دراسة مقارنة لتقييم مقاومة الانسولين بطرق مختلفة وارتباطها بتعدد الاشكال الجينية لــ Calpain-10 في متلازمة تكيس المبايض المتعدد بين النساء العراقيات

Comparative Studies of Different Assessment Methods of Insulin Resistance and its Association with Calpain-10 Gene Polymorphisms in Polycystic

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder affecting women of reproductive age. It is characterized by excess androgen production, ovarian dysfunction and abnormal insulin activity. Excess body weight in women with PCOS accelerates progression towards type 2 diabetes (T2D), by exacerbating insulin resistance (IR). Homeostasis model assessment of insulin resistance index (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI) are the most widely used surrogate indices of IR, which reflect the feedback between fasting serum insulin and glucose. The identification of single nucleotide polymorphisms (SNPs) associated with a disease can help elucidate its pathogenesis, and this knowledge can be used to improve prognosis for women with a particular disorder, such as PCOS. The calpain-10 gene (CAPN10), plays a role in insulin secretion and action. Apart from being a strong candidate for T2D, CAPN10 gene also has been widely evaluated in PCOS due to the fact that PCOS and T2D share a number of etiologic factors.
This study was aimed to assess the incidence of IR in PCOS patients. As well as, the distribution of alleles of the CAPN10 gene, SNP-44 (rs2975760) was analyzed, so as to determine if there is a relation between PCOS and the variant in women of childbearing age from Kerbala province, Iraq.
This study included 120 participants of which 68 women have PCOS subdivided according to their body mass index (BMI) into 45 obese (BMI≥30) and 23 non-obese (BMI<30) subjects. The remaining 52 represent the control group who were apparently healthy women with normal weight and normal menstrual cycle. Patients with PCOS were selected from the Infertility Department, Gynecology and Obstetrics Teaching Hospital, Kerbala Health Directorate / Kerbala-Iraq between November, 2021 and June, 2022. Diagnosis of PCOS is based on Rotterdam criteria. Patients were interviewed and examined for weight, height, waist circumference, and hip circumference.
Five milliliters of venous blood samples were collected at 9 AM after an overnight fast. Blood samples were divided into two parts; the first part was collected in gel tube for biochemical analysis. Levels of serum C-peptide, LH and FSH were measured by chemiluminescent automated immunoassay system. (Free testosterone and insulin were measured by enzyme linked immunosorbent assay (ELISA). The second part of blood was collected in EDTA tube for molecular analysis. The IR was assessed by calculating HOMA-IR using the formula (fasting glucose mg/dl × fasting insulin µU/ml)/405, taking normal value less than (2.7). Genotypes of CAPN-10, SNP-44 (rs2975760) has been identified using Allele-Specific Polymerase Chain Reaction (AS-PCR) technique.
The prevalence of IR based on HOMA-IR was 80% in obese PCOS and 48% in non-obese PCOS women. Glucose and insulin were statistically significance in women with PCOS compared to control women. HOMA-IR was found to be significantly varied in PCOS patients comparing to the controls, pointing to the IR component in this syndrome; while there was no difference between obese and non-obese PCOS subjects. C-peptide modified HOMA-IR and triglyceride glucose index (TyG) were significantly higher in obese PCOS patients compared with controls. Whereas glucose to insulin ratio (G/I), QUICKI, McAuley index and C-peptide index (CPI) were significantly lower in obese PCOS patients compared with controls. HOMA-IR was positively correlated with insulin and TyG in obese and non-obese PCOS subjects respectively. HOMA-IR can also be predicted by TyG. QUICKI method had the highest sensitivity (100%) and specificity (100%). The CAPN-10 gene, SNP-44 (rs2975760) has been reconstructed and analyzed in patients and controls. Genotypes of obese PCOS subjects, non-obese PCOS subjects and control subjects were identified. The genotype distribution was statistically different between obese PCOS women and controls. The association of SNP-44 (rs2975760) allele with IR status was detected. HOMA-IR was greater in CC than in TT and TC in obese PCOS and non-obese PCOS subjects respectively.
Triglyceride glucose index is a valuable indicator to predict IR in women with PCOS, partly due to its analytical and financial ease-of-access in all clinical laboratories. In obese PCOS, the C allele was associated with higher insulin secretion and HOMA-IR compared with the T allele.