Gene-environment interaction between adiponectin gene polymorphisms and environmental factors on the risk of diabetic retinopathy

The Association between ADIPOQ Gene Polymorphisms and Diabetic Retinopathy Risk: A Systematic Review and Meta-Analysis

Background and Objectives: Recent studies have focused on the association between the risk of diabetic retinopathy (DR) and the rs1501299 and rs2241766 polymorphisms of the ADIPOQ gene; however, their results remain inconclusive. Thus, a systematic review and meta-analysis were carried out to clarify the role of these polymorphisms in the development of DR. Materials and Methods: A systematic search of electronic databases (PubMed, Scopus, and Cochrane Library) was conducted until 25 June 2024, and a reference list of relevant articles was collected, which explored the association between the rs1501299 and rs2241766 polymorphisms of the ADIPOQ gene and the risk of DR. The pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated via random-effects model, and the meta-analysis was implemented by using Review Manager 5.4. Results: In total, 6 out of 182 studies, with 1888 cases (DR) and 2285 controls (without DR), were included in the meta-analysis. A statistically significant association between the rs1501299 polymorphism and the DR risk was recorded in G vs. T in the overall analysis (OR = 0.84, 95% CI = 0.72-0.99, p = <0.05, I2 = 23%, n = 5 studies). Additionally, the summary results in the subgroup analysis according to the control type were as follows: the DR versus diabetes mellitus (DM) control type revealed a statistically significant association in G vs. T: OR = 0.81, 95% CI = 0.67-0.97, p = <0.05, I2 = 27%, n = 4 studies; GG vs. GT: OR = 0.72, 95% CI = 0.53-0.98, p = <0.05, I2 = 49%, n = 4 studies; GG vs. (GT + TT): OR = 0.73, 95% CI = 0.55-0.96, p = <0.05, I2 = 44%, n = 4 studies. No significant association was observed between the rs2241766 polymorphism and the DR risk. Conclusions: The current meta-analysis supports the association between the rs1501299 polymorphism of the ADIPOQ gene and the DR risk in patients with DM.

Potential Protective Function of Adiponectin in Diabetic Retinopathy

Adiponectin, one of the most ubiquitous adipokines found in the blood, plays a major role in glucolipid metabolism and energy metabolism and regulation. In recent years, a growing body of research indicates that adiponectin also plays a significant role in diabetic retinopathy. In the present review, we specifically address the protective effects of adiponectin on the development and progression of diabetic retinopathy through improvement in insulin resistance, alleviation of oxidative stress, limiting of inflammation, and prevention of vascular remodeling, with the aim to explore new potential approaches and targets for the prevention and treatment of diabetic retinopathy.

The association of AGER and ALDH2 gene polymorphisms with diabetic retinopathy

PURPOSE

To evaluate the possible associations between AGER (rs1051993, rs2070600) and ALDH2 (rs671) gene polymorphisms with nonproliferative (NPDR) and proliferative (PDR) diabetic retinopathy, in a well-defined Greek population.

MATERIALS

66 NPDR patients and 57 PDR patients participated in our study, along with 156 age- and gender-matched healthy-control subjects (CL). All the participants underwent a complete ophthalmological examination, while clinical and demographic data were collected. Furthermore, they were genotyped for the studied polymorphisms.

RESULTS

No significant differences were detected among the studied groups regarding the participants' age and gender status. We found that the ALDH2 AA genotype was significantly more frequent in PDR patients than in CL (p = 0.014). Furthermore, between NPDR and PDR groups, the AGER rs1051993 GT and TT genotype frequencies were significantly elevated in PDR patients (p < 0.0001 and 0.04, respectively). Moreover, we demonstrated that the heterozygous GT genotype in DR patients is accompanied by 71.11 times higher risk of developing PDR (OR = 71.11: 95% CI- 4.14-1215.2), while the homozygous TT genotype is associated with 12.71 times elevated risk for PDR development (OR = 12.71: 95% CI- 0.63-254.1).

CONCLUSIONS

We documented that the ALDH2 AA and AGER rs1051993 GT and TT genotypes were observed significantly more frequently in PDR Greek diabetic patients. Our findings also support the genetic theory, suggesting that heritability is significantly implicated in the development of DR, providing additional evidence in the understanding of DR pathogenesis.

Polymorphism analysis of ADIPOQ gene in Greek patients with diabetic retinopathy

BACKGROUND

Several genetic polymorphisms have been identified as risk factors for diabetic retinopathy (DR) onset. The purpose of our study was to determine whether ADIPOQ rs1501299 and rs2241766 gene polymorphisms are associated with DR in a cohort of Greek diabetic patients.

MATERIALS AND METHODS

218 patients with type-2 diabetes mellitus (T2DM) were included in the study; 109 suffered from DR and 109 not. All the participants underwent a complete ophthalmological examination, while clinical and demographic data were assessed. Furthermore, they were genotyped for G276T (rs1501299) and T45G (rs2241766) single nucleotide polymorphisms of ADIPOQ gene.

RESULTS

Between the studied groups, no significant differences were detected regarding the demographic and clinical data (p > .05 for all), except for hemoglobin A1c levels and frequency of insulin treatment (higher in DR patients). We detected that the frequency of rs1501299 GT genotype was significantly elevated in DR patients (53% vs. 34%, p = .004) and was associated with a higher risk of developing retinopathy (OR 2.31, 95% CI 1.30-4.11). Furthermore, we demonstrated that the rs1501299 GT genotype was significantly and independently associated with increased odds for DR development in diabetic subjects (OR 2.68, 95% CI 1.38-5.21, p = .004), regardless of the impact of other known risk factors.

CONCLUSIONS

We documented that rs1501299 GT genotype could be recognized as an independent risk factor of retinopathy in T2DM Greek patients, while no role for rs2241766 polymorphism was identified. Further research in different ethnic groups will clarify the exact association of these polymorphisms with the risk of DR development.

Adiponectin Gene Polymorphism (rs17300539) Has No Influence on the Occurrence of Metabolic Syndrome in Women with Polycystic Ovary Syndrome

Adiponectin (rs17300539) is implicated in the pathogenesis of metabolic syndrome (MS), a common comorbidity of polycystic ovarian syndrome (PCOS). The aim of this study was to analyze the association between adiponectin gene polymorphism and incidence of MS in patients with PCOS. The study included 201 women (age 18 to 35 years), among them 81 patients with PCOS without concomitant MS, 70 subjects with PCOS and concomitant, and 50 regularly menstruating controls. Adiponectin gene polymorphism (11391 G/A, rs17300539) was determined by means of a real-time PCR. The study groups did not differ significantly in terms of their age and frequencies of various genotypes of the adiponectin gene polymorphism. The largest proportion in the whole group was Caucasian women (n = 178, 88.56%), who carried the GG genotype of the polymorphism; frequencies of GA and AA genotypes in the whole study group were 10.94% (n = 22) and 0.5% (n = 1), respectively. The presence of G or A allele of the rs17300539 adiponectin gene polymorphism was not associated with a greater likelihood of PCOS with/without concomitant MS. The hereby presented findings imply that MS is a common comorbidity in women with PCOS. However, the incidence of concomitant MS does not seem to be associated with adiponectin gene polymorphism.

Association of Serum Adiponectin with Intima Media Thickness of Dorsalis Pedis Artery and Macroangiopathy in Type 2 Diabetes

OBJECTIVE

To investigate the association of the serum adiponectin level with the intima media thickness of the dorsalis pedis artery (D-IMT) and macroangiopathy in type 2 diabetes (T2DM).

METHODS

We recruited 173 patients with T2DM, of whom 83 had macroangiopathy (MA group) and 90 did not have macroangiopathy (NM group), and 40 normal control subjects (NC group). We measured D-IMT using color B-mode Doppler ultrasonography. Serum adiponectin, blood glucose, lipids, and other clinical characteristics were analyzed. Participants were divided into three subgroups according to serum adiponectin level (high, moderate, and low).

RESULTS

Compared with the NM and NC groups, serum adiponectin levels were significantly decreased in the MA group after adjusting for sex and body mass index. Compared with the NM and NC groups, D-IMT was significantly increased in the MA group. Compared with the moderate- and high-adiponectin subgroups, D-IMT was significantly increased in the low-adiponectin subgroup. The prevalence of diabetic macroangiopathy increased gradually with decreasing adiponectin levels. After controlling for age, sex, smoking, and alcohol drinking, partial correlation analysis showed that adiponectin was negatively correlated with D-IMT. Elevated serum adiponectin was independently associated with a decreased risk for diabetic macroangiopathy by logistic regression analysis. Multiple linear regression analysis revealed that adiponectin was an independent factor of D-IMT. In receiver operating characteristic analyses, the area under the curve for traditional risk factors plus adiponectin for prediction of macroangiopathy was 0.984, while that of traditional risk factors alone was 0.972.

CONCLUSIONS

Adiponectin is lower in patients with T2DM with macroangiopathy. We suggest that D-IMT could represent a noninvasive indicator of diabetic macroangiopathy. Decrease of adiponectin as an independent risk factor for both macroangiopathy and D-IMT among Chinese patients with T2DM suggests that adiponectin might have clinical utility in the prediction of diabetic macroangiopathy. This clinical trial is registered in the "Chinese Clinical Trial Registry." The registration number is ChiCTR-ROC-17011731.

Physical activity and risk of diabetic retinopathy: a systematic review and meta-analysis

AIMS

Diabetic retinopathy (DR) is an important microvascular complication of diabetes mellitus (DM) and a leading cause of visual impairment and blindness among people of working age. Physical activity (PA) or exercise is critical and beneficial for DM patients, whereas studies evaluating the relationship between PA and DR have yielded inconsistent and inconclusive results. The American Diabetes Association's "Standards of Medical Care in Diabetes" has also pointed out the indeterminate roles of PA in DR prevention. The purpose of this systematic review and meta-analysis was to explore the association between PA and DR risk.

METHODS

Medline (accessed by PubMed), EmBase, and Cochrane Library were systematically searched for studies up to June 2018, and the reference lists of the published articles were searched manually. The association between PA and DR risk was assessed using random-effect meta-analysis.

RESULTS

Twenty-two studies were included in this meta-analysis. PA was found to have a protective association with DR [risk ratio (RR) = 0.94, 95% confidence interval (95% CI) 0.90-0.98, p = 0.005] in diabetic patients, and the impact was more pronounced on vision-threatening DR (RR = 0.89, 95% CI 0.80-0.98, p = 0.02). Sedentary behavior could increase the risk of DR (RR = 1.18, 95% CI 1.01-1.37, p = 0.04). Moderate-intensity PA was likely to have a slight protective effect (RR = 0.76, 95% CI 0.58-1.00, p = 0.05).

CONCLUSION

PA is associated with lower DR risk, and more studies should focus on the causality between them.

Effect of adiponectin level and genetic variation of its receptors on diabetic retinopathy: A case-control study

Adiponectin (APN) and its receptors have been reported to be associated with metabolic phenotypes. To better understand the effects of APN levels and its receptors on diabetic retinopathy (DR), we investigated the association of the plasma APN level and variations in APN-related genes with DR, individually and in combination.Patients with type 2 diabetes (T2D; N = 1604), above 20 years of age from the Taiwanese population participated in the study. Demographic information, blood pressure, and serological markers were recorded at enrollment. Genomic DNA was isolated and genotyped. The plasma APN levels were measured by enzyme-linked immunosorbent assay.T2D patients with DR (N = 632) had diabetes for a longer duration, and had higher HbA1c, and systolic and diastolic blood pressure compared to those without DR (N = 972) (P < .001, for all the parameters). Overall, 10 single nucleotide polymorphisms (SNPs) in ADIPOQ and CDH13 susceptibility loci were associated with DR. Gene risk score (GRS) was calculated based on 10 SNPs for each subject and the cumulative effect of genes was observed. Among the subjects with plasma APN level (N = 518), natural logarithm (LN) of APN (LN [APN]; odds ratio [OR] = 1.63, 95% confidence interval [CI] = 1.19-2.25) and GRS (OR = 1.90, 95% CI = 1.11-3.26 for middle range of GRS, and OR = 2.61, 95% CI = 1.48-4.59 for high range of GRS) were independent risk factors for DR after adjustment for other parameters.In conclusion, the plasma APN level and the genetic variations in adiponectin receptors were associated with DR.

Association of Polymorphisms in miRNA Processing Genes With Type 2 Diabetes Mellitus and Its Vascular Complications in a Southern Chinese Population

Objective: To evaluate the potential association between the genetic variants in miRNA processing genes (RAN, XPO5, DICER1, and TARBP2) and susceptibility to type 2 diabetes mellitus (T2DM) and its vascular complications, as well as to further investigate their interaction with environmental factors in type 2 diabetes. Methods: We conducted a case-control study in genotyping of five polymorphic loci, including RAN rs14035, XPO5 rs11077, DICER1 rs13078, DICER1 rs3742330, and TARBP2 rs784567, in miRNA processing genes to explore the risk factors for T2DM and diabetic vascular complications. Haplotype analyses, interactions of gene-gene and interactions of gene-environment were performed too. Results: We identified a 36% decreased risk of developing T2DM in individuals with the minor A allele in DICER1 rs13078 (OR: 0.64; 95%CI: 0.42-0.95; P: 0.026). The AA haplotype in DICER1 was also associated with a protective effect on T2DM compared with the AT haplotype (OR: 0.63; 95%CI: 0.42-0.94; P-value: 0.023). T2DM patients with the TT+TC genotype at RAN rs14035 had a 1.89-fold higher risk of developing macrovascular complications than patients with the CC genotype (OR: 1.89; 95%CI: 1.04-3.45; P-value: 0.037). We also identified two three-factor interaction models. One is a three-factor [DICER1 rs13078, body mass index (BMI), and triglyceride (TG)] interaction model for T2DM (OR: 5.93; 95%CI: 1.25-28.26; P = 0.025). Another three-factor [RAN rs14035, hypertension (HP), and duration of T2DM (DOD)] interaction model was found for macrovascular complications of T2DM (OR = 41.60, 95%CI = 11.75-147.35, P < 0.001). Conclusion: Our study provides new evidence that two single nucleotide polymorphisms (SNPs) of the miRNA processing genes, DICER1 and RAN, and their interactions with certain environmental factors might contribute to the risk of T2DM and its vascular complications in the southern Chinese population.

Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy

Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.

Interactions of TRAF6 and NLRX1 gene polymorphisms with environmental factors on the susceptibility of type 2 diabetes mellitus vascular complications in a southern Han Chinese population

AIMS

To evaluate the effects of TRAF6 and NLRX1 polymorphisms and their interactions with environmental factors on the susceptibility of type 2 diabetes mellitus (T2DM) vascular complications in a southern Han Chinese population.

METHODS

Five single nucleotide polymorphisms (SNPs) were genotyped in a case-control study to estimate risk factors of T2DM vascular complications. Gene-gene and gene-environment interactions and haplotype associations were also estimated.

RESULTS

The CA genotype of the NLRX1 rs4245191 was identified as a risk factor for T2DM macrovascular complications and diabetic cerebral infarction (OR=2.88, 95% CI=1.15-7.22, P=0.024; OR=4.00, 95% CI=1.04-15.38, P=0.043, respectively). A significantly lower T allele frequency in the TRAF6 rs16928973 was observed in T2DM patients with both microvascular and macrovascular complications compared with patients without any complication under the allelic model (T vs. C: OR=0.36, 95% CI=0.14-0.98, P=0.038). No significant differences in haplotypes, gene-gene interactions and gene-environment interactions were observed among T2DM vascular subgroup patients.

CONCLUSIONS

Our study provides evidence that the NLRX1 rs4245191 polymorphisms influence the risk of T2DM macrovascular complications and diabetic cerebral infarction.

[Adiponectin in health and disease]

Over the past 20 years after the discovery of adiponectin, much knowledge about its effect in health and disease has been gained. Adiponectin has antidiabetic, antiatherogenic, anti-inflammatory, immunomodulatory, metabolic, vasoprotective, and antiapoptotic properties. However, an understanding stems from the given literature review that much remains to be explored. Adiponectin has not yet commonly used in clinical practice, but cardiologists, endocrinologists, pediatricians, oncologists, and physicians of many specialties are interested in its preventive and therapeutic applications.

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 CYBB polymorphisms with tuberculosis susceptibility in the Chinese Han population

OBJECTIVE

Reactive oxygen species (ROS) play a major role in the nonspecific innate immune response to invading microorganisms, such as Mycobacterium tuberculosis (MTB). Gp91phox, encoded by CYBB, serves as a key functional subunit of the Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase complex, which is pivotal to ROS generation. Therefore, the aim of the study was to investigate the association of CYBB polymorphisms with tuberculosis (TB) susceptibility.

METHODS

In total, 636 TB patients and 608 healthy, age and gender matched controls were enrolled in this study. All subjects were unrelated ethnic Han Chinese. Two tagSNPs were selected from the HapMap database and genotyped using matrix-assisted laser desorption/ionization time of flight mass spectrometry.

RESULTS

After adjusting for confounders including age, gender and smoking, rs5917471 allele T showed significant association with decreased risk of TB (OR 0.745, 95% CI 0.556-0.999) and pulmonary TB (OR 0.618, 95% CI 0.410-0.931). However, no difference in allelic distribution was observed for the rs6610650 G/A polymorphism with respect to TB or different clinical types of TB. Further stratified analyses demonstrated the protective effect of allele T of rs5917471 was stronger among males (OR 0.500, 95% CI 0.295-0.846), smokers (OR 0.462, 95% CI 0.239-0.896), and male smokers (OR 0.372, 95% CI 0.182-0.761); the individuals carrying the A allele of rs6610650 exhibited an decreased risk of TB among males, smokers and male smokers, with OR (95% CI) of 0.535 (0.290-0.984), 0.442 (0.198-0.988), and 0.350 (0.145-0.845), respectively. There were no statistically significant differences in haplotype distribution between TB and control groups. Smoking and rs5917471 formed the best gene-environment interaction model with the testing balanced accuracy of 53.29% and cross-validation consistency of 9/10.

CONCLUSIONS

This is the first study of the association of CYBB polymorphisms with TB. Our findings suggest that the CYBB polymorphisms are significantly correlated with reduced risk of TB, especially among male smokers. Further studies are needed to verify this association.