Von Hippel-Lindau (VHL) disease, caused by germline mutations in the VHL gene, is characterized by metachronously occurring tumors including pheochromocytoma, renal cell carcinoma (RCC), and hemangioblastoma. Although VHL disease leads to reduced life expectancy, its diagnosis is often missed and tumor screening guidelines are sparse. VHL protein acts as a tumor suppressor by targeting hypoxia-inducible factors (HIFs) for degradation through an oxygen-dependent mechanism. VHL mutants with more severely reduced HIF degrading function carry a high risk of RCC, while mutants with preserved HIF degrading capacity do not cause RCC but still lead to other tumors. VHL disease is classified into clinical types (1 and 2A-2C) based on this genotype-phenotype relationship. We report a case of bilateral pheochromocytomas and no other VHL-related tumors in a patient with Y175C VHL and show that this mutant preserves the ability to degrade HIF in normal oxygen conditions but, similar to the wild-type VHL protein, loses its ability to degrade HIF under hypoxic conditions. This study adds to the current understanding of the structure-function relationship of VHL mutations, which is important for risk stratification of future tumor development in the patients.
Uterine leiomyomas, commonly referred to as fibroids, are benign, estrogen sensitive smooth muscle tumors that occur in the myometrium of the uterine wall. Leiomyomas are common, as it is estimated that 60% of reproductive-aged women are affected, and 80% of women develop leiomyomas during their lifetime. In fact, uterine leiomyomas are the leading cause of abnormal menstrual bleeding or menstrual pain, as well as the number one reason for hysterectomy. Novel treatment options are necessary as current treatments are limited to anti-estrogen therapy or hysterectomy. Estrogen is known to have an effect on the etiology of leiomyomas, but little is known about the proliferative roles of other hormones in leiomyomas. One hormone of interest is prolactin (PRL) which is primarily secreted from the pituitary to regulate lactation, but has been linked to proliferation in breast cancer, perhaps via local prolactin production in breast tissue. With this background, we examined local PRL production and its effects on leiomyomas. RNA isolation and quantitative PCR of human leiomyoma samples (n=20) relative to adjacent myometrium in the same patients confirmed significant expression of both PRL (p= 0.0028) and dopamine receptor D2, a known regulator of PRL production in the pituitary (p<0.0001), with no difference in prolactin receptor expression. Using both immunohistochemistry and immunofluorescence of human leiomyomas samples, we find increased prolactin expression in leiomyomas when compared to adjacent myometrium or control uteri. These results suggest that leiomyomas contain cells producing PRL, which in turn may promote signaling in smooth muscle leiomyoma cells to regulate proliferation. Accordingly, we find that PRL robustly activates STAT5 and MAPK signaling in the rat leiomyoma cell line ELT3. Functional assays were also conducted to evaluate the ability of PRL to induce migration, invasion and proliferation of ELT3 cells. Together, our findings suggest that local prolactin production in leiomyomas may promote their growth, migration, invasion and proliferation. It is possible that this local production is mediated by the dopamine receptor D2. Thus, anti-PRL therapy or dopamine receptor D2 modulation may prove useful in treating this prevalent and often debilitating disease.
In 10 patients, a free-wall plication of inferior or lateral scar was performed. The procedure was done on cardiopulmonary bypass and aortic cross-clamping by means of four or five wide U-stitches. Six patients underwent concomitant mitral annuloplasty and one mitral valve replacement. One patient died postoperatively. There was a sudden and significative end-systolic volume reduction with a rise in ejection fraction. These hemodynamic benefits were partially lost during the follow-up but the mitral regurgitation grade remained unchanged.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.