Below a link to an article recently published in the International Journal of Molecular Medicine. The first author is Dr. Talebizadeh, who was supported by an FPWR grant and the last author is Dr. Butler, who many of you know is very active in PWS research and clinical studies. Here, the investigators examined expression of hunger hormones (ghrelin and PYY) and their respective receptors in brain tissue specimens.
This study defines the specific regions of the brain where these hormones and receptors are expressed and examined whether there were any detectable differences between individuals with PWS and Angelman syndrome compared to control (normal individuals). Basically, they were able to detect expression of both hunger hormones and the receptors in all six regions of the brain they examined. Further, by this assay (reverse transcriptase-polymerase chain reaction), they did not see any significant differences between the different samples.
The limitations of the study are that the assay used is more qualitative (yes/no) than quantitative (exactly how much in sample 1 vs. 2). The study also looked at RNA rather than protein - RNA is the precursor to protein and just because the RNA is there doesn't always mean the protein with be there. The advantage of RNA studies is that it usually can be accomplished fairly readily for a number of different genes. Finally, the use of autopsy specimens is obviously necessary but there is inherent variability in the samples. Like all good studies, this provides some important groundwork that will allow the investigators to follow up - probably with more quantitative analysis of exactly how much expression is present.
As mentioned, this research was supported in part by a grant FPWR provided to Dr. Talebizadeh last year. She is a new investigator and this grant provided her the opportunity to get her PWS research program (which includes, but is not limited to the present study) underway.
Ghrelin, peptide YY and their receptors: Gene expression in brain from subjects with and without Prader-Willi syndrome. Talebizadeh Z, Kibiryeva N, Bittel DC, Butler MG. Int J Mol Med. 15(4):707-11, 2005.