Potential effects of aerobic exercise on the expression of perilipin 3 in the adipose tissue of women with polycystic ovary syndrome: a pilot study

Genetic Association Between Polycystic Ovary Syndrome and the APOA5 rs662799 and PLIN1 rs894160 Metabolic Variants in the Western Saudi Population: A Case-Control Study

Background

Polycystic ovary syndrome (PCOS) is a common endocrinological condition affecting women of reproductive age, associated with insulin resistance and obesity. PCOS pathogenesis is complex and multifactorial, involving genetic and environmental factors.

Objectives

This study aimed to determine and compare genotype and allele frequencies of single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 (APOA5; rs662799) and perilipin 1 (PLIN1; rs894160, rs1052700 and rs6496589) genes in Western Saudi women to investigate their association with PCOS and its clinical characteristics.

Design and methods

This was a case-control study conducted on women with (n = 104) and without (n = 87) PCOS. The SNPs were genotyped using TaqMan genotyping assays.

Results

Significant and direct associations were detected between PCOS susceptibility and APOA5 SNP rs662799 and PLIN1 SNP rs894160 (P < .001). For APOA5 SNP rs662799, women with the A allele were more likely to have PCOS (relative risk [RR] = 1.348, odds ratio [OR] = 2.313, P < .001) and hypertriglyceridaemia (OR = 17.0, P = .5) than women with the G allele. For PLIN1 SNP rs894160, women with the T allele were more likely to have PCOS than women with the C allele (RR = 8.043, OR = 7.427, P < .001). For PLIN1 SNP rs1052700, women with the TT genotype were more likely to have hyperandrogenism (OR = 29.75, P = .02) and an irregular period (OR = 0.07, P = .040) than women with the AT genotype.

Conclusion

We identified novel alleles and genotypes contributing to the genetic risk of PCOS in the Western Saudi population.

Physical exercise alleviates oxidative stress in brown adipose tissue and causes changes in body composition and nutritional behavior in rats with polycystic ovary syndrome

AIM

Polycystic Ovary Syndrome (PCOS) is a very common endocrine disorder in women. We investigate the effect of physical exercise on body composition, nutritional parameters, and oxidative stress in rats with PCOS.

METHODS

Female rats were into three groups: Control, PCOS, and PCOS + Exercise. PCOS was induced by letrozole (1 mg/kg via p.o.) for 21 days consecutively. Physical exercise was swimming, for 21 consecutive days, 1 h/day with 5 % load. In all groups, we assessed the nutritional and murinometric parameters, body composition, thermography, and oxidative stress in brown adipose tissue (BAT) and peri-ovarian adipose tissue (POAT).

KEY FINDINGS

In PCOS we observed an increase (P < 0.05) in body weight vs. the Control group. But, the PCOS + Exercise group prevent this weight gain (P < 0.05). The temperature in BAT, decrease (P < 0.05) in the PCOS group vs. Control group. PCOS + Exercise prevented this reduction (P < 0.05) in BAT temperature vs. PCOS groups. We observed decreases (P < 0.05) in Lee Index and BMI in POS + Exercise vs. PCOS group. In PCOS rats, we observed an increase (P < 0.05) in murinometric (SRWG, EI, and FE) and body composition parameters (TWB, ECF, ICF, and FFM) vs. the Control group. The PCOS + Exercise prevents (P < 0.05) these changes in all groups, compared with PCOS. Regarding the BAT, we observe an increase (P < 0.05) in MPO and MDA levels in the PCOS vs. Control group. PCOS + Exercise prevents (P < 0.05) these increases vs. the PCOS group.

SIGNIFICANCE

PCOS modifies body composition, and nutritional parameters, and induces changes in oxidative stress in BAT. Physical exercise prevented these alterations.

Effects of continuous and intermittent aerobic physical training on hormonal and metabolic profile, and body composition in women with polycystic ovary syndrome: A randomized controlled trial

OBJECTIVE

To evaluate the effects of continuous (CA) and intermittent (IA) aerobic training on hormonal and metabolic parameters and body composition of women with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, interventional, randomized study.

METHODS

Randomized controlled training (RCT) with sample allocation and stratification into three groups: CAT (n = 28) and IAT (n = 29) training and no training [control (CG), n = 30]. Before and after 16 weeks of intervention (CAT or IAT) or observation (CG), hormonal and metabolic parameters, body composition and anthropometric indices were evaluated. Aerobic physical training on a treadmill consisted of 30- to 50-minute sessions with intensities ranging from 60% to 90% of the maximum heart rate.

RESULTS

In the CA group, there was reduction in waist circumference (WC) (P = .045), hip circumference (P = .032), cholesterol (P ≤ .001), low-density lipoprotein (P = .030) and testosterone (P ≤ .001). In the IAT group, there was a reduction in WC (P = .014), waist-to-hip ratio (P = .012), testosterone (P = .019) and the free androgen index (FAI) (P = .037). The CG showed increases in WC (P = .049), total body mass (P = .015), body fat percentage (P = .034), total mass of the arms (P ≤ .001), trunk fat percentage (P = .033), leg fat percentage (P = .021) and total gynoid mass (P = .011).

CONCLUSION

CAT and IAT training reduced anthropometric indices and hyperandrogenism in PCOS, whereas only IAT training reduced the FAI. Furthermore, only CAT training improved the lipid profile.

Exercise Interventions in Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Background: Polycystic ovary syndrome (PCOS) is a common and complex endocrinopathy with reproductive and metabolic manifestations. Exercise training has consistently been found to result in improved clinical outcomes in women with PCOS, but shortfalls with exercise prescription are evident. The aim of this systematic review and meta-analysis was to identify exercise intervention characteristics that provide favourable outcomes in women with PCOS.

Methods: A systematic review of published literature was conducted using EBSCOhost and Ovid Medline up to May 2019. The review adheres to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines as per our PROSPERO protocol (CRD42018088367). Randomised controlled trials, non-randomised controlled trials, and uncontrolled trials that evaluated an exercise intervention of at least moderate intensity in women with PCOS were included. Meta-analyses were performed using general linear mixed modelling and Bayesian inferences about effect magnitudes.

Results: Thirty-three articles were identified for systematic review of which 19 were meta-analysed. Intervention duration ranged from 6 to 26 weeks. A total number of 777 women were included in the meta-analysis. The meta-analysis found that improvements in health outcomes are more dependent on exercise intensity rather than dose. Fixed effects analysis reported a moderate increase in VO_2peak (24.2%; 90% CL, 18.5–30.1), and small reductions in HOMA-IR (−36.2%; 90% CL, −55.3 to −9.0), and waist circumference (−4.2%; 90% CL −6.0 to −2.3) as a result of vigorous intensity exercise. These results are confirmed in the predicted analysis which reported the greatest improvements in VO_2peak, BMI, and waist circumference after vigorous intensity exercise alone or when combined with diet, particularly for women with clinically adverse baseline values.

Conclusions: Exercise training in the management of PCOS is becoming more common. Results from our analysis support the use of exercise and suggest that vigorous intensity exercise may have the greatest impact on cardiorespiratory fitness, body composition, and insulin resistance. Our results indicate that, a minimum of 120 min of vigorous intensity per week is needed to provide favourable health outcomes for women with PCOS with studies of longer duration required to evaluate outcomes with sustained exercise.

TMT Based Proteomic Analysis of Human Follicular Fluid From Overweight/Obese and Normal-Weight Patients With Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is a major endocrine and metabolic disorder with heterogeneous manifestations and complex etiology. As a leading cause of anovulatory infertility, the molecular diversity of the follicular microenvironment has not been fully elucidated. The aim of the present study was to investigate the follicular fluid proteomic profiles of overweight/obese and normal-weight women with PCOS, to identify novel molecular mechanisms underlying PCOS and to determine the effect of obesity on the follicular fluid protein profiles. Methods: Follicular fluid samples were collected from 3 different groups: overweight/obese PCOS patients (n = 29), normal-weight PCOS patients (n = 29), and normo-ovulatory controls (n = 29). We used a quantitative approach with tandem mass tag labeling and liquid chromatography tandem mass spectrometry to identify the differentially expressed proteins. Differential abundance of four selected proteins was confirmed by ELISA. Gene Set Enrichment Analysis was also conducted to further explore our findings. Furthermore, we compared the clinical, hormonal, and biochemical characteristics of overweight/obese and normal-weight patients with PCOS to determine the effects of obesity. Results: A total of 1,153 proteins were identified, of which 41 and 19 proteins were differentially expressed in the overweight/obese PCOS group vs. the control group, and in the normal-weight PCOS group vs. the control group, respectively. Bioinformatics analyses showed that the inflammatory, immunological, and metabolic-related biological processes were co-enriched in both subgroups of PCOS. Apolipoprotein A-II, complement C5, fetuin-B, and stromal cell-derived factor 1 were found to be involved in various processes and were validated using the ELISA analysis. From clinical features and proteomic data, obesity was found to worsen follicular development disturbances in PCOS. Conclusion: In this proteomic study, a panel of proteins were found differentially expressed in the follicular fluid of PCOS. Inflammatory, immunological, and metabolic abnormalities were identified inside the intra-follicular environment, which could be aggravated by obesity. The identified proteins were correlated with follicular growth and may be considered as candidate biomarkers as well as therapeutic targets of PCOS.

Exercise training-induced effects on the abdominal subcutaneous adipose tissue phenotype in humans with obesity

Rodent studies have indicated that physical exercise may improve adipose tissue function. We investigated the effects of a 12-wk supervised, progressive exercise training program on adipocyte morphology and abdominal subcutaneous adipose tissue function in metabolically well-phenotyped subjects with obesity. Men with obesity ( n = 21) participated in a 12-wk supervised, progressive, combined exercise training program consisting of aerobic exercise (30 min at 70% of maximal power output 2 times/wk) and resistance exercise (3 × 10 repetitions at 60% of 1 repeated maximum 1 time/wk), with adjustment of exercise intensity every 4 wk. At baseline and after intervention, abdominal subcutaneous adipose tissue biopsies were collected to determine 1) adipocyte morphology, 2) gene expression of markers for lipolysis, inflammation, browning, adipokines, and mitochondrial biogenesis/function, 3) protein expression of mitochondrial oxidative phosphorylation (OXPHOS) complexes, and 4) ex vivo basal and β2-adrenergic stimulated lipolysis. The exercise training program, which increased maximal aerobic capacity ( P < 0.001) and muscle strength ( P < 0.001), slightly reduced adipose tissue mass (~0.7 kg, P = 0.021) but did not affect abdominal subcutaneous adipocyte size ( P = 0.744), adipose tissue gene expression of markers for mitochondrial biogenesis and function, browning, lipolysis, inflammation and adipokines, total OXPHOS protein content ( P = 0.789), or β2-adrenergic sensitivity of lipolysis ( P = 0.555). A 12-wk supervised, progressive exercise training program did not alter abdominal subcutaneous adipocyte morphology and adipose tissue gene/protein expression of markers related to adipose tissue function or β2-adrenergic sensitivity of lipolysis in male subjects with obesity.

NEW & NOTEWORTHY Studies that investigated the effects of exercise training on adipose tissue function in well-phenotyped humans are scarce. We demonstrate that 12 wk of supervised exercise training improved physical fitness and peripheral insulin sensitivity but did not alter abdominal subcutaneous adipocyte morphology, adipose tissue gene and protein expression of markers related to adipose tissue function, or β2-adrenergic receptor-mediated lipolysis in men with obesity. A prolonged and/or more intense training program may be required to improve human adipose tissue function.

Roles of Perilipins in Diseases and Cancers

Perilipins, an ancient family of lipid droplet-associated proteins, are embedded in a phospho-lipid monolayer of intracellular lipid droplets. The core of lipid droplets is composed of neutral fat, which mainly includes triglyceride and cholesterol ester. Perilipins are closely related to the function of lipid droplets, and they mediate lipid metabolism and storage. Therefore, perilipins play an important role in the development of obesity, diabetes, cancer, hepatic diseases, atherosclerosis, and carcinoma, which are caused by abnormal lipid metabolism. Accumulation of lipid droplets is a common phenomenon in tumor cells. Available data on the pathophysiology of perilipins and the relationship of perilipins with endocrine metabolic diseases and cancers are summarized in this mini-review. The research progress on this family offers novel insights into the therapeutic strategies for these diseases.

The dynamic pattern of PLIN3 in pig oocytes and cumulus cells during in vitro maturation

Lipid droplets (LDs) are the main energy resource for porcine preimplantation embryonic development. PLIN3 has been implicated in LD formation and regulation. Therefore, this study aimed to detect the dynamic pattern of PLIN3 in pig oocytes and cumulus cells (CC) during in vitro maturation (IVM), and to determine the relationship between PLIN3 and LD content. IVM with cumulus-enclosed oocytes (CEO), cumulus-denuded oocytes (DO) and the CCs denuded from the corresponding oocytes (DCC) was performed in porcine follicular fluid (PFF) or PFF-free optimized medium. DO and the DCC were cultured together under the same conditions as described above, while the DO was named DTO and the DCC was named DTCC in this group. Firstly, our results revealed LDs distributed widely in oocytes and CC, while the PLIN3 protein coated these LDs and spread out ubiquitously in the cytoplasm. Secondly, not only the mRNA level but also at protein level of PLIN3 in immature naked oocytes (IO) was higher than that in matured CEO, DO and DTO. Although PLIN3 was expressed at lower levels in CC from immature oocytes (ICC), the protein level of PLIN3 was comparably higher in the ECC and DCC groups. The triglyceride (TG) content in CEO and DO was significantly less abundant compared with that in IO. Therefore, our results indicated that co-culturing of oocytes and CC might affect PLIN3 expression levels in CC but not in oocytes. Lipid accumulation in pig oocytes during maturation might be affected by PLIN3 cross-talk between oocytes and CC.

Insulin resistance enhances the mitogen-activated protein kinase signaling pathway in ovarian granulosa cells

The ovary is the main regulator of female fertility. Granulosa cell dysfunction may be involved in various reproductive endocrine disorders. Here we investigated the effect of insulin resistance on the metabolism and function of ovarian granulosa cells, and dissected the functional status of the mitogen-activated protein kinase signaling pathway in these cells. Our data showed that dexamethasone-induced insulin resistance in mouse granulosa cells reduced insulin sensitivity, accompanied with an increase in phosphorylation of p44/42 mitogen-activated protein kinase. Furthermore, up-regulation of cytochrome P450 subfamily 17 and testosterone and down-regulation of progesterone were observed in insulin-resistant mouse granulosa cells. Inhibition of p44/42 mitogen-activated protein kinase after induction of insulin resistance in mouse granulosa cells decreased phosphorylation of p44/42 mitogen-activated protein kinase, downregulated cytochrome P450 subfamily 17 and lowered progesterone production. This insulin resistance cell model can successfully demonstrate certain mechanisms such as hyperandrogenism, which may inspire a new strategy for treating reproductive endocrine disorders by regulating cell signaling pathways.

Adipose tissue depot specific differences of PLIN protein content in endurance trained rats

Adipose tissue is classified as either white (WAT) or brown (BAT) and differs not only by anatomical location but also in function. WAT is the main source of stored energy and releases fatty acids in times of energy demand, whereas BAT plays a role in regulating non-shivering thermogenesis and oxidizes fatty acids released from the lipid droplet. The PLIN family of proteins has recently emerged as being integral in the regulation of fatty acid storage and release in adipose tissue. Previous work has demonstrated that PLIN protein content varies among adipose tissue depots, however an examination of endurance training-induced depot specific changes in PLIN protein expression has yet to be done. Male Sprague-dawley rats (n = 10) underwent 8-weeks of progressive treadmill training (18-25 m/min for 30-60 min at 10% incline) or remained sedentary as control. Following training, under isoflurane induced anesthesia epidydmal (eWAT), inguinal subcutaneous (iWAT) and intrascapular brown adipose tissue (BAT) was excised, and plasma was collected. Endurance training resulted in an increase in BAT PLIN5 and iWAT PLIN3 content, while there was no difference in PLIN protein content in endurance trained eWAT. Interestingly, endurance training resulted in a robust increase in ATGL and CGI-58 in eWAT alone. Together these results suggest the potential of a depot specific function of PLIN3 and PLIN5 in adipose tissue in response to endurance training.

Perilipin 3 Differentially Regulates Skeletal Muscle Lipid Oxidation in Active, Sedentary, and Type 2 Diabetic Males

CONTEXT

The role of perilipin 3 (PLIN3) on lipid oxidation is not fully understood.

OBJECTIVE

We aimed to 1) determine whether skeletal muscle PLIN3 protein content is associated with lipid oxidation in humans, 2) understand the role of PLIN3 in lipid oxidation by knocking down PLIN3 protein content in primary human myotubes, and 3) compare PLIN3 content and its role in lipid oxidation in human primary skeletal muscle cultures established from sedentary, healthy lean (leans), type 2 diabetic (T2D), and physically active donors.

DESIGN, PARTICIPANTS, AND INTERVENTION

This was a clinical investigation of 29 healthy, normoglycemic males and a cross-sectional study using primary human myotubes from five leans, four T2D, and four active donors. Energy expenditure, whole-body lipid oxidation, PLIN3 protein content in skeletal muscle tissue, and ex vivo muscle palmitate oxidation were measured. Myotubes underwent lipolytic stimulation (palmitate, forskolin, inomycin [PFI] cocktail), treatment with brefeldin A (BFA), and knockdown of PLIN3 using siRNA.

SETTING

Experiments were performed in a Biomedical Research Institute.

MAIN OUTCOME MEASURES

Protein content, 24-hour respiratory quotient (RQ), and ex vivo/in vitro lipid oxidations.

RESULTS

PLIN3 protein content was associated with 24-h RQ (r = -0.44; P = .02) and skeletal muscle-specific ex vivo palmitate oxidation (r = 0.61; P = .02). PLIN3 knockdown showed drastic reductions in lipid oxidation in myotubes from leans. Lipolytic stimulation increased PLIN3 protein in cells from leans over T2Ds with little expression in active participants. Furthermore, treatment with BFA, known to inhibit coatomers that associate with PLIN3, reduced lipid oxidation in cells from lean and T2D, but not in active participants.

CONCLUSIONS

Differential expression of PLIN3 and BFA sensitivity may explain differential lipid oxidation efficiency in skeletal muscle among these cohorts.