Subcutaneous adipocyte apoptosis in HIV-1 protease inhibitor-associated lipodystrophy.

BACKGROUND: Inhibitors of HIV-1 protease produce a rapid decrease in plasma HIV-1 RNA, with concomitant immune reconstitution. However, severe metabolic side effects together with a previously unseen form of lipodystrophy have been associated with long-term use of protease-inhibitor therapy. The pathogenic mechanisms underlying HIV-1 protease inhibitor-associated lipodystrophy are still largely unknown. METHODS: Fourteen HIV-infected patients with HIV-1 protease inhibitor-associated lipodystrophy had a biopsy of subcutaneous fat performed in the antero-lateral aspect of the right leg. The samples were submitted for standard pathologic study together with a careful search for adipocyte apoptosis. Apoptosis was assessed by the terminal deoxynucleotidyl transferase dUTP-digoxigenin nick end labelling (TUNEL) method, using the ApopTag kit (Oncor, Gaithersburg, Maryland, USA). The procedure was performed between three and five times for each sample. Appropriate positive and negative controls were used. Controls which were subcutaneous fat biopsies from patients with untreated melanoma were also examined for the presence of apoptosis. RESULTS: Fourteen HIV-infected patients with a mean exposure to HIV-1 protease inhibitors of 12.6 +/- 3.7 months (range: 6-21 months), developed the characteristic features of HIV-1 protease inhibitor-associated lipodystrophy. All but one patient had an abnormal waist:hip ratio, and they all exhibited an abnormal serum lipid profile. Pathologically, subcutaneous fat atrophy was a constant feature, along with focal lipogranuloma formation and vascular proliferation. One of the eleven assessable biopsy samples was negative for the presence of apoptosis, six showed focally positive apoptotic cells, and the remaining four biopsies demonstrated moderate positivity. Apoptotic changes were also detected in endothelial cells. Apoptotic changes were more pronounced in patients with higher increases in CD4 and CD8 counts, and in those with a greater decay in plasma viral load. CONCLUSIONS: Subcutaneous adipocyte apoptosis occurs in lipoatrophic areas of patients with HIV-1 protease inhibitor-associated lipodystrophy.

Molecular pathology of multiple endocrine neoplasia type I: two novel germline mutations and updated classification of mutations affecting MEN1 gene.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined development of tumors in several endocrine glands and other tissues. The MEN1 gene was recently identified and isolated by positional cloning. This gene was screened in two unrelated MEN1 Spanish kindreds (with four affected members and seven asymptomatic members) using single-strand conformation polymorphism, DNA sequencing, and restriction enzyme analysis. Two novel germline mutations were identified: a missense in exon 2 (H139R) and a splice-site in intron 9 (1461-2A>C). These findings allowed us to identify the MEN1 carriers among the seven asymptomatic members analyzed. An updated review of the mutations and polymorphisms found in the analysis of the MEN1 gene is provided. The report of all germline mutations causing MEN1 and easy access to this updated information are both of special diagnostic interest, because this greatly facilitates the task of attributing the disorder to a specific mutation found in a given MEN1 family. This is especially helpful in the critical differentiation of missense mutations from nonsynonymous polymorphisms that fit the pattern of segregation of the disease, but do not cause it.

Sustentacular cells occur frequently in the familial form of medullary thyroid carcinoma.

The presence and distribution of S-100-immunoreactive sustentacular cells were investigated by immunohistochemistry in 67 medullary thyroid carcinomas (MTCs). The familial or sporadic status of the tumours was assessed by clinical data and confirmed by the identification of RET germline mutations using the polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and restriction analysis. Sustentacular cells were detected in 19 tumours (28.3 per cent). They were found significantly more frequently in the familial (15/24, 62.5 per cent) than in the sporadic MTCs (4/43, 9.3 per cent). The results indicate that sustentacular cells are commonly found in familial MTC and their presence in any MTC may be regarded as an indirect indicator that the tumour might be of the familial type.