Inflammation in response to glucose ingestion is independent of excess abdominal adiposity in normal-weight women with polycystic ovary syndrome

Abstract

Context: Inflammation and excess abdominal adiposity (AA) are often present in normal-weight women with polycystic ovary syndrome (PCOS).

Objective: We determined the effects of hyperglycemia on nuclear factor-κB (NFκB) activation in mononuclear cells (MNC) of normal-weight women with PCOS with and without excess AA.

Design: This was a prospective controlled study.

Setting: The study was conducted at an academic medical center.

Patients: Fifteen normal-weight, reproductive-age women with PCOS (seven normal AA, eight excess AA) and 16 body composition-matched controls (eight normal AA, eight excess AA) participated in the study.

Main outcome measures: Body composition was measured by dual-energy absorptiometry. Insulin sensitivity was derived from an oral glucose tolerance test (IS(OGTT)). Activated NFκB and the protein content of p65 and inhibitory-κB were quantified from MNC, and TNFα and C-reactive protein (CRP) were measured in plasma obtained from blood drawn while fasting and 2 h after glucose ingestion.

Results: Compared with controls, both PCOS groups exhibited lower IS(OGTT), increases in activated NFκB and p65 protein, and decreases in inhibitory-κB protein. Compared with women with PCOS with excess AA, those with normal AA exhibited higher testosterone levels and lower TNFα and CRP levels. For the combined groups, the percent change in NFκB activation was negatively correlated with IS(OGTT) and positively correlated with androgens. TNFα and CRP were positively correlated with abdominal fat.

Conclusion: In normal-weight women with PCOS, the inflammatory response to glucose ingestion is independent of excess AA. Circulating MNC and excess AA are separate and unique sources of inflammation in this population.

Fig. 1.

A, EMSA showing NFκB in nuclear extracts from MNC. A supershift of the NFκB band occurred during incubation with specific antibodies against NFκB subunits but not during incubation with nonspecific (NS) IgG. Neutralization of the NFκB band occurred during incubation with a specific cold competitor (SPC) of the oligonucleotide consensus sequence but not during incubation with a nonspecific cold competitor (NSC). B, Representative EMSA bands from the four study groups showing the quantity of NFκB in nuclear extracts from MNC in samples collected before and after the glucose ingestion. The samples used to quantify NFκB from both study groups were run on the same gel. C, Densitometric quantitative analysis comparing the change from baseline (percent) in MNC-derived activated NFκB between fasting and 2 h after the glucose ingestion samples. There was no significant difference in the response between the PCOS groups or the control groups. *, Response in women with PCOS with normal AA was significantly greater compared with that of either control group (P < 0.05); †, response in women with PCOS with excess AA was significantly greater compared with that of either control group (P < 0.005).

Fig. 2.

Representative Western blots from the four study groups showing the change in quantity of p65 and actin (A), and IκB (C) and actin in MNC homogenates in samples collected before and after glucose ingestion. The samples used to quantify proteins from both study groups were run on the same gel. Densitometric quantitative analysis comparing the change from baseline (percent) in MNC-derived p65 (B) and IκB protein content (D) between fasting and 2 h after glucose ingestion samples. There was no significant difference in the response between the PCOS groups or the control groups. *, In women with PCOS with normal AA, the p65 response was significantly greater and the IκB response was significantly reduced compared with that of either control group (p65: P < 0.007; IκB: P < 0.0004); †, In women with PCOS with excess AA, the p65 response was significantly greater and the IκB response was significantly reduced compared with that of either control group (p65: P < 0.003; IκB: P < 0.002).

Fig. 3.

Plasma levels of TNFα (A) and CRP (B) measured in fasting blood samples. Plasma TNFα and CRP levels were significantly higher in women with PCOS with excess AA compared with controls with normal AA (*, TNFα: P < 0.005; CRP: P < 0.0002), controls with excess AA (†, TNFα: P < 0.05; CRP: P < 0.02) and women with PCOS with normal AA (‡, TNFα: P < 0.002; CRP: P < 0.0006). Plasma CRP levels were significantly higher in controls with excess AA compared with controls with normal AA (triple dagger, P < 0.05).