First, by myxoedema I am specifically meaning the swelling so strongly associated with hypothyroidism - the non-pitting oedema which affects so many.
Second, this is simply one new paper announcing their specific findings. It does not mean it is the only reason.
As I read it, the paper says that proper levels of T3 result in the production of hyaluronic acid slowing down and everything being good. But with low levels of T3, the body keeps making hyaluronic acid even when there is already plenty. So it collects and causes the swelling. Hyaluronic acid manages to cause the retention of large amounts of water.
If correct, it is interesting that this is a very specific T3 function.
In Vitro Cell Dev Biol Anim. 2013 Feb 9. [Epub ahead of print]
Triiodothyronine (T3) inhibits hyaluronate synthesis in a human dermal equivalent by downregulation of HAS2.
Pouyani T, Sadaka BH, Papp S, Schaffer L.
Department of Pharmaceutical Sciences, Northeastern University, Bouvé College of Health Sciences, Boston, MA, 02115, USA, email@example.com.
Triiodothyronine (T3) is a thyroid hormone that can have varying effects on skin. In order to assess the effects of T3 on the human dermis, we prepared dermal equivalents using neonatal dermal cells via the process of self-assembly in the presence of differing concentrations of T3. These dermal equivalents were prepared in the absence of serum and a three dimensional matrix allowing for the direct assessment of different concentrations of T3 on dermal extracellular matrix formation. Three different concentrations of T3 were chosen, 20 pM, which is part of the base medium, 0.2 nM T3 and 2 nM T3. We find that self-assembled dermal equivalents formed under these conditions show a progressive "thinning" with increasing T3 concentrations. While we observed no change in total collagen content, inhibition of hyaluronate (HA) synthesis was observed in the 0.2- and 2-nM T3 constructs as compared to the 20-pM construct. Other glycosaminoglycan synthesis was not affected by increasing T3 concentrations. In order to identify the gene(s) responsible for inhibition of HA synthesis in the 2-nM T3 dermal equivalent, we conducted a differential gene array analysis. The results of these experiments demonstrate the differential expression of 40 genes, of these, 34 were upregulated and 6 genes were downregulated. The results from these experiments suggest that downregulation of HAS2 may be responsible for inhibition of hyaluronate synthesis in the self-assembled 2-nM T3 human dermal matrix.
PMID: 23397370 [PubMed - as supplied by publisher]
The picture is of Chinese Shar-Pei dogs - seems their characteristic wrinkled skin collects hyaluronic acid which forms "socks". Also the meatmouth Shar-Pei (A–C) is predisposed to a breed-specific periodic fever syndrome called Familial Shar-Pei Fever (FSF). Well I never...