency virus (HIV) patients are seropositive for cytomegalovirus (CMV) but a smaller proportion experience end-organ disease. This observation may reflect variations in genes affecting inflammatory and natural killer cell responses. DNA samples were collected from 240 HIV-infected patients followed at the University Hospitals/Case Medical Center (Cleveland, OH) between 1993 and 2008. Seventy-eight patients (African Americans = 41, Caucasians = 37) experienced CMV disease. Genotypes were determined using allele-specific fluorescent probes or multiplex polymerase chain reaction sequence-specific primers. IL12B3'UTR*(1) and SLC11A1 D543N*(1,2) were associated with CMV disease in African American patients (p = 0.04 and p = 0.02, respectively). IL10-1082*(1,2) and LILRB1 I142T*(1) were associated with CMV disease in Caucasians (p = 0.02 and p = 0.07, respectively). DARC T-46C*(1) and CD14 C-159T*(2) were associated with low nadir CD4(+) T cell counts in African American patients (p = 0.002 and p = 0.01, respectively). Caucasian patients carrying TNFA-308*2, TNFA-1031*(2), IL2-330*(1), CCL2-2518*(2), or LILRB1 I142T*(1) had significantly lower nadir CD4(+) T cells in a bootstrapped multivariable model (p = 0.006-0.02). In general, polymorphisms associated with CMV disease and CD4(+) T cell counts were distinct in Caucasian and African American patients in the United States. The LILRB1 I142T polymorphism was associated with both CMV disease and low nadir CD4(+) T cell counts in Caucasians, but the clearest determinant of low nadir CD4(+) T cell count in African American patients was DARC T-46C.

Metabolic correction in the management of diabetic peripheral neuropathy: improving clinical results beyond symptom control

Current Clinical Management Guidelines of Diabetic Peripheral Neuropathy (DPN) are based on adequate glucose control and symptomatic pain relief. However, meticulous glycemic control could delay the onset or slow the progression of diabetic neuropathy in patients with DM type 2, but it does not completely prevent the progression of the disease. Complications of DPN as it continues its natural course, produce increasing pain and discomfort, loss of sensation, ulcers, infections, amputations and even death. In addition to the increased suffering, disability and loss of productivity, there is a very significant economic impact related to the treatment of DPN and its complications. In USA alone, it has been estimated that there are more than 5,000,000 patients suffering from DPN and the total annual cost of treating the disease and its complications is over $10,000 million dollars. In order to be able to reduce complications of DPN, it is crucial to improve or correct the metabolic conditions that lead to the pathology present in this condition. Pathophysiologic mechanisms implicated in diabetic neuropathy include: increased polyol pathway with accumulation of sorbitol and reduced Na+/K+-ATPase activity, microvascular damage and hypoxia due to nitric oxide deficit and increased oxygen free radical activity. Moreover, there is a decrease in glutathione and increase in homocysteine. Clinical trials in the last two decades have demonstrated that the use of specific nutrients can correct some of these metabolic derangements, improving symptom control and providing further benefits such as improved sensorium, blood flow and nerve regeneration. We will discuss the evidence on lipoic acid, acetyl-L-carnitine, benfotiamine and the combination of active B vitamins L-methylfolate, methylcobalamin and piridoxal-6-phosphate. In addition, we discuss the role of metformin, an important drug in the management of diabetes, and the presence of specific polymorphic genes, in the risk of developing DPN and how metabolic correction can reduce these risks.

Systemic and spinal administration of etanercept, a tumor necrosis factor alpha inhibitor, blocks tactile allodynia in diabetic mice

Painful diabetic neuropathy is one of the most common forms of neuropathic pain syndromes. Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that has been implicated as a key pain mediator in the development and maintenance of neuropathic pain conditions. Recent studies showed that endogenous TNF-alpha production was also accelerated in neural tissues and spinal cord under chronic hyperglycemia. Thus, in this study, we investigated whether pharmacological inhibition of TNF-alpha by etanercept, a TNF-alpha antagonist, could block behavioral sign of diabetic neuropathic pain. Diabetes was induced by streptozotocin (STZ) (200 mg/kg, i.p.) in Balb-c mice and behavioral tests were performed between 45 and 60 days after STZ administration. Mechanical and thermal sensitivities were measured by a series of calibrated Von Frey filaments and hot plate test, respectively. Etanercept was given by either intravenous (i.v.), intrathecal (i.th.) or intraplantar (i.pl.) routes to the diabetic mice. Tactile allodynia, but not thermal hyperalgesia, developed in diabetic mice. Both i.v. (1, 10 and 20 mg/kg) or i.th. (1, 5 and 10 μg/mouse) treatments with etanercept produced dose dependent reversal of tactile allodynia in diabetic mice. However, etanercept was found to be inactive against allodynia when given i.pl. (1, 5 and 10 μg/mouse). Our results suggest that etanercept has promising effects on diabetic neuropathic pain with antiallodynic effects when given systemically or intrathecally.

Differential gene expression pattern of diabetic rat retinas after intravitreal injection of erythropoietin

BACKGROUND

To profile the pattern of gene expression in diabetic rat retinas with or without intravitreal injection of erythropoietin.

DESIGN

By using streptozotocin-induced diabetic rats, after intravitreal injection of erythropoietin, neurosensory retinas were collected to determine the effect of erythropoietin on gene expression.

PARTICIPANTS

Three groups of Sprague-Dawley rats were studied: normal control (15), diabetic rats with saline injection (15) and diabetic rats with intravitreal erythropoietin treatment (15).

METHODS

Diabetes was induced by intra-peritoneal injection of streptozotocin. Intravitreal injection of erythropoietin was performed at the following time points: 0, 30 and 120 days after diabetes onset. Four days after each injection at above-mentioned time points, the retinas were harvested for microarray assay. The real-time PCR was used to evaluate the microarray data.

RESULTS

Genes encoding inflammatory factors, such as interleukin-2 and interleukin-11, which were upregulated in the diabetic retinas, were restored after erythropoietin treatment. Genes encoding pro-apoptotic effectors, like Tnfrsf5, Bid3 and Bcl2l1, were also upregulated in diabetic rats and attenuated in erythropoietin-treated group. In addition, real-time PCR were employed to confirm the changes of the genes Trex2, G1P2, DHX58, RGD1311906 and LOC689064, which have not been reported in diabetic retinopathy.

CONCLUSIONS

Intravitreal erythropoietin treatment is able to normalize the gene expression responsible for pro-apoptotic and inflammatory responses noted in diabetic retinas.

Suppressing an anti-inflammatory cytokine reveals a strong age-dependent survival cost in mice

Background

The central paradigm of ecological immunology postulates that selection acts on immunity as to minimize its cost/benefit ratio. Costs of immunity may arise because the energetic requirements of the immune response divert resources that are no longer available for other vital functions. In addition to these resource-based costs, mis-directed or over-reacting immune responses can be particularly harmful for the host. In spite of the potential importance of immunopathology, most studies dealing with the evolution of the immune response have neglected such non resource-based costs. To keep the immune response under control, hosts have evolved regulatory pathways that should be considered when studying the target of the selection pressures acting on immunity. Indeed, variation in regulation may strongly modulate the negative outcome of immune activation, with potentially important fitness consequences.

Methodology/Principal Findings

Here, we experimentally assessed the survival costs of reduced immune regulation by inhibiting an anti-inflammatory cytokine (IL-10) with anti-IL-10 receptor antibodies (anti-IL-10R) in mice that were either exposed to a mild inflammation or kept as control. The experiment was performed on young (3 months) and old (15 months) individuals, as to further assess the age-dependent cost of suppressing immune regulation. IL-10 inhibition induced high mortality in old mice exposed to the mild inflammatory insult, whereas no mortality was observed in young mice. However, young mice experienced a transitory lost in body mass when injected with the anti-IL-10R antibodies, showing that the treatment was to a lesser extent also costly for young individuals.

Conclusions

These results suggest a major role of immune regulation that deserves attention when investigating the evolution of immunity, and indicate that the capacity to down-regulate the inflammatory response is crucial for late survival and longevity.