A novel genetically-obese rat model with elevated 11beta-hydroxysteroid dehydrogenase type 1 activity in subcutaneous adipose tissue

11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the conversion of inactive glucocorticoids to active glucocorticoids and plays an important role in the development of obesity and metabolic syndrome. 11β-HSD1 activity is lower in liver and higher in omental adipose tissue of obese rodent models like obese zucker rats, Ob/Ob and db/db mice. Here, we report the 11β-HSD1 activity in liver and adipose tissue of lean and obese rats of WNIN/Ob strain, a new genetic rat model of obesity. 11β-HSD1 activity in liver, omental and subcutaneous adipose tissues of 3 month-old male WNIN/Ob lean and obese rats was assayed. As observed in other rodent models, 11β-HSD1 activity was lower in liver and higher in omental adipose tissue. In contrast to other rodent obese models, WNIN/Ob obese rats had elevated 11β-HSD1 activity in subcutaneous adipose tissue, which is in line with the observation in human obesity. Here, we conclude that dysregulation of 11β-HSD1 in WNIN/Ob obese rat model is identical to human obesity, which makes it an excellent model for studying the effect of 11β-HSD1 inhibitors in ameliorating obesity and metabolic syndrome

Prostaglandin-Endoperoxide Synthase 2 (PTGS2) in the Oviduct: Roles in Fertilization and Early Embryo Development

Abstract The mammalian oviduct is a dynamic organ where important events such as final maturation of oocytes, transport of gametes, sperm capacitation, fertilization, embryo development, and transport take place. Prostaglandin-endoperoxide synthase 2 (PTGS2), also known as cyclooxygenase 2 (COX-2), is the rate-limiting enzyme in the production of prostaglandins (PGs) and plays an essential role during early pregnancy, including ovulation, fertilization, implantation, and decidualization. Even though the maternal-embryo communication originates in the oviduct, not many studies have systemically investigated PTGS2 signaling during early development. Most of the studies investigating implantation and decidualization processes in Ptgs2-/- mice employed embryo transfer into the uterus, thereby bypassing the mammalian oviduct. Consequently, an understanding of the mechanistic action as well as the regulation of PTGS2 and derived PGs in oviductal functions is far from complete. In this review, we aim to focus on the importance of PTGS2 and associated PGs signaling in the oviduct particularly in humans, farm animals, and laboratory rodents to provide a broad perspective to guide further research in this field. Specifically, we review the role of PTGS2-derived PGs in fertilization, embryo development, and transport. We focus on the actions of ovarian steroid hormones on PTGS2 regulation in the oviduct. Understanding of cellular PTGS2 function during early embryo development and transport in the oviduct will be an important step toward a better understanding of reproduction and may have potential implication in the assisted reproductive technology.</jats:p

Mechanism of semen liquefaction and its potential for a novel non-hormonal contraception†

AbstractSemen liquefaction is a proteolytic process where a gel-like ejaculated semen becomes watery due to the enzymatic activity of prostate-derived serine proteases in the female reproductive tract. The liquefaction process is crucial for the sperm to gain their motility and successful transport to the fertilization site in Fallopian tubes (or oviducts in animals). Hyperviscous semen or failure in liquefaction is one of the causes of male infertility. Therefore, the biochemical inhibition of serine proteases in the female reproductive tract after ejaculation is a prime target for novel contraceptive development. Herein, we will discuss protein components in the ejaculates responsible for semen liquefaction and any developments of contraceptive methods in the past that involve the liquefaction process.</jats:p

Blocking serine protease activity prevents semenogelin degradation leading to hyperviscous semen in humans

Abstract Prostate-specific antigen (PSA) is a prostate-specific serine protease enzyme that hydrolyzes gel-forming proteins (semenogelins) and changes the semen from gel-like to watery viscosity, a process called semen liquefaction. Highly viscous semen and abnormal liquefaction reduce sperm motility and contribute to infertility. Previously, we showed that nonspecific serine protease inhibitor (AEBSF) prevented proteolytic degradation of semenogelin in mice. However, it is unclear whether similar effect could be recapitulated in fresh human ejaculates. Therefore, in this study we evaluated the effect of AEBSF on the degradation of semenogelin (SEMG1) and its subsequent impact on semen liquefaction and sperm motility in fresh semen ejaculates collected from healthy men. We found that AEBSF showed a dual contraceptive action where it effectively 1) prevented degradation of SEMG1 resulting in viscous semen and 2) decreased sperm motility in human semen samples. However, the impact of AEBSF on sperm motility and viability could be due to its inhibitory activity toward other serine proteases or simply due to its toxicity. Therefore, to determine whether inhibition of PSA activity alone could disrupt SEMG1 degradation and contribute to hyperviscous semen, a neutralizing PSA antibody was used. We found that PSA antibody effectively prevented SEMG1 degradation with a subtle impact on sperm motility. These findings suggest that the target inhibition of PSA activity can prevent proteolytic degradation of SEMG1 and block liquefaction process, resulting in hyperviscous semen. As it is currently unknown if blocking semen liquefaction alone could prevent pregnancy, it needs further extensive studies before drawing any translational conclusions.</jats:p

Phospholipid Nanoparticles Increase P/F Ratio in Septic Shock

Introduction: Acute respiratory and cardiac failure commonly occur in septic shock patients and may contribute to higher in-hospital mortality. The current protocol for treating septic shock has continued controversy with the use of vasopressors to elevate the mean arterial pressure (MAP) between 60 to 65 mmHg. Hypotension that is minimally responsive to vasopressors occurs in septic shock primarily because of the overproduction of nitric oxide (NO). VBI-S is a phospholipid nanoparticle emulsion that exhibits concentration-dependent absorption and release of NO. We hypothesized that because of this property, infusion of VBI-S would result in the reversal of the patient’s hypotensive state. In our phase IIa clinical trial, VBI-S was administered to severely ill septic patients in whom fluids had failed to increase their MAP greater than or equal to 65 mm Hg. In addition to measuring the changes in MAP, we measured the ratio of arterial pO2 over the fraction of inspired oxygen (P/F). Methods: This was an open-label phase IIa study of 20 patients aged 18 years and above. Hypotensive septic shock patients in whom fluids had failed to elevate MAP above 65 mmHg received VBI-S infusion. VBI-S was infused as a volume sufficient to increase MAP by 10 mmHg or more. A mean of 560.96 ± 83.24 cc was given within 24 hours. The P/F ratio was measured in 17 patients and were analyzed at 24 hours and 48 hours post VBI-S infusion. Data are mean ± SE. Results: The enrolled patients (N = 20) had a sequential organ failure assessment (SOFA) score of 14.0 indicating severe sepsis. All patients were on 1-4 vasopressors. Within a mean of 90 minutes after VBI-S infusion, the MAP increased from 64.50 ± 0.96 to 77.50 ± 1.06 mmHg (p \u3c 0.0001). Patients (N=17) also had an increased P/F from 2.0 ± 0.20 to 2.6 ± 0.20 (p = 0.0024) within 24 hours post-VBI-S infusion and to 2.5 ± 0.22 (p = 0.0210) within 48 hours post-VBI-S infusion. Conclusions: Intravenous infusion of VBI-S increased both the MAP and P/F ratio in septic shock patients. No adverse effects of VBI-S were observed. Future research should establish the biochemical effects of VBI-S in other medical conditions mediated by NO overproduction resulting in decreased MAP and P/F

Reanimation After Hemorrhagic Shock Using Intra-arterially Infused Phospholipid Nanoparticles

Introduction: On the battlefield, 91% of potentially survivable mortality is due to blood loss leading to clinical death (CD) before transport to a medical facility. Therefore, we developed a rat model of CD due to severe rapid blood loss. In prior experiments, we found that intraarterial (IA) infusion was superior to intravenous (IV) in restoring cardiac contraction and respiration. Blood cannot be available to the battlefield. There is a need for an effective reanimation fluid. Therefore, we investigated the use of VBI-1, which is a phospholipid nanoparticle emulsion (particle diameter is 17 nm) that absorbs nitric oxide (NO). NO is produced early during hemorrhagic shock and induces hypotension. These findings have led us to hypothesize that the IA infusion of VBI-1 will be superior to other fluids in increasing mean arterial blood pressure (MAP). Methods: Six female and 6 male rats were subjected to reanimation with either shed blood or VBI-1. Under isoflurane anesthesia, both femoral arteries were canulated. CD was induced by withdrawing blood until respiration ceased. This occurred after withdrawing 40 to 45% of the blood at a rate of 1.5 mL/min. Immediately following CD, shed blood or VBI-I was infused IA in an equivalent volume to the blood loss at a rate of 10 mL/min. MAP was continuously measured for 12 hours post infusion. Data are mean ± SE. Results: In preliminary experiments, VBI-1 was superior to blood, Ringer’s lactate, and VBI-S, another phospholipid particle formulation (diameter is 250 nm), in elevating MAP at 4 hours after CD. Therefore, we decided to directly compare blood and VBI-1 to extend reanimation to 12 hours. MAP ± SE prior to blood withdrawal for blood was 79.9 ± 4.9 and VBI-1 was 80.1 ± 2.7. At CD, MAP for blood was 10.6 ± 1.5 and VBI-1 was 8.8 ± 1.9. MAP 12 hours post-blood infusion was 65.4 ± 13.0, whereas post-VBI-1 infusion was 53.4 ± 8.6 mmHg. 2-way ANOVA showed no significant difference between shed blood and VBI-1 infusion (p = 0.2120). Conclusions: After CD, IA infusion of VBI-1 increased MAP to a level that was equivalent to blood and spontaneous respiration returned. No adverse effects of VBI-1 were observed. Future research should establish the effects of VBI-1 on different organ systems

Estrogen receptor alpha isoform ERdelta7 in myometrium modulates uterine quiescence during pregnancyResearch in context

Background: Circulating estrogen (E2) levels are high throughout pregnancy and increase towards term, however its local tissue specific actions vary across gestation. For example, myometrial E2 regulated uterotonic action is disabled until term, whereas it's proliferative function is maintained in the breast. We have identified gestationally regulated splicing events, mediated by hnRNPG and modulated by E2 that generate alternatively spliced estrogen receptor alpha (ERα) variants (ERΔ7 and ERα46) in the myometrium. These variants allow for differential, gestationally regulated, modulation of the uterotonic action of E2. Methods: Human myometrium isolated from preterm and term non-laboring and laboring pregnant women were analyzed for ERα isoforms and splice factor levels. Lentiviral mediated shRNA knockdown of hnRNPG and overexpression of ERΔ7 were performed in human myometrial (hTERT-HM) cells. Functional 3D collagen contraction assays were executed. Findings: ERΔ7 acts as a dominant negative repressor of the uterotonic action of ERα66 and ERα46 isoforms through the regulation of the myometrial gap junction protein GJA1. Elimination of hnRNPG inhibits the generation of ERΔ7 while overexpression of ERΔ7 inhibited GJA1 expression. Moreover in vivo human myometrial hnRNPG levels decline at term in an E2 dependent manner resulting in a withdrawal of ERΔ7 levels and its tocolytic action at term. Interpretation: Our findings implicate the unique role of ERΔ7 as a modulator of myometrial quiescence and define the mechanism of ERΔ7 generation, through hormonally regulated splicing events. Fund: This study was supported by NIH OPRU U01 supplement (HD047905), University of Pittsburgh and Wayne State University Perinatal Research Initiative (USA). Keywords: Estrogen receptor alpha, Alternative splicing, hnRNPG, Myometrium, Parturition, GJA