Aquaglyceroporin-7 Overexpression in Women with the Polycystic Ovary Syndrome

Abstract

Background: Aquaglyceroporin-7 (AQP7) is an adipose glycerol channel protein that has been suggested to be involved in whole-body glucose homeostasis and insulin sensitivity. The aim of this study was to investigate the expression of AQP7 in visceral adipose tissues from women with the polycystic ovary syndrome (PCOS). Methods:AQP7 mRNA and protein levels were measured in omental adipose tissue from 5 women with the PCOS and 4 healthy controls matched for body mass index and age; this was done by the real-time polymerase chain reaction (PCR) and Western blotting. -Results: The women with the PCOS had significantly higher homeostasis model insulin resistance indices (HOMA_IR) and their quantitative insulin sensitivity check indices were significantly lower compared to the controls (p < 0.05). No significant difference was noted between the two groups for the plasma glycerol concentration. AQP7 mRNA expression and protein levels in omental adipose tissue from women with the PCOS were significantly higher than those of the controls (p = 0.007). AQP7 expression showed a positive correlation with fasting insulin levels, insulin levels at 2 h after glucose loading and HOMA_IR in women with the PCOS. Conclusion:AQP7 overexpression may be related to insulin sensitivity and glucose homeostasis in women with the PCOS.

Induction of heme-oxygenase-1 (HO-1) does not enhance adiponectin production in human adipocytes: Evidence against a direct HO-1 – Adiponectin axis

“…and increased circulating levels of the beneficial adipokine adiponectin, in in vivo studies in rodents (Cao et al, 2012a;Cao et al, 2011;Cao et al, 2012c;Hinds et al, 2014;Kim et al, 2008;L'Abbate et al, 2007;Li et al, 2008;Ndisang and Jadhav, 2014;Vanella et al, 2012;Vanella et al, 2013), and in vitro studies, showing increased adiponectin secretion from adipocytes (Kim et al, 2008;Vanella et al, 2013). These observations stimulated the proposal of a HO-1adiponectin axis (Cao et al, 2012a;Cao et al, 2011;Issan et al, 2012;Kim et al, 2010;Li et al, 2008;Ndisang and Jadhav, 2014;Salamone and Li Volti, 2010;Seow et al, 2011;Vanella et al, 2012) which could underpin, at least in part, the favourable effects of HO-1 induction reported in most pre-clinical models of obesity and related cardiometabolic disorders. Thus, we reasoned information affording a greater understanding of the cellular and molecular framework of the HO-1adiponectin axis would help to identify, validate and progress development of efficacious therapeutic approaches.…”

“…Accumulating evidence has led to the suggestion that HO-1 may mediate at least some of its beneficial effects by increasing circulating adiponectin levels through what has been termed the "HO-1adiponectin axis" (Cao et al, 2012a;Cao et al, 2011;Issan et al, 2012;Kim et al, 2010;Li et al, 2008;Ndisang and Jadhav, 2014;Salamone and Li Volti, 2010;Seow et al, 2011;Vanella et al, 2012). For example, chronic administration of obese mice with the HO-1 inducer cobalt protoporphyrin (CoPP) was reported to increase HO-1 protein, prevent weight gain and decrease fat content (in the absence of any change in food intake), reduce circulating inflammatory cytokines (including TNFα and IL-6) and increase circulating adiponectin levels (Li et al, 2008).…”

Implications of Aquaglyceroporin 7 in Energy Metabolism

“…Most of the studies evaluating AQP7 mRNA expression in subcutaneous or visceral WAT in association with T2D did not find any significant changes [50,52,54,56]; however, increased AQP7 abundance in visceral WAT from type 2 diabetics has been shown [18,54]. A significant increase in visceral WAT AQP7 expression was also found in a small cohort of insulin-resistant women with polycystic ovary syndrome (PCOS) characterized by endocrinological dysfunction, hyperandrogenism, absence of ovulation and polycystic ovaries [57]. In summary, taking into account that these studies were not designed to identify if a changed AQP7 abundance would be a cause or a consequence of obesity or T2D, and that most of them were conducted in mixed gender cohorts, the results agree with an association between reduced AQP7 abundance and obesity, whereas a direct association between dysregulated AQP7 abundance and T2D seems less evident.…”

Prevalence of the Polycystic Ovary Syndrome in Female Residents of Chengdu, China

“…In addition, there is little information about the changes in the prevalence of PCOS from the ovaries maturing to being exhausted. So, until now there are no interventions which can efficiently prevent or cure PCOS, not only because of the limitations of knowledge about the pathogenesis of PCOS [3,4,5], but also of the epidemiological features of PCOS.…”