TGF-β1 and IGF-I gene variations in type 1 diabetes microangiopathic complications

Association of the Combined Effects between Insulin-Like Growth Factor-1 Gene Polymorphisms and Negative Life Events with Major Depressive Disorder among Chinese population in the Context of Oxidative Stress

Background

Oxidative stress may be increased in a number of psychiatric disorders, including major depressive disorder (MDD). MDD has been shown to be related to insulin-like growth factor-1 (IGF-1) as well as to negative life events; exploring the interaction of IGF-1 polymorphisms and negative life events on the risk of MDD is needed. The aim of this study was to analyze the single and combined effects of IGF-1 polymorphisms (rs972936 and rs978458) and negative life events with MDD among Chinese population.

Methods

420 MDD patients (according to DSM-V) and 420 age- and gender-matched control subjects were recruited in a case-control study. Negative life events were assessed using standard rating scales. IGF-1 rs972936 and rs978458 were identified by sequencing. The chi-square (χ²) tests were performed to explore the association of negative life events and IGF-1 polymorphisms with MDD.

Results

Our results found that the negative life events were associated with the risk of MDD (P < 0.001; OR = 3.28, 95% CI: 2.19-4.85). The genotypes of IGF-1 were associated with the risk of MDD (P < 0.001); carrying the IGF-1 rs972936 C allele (OR = 1.53, 95% CI: 1.26-1.85) and rs978458 T allele (OR = 1.92, 95% CI: 1.58-2.34) had a higher risk of MDD. The combined effects between IGF-1 rs978458 and negative life events were associated with the risk of MDD (P < 0.05; OR = 2.94, 95% CI: 1.23-7.03), but IGF-1 rs972936 was not associated (P > 0.05).

Conclusions

Based on the oxidative stress hypothesis, we confirm that carrying IGF-1 rs972936 C allele and rs978458 T allele have a higher risk of MDD and the combined effects between IGF-1 rs978458 and negative life events were associated with the risk of MDD among Chinese population.

Dietary Acid Load and Its Interaction with IGF1 (rs35767 and rs7136446) and IL6 (rs1800796) Polymorphisms on Metabolic Traits among Postmenopausal Women

The objective of this study was to explore the effects of dietary acid load (DAL) and IGF1 and IL6 gene polymorphisms and their potential diet–gene interactions on metabolic traits. A total of 211 community-dwelling postmenopausal women were recruited. DAL was estimated using potential renal acid load (PRAL). Blood was drawn for biochemical parameters and DNA was extracted and Agena^® MassARRAY was used for genotyping analysis to identify the signalling of IGF1 (rs35767 and rs7136446) and IL6 (rs1800796) polymorphisms. Interactions between diet and genetic polymorphisms were assessed using regression analysis. The result showed that DAL was positively associated with fasting blood glucose (FBG) (β = 0.147, p < 0.05) and there was significant interaction effect between DAL and IL6 with systolic blood pressure (SBP) (β = 0.19, p = 0.041). In conclusion, these findings did not support the interaction effects between DAL and IGF1 and IL6 single nucleotide polymorphisms (rs35767, rs7136446, and rs1800796) on metabolic traits, except for SBP. Besides, higher DAL was associated with higher FBG, allowing us to postulate that high DAL is a potential risk factor for diabetes.

Oxidative Stress as the Main Target in Diabetic Retinopathy Pathophysiology

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus (DM) causing vision impairment even at young ages. There are numerous mechanisms involved in its development such as inflammation and cellular degeneration leading to endothelial and neural damage. These mechanisms are interlinked thus worsening the diabetic retinopathy outcome. In this review, we propose oxidative stress as the focus point of this complication onset.

Pro-apoptotic effects of micro-ribonucleic acid-365 on retinal neurons by targeting insulin-like growth factor-1 in diabetic rats: An in vivo and in vitro study

AIMS/OBJECTIVE

The present study aimed to explore the effects of micro-ribonucleic acid-365 (miR-365) on apoptosis of retinal neurons by targeting insulin-like growth factor-1 (IGF-1) in diabetes mellitus rats.

MATERIALS AND METHODS

High glucose-induced retinal neurons were assigned into the blank (with no plasmid transfection), negative control (with plasmid transfection), anti-miR-365 (transfected miR-365 antagomir), transfected IGF-1 short hairpin RNA plasmid (sh-IGF-1) and transfected miR-365 antagomir and IGF-1 shRNA plasmid (anti-miR-365 + sh-IGF-1) groups. Proliferation and apoptosis of retinal neurons were detected by 5-ethynyl-2'-deoxyuridine assay and Hoechst 33342 staining, respectively. Expressions of miR-365, IGF-1, Bcl-2-associated X protein (Bax) and Bcl-2 were determined by reverse transcription quantitative polymerase chain reaction and western blotting. A control group contained 10 healthy rats. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining was used to evaluate apoptosis of retinal neurons in rats.

RESULTS

In the anti-miR-365 group, the apoptosis rate and Bax expression were reduced in comparison with the negative control and blank groups, whereas the sh-IGF-1 and anti-miR-365 + sh-IGF-1 groups presented an opposite trend. Compared with the normal group, expressions of miR-365 and Bax were increased, and expressions of IGF-1 and Bcl-2 were decreased, with more apoptotic cells in diabetes mellitus rat models. The sh-IGF-1 group had lower Bax expression, and higher expressions of IGF-1 and Bcl-2 with fewer apoptotic cells. Additionally, Bax expression was upregulated, expressions of IGF-1 and Bcl-2 were downregulated, and apoptotic cells were higher in the anti-miR-365 + sh-IGF-1 groups than the anti-miR-365 group.

CONCLUSION

The results of the present study suggest that suppressed miR-365 increases the IGF-1 expression, leading to anti-apoptotic effects on retinal neurons in diabetic rats.

IGF1 gene polymorphisms associated with diabetic retinopathy risk in Chinese Han population

Objective

This study aimed to explore the association of insulin-like growth factor 1 gene (IGF1) polymorphisms with diabetic retinopathy (DR) in a Chinese Han population.

Methods

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping. Genotype frequencies were compared by chi-square test. Odds ratio (OR) with 95% confidence interval (95%CI) was calculated to express the risk intensity of DR. Linkage disequilibrium between IGF1 polymorphisms was analyzed by Haploview. Serum IGF1 concentration was measured by enzyme-linked immunosorbent assays (ELISA) and assessed by student's t test.

Results

AG genotype of rs6218 and TT genotype of rs35767 were significantly associated with the elevated risk of DR (rs6218: OR=1.77, P=0.04; rs35767: OR=2.32, P=0.03) and type II diabetes mellitus (T2DM) (rs6218: OR=1.92, P=0.00. rs35767: OR=2.29, P=0.02). Only T allele of rs35767 significantly increased the risk of DR (OR=1.45, P=0.04), however, rs6218 (OR=1.92, P=0.00), rs35767 (OR=0.02, P=0.02) and rs5742612 (OR=2.21, P=0.04) showed obvious association with T2DM. Haplotypes were only associated with T2DM, but not DR. Minor allele homozygote of rs35767 was obviously correlated with serum IGF1 level.

Conclusion

IGF1 rs6218 and rs35767 polymorphisms contribute to the risk of DR. IGF1 rs35767 polymorphism may participate in the regulation of serum IGF1 concentration in DR.

Effects of Cordyceps sinensis on the Expressions of NF-κB and TGF-β1 in Myocardium of Diabetic Rats

Objective. To investigate the effect of Cordyceps sinensis (CS) on the expressions of NF-κB and TGF-β1 in myocardium of streptozotocin-induced diabetic rats. Methods. A total of 53 healthy male SD rats, mice age of 8 weeks and weight of 220 ± 20 g, were randomly divided into five groups by randomized block design: normal control group (n = 10), diabetic group (n = 10), low dose of CS group (n = 12; CS 0.6 g·kg(-1)·d(-1)), middle dose of CS group (n = 11; CS 2.5 g·kg(-1)·d(-1)), and high dose of CS group (n = 10; CS 5 g·kg(-1)·d(-1)). The diabetic models with tail intravenous injection by streptozotocin (45 mg·kg(-1)). Diabetic rats were sacrificed after 8 weeks; the expressions of NF-κB and TGF-β1 proteins and mRNA in the cardiac muscle were determined by using immunohistochemistry staining and reverse transcription polymerase chain reaction (RT-PCR) method. The data were analyzed using one factor analysis of variance. Result. The expressions of NF-κB and TGF-β1 proteins and mRNA in the cardiac muscle of diabetic rats were significantly raised (P < 0.05), which could be decreased by CS (P < 0.05). Conclusions. The changes on the expressions of NF-κB and TGF-β1 in myocardium may be involved in the occurrence of diabetic cardiomyopathy (DC). CS may play its role on myocardial protection by regulating the expressions of NF-κB and TGF-β1 in myocardium.

Update on genetics and diabetic retinopathy

Clinical risk factors for diabetic retinopathy (DR), such as duration of disease and degree of glucose control, do not adequately predict disease progression in individual patients, suggesting the presence of a genetic component. Multiple smaller studies have investigated genotype–phenotype correlations in genes encoding vascular endothelial growth factor, aldose reductase, the receptor for advanced glycation end products, and many others. In general, reported results have been conflicting, due to factors including small sample sizes, variations in study design, differences in clinical end points, and underlying genetic differences between study groups. At this time, there is no confirmed association with any risk allele reported. As we continue to collect data from additional studies, the role of genetics in DR may become more apparent.

Association of transforming growth factor-β1 polymorphisms with the risk of diabetes mellitus

The association between transforming growth factor-β1 (TGF-β1) polymorphisms with the risk of diabetes mellitus (DM) remains elusive. We aimed to evaluate the relationship between TGF-β1 polymorphisms and DM risk. We searched the association studies according to a predefined criteria using electronic databases. The strength of association between TGF-β1 codon 10/25 polymorphisms and the risk of DM was evaluated by odds ratio (OR) with the corresponding 95% confidence interval (CI). Six case-control studies were identified for the analysis of the association between TGF-β1 codon 10/25 polymorphism and the risk of DM. CC genotype at the codon 10 polymorphism was associated with the risk of type 2 DM (T2DM) (P = 0.026, OR = 1.397, 95% CI = 1.041-1.874). No marked association was observed between codon 25 polymorphism and the risk of DM. No evidence of marked publication bias was observed. CC genotype at the TGF-β1 codon 10 site may be an indicator for the risk of T2DM. However, further larger studies should be performed in the future.

Association of chemokine ligand 5/chemokine receptor 5 gene promoter polymorphisms with diabetic microvascular complications: A meta-analysis

Aims/Introduction

Chemokine ligand 5 (CCL5) is a member of the CC‐chemokine family expressed in various organs. It contributes to the migration of monocytes/macrophages into injured vascular walls by binding with its receptor chemokine receptor 5 (CCR5). Many studies have accessed the association between CCL5/CCR5 gene promoter polymorphisms and diabetic microvascular complications (DMI). However, the results are conflicting and inconclusive. The aim of the present study was to evaluate the association more precisely.

Materials and Methods

Trials were retrieved through PubMed, Embase, Medline, China National Knowledge Infrastructure, Web of Science and Cochrane database without restrictions on language. The pooled odds ratio (OR) and 95% confidence interval (CI) were used to describe the strength of association with DMI.

Results

Data were obtained from 11 case–control studies that included 2,737 DMI patients and 2,435 diabetic control subjects. In the overall analysis, the CCL5‐403 G/A and CCL5‐28 C/G gene polymorphisms were not significantly associated with the risk of DMI. However, CCR5‐59029 G/A was an independent risk factor of DMI in a dominant model (OR 1.77, 95% CI 1.06–2.97). Subgroup analysis showed that the risk of the CCR5 59029A‐positive genotype was significant in Asians (OR 2.08, 95% CI 1.68–2.57). In addition, the CCR5 59029A‐positive genotype was associated with increased risk of albuminuria.

Conclusions

There were no associations of CCL5 gene promoter polymorphism with the risk of DMI. However, the 59029A polymorphism in CCR5 might affect individual susceptibility for DMI.