Obesity and Insulin Resistance Are the Main Determinants of Postprandial Lipoprotein Dysmetabolism in Polycystic Ovary Syndrome

Evaluation of serum telomerase activity in normal-weight young girls with polycystic ovary syndrome and its relation to metabolic parameters

OBJECTIVES

This study investigated the discriminative value of serum telomerase levels in polycystic ovary syndrome (PCOS) and its relation to metabolic parameters.

METHODS

Patients aged 16-23 years old who visited an adolescent outpatient clinic were included in the study. Our study consisted of 45 non-obese girls with polycystic ovary syndrome (PCOS), while our control group consisted of 45 healthy girls with normal menstrual cycles and no signs of hyperandrogenism. During the early follicular phase, all individuals were analyzed for serum telomerase levels, blood cell count, biochemical parameters, basal hormone levels, lipid profile and homeostatic model assessment of insulin resistance (HOMA-IR) index.

RESULTS

Serum telomerase levels in PCOS patients were considerably lower (80.0 ± 52.8 IU/mL) than in the controls (113.1 ± 54.9 IU/mL) (p=0.004). We observed that blood telomerase levels less than 108.6 distinguished PCOS group from healthy controls with a sensitivity of 73.33% and a specificity of 57.78%. Low-density lipoprotein cholesterol, HOMA-IR index, Ferriman-Gallwey score and dehydroepiandrosterone sulfate values were higher in the study group. Moreover, serum telomerase levels were inversely correlated with body mass index (r=-0.339, p=0.023) and triglycerides (r=-0.511, p=0.002) in this group. Telomerase levels were also considerably lower in patients with metabolic syndrome (p=0.005).

CONCLUSIONS

Serum telomerase activity is lower in PCOS patients than in healthy controls. Furthermore, decreased serum telomerase levels may correlate well with the metabolic complications of PCOS.

ApoB48-Lipoproteins Are Associated with Cardiometabolic Risk in Adolescents with and without Polycystic Ovary Syndrome

CONTEXT

Adolescents with polycystic ovary syndrome (PCOS) have increased incidence of cardiometabolic risk factors including dyslipidemia. Atherogenic apolipoprotein (apo) B-lipoprotein remnants are associated with increased cardiovascular disease (CVD) risk.

OBJECTIVE

The aim of this study was to determine the concentrations of fasting plasma apoB-lipoprotein remnants, apoB48 and apoB100, and their association with cardiometabolic risk factors and androgen indices in adolescent girls with and without PCOS.

DESIGN SETTING AND PARTICIPANTS

Participants (n = 184) aged 17 years were recruited in the Menstruation in Teenagers Study from the Western Australian Pregnancy Cohort (Raine) Study.

THE MAIN OUTCOME MEASURES

Fasting plasma apo-B48 and -B100 lipoprotein remnant concentrations in adolescent girls with and without PCOS.

RESULTS

Fasting plasma apoB48-lipoprotein remnants but not apoB100-lipoprotein remnants were elevated in adolescent girls with increased cardiometabolic risk compared with those with lower cardiometabolic risk (13.91 ± 5.06 vs 12.09 ± 4.47 µg/mL, P < .01). ApoB48-lipoprotein remnants were positively correlated with fasting plasma triglycerides (b = .43, P < .0001). The prevalence of increased cardiometabolic risk factors was 2-fold higher in those diagnosed with PCOS (35.3%) than in those without PCOS (16.3%).Conclusion: Adolescents with PCOS have a 2-fold higher incidence of cardiometabolic risk factors than those without PCOS. Fasting apoB48-lipoprotein remnants are elevated in adolescent girls with a high prevalence of cardiometabolic risk factors.

TLR2 and TLR4 Surface and Gene Expression in White Blood Cells after Fasting and Oral Glucose, Lipid and Protein Challenges: Influence of Obesity and Sex Hormones

We studied if macronutrients of the diet have different effects on leukocyte activation, and if these effects are influenced by sex hormones or obesity. We analyzed leukocyte cell surface and gene expression of toll-like receptors 2 and 4 (TLR2 and TLR4) during fasting and after macronutrient loads in women with polycystic ovary syndrome and female and male controls. Fasting TLR2 surface expression in neutrophils was higher in men than in women. Obese subjects presented higher TLR2 gene expression than nonobese individuals, particularly in men. In contrast, surface TLR4 expression was lower in men and in obese individuals. Postprandial cell-surface expression decreased similarly after all macronutrient loads. Neutrophil TLR2 decreased only in obese subjects whereas TLR4 showed a greater decrease in nonobese individuals. However, TLR2 gene expression increased after glucose ingestion and decreased during the lipid load, while TLR4 was induced in response to lipids and mostly to glucose. Postprandial TLR gene expression was not influenced by group of subjects or obesity. Both cell-surface and gene postprandial expression inversely correlated with their fasting levels. These responses suggest a transient compensatory response aiming to prevent postprandial inflammation. However, obesity and sex hormones showed opposite influences on surface expression of TLR2 and TLR4, but not on their gene expression, pointing to regulatory posttranscriptional mechanisms.

In women with PCOS, waist circumference is a better surrogate of glucose and lipid metabolism than disease status per se

OBJECTIVE

Cardiometabolic abnormalities are recognized in polycystic ovary syndrome (PCOS). However, over-emphasis on PCOS as a risk factor potentially results in over-investigation and treatment of some women with and under-recognition of cardiometabolic risk in obese women without PCOS. Our objective was to explore the association between waist circumference (WC) and indices of glucose and lipid metabolism in women with and without PCOS.

DESIGN, PATIENTS AND MEASUREMENTS

(i) An exploratory cross-sectional study investigating association of potential cardiometabolic risk markers (PCOS status, anthropometric measures, hsCRP, HOMA-IR, SHBG, testosterone) with indices of glucose (frequently sampled intravenous glucose tolerance test) and lipid metabolism (postprandial studies and lipoprotein particle size) in 61 women with (n = 29) and without (n = 32) PCOS; (ii) a cross-sectional study in 103 PCOS women and 102 BMI-matched controls to explore if between-group differences in indices of lipid and glucose metabolism persist after adjusting for WC. NIH criteria were used for PCOS diagnosis.

RESULTS

Study 1: Univariate correlations and stepwise regression modelling identified waist circumference (WC), as a better surrogate than PCOS status, independently predicting multiple variables of glucose and lipid metabolism. Study 2: Fasting insulin and triglyceride, hsCRP and insulin resistance (according to HOMA-IR and SiM [Avignon index]) were greater, while fasting HDL was lower in women with PCOS compared to BMI-matched women without PCOS. None of these differences persisted when a subset of 80 women with PCOS was compared with 80 women without PCOS, pair-matched for WC.

CONCLUSION

Some cardiometabolic abnormalities in PCOS are related to central obesity, and following adjustment for WC does not differ from normal subjects. Waist circumference measurement has potential to take precedence over PCOS status as part of the assessment of cardiometabolic risk in reproductive-age women.

CXC Ligand 5 cytokine serum level in women with polycystic ovary syndrome and normal body mass index: A case-control study

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disease and associated with insulin resistance. CXC Ligand 5 (CXCL5) is a new cytokine which is secreted from white adipose tissue during obesity and by blocking insulin signaling pathway inhibits the activity of insulin and promotes insulin resistance.

OBJECTIVE

The aim of this study was to assess serum level of CXCL5 in PCOS women with normal body mass index.

MATERIALS AND METHODS

In this case-control study, 30 PCOS women with normal body mass index as the case group and 30 non-PCOS women as the controls were enrolled. Serum levels of CXCL5, insulin and other hormones factors related with PCOS were measured by ELISA method, also the biochemical parameters were measured by autoanalyzer.

RESULTS

Significant increases in serum insulin concentration, homeostasis model assessments of insulin resistance, luteinizing hormone, luteinizing hormone/follicle-stimulating hormone, fasting blood sugar, testosterone, and prolactin were observed in the case group compared to the controls. were in the serum level of CXCL5, cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol,dehydroepiandrosterone-sulfate, creatinine, and homeostasis model assessment of beta cell function between these two groups.

CONCLUSION

In this study, no significant change was observed in serum concentrations of CXCL5 in PCOS women with normal BMI.

Changes in triglycerides and high-density lipoprotein cholesterol may precede peripheral insulin resistance, with 2-h insulin partially mediating this unidirectional relationship: a prospective cohort study

Background

Results of longitudinal researches regarding the temporal relationship between dyslipidemia and insulin resistance (IR) are inconsistent. This study assessed temporal relationships of blood lipids with IR and determined whether there are any mediating effects existed in these temporal relationships.

Methods

This study examined a longitudinal cohort of 3325 subjects aged 20–74 years from China with an average of 4.2 years follow-up. Measurements of fasting blood lipids, as well as fasting and 2-h serum glucose and insulin, were obtained at two time points. The Gutt index and HOMA-IR were calculated as indicators of peripheral IR and hepatic IR. A cross-lagged path analysis was performed to examine the temporal relationships between blood lipids and IR. A mediation analysis was used to examine mediating effect.

Results

After adjusting for covariates, the cross-lagged path coefficients from baseline TG and HDL-C to follow-up Gutt index were significantly greater than those from baseline Gutt index to follow-up TG and HDL-C (β₁ = −0.131 vs β₂ = −0.047, P < 0.001 for TG; β₁ = 0.134 vs β₂ = 0.023, P < 0.001 for HDL-C). The path coefficients from baseline TG and HDL-C to follow-up 2-h insulin were significantly greater than those from baseline 2-h insulin to follow-up TG and HDL-C (β₁ = 0.125 vs β₂ = 0.040, P < 0.001 for TG; β₁ = −0.112 vs β₂ = −0.026, P < 0.001 for HDL-C). 2-h insulin partially mediated the effect of TG/HDL-C on Gutt index with a 59.3% mediating effect for TG and 61.0% for HDL-C.

Conclusions

These findings provide strong evidence that dyslipidemia probably precede peripheral IR and that 2-h insulin partially mediates this unidirectional temporal relationship.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0469-3) contains supplementary material, which is available to authorized users.