Long Term Results of Parathyroidectomy in Uremic Patients: Analysis of Growth Factors Expression and Histomorphometric Findings. 
Rosa M.A. Moyses, Francisco R.L. Santos, Melani R.Custodio, Luciene M. Reis, Vanda Jorgetti, Irene L. Noronha. Renal Division/Dept. Internal Medicine, University of Sao Paulo, Sao Paulo, Brazil. 

Parathyroidectomy (PTX) is the procedure of choice for uremic patients who have secondary hyperparathyroidism (SHP) and are unresponsive to medical treatment. We carried out a prospective study in 9 hemodialyzed patients (6 females and 3 males) who were submmited to total PTX with auto 
transplantation in the forearm. Iliac bone biopsies were performed before and 1 year after PTX. These biopsies were submitted to histomorphometric studies and to immunohistochemical staining to evaluate the 
transforming growth factor b (TGFb) and fibroblastic growth factor-b(FGF) expression in bone biopsies.  
Table 1 summarizes our findings (mean values). 

PTX reduced trabecular bone volume(BV/TV), osteoid volume(OV/BV), osteoid thickness(O.Th), osteoid surface(OS/BS), osteoblastic surface(Ob.S/BS), osteoclastic surface(Oc.S/BS), and fibrosis(FB.V). This dramatic decrease in fibrosis paralled the significant reduction in TGFb and FGF expression, suggesting that these growth factors may be involved in the pathogenesis of SHP fibrosis. 

On the other hand, there was an increase in trabecular separation(Tb.Sp), and a decrease in trabecular number(Tb.N), with similar trabecular hickness(Tb.Th) values, characterizing a lower connectivity among trabeculae. In addition, in the post-PTX group there was an increase in aluminum deposition (Al/BS), and 6 patients developed low bone turnover diseases : 2 Osteomalacia and 4 Adynamic Diseases. 

These results suggest that TGFB and FGF may play a role in the development of SHP fibrosis. PTX corrected almost all clinical signs and bone biopsy features of SHP, but decreased the trabecular connectivity and 
increased Al deposition. These abnormalities may determine a high risk of bone fractures in these patients in the future. 

Poster Session: Bone Disease (9:30 AM-5:00 PM) 
           Presentation Date: Friday, November 5, 1999, Time: 9:30AM, Room: Halls B and C