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Disease Markers
Volume 35, Issue 4, Pages 249–259
http://dx.doi.org/10.1155/2013/531736
Research Article

Association of Obesity-Mediated Insulin Resistance and Hypothalamic Volumes: Possible Sex Differences

1Brain, Obesity, and Diabetes Laboratory (BODyLab), Department of Psychiatry, New York University School of Medicine, 145 East 32nd Street, 8th Floor, New York, NY 10016, USA
2Department of Medicine, New York University School of Medicine, 145 East 32nd Street, 8th Floor, New York, NY 10016, USA
3Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA

Received 7 June 2013; Revised 25 July 2013; Accepted 7 August 2013

Academic Editor: Viswanath Devanarayan

Copyright © 2013 Jenny Ha et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The hypothalamus is important in hunger and metabolism. Although a lot is known about the basic role of the human hypothalamus, less is known about how the in vivo volume is affected in obesity, particularly among adolescents. Based on pediatric body mass index percentiles, 95 participants were assigned to lean or obese groups. All subjects had medical evaluations, including fasting blood tests, to assess insulin sensitivity and circulating CRP and neurotrophins (NGF and BDNF) and an MRI of the brain. Hypothalamic volumes were measured by a segmentation method combining manual and automated steps. Overall, obese participants had descriptively smaller hypothalamic volumes, although this difference did not reach statistical significance; however, among obese participants, females had significantly smaller hypothalamic volumes than their male counterparts. There was a significant interaction between insulin resistance and sex on hypothalamus volume; obese females with significant insulin resistance have smaller hypothalamic volumes than obese males. Obese adolescents had higher circulating CRP and neurotrophin levels. Furthermore, among obese females, BDNF concentrations were inversely associated with hypothalamus volumes ( ). Given this negative association between BDNF and hypothalamus volumes among obese insulin-resistant females, elevated neurotrophin levels may suggest an attempt at protective compensation.