It is a pity we do not have an adequate animal model for endometriosis.I therefore started with the help of the EU the baboon project in Kenya at the IPR. This was done under direct supervision of Chandrit Bambra and Mohamed Isahakia by Thomas D’Hooghe who used the data for his PhD with myself and Bambra as promotors. Since then, after several years, is has become clear that the baboon is not an adequate model for endometriosis .
First, baboons do have endometriosis but we found only minimal superficial lesions. In the first articles the point scoring system of the rAFS has been multiplied by 2 with the argument that the baboon is small. This mistake has been repeated systematically later on and I only realised afterwards that without this almost all animals would have been classified as class I and that almost all significances in results would disappear in the articles.
Baboons with severe endometriosis as deep and cystic ovarian endometriosis are not available for research. These lesions have been observed only occasionally in primates and we were unable to induce these lesions in baboons even not using immunosuppressive drugs, experiments that were pretty expensive.
Only typical lesions could be induced by injecting menstrual endometrium, but whether this would be useful as a model remains unexplored.
The published results should be interpreted with caution. The over 20 articles (in all of of them I am the last author except the last 2) are based only on some 250 laparoscopies in 50 baboons. Reassesing the articles I realised that although all articles have been published as significant at the 0.05 level, all significances are based on 1 animal only and will disappear if one animal would have been misclassified. Looking backwards this is surprising. In addition, in the last 2 articles I refused to be a co-author because of lack of internal consistency of the data.
At he end of the experiments, most of the baboons died from tuberculosis, making repeat experiments virtually impossible.
It was described in the baboon that TNFa was effective for endometriosis treatment, but this was not confirmed in the human.
The baboon therefore cannot be considered as an adequate model for endometriosis, something I have been telling repetitively at international meetings. To publish this message as a comment in the peer reviewed literature, however, remains difficult since comments only are not acceptable for publication. Thus eventual mistakes tend to be carried forward, and doubt will continue until the day the experiments are repeated and confirmed or not.
Prof P.R. Koninckx