Myostatin and its association with abdominal obesity, androgen and follistatin levels in women with polycystic ovary syndrome.
OBJECTIVE
What is the role of myostatin and its relationship with obesity, androgens and follistatin levels in women with polycystic ovary syndrome (PCOS)? SUMMARY ANSWERS: The myostatin level was positively correlated to the risk of abdominal obesity, but negatively associated with circulating levels of dehydroepiandrosterone sulfate (DHEAS) and follistatin in women with PCOS.


BACKGROUND
Myostatin is a well-known negative regulator of skeletal muscle and is involved in metabolism; however, little is known about the role of myostatin in women with PCOS. In this study, we found that the myostatin level was positively related to the risk of abdominal obesity, but negatively related to the circulating levels of DHEAS and follistatin in women with PCOS. Such a relationship might imply a potential regulatory role of androgens and follistatin in the metabolism of skeletal muscle in women with PCOS.


METHODS
A cross-sectional case-control study.


METHODS
A total of 239 untreated, consecutive women with PCOS and 38 healthy volunteer women without PCOS were enrolled and studied in a tertiary medical center.


RESULTS
Myostatin level was higher in women with PCOS than those without PCOS (16.6±15.6 and 14.2±9.7, P=0.025), but were not significantly different between non-obese women with and without PCOS after considering the effect of obesity (P=0.09). Stepwise multivariate regression analysis in women revealed that only the presence of PCOS (β=0.256, P=0.0001), total testosterone (β=0.159, P=0.031), DHEAS (β=-0.188, P=0.0003) and follistatin (β=-0.171, P=0.0001) levels were left in the final model and were significantly related to the myostatin level after considering all the explanatory variables. By using stepwise multivariate regression analysis, the total testosterone levels (β=0.196, P=0.003) were positively, but the DHEAS (β=-0.196, P<0.0001) and follistatin (β=-0.151, P=0.0001) levels were negatively, related to myostatin levels in women with PCOS after adjustment for age, anthropometric measurements, insulin sensitivity index and hormonal profiles. The high myostatin level was associated with the increased risk of abdominal obesity after further adjusting the androgens and follistatin levels in women with PCOS.


CONCLUSIONS
This study is a cross-sectional case-control design, and therefore, cannot answer the cause-effect relationship among the androgens, follistatin and myostatin levels. The small sample size and non-obese control group may also limit the application of the conclusion of the present study to general population other than women with PCOS. In addition, lack of data regarding muscle mass is another limitation in this study that prevents clarification of the relationship between myostatin, lean mass and obesity and therefore restricts the clinical application of the results.


CONCLUSIONS
Future studies to investigate the efficacy of exercise and lifestyle modification in treating women with PCOS should consider the myostatin, follistatin and androgen levels as well as the effect of muscle mass and BMI.


BACKGROUND
This study was supported by grants NSC97-2314-B002-079-MY3, NSC98-2314-B002-105-MY3 and NSC 100-2314-B002-027-MY3 from the National Science Council of Taiwan. There is no competing interest declared in this study.
Department of Obstetrics and Gynecology, National Taiwan University Hospital, and Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Mei-Jou
MJ
Chen
Der-Sheng
DS
Han
Jehn-Hsiahn
JH
Yang
Yu-Shih
YS
Yang
Hong-Nerng
HN
Ho
Wei-Shiung
WS
Yang
D000328:Adult; D000728:Androgens / Q000097:blood*; D000886:Anthropometry / Q000379:methods; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D005260:Female; D038681:Follistatin / Q000097:blood*; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D009154:Mutation; D055435:Myostatin / Q000096:biosynthesis* / Q000378:metabolism / Q000502:physiology*; D009765:Obesity; D056128:Obesity, Abdominal / Q000378:metabolism*; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000378:metabolism
D000728:Androgens; D038681:Follistatin; D055435:Myostatin; D019314:Dehydroepiandrosterone Sulfate