Glucose and lipopolysaccharide regulate proatherogenic cytokine release from mononuclear cells in polycystic ovary syndrome

Lipid-induced mononuclear cell cytokine secretion in the development of metabolic aberration and androgen excess in polycystic ovary syndrome

STUDY QUESTION

What is the effect of saturated fat ingestion on mononuclear cell (MNC) TNFα, IL-6 and IL-1β secretion and circulating IL-6 levels in women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Women with PCOS exhibit increases in MNC-derived TNFα, IL-6 and IL-1β secretion and circulating IL-6 following saturated fat ingestion even in the absence of obesity, and these increases are linked to metabolic aberration and androgen excess.

WHAT IS KNOWN ALREADY

Cytokine excess and metabolic aberration is often present in PCOS.

STUDY DESIGN, SIZE, DURATION

A cross-sectional design was used in this study of 38 reproductive-age women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Groups of 19 reproductive-age women with PCOS (10 lean, 9 obese) and 19 ovulatory controls (10 lean, 9 obese) participated in this study that was performed at a tertiary academic medical centre. TNFα, IL-6 and IL-1β secretion was measured from cultured MNC, and IL-6 was measured in plasma from blood sampling while fasting and 2, 3 and 5 h after saturated fat ingestion. Insulin sensitivity was determined using the Matsuda index following an oral glucose tolerance test. Androgen secretion was evaluated with blood sampling while fasting and 24, 48 and 72 h after an HCG injection.

MAIN RESULTS AND THE ROLE OF CHANCE

Lean and obese women with PCOS exhibited lipid-induced incremental AUC increases in MNC-derived TNFα (489-611%), IL-6 (333-398%) and IL-1β (560-695%) secretion and in plasma IL-6 levels (426-474%), in contrast with lean control subjects. In both PCOS groups, insulin sensitivity was lower (42-49%) and androgen secretion after HCG injection was greater (63-110%) compared with control subjects. The MNC-derived TNFα, IL-6 and IL-1β and circulating IL-6 responses were inversely associated with insulin sensitivity and directly associated with fasting lipids and androgen secretion after HCG injection.

LIMITATIONS, REASONS FOR CAUTION

The sample size of each of the four study groups was modest following group assignment of subjects by body mass.

WIDER IMPLICATIONS OF THE FINDINGS

This study showcases the unique pro-inflammatory contribution of circulating MNC in the development of metabolic aberration and androgen excess in PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by grant R01 DK107605 to F.G. from the National Institutes of Health, the Indiana Clinical and Translational Sciences Institute Clinical Research Center which is funded in part by grant UL1TR002529 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award, and the Indiana University Center for Diabetes and Metabolic Diseases funded by grant P30 DK097512 from the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. No conflicts of interest, financial or otherwise, are declared by the authors.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01489319.

Dietary α-Linolenic Acid-Rich Flaxseed Oil Exerts Beneficial Effects on Polycystic Ovary Syndrome Through Sex Steroid Hormones-Microbiota-Inflammation Axis in Rats

Polycystic ovary syndrome (PCOS) represents a common endocrine-metabolic disorder disease with chronic low-grade inflammation and alteration of intestinal flora. Serving as functional food, flaxseed oil (FO), which is rich in plant-derived α-linolenic acid of omega-3 polyunsaturated fatty acids, has been proven to benefit for chronic metabolic diseases. However, the exact role of dietary FO on PCOS remains largely unclear. In the present study, 6-week-old female Sprague-Dawley rats were randomly divided into four groups (eight rats/group), including (a) pair-fed (PF) control (CON) group (PF/CON), (b) FO-fed CON group (FO/CON), (c) PF with letrozole-induced PCOS model (MOD) group (PF/MOD), and (d) FO-fed MOD group (FO/MOD). All rats were fed a standard diet. After 3 weeks of modeling and subsequent 8 weeks of treatment, the rats in diverse groups were euthanized and associated indications were investigated. The results showed that dietary FO ameliorated the disorder of estrous cycle and ovarian morphology. In parallel, dietary FO improved the sex steroid hormone disturbance (luteinizing hormone/follicle-stimulating hormone, estrogen, testosterone, and progesterone), body weights, dyslipidemia, and insulin resistance. Moreover, FO treatment improved plasma and ovary inflammatory interleukin (IL)-1β, IL-6, IL-10, and IL-17A, tumor necrosis factor-α, and monocyte chemoattractant protein-1. Additionally, FO intervention significantly modulated the composition of gut microbiota and vaginal microbiota by increasing the abundances of Allobaculum, Lactobacillus, Butyrivibrio, Desulfovibrio, Bifidobacterium, Faecalibacterium, Parabacteroides as well as decreasing the abundances of Actinobacteria, Bacteroides, Proteobacteria, and Streptococcus, the ratio of Firmicutes/Bacteroidetes. A decrease in plasma lipopolysaccharide level and an increase in short-chain fatty acids, including acetic acid, propionic acid, butyric acid and pentanoic acid, were determined after dietary FO supplementation. Correlation analysis revealed close relationships among sex steroid hormones, inflammation, and gut/vaginal microbiota. Collectively, this study demonstrated that dietary FO ameliorated PCOS through the sex steroid hormones-microbiota-inflammation axis in rats, which may contribute to the understanding of pathogenesis and potentially serve as an inexpensive intervention in the control of PCOS.

A Rat Model of Maternal Polycystic Ovary Syndrome Shows that Exposure to Androgens In Utero Results in Dysbiosis of the Intestinal Microbiota and Metabolic Disorders of the Newborn Rat

Background

Intestinal dysbiosis, or dysbacteriosis, is an abnormal interaction between the intestinal microbiota and the host cells due to altered microbial diversity. This study aimed to investigate the metabolic effects and changes in the intestinal microbiota in newborn rats following exposure to increased levels of maternal androgens in a rat model of maternal polycystic ovary syndrome (PCOS).

Material/Methods

The administration of androgen developed the rat maternal PCOS model during pregnancy. Maternal rat ovarian follicles were counting and assessed by histology. The metabolic phenotype of newborn rats was evaluated and included an insulin tolerance test, a glucose tolerance test, and measurement of serum levels of triglyceride, insulin, cholesterol, adiponectin, and leptin. Expression of pro-inflammatory cytokines was detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), serum levels were measured by enzyme-linked immunosorbent assay (ELISA), and proteins associated with adipose tissue remodeling and adipocyte differentiation were measured by Western blot.

Results

Markers of systemic inflammation were significantly increased in the female offspring but not in the male offspring born to rat in the PCOS model. Following birth, newborn rats that received antibiotics showed an improved metabolic phenotype, with reduced serum lipid levels, insulin resistance, body weight, inflammation of adipose tissue, and serum levels of inflammatory cytokines compared with controls. Probiotics had no significant effects on these parameters in newborn rats.

Conclusions

In a rat model of maternal PCOS, exposure to androgens in utero resulted in dysbiosis of the intestinal microbiota and metabolic disorders of the newborn female rats.

Detection of T lymphocyte subsets and related functional molecules in follicular fluid of patients with polycystic ovary syndrome

Immune responses play an important role in the pathogenesis of polycystic ovary syndrome (PCOS). However, the characteristics of T lymphocyte subsets in PCOS remain insufficiently understood. In this study, lymphocytes of follicular fluid (FF) were obtained from oocyte retrieval before in-vitro fertilization (IVF) in infertile women with or without PCOS. The levels of cluster of differentiation 25 (CD25), CD69, programmed death 1 (PD-1), interferon-γ (IFN-γ), interleukin 17A (IL-17A) and IL-10 in T lymphocytes were determined by flow cytometry. Our results showed that the percentage of FF CD8⁺ T cells was significantly decreased in infertile patients with PCOS (P < 0.05). Furthermore, the levels of CD69 and IFN-γ were significantly decreased and the level of PD-1 was increased in both CD4⁺ and CD8⁺ T cells from infertile patients with PCOS (P < 0.05). Moreover, the expression of PD-1 on CD4⁺ or CD8⁺ T cells was positively correlated with the estradiol (E2) levels in the serum and reversely correlated with the expression of IFN-γ in CD4⁺ or CD8⁺ T cells in infertile patients with PCOS. These results suggested that T cell dysfunction may be involved in the pathogenesis of PCOS.

MIF May Participate in Pathogenesis of Polycystic Ovary Syndrome in Rats through MAPK Signalling Pathway

The polycystic ovary syndrome (PCOS) model was established in rats and correlation between the expression of macrophage migration inhibitory factor (MIF) and cytokinesis with the MAPK signalling pathway in the rat ovary was measured. The PCOS model in rats was established by dehydroepiandrosterone (DHEA). Thirty sexually immature female Sprague-Dawley rats were randomly and equally assigned to three groups: control group, PCOS group, and PCOS with high-fat diet (HFD) group. Serum hormones were assayed by radioimmunoassay (RIA). The ovaries were immunohistochemically stained with MIF, and the expression of MIF, p-JNK and p-p38 was detected by Western blotting in ovaries. The serum testosterone level, LH concentration, LH/FSH ratio, fasting insulin level and HOMA IR index in the PCOS group (6.077±0.478, 13.809±1.701, 1.820±0.404, 10.83±1.123 and 1.8692±0.1096) and PCOS with HFD group (6.075±0.439, 14.075±1.927, 1.779±0.277, 10.20±1.377 and 1.7736±0.6851) were significantly higher than those in the control group (4.949±0.337, 2.458±0.509, 1.239±0.038, 9.53±0.548 and 1.5329±0.7363), but there was no significant difference between the PCOS group and PCOS with HFD group. The expression levels of MIF, p-JNK, and p-p38 in the PCOS group (0.4048±0.013, 0.6233±0.093 and 0.7987±0.061) and PCOS with HFD group (0.1929±0.012, 0.3346±0.103 and 0.3468±0.031) were obviously higher than those in control group (0.2492±0.013, 0.3271±0.093 and 0.3393±0.061), but no significant difference was observed between PCOS group and PCOS with HFD group. It was suggested that MIF may participate in the pathogenesis of PCOS through the MAPK signalling pathway in PCOS rats induced by DHEA.

Follicular fluid cytokine composition and oocyte quality of polycystic ovary syndrome patients with metabolic syndrome undergoing in vitro fertilization

PURPOSE

To provide insights into the correlation among lipid metabolism, cytokine profiles in the follicular fluid (FF) and embryo quality of women with Polycystic Ovary Syndrome (PCOS) with metabolic syndrome (MS).

METHODS

Ninety women undergoing in vitro fertilization (IVF) treatment were recruited, including 60 PCOS patients (PCOS non MS and PCOS MS) and 30 age-matched controls. Individual FF samples were analyzed using the cytometric multiplex immunoassay.

RESULTS

In the FF, the PCOS MS group was associated with higher, total cholesterol (TC), triglyceride (TG) and lower high-density lipoprotein (HDL) concentrations compared with that in the control group (P<0.05). The FF tumor necrosis factor-α (TNF-α) level in the PCOS MS group was 3.89±1.18ng/mL, which was significantly higher compared with the control (2.94±1.02ng/mL) and PCOS non-MS groups (3.05±1.21ng/mL) (P=0.002), while the granulocyte colony-stimulating factor (G-CSF) level in the PCOS MS group (4.18±1.33ng/mL) was lower compared with the control (5.61±1.82ng/mL) and PCOS non-MS groups (5.32±1.91ng/mL) (P=0.004). The FF G-CSF showed a trend toward negative relationship with TG and TC; TNF-α concentration was positively associated with TG. The percentage of top-quality embryo decreased in the PCOS MS group than in the other two groups (20% vs. 38.4% and 34.6%).

CONCLUSIONS

In conclusion, there was an elevated lipolysis condition within the FF of PCOS MS patients and the TNF-α and G-CSF levels in FF were associated with top-quality embryo percentage. TNF-α and G-CSF may be the key cytokines involved in the mechanism of decreased embryo development potential in PCOS MS patients.

Association between HbA1c levels with severity of coronary artery disease and short-term outcomes of acute ST-elevation myocardial infarction in nondiabetic patients

BACKGROUND

The severity of coronary artery disease (CAD) is directly related to the quality of glucose control in diabetic patients. Additionally, mortality after an acute coronary syndrome is higher in patients with diabetes and it correlates to the level of glucose control. However, the role of higher gluconated hemoglobin in the process of coronary atherosclerosis and clinical outcome of acute myocardial infarction is unknown.

OBJECTIVES

To evaluate the association of HbA1c level and severity of CAD and short-term outcomes of acute ST-elevation myocardial infarction (STEMI) in nondiabetics.

METHODS

A total of 290 nondiabetic patients with STEMI were prospectively enrolled following their admission. Patients were stratified into 2 groups based on the median percent of HbA1c (⩽5.8% 'Low' and >5.8% 'High'). The severity of CAD based on the Califf scoring system, in-hospital mortality and morbidities of STEMI were compared between groups. Patients were followed for 1 year after discharge to assess readmission and mortality rate.

RESULTS

The severity score for CAD was significantly higher in the 'High' versus 'Low' HbA1c group (7.7 ± 2.7 and 5.5 ± 2.6, p = 0.001). A total of 15 patients died in both groups during the follow-up period. While in-hospital mortality was similar between the two groups, 12-month mortality was significantly higher in the 'High' group (7.7% versus 2.7%, p = 0.043). In addition, the rehospitalization rate within 1 year was 8.8% in the 'Low' group, which was significantly lower than 19.0% in the 'High' group (p = 0.016).

CONCLUSION

Among nondiabetic patients presenting with STEMI, the severity of CAD was higher in those with HbA1c level >5.8%; 1-year mortality and hospital readmission rates were also higher in this group of patients.

Adipose tissue dysfunction, adipokines, and low-grade chronic inflammation in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS), a complex condition that affects women of reproductive age, is characterized by ovulatory dysfunction and androgen excess. Women with PCOS present higher prevalence of obesity, central adiposity, and dyslipidemia, and face increased risk of type 2 diabetes. PCOS is closely linked to functional derangements in adipose tissue. Adipocytes seem to be prone to hypertrophy when exposed to androgen excess, as experienced by women with PCOS, and both adipose tissue hypertrophy and hyperandrogenism are related to insulin resistance. Hypertrophic adipocytes are more susceptible to inflammation, apoptosis, fibrosis, and release of free fatty acids. Disturbed secretion of adipokines may also impact the pathophysiology of PCOS through their influence on metabolism and on sex steroid secretion. Chronic low-grade inflammation in PCOS is also related to hyperandrogenism and to the hypertrophy of adipocytes, causing compression phenomena in the stromal vessels, leading to adipose tissue hypoperfusion and altered secretion of cytokines. Lifestyle changes are the first-line intervention for reducing metabolic risks in PCOS and the addition of an insulin-sensitizing drug might be required. Nevertheless, there is not sufficient evidence in favor of any specific pharmacologic therapies to directly oppose inflammation. Further studies are warranted to identify an adipokine that could serve as an indirect marker of adipocyte production in PCOS, representing a reliable sign of metabolic alteration in this syndrome.