Death of adrenocortical cells during murine acute T. cruzi infection is not associated with TNF-R1 signaling but mostly with the type II pathway of Fas-mediated apoptosis.

Earlier studies from our laboratory demonstrated that acute experimental Trypanosoma cruzi infection promotes an intense inflammation along with a sepsis-like dysregulated adrenal response characterized by normal levels of ACTH with raised glucocorticoid secretion. Inflammation was also known to result in adrenal cell apoptosis, which in turn may influence HPA axis uncoupling. To explore factors and pathways which may be involved in the apoptosis of adrenal cells, together with its impact on the functionality of the gland, we carried out a series of studies in mice lacking death receptors, such as TNF-R1 (C57BL/6-Tnfrsf1a tm1Imx or TNF-R1-/-) or Fas ligand (C57BL/6 Fas-deficient lpr mice), undergoing acute T. cruzi infection. Here we demonstrate that the late hypercorticosterolism seen in C57BL/6 mice during acute T. cruzi infection coexists with and hyperplasia and hypertrophy of zona fasciculata, paralleled by increased number of apoptotic cells. Apoptosis seems to be mediated mainly by the type II pathway of Fas-mediated apoptosis, which engages the mitochondrial pathway of apoptosis triggering the cytochrome c release to increase caspase-3 activation. Fas-induced apoptosis of adrenocortical cells is also related with an exacerbated production of intra-adrenal cytokines that probably maintain the late supply of adrenal hormones during host response. Present results shed light on the molecular mechanisms dealing with these phenomena which are crucial not only for the development of interventions attempting to avoid adrenal dysfunction, but also for its wide occurrence in other infectious-based critical illnesses.

Bilateral adrenocortical uptake of Ga-67 SPECT during septicemia in a heart transplant patient.

Gallium-67 scintigraphy is a valuable agent in the management of fever of unknown origin. The use of SPECT increases its sensitivity and may demonstrate unexpected findings. We report on a heart-transplanted 55-year-old man with postsurgical fever of unknown origin. Ga-67 SPECT showed bilateral abnormal adrenal gland uptake that disappeared after intensive antibiotic therapy as assessed by a new Ga-67 scintigraphy obtained 3 months later. Unilateral and bilateral adrenal uptake of gallium has been reported in several clinical settings, ranging from adrenocortical adenomas to malignant disease such as lymphoma or adrenal metastases. Only one similar case, septicemia with transient adrenal uptake of gallium, has been previously reported.

Infection of cultured human adrenal cells by different strains of HIV.

OBJECTIVE: To determine whether human adrenal cells can be infected by HIV. METHODS: Cultured human fetal adrenal cells and the SW13 human adrenocortical carcinoma cell line were inoculated with several HIV-1 and HIV-2 strains. Virus replication was detected by viral core antigen enzyme-linked immunosorbent and reverse transcriptase assays. CD4 expression was measured by Northern blot and polymerase chain reaction procedures. RESULTS: HIV infection of these adrenal cells was detected and was most evident after cocultivation of the inoculated cells with peripheral blood mononuclear cells. Infection does not involve the CD4 molecule, which is not expressed by these adrenal cells. The relative level of HIV replication depended on the viral strain used. Virus production occurred best in cells that maintained evidence of adrenal cell function. Infection did not appear to disturb steroidogenesis measured in the cells. CONCLUSIONS: These observations indicate that human adrenal cells are susceptible to HIV infection, and provide further evidence of the polytropic nature of the virus.

Intracellular parasitism of parenchymal cells by Mycobacterium leprae.

The liver, skeletal muscle, and adrenal gland obtained from two nine-banded armadillos infected with Mycobacterium leprae were studied using an electron microscope. M. leprae were found in varying numbers inside hepatocytes, Kupffer's cells, striated muscle cells, adrenal cortical and adrenal medullary cells, endothelial cells, and macrophages. There was evidence to suggest that M. leprae were actively phagocytosed by the liver and skeletal muscle cells. The inert nature of M. leprae and its behavior as an almost ideal parasite of parenchymal cells are emphasized. The question of whether this unique parasitism of parenchymal cells and the possible processing and presentation of M. leprae antigens by these cells could be responsible for aberrant immune responses is raised.

Cooperative transforming activities of ras, myc, and src viral oncogenes in nonestablished rat adrenocortical cells.

Early-passage rat adrenocortical cells were infected with Kirsten murine sarcoma virus and MMCV mouse myc virus, two retroviruses carrying the v-Ki-ras and v-myc oncogenes, respectively. Efficient morphological transformation required coinfection with the two viruses, was dependent on the presence of high serum concentrations, and was not immediately accompanied by growth in soft agar. The doubly infected cells coordinately acquired the capacity for anchorage- and serum-independent growth during passage in culture. The appearance of such highly transformed cells was correlated with the emergence of a dominant clone, as suggested by an analysis of retrovirus integration sites. These results indicate that the concerted expression of v-Ki-ras and v-myc could induce rapid morphological transformation of nonestablished adrenocortical cells but that an additional genetic or epigenetic event was required to permit full transformation by these two oncogenes. In contrast, v-src, introduced by retrovirus infection in conjunction with v-myc, rapidly induced serum- and anchorage-independent growth. Therefore, the p60v-src protein-tyrosine kinase, unlike p21v-ras, is apparently not restricted in the induction of a highly transformed phenotype in adrenocortical cells. This system provides an in vitro model for the progressive transformation of epithelial cells by dominantly acting oncogenes.

Development of serum independence in Kirsten murine sarcoma virus-infected rat adrenal cells.

Cells cultured from explants of adult rat adrenal cortex are spindle shaped and divide rapidly in media with 10-25% fetal bovine serum (FBS), but are epithelial-like and stationary in 3-6% horse serum (HS). Fully transformed Kirsten murine sarcoma virus (KiMSV)-infected cells lose this differential response to serum. To determine at what stage in the transformation process this loss occurs, cultures in passages 1-2 were infected with KiMSV, propagated for up to 30 weeks in FBS, and parallel cultures were transferred to HS prior to transformation, within 4 weeks after appearance of foci, or after complete transformation (exhibiting altered culture morphology, increased growth rate and tumorigenicity). In 7 lines grown in FBS, foci appeared 1-14 weeks post-infection and most cultures were completely transformed 1-3 weeks thereafter. Substitution of HS for FBS prior to focus formation caused partial reversion to epithelial-like morphology and reduction in growth rate. Transformation was delayed or prevented altogether, but could be elicited by addition of 1% FBS to HS. HS-substitution within 4 weeks after appearance of foci caused regression of foci, slowing of growth, and delays of complete transformation lasting up to 5 months. In three lines, HS effects on cell shape and on proliferation were dissociated, suggesting separate controls of these two parameters. HS-substitution after complete transformation did not reduce growth or reverse morphologic changes. The results indicate that, in some cases, transformation by acute oncogenic retroviruses is a multistep process involving epigenetic regulation, and that autonomy from environmental controls is acquired gradually by the infected cells. The results also demonstrate that acute transforming retroviruses can cause prolonged latent infections, the phenotypic expression of which depends on environmental factors.

Viral antigen in endocrine cells of the pancreatic islets and adrenal cortex of Pekin ducks infected with duck hepatitis B virus.

Endocrine cells in the pancreas and adrenal glands of duck hepatitis B virus-infected ducks were examined for the presence of viral antigen. Analysis of pancreas tissue was based on double immunofluorescence assays in which anti-duck hepatitis B virus serum was used to detect viral antigen, and anti-glucagon and anti-insulin serum were used, respectively, to identify endocrine alpha and beta cells. Assays of pancreas from infected ducks ranging in age from 3 to 20 weeks indicated that subpopulations of both alpha and beta cells expressed viral antigen. A higher percentage of viral antigen-positive cells was observed in alpha-islets than in beta-islets. As assayed by immunofluorescence and immunoperoxidase staining with anti-viral serum, small clusters of viral antigen-positive cells were detected in the adrenal glands of young infected ducks. These cells were identified as cortical cells on the basis of histologic criteria.

Morphological and functional differentiation of Kirsten murine sarcoma virus-transformed rat adrenocortical cell lines.

This study was undertaken to examine relationships of the phenotype of malignant cells to target cell properties and to events early in the transformation process. Eighteen transformed lines were obtained by Kirsten murine sarcoma virus infection of cells from adrenal glands of rats ages 4 to 30 weeks, at first or second passages in culture. They were grown either as fibroblastic adrenocortical stem cells or as more differentiated epithelial cells, depending on culture conditions. Of 14 lines examined for their capacity to synthesize corticosteroids, 11 converted [14C]pregnenolone to progesterone, and one converted to deoxycorticosterone. In vivo, seven lines produced tumors resembling pleomorphic carcinomas, six lines grew as sarcomas, four grew as mixed tumors, and one line produced anaplastic tumors. Distinguishing features in culture of the carcinoma-producing lines were early onset and rapid progression of morphological transformation, a noncohesive epithelial cell form in some lines, lack of extracellular matrix, and, possibly, and origin in older animals. In contrast, sarcoma-producing cells were fibroblastic and cohesive, produced extracellular matrix, and transformed morphologically after longer and less well-defined periods in culture. The variation in histopathology was unrelated to the differentiation of the target cells and to the capacity of the transformed cells to synthesize corticosteroids. The results show that adrenocortical cells, transformed by Kirsten murine sarcoma virus after short-term culture, usually retain some functional differentiation and sometimes resemble human adrenocortical carcinomas histologically. The susceptibility of adrenocortical cells to Kirsten murine sarcoma virus raises the possibility that mesodermally derived epithelia in general may be target tissues for C-type sarcoma viruses.