Kinulpe Honorato-Sampaio

Gonadotropin Stimulation Increases the Expression of Angiotensin-(1—7) and Mas Receptor in the Rat Ovary

We have previously shown the presence of immunoreactive angiotensin-(1—7) [Ang-(1—7)] in rat ovary homogenate and its stimulatory effect on estradiol and progesterone production in vitro. In the current study, we investigated the presence and cellular distribution of Ang-(1—7) and the Mas receptor, the expression of Mas and angiotensin-converting enzyme 2 (ACE2) messenger RNA (mRNA), and the enzymatic activity in the rat ovary following gonadotropin stimulation in vivo. Immature female Wistar rats (25 days old) were injected subcutaneously (SC) with equine chorionic gonadotropin (eCG, 20 IU in 0.2 mL) or vehicle 48 hours before euthanasia. Tissue distributions of Ang-(1—7), Mas receptor, and ACE2 were evaluated by immunohistochemistry, along with angiotensin II (Ang II) localization, while the mRNA expression levels of Mas receptor and ACE2 were evaluated by real-time polymerase chain reaction (PCR). In addition, we determined the activity of neutral endopeptidase (NEP), prolyl endopeptidase (PEP), and ACE by fluorometric assays. After eCG treatment, we found strong immunoreactivity for Ang-(1—7) and Mas primarily in the theca-interstitial cells, while Ang II appeared in the granulosa but not in the thecal layer. Equine chorionic gonadotropin treatment increased Mas and ACE2 mRNA expression compared with control animals (3.3- and 2.1-fold increase, respectively; P < .05). Angiotensin-converting enzyme and NEP activities were lower, while PEP activity was higher in the eCG-treated rats (P < .05). These data show gonadotropin-induced changes in the ovarian expression of Ang-(1—7), Mas receptor, and ACE2. These findings suggest that the renin-angiotensin system (RAS) branch formed by ACE2/Ang-(1—7)/Mas, fully expressed in the rat ovary and regulated by gonadotropic hormones, could play a role in the ovarian physiology.

Angiotensin-(1–7) induces ovulation and steroidogenesis in perfused rabbit ovaries

A local renin–angiotensin system has been described in several organs, including the ovary; however, data indicating a role for angiotensin II in the induction of ovulation are controversial. We have previously shown the presence of a novel peptide, angiotensin‐(1–7) [Ang‐(1–7)], in the rat ovary and its effect on steroidogenesis. The objective of the present study was to determine whether Ang‐(1–7) plays a role in ovulation. We first determined the presence and distribution of Ang‐(1–7) and the receptor Mas in rabbit ovaries by immunohistochemistry. Angiotensin‐(1–7) and Mas immunoreactivity were observed in interstitial cells and oocytes of immature ovaries. Immunoreactivity for Ang‐(1–7) and Mas was also observed in theca and granulosa cells of preovulatory follicles in ovaries of gonadotrophin‐stimulated rabbits. To verify the effect of Ang‐(1–7) in ovulation and steroidogenesis, we used isolated ovaries from immature rabbits pretreated with equine chorionic gonadotrophin (50 i.u., 48 h before the experiment) and then perfused in vitro. The ovulatory efficiency was determined by the number of oocytes compared with the number of preovulatory follicles present in the ovary. Angiotensin‐(1–7) stimulated oestradiol production and enhanced ovulatory efficiency, which was blocked by the specific Ang‐(1–7) antagonist, A‐779. Ovulation induced by human chorionic gonadotrophin was also antagonized by A‐779. These results show, for the first time, the involvement of a novel regulatory peptide system, Ang‐(1–7) and Mas, in the ovulatory process. More importantly, because A‐779 antagonized hCG‐induced ovulation, it may be inferred that Ang‐(1–7) plays an important role in ovulation, possibly as a mediator of gonadotrophin action.

Evidence that angiotensin-(1-7) is an intermediate of gonadotrophin-induced oocyte maturation in the rat preovulatory follicle.

Several studies have shown the presence of components of the renin–angiotensin system in mammalian ovaries and their involvement in ovarian physiology. We have previously shown the presence of angiotensin‐(1–7) [Ang‐(1–7)], an important biologically active component of the renin–angiotensin system, and its receptor, Mas, in rat, rabbit and human ovaries. We have also shown the involvement of Ang‐(1–7) in the rabbit ovulatory process in vitro. In the present study, we observed that Ang‐(1–7) stimulated the resumption of meiosis in oocytes of rat preovulatory follicles, reaching more than 30% of oocytes with germinal vesicle breakdown. The specific antagonist of the Mas receptor, A‐779, inhibited the germinal vesicle breakdown induced by Ang‐(1–7) and reduced the oocyte maturation stimulated by luteinizing hormone (LH). Immunohistochemistry showed that LH increased both Ang‐(1–7) and angiotensin‐converting enzyme 2 (ACE2) staining in preovulatory follicles. The effect of gonadotrophins on mRNA expression of Mas and ACE2 in ovaries of immature equine chorionic gonadotrophin‐primed rats was analysed by real‐time PCR after 6 h of human chorionic gonadotrophin (hCG) injection, which exhibits LH‐like effects. After hCG treatment, ACE2 mRNA expression was higher in the ovaries of treated rats than in the ovaries of control rats, whereas Mas mRNA levels were unchanged. A‐779 changed the steroidogenesis stimulated by LH. An increased testosterone concentration and decreased progesterone levels were measured in the follicle medium. In conclusion, our results suggest that LH upregulates the ACE2–Ang‐(1–7)–Mas axis and that Ang‐(1–7) promotes meiotic resumption, possibly as a gonadotrophin intermediate.

Observations on the seasonal breeding biology and fine structure of the egg surface in the white piranha Serrasalmus brandtii from the São Francisco River basin, Brazil

In the Juramento Reservoir, south-eastern Brazil, the white piranha Serrasalmus brandtii showed a prolonged reproductive season, with evidence for multiple spawning and a reproductive peak associated with seasonal rains. The egg surface exhibited a honeycomb-like pore canal arrangement and an adhesive apparatus surrounding the micropyle. Electron microscopic analysis suggests a role for the micropylar cell and neighbouring follicular cells in secretion of substances for egg attachment.

Downregulation of natriuretic peptide system and increased steroidogenesis in rat polycystic ovary

Atrial natriuretic peptide (ANP) is known to regulate ovarian functions, such as follicular growth and steroid hormone production. The aim of the present study was to investigate the natriuretic peptide system in a rat model of chronic anovulation, the rat polycystic ovary. Adult female Wistar rats received a single subcutaneous injection of 2mg estradiol valerate to induce polycystic ovaries, while the control group received vehicle injection. Two months later, their ovaries were quickly removed and analyzed. Polycystic ovaries exhibited marked elevation of testosterone and estradiol levels compared to control ovaries. The levels of ANP and the expression of ANP mRNA were highly reduced in the polycystic ovaries compared to controls. By immunohistochemistry, polycystic ovaries showed weaker ANP staining in stroma, theca cells and oocytes compared to controls. Polycystic ovaries also had increased activity of neutral endopeptidase, the main proteolytic enzyme that degrades natriuretic peptides. ANP receptor C mRNA was reduced and ANP binding to this receptor was absent in polycystic ovaries. Collectively, these results indicate a downregulation of the natriuretic peptide system in rat polycystic ovary, an established experimental model of anovulation with high ovarian testosterone and estradiol levels. Together with previous evidence demonstrating that ANP inhibits ovarian steroidogenesis, these findings suggest that low ovarian ANP levels may contribute to the abnormal steroid hormone balance in polycystic ovaries.

Membranous glomerulonephritis secondary to syphilis

A 57-year-oldmanpresentedwithbilaterallegswelling,myal-gia, weight gain, and reduced urine output for three months.He exhibited no signs and symptoms of urinary tract infec-tion or sexually transmitted disease (STD). He reported a pastmedical history of diabetes mellitus and hypertension for 20years, and bariatric surgery and abdominoplasty from aboutfive years ago. Blood cell count was normal. Serum creati-nine and creatinine clearance were 1.9mg/dL and 49mL/min,respectively. A 24-h urine collection revealed 19g of protein.These resultswere consistentwithnephroticsyndrome.Sero-logical tests for hepatitis and HIV were negative and thevenereal disease research laboratory (VDRL) test was posi-tive with a titer of 1:1024. The ultrasound showed normalkidney size with some suggestive features of acute parenchy-mal disease. He was treated with losartan, furosemide,

Bacterial biofilm in chronic venous ulcer.

presence of bacterial biofilm in chronic wounds may explain Venous leg ulcer (VLU) is a type of chronic wound that can take a long time to heal, being the most advanced presentation of chronic venous insufficiency (CVI).1 VLUs are usually recurrent, affecting work productivity, quality of life and high public health care treatment costs. It is estimated that VLUs affect up to 1% of the adult population.1 These chronic wounds are usually infected by a diverse microbial flora, which may probably contribute to the nonhealing phenotype.2 A study developed at the university hospital of the Federal University of Minas Gerais, Belo Horizonte, Brazil, included patients with VLU to investigate the presence of bacterial biofilm. A VLU biopsy was performed in a total of 45 patients who had not used antibiotics and presented signs of CVI, such as edema, varicose veins, hyperpigmentation, and lipodermatosclerosis (Fig. 1A). The samples were submitted to bacteriological tests to characterize the bacterial flora and examined by transmission electron microscopy

Comparative morphology of the oocyte surface and early development in four characiformes from the São Francisco River, Brazil.

Early development from the egg fertilization to complete resorption of the yolk‐sac is a critical period in the life cycle of teleost fish. Knowledge of this process provides essential parameters for aquaculture and identification of spawning sites in the wild. In the present study, a comparative morphological analysis of the oocyte surface as well as early development was performed in four commercially valuable species from the São Francisco River: Brycon orthotaenia, Leporinus obtusidens, Prochilodus argenteus, and Salminus franciscanus. Stripped oocytes, embryo, and yolk‐sac larvae were analyzed by scanning electron microscopy (SEM) and histology. A set of 10 lectins was used for investigation of lectin‐binding pattern in oocytes. In the four species, the outer layer of the zona radiata reacted to most lectins, indicating complex polysaccharides at the oocyte surface while no reactivity was detected in the inner zona radiata and yolk globules. Typical structural arrangements were recognized at the micropylar region by SEM. The four species showed nonadhesive eggs, short embryonic period (18–20 h at 24 ± 1°C), and poorly developed larvae at hatching. At 24 h posthatching (hph), larvae of the four species had neuromasts on the body surface. Rudimentary cement glands for larval attachment were identified on the cephalic region at 24 and 48 hph in B. orthotaenia and S. franciscanus, and following they were in regression. The time for whole yolk resorption varied among species from 48 to 120 hph, occurring earlier in S. franciscanus, followed by B. orthotaenia, P. argenteus, and L. obtusidens. The formation of the digestive tract and the mouth opening indicated initiation of exogenous feeding 24 h before complete resorption of the yolk. Together, our data indicate similarities in the early development among species that may be related to the life cycle strategies and phylogeny. J. Morphol. 276:1258–1272, 2015.

The effect of angiotensin-converting enzyme inhibition throughout a superovulation protocol in ewes

Many studies identified new components of the renin–angiotensin system (RAS), such as Angiotensin-(1-7) [Ang-(1–7)] and Angiotensin-converting enzyme type 2 (ACE2), in mammalian ovaries.We previously showed Angiotensin-Converting Enzyme (ACE) inhibition, which increases the level of Ang-(1–7), stimulated ovarian estradiol output in ewe after estrous synchronization. Considering that Ang-(1–7) stimulates ovarian function and elevated estradiol before ovulation is associated with increased chance of achieving pregnancy, the present study investigated whether ACE inhibition throughout a superovulation protocol in ewe might improve ovulation outcome. At first, immunohistochemistry in ovaries of nonpregnant ewes revealed localization of Angiotensin II (Ang II), Ang-(1–7) and ACE2 in theca cells of antral follicles and in corpus luteum. Ang II and Ang-(1–7)were also detected in follicular fluid (FF) by Radioimmunoassay (RIA). Enalapril treatment throughout the superovulation protocol decreased 17β-estradiol (E2) output and raised progesterone:estradiol (P4:E2) ratio without a direct influence on ovulation and quality of embryos.

Genetic deletion of the Angiotensin-(1–7) receptor Mas leads to a reduced ovulatory rate

HighlightsGenetic deletion of Angiotensin (1–7) receptor Mas promotes a reduced ovulatory outcome.Knockout (Mas‐KO) mice exhibit reduced follicularpool.Mas receptor deletion promotes a lower IGF‐1 expression in the ovary. ABSTRACT Angiotensin‐(1–7) [Ang‐(1–7)] is a component of Renin‐Angiotensin System (RAS) that acts through activation of the G‐protein‐coupled receptor Mas. Recent studies highlight Ang‐(1–7) as an intermediate of gonadotropin in ovarian physiology. Genetically Mas‐deficient mice allow the investigation of Ang‐(1–7) in the ovulatory process. Therefore, the present study aimed to analyze the effects of Mas gene deletion on ovulation to confirm our hypothesis that Mas Knockout (Mas‐KO) mice exhibit impairment in the ovulatory outcome. First, we evaluated the breeding data from our animal facilities and from a breeding experiment. The ovulation was observed directly from oviducts after a superovulation protocol and in the estrus morning. We also checked the follicular pool and mRNA expression of Insulin‐like growth factor‐1 (IGF‐1) in ovaries to investigate a possible reason underlying the reduced ovulation. Mas‐KO mice showed a reduced litter size and decreased spontaneous ovulatory rate. Ovarian stimulation by gonadotropins reversed ovulation outcome in Mas‐KO mice. Mas deficiency also promoted a reduced ovarian follicular pool and lower IGF‐1 mRNA levels, suggesting that Mas receptor plays a role in the survival of ovarian follicle. The reduction of ovulatory rate highlights the relevance of Ang‐(1–7)/Mas axis in female reproduction, probably through a reduction of IGF‐1 mRNA levels.