Stem cells: are they the answer to the puzzling etiology of endometriosis?

Endometriosis is a chronic benign disease characterized by the presence of abnormally located tissue resembling the endometrium with glands and stroma. This disease has a high degree of morbidity due to chronic pelvic pain and infertility. The disease is likely to be polygenic and multifactorial, but the exact pathogenic mechanisms are still not entirely clear. Recently, adult stem cells have been identified in several tissues, including the endometrium. These cells are probably involved in the regenerative ability of the endometrial cycle, and also in the pathogenesis of proliferative gynaecological diseases, such as endometriosis. The identification of stem cells in animal and human tissues is very complex and the putative stem cells are supposed to be found through several assays such as clonogenicity, label-retaining cells, "side-population" cells, undifferentiation markers, and cellular differentiation. Bone marrow-derived stem cells transplanted into humans and animals have also been identified in eutopic endometrium and endometriotic implants. This review evaluates the available evidence regarding stem/progenitor cells in the human endometrium and explores the possible involvement of these cells in the etiology of endometriosis.

Vero cells infected with the Lederle strain of canine distemper virus have increased Fas receptor signaling expression at 15 h post-infection

We evaluated the expression of the Fas receptor gene in Vero cells infected with the Lederle vaccine strain of canine distemper virus using RT-PCR. Vero cells were plated, and after being grown for 24 h in MEM with 5% FBS, 80-90% confluent monolayer cultures were infected with the virus. The cells were harvested at 3, 6, 9, and 15 h post-infection. Uninfected Vero cells were used as a control. Total RNA was isolated from Vero cells using 1 mL Trizol(®) LS, and RT was performed using 2 μg total RNA. Primer pairs for RT-PCR amplification for the canine distemper virus nucleocapsid gene, the S26 reference gene, and the Vero rFas gene were used to analyze expression in Vero cells. RT-PCR results revealed virus activity at 3, 6, 9, and 15 h in the virus-infected Vero cells. The S26 housekeeping gene was amplified in virus infected and control samples. However, expression of the cell death receptor Fas was detected in Vero cells only at 15 h post-infection. We suggest that the Lederle vaccine induces apoptosis by Fas receptor signaling, possibly through caspase-8 signaling rather than through mitochondrial signaling in the infected cells.

Caspase-3/-8/-9, Bax and Bcl-2 expression in the cerebellum, lymph nodes and leukocytes of dogs naturally infected with canine distemper virus

Canine distemper is an immunosuppressive disease caused by the canine distemper virus (CDV). Pathogenesis mainly involves the central nervous system and immunosuppression. Dogs naturally infected with CDV develop apoptotic cells in lymphoid tissues and the cerebellum, but this apoptotic mechanism is not well characterized. To better understand this process, we evaluated the expression of Bax, Bcl-2, and caspase-3, -8 and -9, by evaluating mRNA levels in the peripheral blood, lymph nodes and cerebellum of CDV-infected (CDV+) and uninfected (CDV-) dogs by real-time polymerase chain reaction (PCR). Blood samples from 12 CDV+ and 8 CDV- dogs, diagnosed by reverse transcription-PCR, were subjected to hematological analysis and apoptotic gene expression was evaluated using real-time-PCR. Tissues from the cerebellum and lymph nodes of four CDV+ and three CDV-dogs were also subjected to real time-PCR. No significant differences were found between CDV+ and CDV- dogs in the hemotological results or in the expression of caspase-3, -8, -9, Bax, and Bcl-2 in the peripheral blood. However, expression of Bax, caspase-3, -8 and -9 was significantly higher in the cerebellum of CDV+ compared to CDV- dogs. Expression of caspase-3 and -8 was significantly higher in the lymph nodes of CDV+ compared to CDV- dogs. We concluded that infection with CDV induces apoptosis in the cerebellum and lymph nodes in different ways. Lymph node apoptosis apparently occurs via caspase-3 activation, through the caspase-8 pathway, and cerebellum apoptosis apparently occurs via caspase-3 activation, through the caspase-8 and mitochondrial pathways.

Expression of the proto-oncogene c-fos and the immunolocalization of c-fos, phosphorylated c-fos and estrogen receptor beta in the human testis

Spermatogenesis is under the control of a complex endocrine and paracrine system, including estrogen receptor (ER) signaling. In many target cells, ER promotes the transcription of c-fos and other proto-oncogenes to regulate cell growth and differentiation. Thus, in this study we evaluated the expression of the proto-oncogene c-fos and the immunolocalization of c-fos, phosphorylated c-fos and ERbeta proteins in the human testis. Testis tissue samples were obtained from 12 men undergoing orchiectomy as adjuvant treatment for prostate cancer, and were stained by immunohistochemistry for c-fos, phosphorylated c-fos and ERbeta localization. Both forms of c-fos proteins were immunoreactive, mainly in germ cells (spermatogonia, spermatocytes and spermatids) and Sertoli cells, while ERbeta was primarily present in somatic cells (Leydig, Sertoli and myofibrillar cells). In addition, testicular biopsies obtained from infertile men with obstructive azoospermia/normal spermatogenesis (n=8) or non-obstructive azoospermia/severely impaired spermatogenesis (n=12) were evaluated for c-fos and ERbeta mRNA levels using real time polymerase chain reaction. The expression of c-fos mRNA was significantly lower (fold change = 0.08, p<0.05) whereas that of ERbeta mRNA was higher (fold change = 9.43, p<0.05) in the testis of men with non-obstructive azoospermia compared to those with obstructive azoospermia. These findings suggest a complex interrelation between estrogen signaling and c-fos transcriptional activity within the human testis, with the increase of ERbeta mRNA being putatively a compensatory mechanism for lower c-fos expression in infertile men with damaged spermatogenesis.

Apoptosis in the cerebellum of dogs with distemper

Canine distemper virus (CDV) may induce multifocal demyelination in the central nervous system of infected dogs. The pathogenesis of this process is not clear. The present work identifies the presence of apoptotic cells in white and grey matter of dogs'cerebellum, naturally infected with CDV. Fifteen dogs with clinical signs of canine distemper that tested positive for CDV nucleoprotein were used. Brain specimens were processed and embedded in paraffin. Sections 5 microm thick were stained with hematoxylin-eosin and Shorr. Other sections were submitted to TUNEL reaction and to immunohistochemistry for CDV nucleoprotein detection. Acute and chronic demyelinated plaques were observed in the white matter, while apoptosis occurred particularly in the granular layer of grey matter. Apoptosis seems to play an important role in the pathogenesis of canine distemper demyelination.