Association of IL-18 genotype with impaired glucose regulation in Korean women with polycystic ovary syndrome

The double-edged role of IL-18 in reproductive endocrine and reproductive immune related disorders

Interleukin (IL)-18 is one of the members of IL-1 family cytokines, it was originally named as interferon gamma (IFN-γ) inducing factor. IL-18 is a pleiotropic immune regulator and has a bidirectional regulatory effect on immunity. It exerts a potent pro-inflammatory effect by inducing the expression of IFN-γ, also has an important anti-inflammatory role. In recent years, IL-18 has received widespread attention and become a research hotspot. Previous studies have described the roles of IL-18 in the pathogenesis of many diseases. However, the biologic activities of IL-18 and its role in the reproductive endocrine and reproductive immune related diseases are still not well understood, such as endometriosis (EMS), recurrent spontaneous abortion (RSA), polycystic ovary syndrome (PCOS), and infertility, which are closely related to inflammation and immunity. Here, we reviewed the research progress of IL-18 in these diseases in the past few years. This article provides an overview of the latest knowledge about the roles of IL-18 in these diseases, with a view to providing new possibilities for the diagnosis and treatment of reproductive endocrine and reproductive immune related disorders.

Genetic polymorphisms -137 (G > C) (rs187238) and -607 (C > A) (rs1946518) and serum level of interleukin 18 in Fars ethnic groups with metabolic syndrome in Northern Iran

INTRODUCTION

We aimed to determine the genetic polymorphisms and serum level of interleukin 18 in Fars ethnic groups.

MATERIAL AND METHODS

226 Fars ethnic groups were participated. The ATP III criteria were used to assess MS components. The SNPs of the IL-18 gene were determined with ARMS-PCR.

RESULTS

The GG, GC, and CC genotypes of -137 were 50%, 40%, and 10%. The CC, CA, and AA genotypes of -607 were 45%, 37%, and 18%. The GG, GC, and CC genotypes of -137 were 44.20%, 43.40%, and 12.40%, and were 55.75%, 36.28%, and 7.97% in subjects with and without MS, respectively. The CC, CA, and AA genotypes of -607 were 48.70%, 37.20%, and 14.20% and were 41.60%, 37.20%, and 21.20% in both groups, respectively.

CONCLUSION

IL-18 gene may different in specific populations, different ethnic groups and geographic regions. The IL-18 polymorphisms might not be used as a marker of metabolic syndrome.

Sex hormone binding globulin - an important biomarker for predicting PCOS risk: A systematic review and meta-analysis

Sex hormone-binding globulin (SHBG) is a glycoprotein which regulates bioavailability of sex steroid hormones. Interest in SHBG has escalated in recent years because of its inverse association with polycystic ovary syndrome (PCOS), obesity, insulin resistance, metabolic syndrome, and diabetes type II. This meta-analysis was performed to examine the associations of SHBG with PCOS and to correlate serum SHBG levels with various PCOS associated endocrine and metabolic dysregulation as well as to determine the effects of various therapeutic agents on serum SHBG levels in PCOS patients in order to assess the true accuracy of SHBG in the prediction of PCOS. A literature search was performed using Pub-Med, Science direct, google scholar, EMBASE, and Cochrane library. A total of 675 relevant records were identified, of which 62 articles were included. Meta-analysis using a random-effects model was performed using STATA version 13 to calculate standardized mean difference (SMD) with 95% confidence intervals (95 % CIs). SHBG levels in controls were significantly higher than that of PCOS patients (SMD= -0.83, 95%CI = -1.01, -0.64), with significant heterogeneity across studies (I²= 93.9% and p=0.000). Our results suggest that the lower serum SHBG levels are associated with the risk of PCOS. SHBG may also play an important role in various metabolic disturbances in PCOS patients. Therapeutic interventions improved SHBG levels in PCOS women which further reduced PCOS associated complications. Therefore, SHBG levels may prove to be a useful biomarker for the diagnosis and treatment of PCOS. Systematic review registration: PROSPERO CRD42017057972 Abbreviations: PCOS: polycystic ovary syndrome; SHBG: sex hormone-binding globulin.

Association of IL-1β, IL-1Ra and FABP1 gene polymorphisms with the metabolic features of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), a highly prevalent endocrinopathy is currently being designated as chronic low grade inflammatory state. IL-1β, IL-1Ra and FABP1 are critical mediators of inflammatory processes and are speculated to play a role in the pathogenesis of PCOS. The aim of this study was to study the association of IL-β, IL-1Ra and FABP1 gene polymorphisms with PCOS and related metabolic features.

SUBJECTS

95 PCOS and 45 age matched healthy control subjects were enrolled in this study.

METHODS

Polymorphism in genes IL-1β, IL-1Ra and FABP1 was studied by PCR, PCR-RFLP and sequencing methods, respectively. Hormonal and lipid profiles were evaluated for all the subjects.

RESULTS

Hormonal and lipid profiles showed significant differences between PCOS and control subjects. Allele and genotype frequencies of IL-1β, IL-1Ra and FABP1 gene polymorphisms did not vary between the control and PCOS group. However, T allele of C[-511]T variant of IL-1β, allele II in intron 2 of IL-1Ra and A allele of A/G variant of FABP1 (rs2197076) showed significant association with many metabolic features associated with PCOS.

CONCLUSIONS

Polymorphism in genes encoding cytokines and proteins involved in lipid metabolism can provide insights into the genetics of the disease and may contribute to assess the associated risk of cardiovascular diseases (CVD), dyslipidemia and metabolic syndrome (MetS) associated with PCOS.

Polymorphisms of Cytokine Genes and Polycystic Ovary Syndrome: A Review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the endocrinopathy that affects women in their reproductive age. The physiopathology involves multifactorial mechanisms, including cytokine gene regulation.

METHODS

The review was conducted in the database PubMed, with articles published between 2005 and 2015. The selected studies evaluated the single-nucleotide polymorphisms (SNPs) of cytokines genes in association with PCOS. Twenty-four studies met the inclusion criteria and showed the SNPs of cytokines that were associated or not with PCOS.

RESULTS

The disease susceptibility was associated with interleukin (IL) 1A, IL1B, IL1RN, and IL6 alleles and genotypes. The tumor necrosis factor (TNF) -1032 C/T genotype and C allele were risk factors and T/T genotype was a protector marker to disease. The IL18 SNPs were not associated with PCOS per se, but IL18-137 C and G alleles were related to the protection of insulin resistance and glucose tolerance, respectively. One research found association between TGFB1 and PCOS. However, the TNF -308, IL10, and interferon (IFN) SNPs did not appear to influence PCOS genetic susceptibility.

CONCLUSIONS

This study sought to contribute and clarify the SNPs in cytokine genes that influence the development of PCOS. Most studies occurred in Asia; most SNPs studied were in IL1B -511, TNF -1031, and IL6-174; and most of them were associated with the susceptibility to PCOS development. Nevertheless, further investigations based on genome-wide association studies and cytokine gene SNPs are needed to better characterize the risk factors to PCOS.

Single nucleotide polymorphisms in the TGF-β1 gene are associated with polycystic ovary syndrome susceptibility and characteristics: a study in Korean women

PURPOSE

Although many hypotheses regarding the pathogenesis of polycystic ovary syndrome (PCOS) have been generated, genetic studies have not identified specific genes that play a role in PCOS etiopathogenesis. This study aimed to investigate the relationship between TGF-β1 gene polymorphism and PCOS in Koreans.

METHOD

A total of 51 Korean women with PCOS and 69 healthy women were enrolled. We analyzed 4 single nucleotide polymorphisms (SNPs) of the TGF-β1 gene (rs11466313, rs1800469, rs2317130, and rs4803457). We also analyzed laboratory measurements, such as free testosterone, glucose, and cholesterol.

RESULTS

The frequencies of rs1800469T allele negativity, rs4803457T allele negativity, the rs1800469CC genotype, and the rs4803457CC genotype showed positive associations with PCOS (P = 0.003, P = 0.027, P = 0.009, and P=0.031, respectively), whereas the haplotypes rs1800469C-rs4803457T and rs1800469T-rs4803457T showed negative associations with PCOS. A strong protective effect of the "rs1800469CT-rs4803457TT" combination (OR = 0.09) and a strong risk effect of "rs1800469CC-rs4803457CC" (OR = 6.23) for PCOS were observed. The rs1800469C/T and rs2317130C/T SNPs exhibited associations with several laboratory measurements with various levels of significance.

CONCLUSION

The results demonstrated an association of TGF-β1 gene polymorphisms with the development and/or characteristics of PCOS in the Korean population.

Associations between TNF-α and interleukin gene polymorphisms with polycystic ovary syndrome risk: a systematic review and meta-analysis

BACKGROUND

The associations between TNF-α and Interleukin gene polymorphisms and polycystic ovary syndrome (PCOS) risk have been studied in numerous epidemiological studies, but the results remain controversial. To investigate whether these polymorphisms facilitate susceptibility to PCOS, we conducted a comprehensive systematic review and meta-analysis.

METHODS

PubMed, Embase, Web of Science, Medline, CNKI, and Google Scholar were searched to obtain the genetic association studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Odds ratios (OR) with corresponding 95 % confidence intervals (CI) were used to assess the strengths of the associations. Funnel plots and Egger's tests were performed to test for possible publication bias. All statistical analyses were performed using Review Manager 5.2 and STATA11.0.

RESULTS

Eighteen articles were included in the final meta-analysis. The studies involved the following polymorphisms: TNF-α -308G > A, TNF-α -805C>T, TNF-α -1031 T>C, IL-1A -889C>T, IL-1B -511C>T, IL-1B +3953 T>C, IL-6 -174G>C, IL-10 -819C>T, IL-10 -1082A>G, IL-18 -607C>A, and IL-18 -137G>C. Our results show a significant association between PCOS risk and the TNF-α -1031 T>C polymorphism (For TC+CC vs. TT: OR=2.09, 95 % CI=1.58-2.76, p<0.0001. For C allele vs. T allele: OR=1.67, 95 % CI=1.33-2.09, p<0.0001) and between PCOS risk and the IL-6 -174>C polymorphism (For CC+GC vs. GG: OR=0.49, 95 % CI=0.25-0.95, p=0.03. For CC vs. GG: OR=0.48, 95 % CI=0.28-0.80, p=0.005. For C vs. G: OR=0.60, 95 % CI=0.42-0.87, p=0.007). No associations were found with the other genetic models.

CONCLUSION

The results of the meta-analysis suggest positive associations between the TNF-α -1031 T>C and IL-6 -174G>C polymorphisms and the risk of PCOS. No associations are found between PCOS risk and the TNF-α -308G>A, TNF-α -805C>T, IL-1A -889C>T, IL-1B -511C>T, IL-1B +3953C>T, IL-10 -819C>T, IL-10 -1082 A>G, IL-18 -607C>A, and IL-18 -137G>C polymorphisms. However, due to the heterogeneity and low quality of the studies related to PCOS polymorphisms in the meta-analysis, the results should be interpreted with caution. Future multi-ethnicity studies of homogeneous populations of PCOS patients with larger sample sizes and well-matched controls are needed.

Endogenous interleukin 18 suppresses hyperglycemia and hyperinsulinemia during the acute phase of endotoxemia in mice

BACKGROUND

Hyperglycemia associated with insulin resistance is common among critically ill patients. Interleukin (IL)-18 has been linked with hyperglycemia and insulin resistance in chronic disease, but the relation between IL-18 and insulin resistance during critical illness was unexplored. This study investigated whether IL-18 modulates hyperglycemia and insulin resistance during acute inflammation.

METHODS

We injected lipopolysaccharide (LPS) 40 mg/kg into wild-type (WT) and IL-18 knockout (KO) mice to induce endotoxemia and examined insulin resistance and insulin-dependent signaling pathways during the acute phase.

RESULTS

During the first hour after LPS treatment, IL-18 KO mice showed higher blood glucose and insulin and less insulin receptor substrate-1 and less phosphorylated Akt in the liver compared with WT mice. Interleukin-18 KO mice exhibited better survival after LPS treatment.

CONCLUSIONS

The findings suggest that endogenous IL-18 may attenuate hyperglycemia and modulate insulin signaling in liver. Accordingly, IL-18 may modulate glucose tolerance during acute inflammation.

Correlation between IL-1β, IL-1Ra gene polymorphism and occurrence of polycystic ovary syndrome infertility

OBJECTIVE

To explore the relationship between IL-1β, IL-1Ra gene polymorphism and the occurrence of polycystic ovary syndrome (PCOS) infertility.

METHODS

A total of 59 PCOS infertility cases visiting the reproductive center of our hospital from Mar. 2010 to Mar. 2012 and 56 healthy women were selected. ELISA method was used for the detection of IL-1β, IL-1Ra levels, and the levels of serum supersensitivity C reaction protein (US-CRP), insulin (FINS), follicule-stimulating hormone (FSH) and fasting blood-glucose (FBG) were detected. PCR analysis technology was adopted to detect the gene polymorphism of the 511 site of IL-1β and the second introne of IL-1Ra.

RESULTS

The levels of IL-1β, IL-1Ra, US-CRP, FINS and FBG in blood serum of patients in PCOS group were significantly higher than those in control group (P<0.05 or P<0.01). The level of FSH in PCOS group was significantly lower than that in control group (P<0.05). The genotypic frequency of T/T, the 511 site of IL-1β in PCOS group was 42.37%, significantly higher than 12.50% in control group (P<0.01). The frequency of T allele was also significantly higher than that in control group (P<0.01). The genotypic frequency of I/V, the second introne of IL-1Ra in PCOS group was 20.34%, signiciantly higher than 3.57% in control group (P<0.05). The frequency of V allele in PCOS group was significantly higher than that in control group (P<0.05).

CONCLUSIONS

T allele of the 511 site of IL-1β gene and V allele of the second introne of IL-1Ra gene might be the genetic basis of the rising of IL-1β, IL-1Ra and US-CRP levels in blood serum of PCOS patients, and are associated with the infertility occurrence of PCOS patients.