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Volume 08 No. 02
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Accepted Papers

Letters to the Editor

Could Leptin Mediate Insulin Resistance Through Cytokine Signaling?

Michael Polkey, Ph.D.1; Mary J. Morrell, Ph.D.2
1Brompton Hospital, Department of Sleep & Ventilation, Fulham Road, London, UK; 2National Heart and Lung Institute, Imperial College London, South Kensington Campus, London, UK

We thank Dr. Pallayova for her interest in our work,1 and for drawing our attention to hers.2 We think the two studies are not really comparable, first because we did not measure circulating inflammatory cytokines, but also, perhaps more importantly in our view, because her cohort did not contain a control group. We believe her hypothesis, that tissue mediated effects of NPY may differ from circulating effects, is novel, and deserves further investigation. Interestingly a recent observation indicates that circulating NPY seems to relate to the presence of hypertension (a manifestation of sympathetic activation) rather than OSA.3 However, at present we are not aware of data which would support Dr. Pallayova's hypothesis directly.


The authors have indicated no financial conflicts of interest.


Polkey M; Morrell MJ. Could leptin mediate insulin resistance through cytokine signaling? J Clin Sleep Med 2012;8(2):229.



Papaioannou I, Patterson M, Twigg GL, et al., authors. Lack of association between impaired glucose tolerance and appetite regulating hormones in patients with obstructive sleep apnea. J Clin Sleep Med. 2011;7:486–92. [PubMed]


Pallayova M, Steele KE, Magnuson TH, et al., authors. Sleep apnea predicts distinct alterations in glucose homeostasis and biomarkers in obese adults with normal and impaired glucose metabolism. Cardiovasc Diabetol. 2010;9:83[PubMed Central][PubMed]


Li NF, Yao XG, Zhu J, et al., authors. Higher levels of plasma TNF-alpha and neuropeptide Y in hypertensive patients with obstructive sleep apnea syndrome. Clin Exp Hypertens. 2010;32:54–60. [PubMed]