12 research outputs found
Uncovering the multifaceted roles played by neutrophils in allogeneic hematopoietic stem cell transplantation
Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a life-saving procedure used for the treatment of selected hematological malignancies, inborn errors of metabolism, and bone marrow failures. The role of neutrophils in alloHSCT has been traditionally evaluated only in the context of their ability to act as a first line of defense against infection. However, recent evidence has highlighted neutrophils as key effectors of innate and adaptive immune responses through a wide array of newly discovered functions. Accordingly, neutrophils are emerging as highly versatile cells that are able to acquire different, often opposite, functional capacities depending on the microenvironment and their differentiation status. Herein, we review the current knowledge on the multiple functions that neutrophils exhibit through the different stages of alloHSCT, from the hematopoietic stem cell (HSC) mobilization in the donor to the immunological reconstitution that occurs in the recipient following HSC infusion. We also discuss the influence exerted on neutrophils by the immunosuppressive drugs delivered in the course of alloHSCT as part of graft-versus-host disease (GVHD) prophylaxis. Finally, the potential involvement of neutrophils in alloHSCT-related complications, such as transplant-associated thrombotic microangiopathy (TA-TMA), acute and chronic GVHD, and cytomegalovirus (CMV) reactivation, is also discussed. Based on the data reviewed herein, the role played by neutrophils in alloHSCT is far greater than a simple antimicrobial role. However, much remains to be investigated in terms of the potential functions that neutrophils might exert during a highly complex procedure such as alloHSCT
Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period
Objective: To evaluate morphometric-stereological changes in the epididymal caput, sperm quality, and fertility parameters in rats treated with finasteride and after a 30-day post-treatment recovery period. Design: Experimental study in a research laboratory. Setting: Reproductive biology research laboratory. Animal(s): Male and female Sprague Dawley rats. Intervention(s): Treatment with finasteride (5 mg/kg/day) for 56 days followed by 30 days without treatment. Main Outcome Measure(s): Serum hormone analyses, morphometric-stereological and ultrastructural evaluation of the epididymal caput, sperm transit time, natural mating, in utero insemination, sperm membrane integrity, and fertility parameters. Result(s): Serum dihydrotestosterone levels in the finasteride group decreased by similar to 40% compared with that of control rats. Ultrastructural analysis revealed significant reductions in several morphometric-stereological parameters of the epididymal caput. All parameters recovered significantly in the post-treatment period. There was no alteration in daily sperm production in the finasteride group. However, significant reductions in sperm transit time, motility, sperm membrane integrity, and fertility parameters were observed in rats treated with finasteride. Conclusion(s): Treatment with finasteride caused morphometric-stereological and functional changes in the epididymis and in sperm function that led to a reduction in fertility parameters. A 30-day post-treatment recovery period was insufficient to restore normal sperm motility, sperm transit time, and some fertility parameters. (Fertil Steril (R) 2012;97:1444-51. (C) 2012 by American Society for Reproductive Medicine.)97614441451National Counsel of Technological and Scientific Developmen
Diet-induced obesity in rats leads to a decrease in sperm motility
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Background: Obesity is rapidly becoming a worldwide epidemic that affects children and adults. Some studies have shown a relationship between obesity and infertility, but until now it remains controversial. Thus, the aim of the present study was to investigate the effect of high-fat diet-induced obesity on male reproductive parameters. Methods: In a first experiment, male Wistar rats were fed a high-fat diet (HFD) or standard chow (SD) for 15, 30 or 45 weeks, after which they were evaluated by adiposity index, serum leptin levels, reproductive organ weights and sperm counts. In a second experiment, rats received HFD or SD only for 15 weeks, long enough to cause obesity. Sexual hormones and sexual behavior were evaluated in these animals, as well as fertility after natural mating. Another group of rats was submitted to motility analysis and fertility evaluation after in utero insemination. Results: After 15, 30 or 45 weeks, HFD-fed animals presented significant increases in obesity index and serum leptin levels. Reproductive organ weights and sperm counts in the testis and epididymis were similar between the two groups at all timepoints studied. Sexual behavior was not altered by the diet regimen, and HFD fertility after natural mating was also similar to SD-fed animals. Intergroup testosterone levels were also comparable, but estradiol levels were increased in HFD rats. Furthermore, sperm quality was reduced in HFD animals as evidenced by their decreased percentage of sperm with progressive movement. This altered motility parameter was followed by a trend toward reduction in fertility potential after artificial in utero insemination. Conclusions: The results reported herein showed that obesity can affect sperm quality, by reducing sperm motility, without affecting other sperm parameters. The low sperm quality caused a slight reduction in fertility potential, showing that obesity may lead to impairment in male fertility.9Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Acceleration of Sperm Transit Time and Reduction of Sperm Reserves in the Epididymis of Rats Exposed to Sibutramine
Sibutramine is a drug globally used for the treatment of obesity. The aim of this study was to investigate male reproductive disorders caused by sibutramine in adult rats. Wistar rats were treated for 28 consecutive days (gavage) with 10 mg/kg of sibutramine. Control animals received only vehicle (dimethylsulfoxide and saline). The rats were sacrificed for evaluation of body and reproductive organ weights, sperm parameters, hormone levels (luteinizing hormone, follicle-stimulating hormone, and testosterone), testicular and epididymal histopathology, sexual behavior, fertility and in vitro contractility of the epididymal duct. Sibutramine decreased (P < .05) weights of the epididymis and ventral prostate, but not of other reproductive organs. The sperm number and transit time in the epididymal cauda were decreased (P < .001), but the daily sperm production was not altered. Moreover, morphology and sperm motility, histopathology of the testes and epididymis, sexual behavior, fertility, and serum hormone levels were not altered by the treatment. Sibutramine increased the potency of norepinephrine and, per se, increased the mechanical activity of the epididymal duct in vitro. Thus, although sibutramine in these experimental conditions did not interfere with the reproductive process of rats, it provoked acceleration of the sperm transit time and a decrease in the sperm reserves in the epididymal cauda. This alteration is probably related to the sympathomimetic effect of this drug, as shown by the in vitro assays. In humans, use of this drug might present a threat for male fertility because sperm reserves in men are naturally lower than those in rats.32671872
Androgen deprivation from pre-puberty to peripuberty interferes in proteins expression in pubertal and adult rat epididymis
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Few studies have focused on experimental testosterone deprivation in immature animals. Therefore, this study used sexually immature rats aiming to evaluate the testes and epididymis histology and proteins expression in these organs on PND50 and 75, after premature antiandrogen exposure, from PND21 to 44. Although the androgen deprivation from pre-puberty up to peripuberty did not alter the histological organization of the testes and epididymis either at puberty or at adulthood, the treatment impaired the expression of specific proteins in epididymal tissue at puberty and adulthood (androgen receptor, calmodulin, Rab11A). These changes may be related to impaired epididymal function, sperm quality and fertility capacity as observed in a previous study. Further studies are necessary to better investigate the molecular mechanisms involved in the impairment on reproductive competence of male rats after precocious hormonal injury. (c) 2013 Elsevier Inc. All rights reserved.386571Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [FAPESP 07/59079-4]CNPq [501339/2010-8, 304958/2009-3
Assessment of Female Reproductive Endpoints in Sprague-Dawley Rats Developmentally Exposed to Diuron: Potential Ovary Toxicity
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)BACKGROUND: Diuron is widely used in agriculture but its deleterious effects on the reproductive system and mammary gland are still poorly understood. This study evaluated whether early-life-stage exposure to Diuron alters puberty onset or susceptibility to mammary carcinogenesis in female Sprague-Dawley rats. METHODS AND RESULTS: Pregnant rats received basal diet or diet containing Diuron at 500, 750, and 1,250 ppm, from gestational day 12 to the end of lactation (postnatal day 21 [PND21]). After weaning, female offspring continued receiving basal diet or diet containing Diuron until PND 51. At PND 51, female Sprague-Dawley offspring received a single dose of 50 mg/kg b.w. of 7,12-dimethylbenz(a) anthracene (DMBA) for initiation of mammary carcinogenesis. The animals were sacrificed on PND 51, 75, and 226 to 233 (week 25) for mammary gland morphology, reproductive organs and tumor analysis, respectively. There were no significant differences among groups on vaginal opening, estrous cycle, mammary morphology, or carcinogenesis. However, reductions in ovary weight and corpora lutea were observed at PND 75 in the group treated with Diuron at 1,250 ppm. CONCLUSIONS: The findings suggesting that Diuron exposure (1,250 ppm) may have been potentially toxic to the ovaries. Birth Defects Res (Part B) 92:478-486, 2011. (C) 2011 Wiley Periodicals, Inc.925SI478486Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2006/01330-0
Corporate Governance in Brazilian Companies: The Influence of the Founder in the Financial Decisions.
All over the world, corporate governance is adopting a new process of leadership and simultaneously propagating responsible governance for the welfare of stakeholders. This research has allowed us to identify new directions for future research. It examines the influence of several contextual factors in the framework of the financial decisions, where company has the right to have a transparent accountability, based on the influence of the founder, dispersion and type of ownership, size, economic sector and environment.
The aim of this research is to analyse the influence of the founder in the financial decisions based on the comparability of the level of indebtedness among Brazilian companies managed by its founder and those managed by professionals.
The methodology focuses the theoretical analysis on the literature review about Corporate Governance and Corporate Finance. The empirical analysis is based on econometric analysis supported on the multiple regression model and fixed effects method. The sample includes 356 non-financial Brazilian companies, with accounting data from the period 2004–2009, on a total of 2136 observations.
The results find supporting evidence that lower debt in those companies of the sample in which the founder is the manager of the company and, in contrast, bigger
indebted level of the professional manager. Further findings confirm a reduction of the investment level in businesses run by its founder, as well as, their preference for using equity. The founder has quite peculiar biases relation with decision making process. Generally, the founder has a personal need and his or her own interest, is based on the entrepreneurship decisions