Current Pharmaceutical Design - Volume 24, Issue 9, 2018

Inflammatory activation, a major driver of preterm birth and subsequent neonatal morbidity, is an attractive pharmacological target for new preterm birth therapeutics. Inflammation elicited by intraamniotic infection is causally associated with preterm birth, particularly in infants delivered ≤34 weeks' gestation. However, sterile triggers of PTB, including placental ischaemic injury, uterine distention, cervical disease, or imbalance in the immune response, also act through inflammatory mediators released in response to tissue damage. Toll-like Receptors (TLRs) are critical upstream gate-keepers controlling the inflammatory activation that precedes preterm delivery, as well as in normal term labour. In particular, TLR4 is implicated for its capacity to sense and integrate a range of disparate infectious and sterile pro-inflammatory triggers, and so acts as a point-ofconvergence through which a range of infectious and sterile agents can activate and accelerate the parturition cascade. Recent studies point to the TLR4 signalling complex as a tractable target for the inhibition of fetal, placental & intraamniotic inflammatory cytokine production. Moreover, studies on mice show that novel small molecule antagonists of TLR4 signalling are highly effective in preventing preterm birth induced by bacterial mimetic LPS, heat-killed E. coli or the TLR4-dependent pro-inflammatory lipid, Platelet Activating Factor (PAF). In this review, we discuss the role of TLR4 in regulating the timing of birth and the potential utility of TLR4 antagonists as novel therapeutics for preterm delivery.

Parturition is defined as the action or process of giving birth to offspring. Normal term human parturition ensues following the maturation of fetal organ systems typically between 37 and 40 weeks of gestation. Our conventional understanding of how parturition initiation is signaled revolves around feto-maternal immune and endocrine changes occurring in the intrauterine cavity. These changes in turn correlate with the sequence of fetal growth and development. These important physiological changes also result in homeostatic imbalances which result in heightened inflammatory signaling. This disrupts the maintenance of pregnancy, thus leading to laborrelated changes. However, the precise mechanisms of the signaling cascades that lead to the initiation of parturition remain unclear, although exosomes may be a mediator of this process. Exosomes are a subtype of extracellular vesicles characterised by their endocytic origin. This involves the trafficking of intraluminal vesicles into multivesicular bodies (MVB) and then exocytosis via the plasmatic membranes. Exosomes are highly stable nanovesicles that are released by a wide range of cells and organs including the human placenta and fetal membranes. Interestingly, exosomes from placental origin have been uncovered in maternal circulation across gestation. In addition, their concentration is higher in pregnancies with complications such as gestational diabetes and preeclampsia. In normal gestation, the concentration of placental exosomes in maternal circulation correlates with placental weight at third trimester. The role of placental exosomes across gestation has not been fully elucidated, although recent studies suggest that placental exosomes are involved in maternal-fetal inmmuno-tolerance, maternal systemic inflammation and nutrient transport. The content of exosomes is of particular importance, encompassing a large range of molecules such as mRNA, miRNAs, DNA, lipids, cell-surface receptors, and protein mediators. These can in turn interact with either adjacent or distal cells to reprogram their phenotype and regulate their function. Many of the pro-parturition proinflammatory mediators reach maternal compartments from the fetal side via circulation, but major impediments remain, such as degradation at various levels and limited halflife in circulation. Recent findings suggest that a more effective mode of communication and signal transport is through exosomes, where signals are protected and will not succumb to degradation. Thus, understanding how exosomes regulate key events throughout pregnancy and parturition will provide an opportunity to understand the mechanisms involved in the maternal and fetal metabolic adaptations during normal and pathological pregnancies. Subsequently, this will assist in identifying those pregnancies at risk of developing complications. This may also allow more appropriate modifications of their clinical management. This review will hence examine the current body of data to summarise our understanding of how signaling pathways lead to the beginning of parturition. In addition, we propose that extracellular vesicles, namely exosomes, may be an integral component of these signaling events by transporting specific signals to prepare the maternal physiology to initiate parturition. Understanding these signals and their mechanisms in normal term pregnancies can provide insight into pathological activation of these signals, which can cause spontaneous preterm parturition. Hence, this review expands on our knowledge of exosomes as professional carriers of fetal signals to instigate human parturition.

Background: Preterm birth (PTB), defined as birth before 37 completed weeks of gestation, occurs in up to 18 percent of births worldwide and accounts for the majority of perinatal morbidity and mortality. While the single most common cause of PTB has been identified as inflammation, safe and effective pharmacotherapy to prevent PTB has yet to be developed. Methods: Our group has used an in vivo model of inflammation-driven PTB, biochemical methods, pharmacological approaches, a novel endothelin receptor antagonist that we synthesized and RNA knockdown to help establish the role of endothelin-1 (ET-1) in inflammation-associated PTB. Further, we have used our in vivo model to test whether sphingosine kinase, which acts downstream of ET-1, plays a role in PTB. Results: We have shown that levels of endothelin converting enzyme-1 (ECE-1) and ET-1 are increased when PTB is induced in timed pregnant mice with lipopolysaccharide (LPS) and that blocking ET-1 action, pharmacologically or using ECE-1 RNA silencing, rescues LPS-induced mice from PTB. ET-1 activates the sphingosine kinase/sphingosine-1-phosphate (SphK/S1P) pathway. S1P, in turn, is an important signaling molecule in the proinflammatory response. Interestingly, we have shown that SphK inhibition also prevents LPS-induced PTB in timed pregnant mice. Further, we showed that SphK inhibition suppresses the ECE-1/ET-1 axis, implicating positive feedback regulation of the SphK/S1P/ECE-1/ET-1 axis. Conclusion: The ET-1/SphK/SIP pathway is a potential pharmacotherapeutic target for the prevention of PTB.

Background: Preterm birth (PTB), or birth that occurs before 37 weeks of gestation, accounts for the majority of perinatal morbidity and mortality. As of 2016, PTB has an occurrence rate of 9.6% in the United States and accounts for up to 18 percent of births worldwide. Inflammation has been identified as the most common cause of PTB, but effective pharmacotherapy has yet to be developed to prevent inflammation driven PTB. Our group has discovered that N,N-dimethylacetamide (DMA), a readily available solvent commonly used as a pharmaceutical excipient, rescues lipopolysaccharide (LPS)-induced timed pregnant mice from PTB. Methods: We have used in vivo, ex vivo and in vitro approaches to investigate this compound further. Results: Interestingly, we found that DMA suppresses cytokine secretion by inhibiting nuclear factor-kappa B (NF-ΚB). In ongoing work in this exciting line of investigation, we are currently investigating structural analogs of DMA, some of them novel, to optimize this approach focused on the inflammation associated with PTB. Conclusion: Successful development of pharmacotherapy for the prevention of PTB rests upon the pursuit of multiple strategies to solve this important clinical challenge.

During gestation, the immune response of the placenta to viruses and other pathogens plays an important role in determining a pregnant woman's vulnerability toward infectious diseases. Located at the maternalfetal interface, trophoblast cells serve to minimize the spread of viruses between the host and developing fetus through an intricate system of innate antiviral immune signaling. Adverse pregnancy outcomes, ranging from learning disabilities to preterm birth and fetal death, are all documented results of a viral breach in the placental barrier. Viral infections during pregnancy can also be spread through blood and vaginal secretions, and during the post-natal period, via breast milk. Thus, even in the absence of vertical transmission of viral infection to the fetus, maternal health can still be compromised and threaten the pregnancy. The most common viral DNA isolates found in gestation are adenovirus, cytomegalovirus, and enterovirus. However, with the recent pandemic of Ebola virus, and the first documented case of a neonate to survive due to experimental therapies in 2017, it is becoming increasingly apparent that the changing roles and impacts of viral infection during pregnancy needs to be better understood, while strategies to minimize adverse pregnancy outcomes need to be identified. This review focuses on the adverse impacts of viral infection during gestation, with an emphasis on Ebola virus.

Studies indicate that Polycystic Ovarian Syndrome (PCOS) features (e.g. insulin instability, food cravings, overproduction of androgens and menstrual irregularities) are associated with increased appetite, impaired impulse control and feelings of body dissatisfaction. Counter intuitively, binge eating behaviors have been shown to reinforce PCOS symptomatology, precipitating concurrently body dissatisfaction, weight gain, insulin instability and overproduction of androgens. The present systematic literature review aspires to investigate the relationship between binge eating, in the broader context of eating disorder behaviors, and Polycystic Ovarian Syndrome (PCOS), taking into account shared characteristics between EDs (Eating Disorders) and PCOS. To address this aim, the PRISMA guidelines are adopted. A total of 21 studies, which investigated the presence of binge eating in PCOS population and the presence of PCOS in EDs population, were synthesized. Findings suggested that an increased prevalence of binge eating has been reported in women with Polycystic Ovarian Syndrome (PCOS); and that women suffering from BN (Bulimia Nervosa) and BED (Binge Eating Disorder) are more likely to display polycystic ovaries. Further research on their shared liability is required in order to inform more efficient prevention and treatment initiatives for populations presenting with comorbid features.

Background: Insulin increases glucose uptake in muscles and fat and inhibits hepatic glucose production, thus serving as the primary regulator of the blood glucose level. In type 2 diabetes, insufficient insulin release and suppressed insulin action [named insulin resistance] lead to increased glucose production in liver and decreased glucose uptake by muscles and fat tissues, resulting in elevated blood glucose concentration which is dangerous to human health. Therefore, the anti-diabetic therapies are aimed at inhibiting excess blood glucose. Methods: A comparative analysis of two distinct glucose-lowering modes was used to develop a new feedback model for the purpose of identification of pharmacological targets in diabetes treatment. Results: The current brief opinion proposes an original feedback control of glucose-lowering regulation and its models which allow comparing two distinct strategies of glucose level correction, i.e., one of them allows reducing the increased threshold of insulin resistance, whereas the other allows overcoming this threshold/barrier using exogenous insulin treatment. Also, this analytic research presents selected examples comparing the influence of the two analyzed strategies on the normalization of glucose metabolism, their therapeutic potential and side effects associated with additional weight gain. These models show the pathological mechanism by which exogenous insulin provokes formation of a «vicious cycle» by its side effects associated with additional weight gain. Conclusion: The presented model and findings can contribute to the development of new anti-diabetic targets and drugs with minimal side effects.

Leptin antagonists (L39A/D40A/F4lA mutants) of mouse, human, rat and ovine leptins were developed in our laboratory by rational mutagenesis, expressed in Escherichia coli, refolded and purified to homogeneity. Pegylation of these antagonists resulted in long-acting reagents suitable for in-vivo studies. Further selection of high-affinity leptin antagonists was achieved by random mutagenesis of the whole open reading frame followed by yeast- surface display; an additional mutation (D23L) increased their affinity toward leptin receptor 60-fold. This superactive pegylated mouse leptin antagonist (PLA) exhibited a strong orexigenic effect, leading, in 10–14 days, to a 40% increase in body weight resulting mainly from obesity; this was reversed once PLA treatment was ceased. Cachexia is common in patients with Chronic Kidney Disease (CKD). Our studies suggested that leptin mediates cachexia by decreasing food intake while increasing energy consumption in CKD mice. We showed that PLA ameliorates CKD-associated cachexia in mice. Leptin may also contribute to the development of muscle and renal fibrosis in CKD, serious complications associated with increased morbidity and mortality. Transforming growth factor (TGF)-β signaling may be the most potent mediator of fibrogenesis in multiple organs, and leptin is a co-activator of TGF-β. Muscle fibrosis was evident in our CKD mice and PLA treatment significantly reduced the mRNA levels of TGF- β1 and its downstream targets in their muscle and renal tissues. PLA may offer a novel therapeutic strategy for CKD-associated cachexia, muscle and renal fibrosis to improve CKD patients' survival and quality of life.

Background: Metabolic syndrome (MetS), as a cluster of metabolic derangements which are major risk factors for vascular disease is one of the most important threats to public health. Although the epidemiological and limited amount of basic science and clinical evidence link MetS to several male urogenital disorders, a holistic approach aiming to define common mechanistic pathways and new possible therapeutic targets are lacking. Objective: The current review has focused on providing scientific evidence on the role of MetS and its components on male urogenital disorders and the definition of new therapeutic targets. Method: In this review, current clinical and basic science literature were assessed examining the role of MetS in etiology and pathogenesis of male urogenital disorders and performed through PubMed from 2000 to May 2017. Results and Conclusion: MetS shows an important association with common male urogenital disorders such as benign prostatic enlargement, lower urinary tract symptoms, erectile dysfunction, infertility and renal disease. MetS affects male urogenital system mainly through endocrine and vascular mechanisms. Obesity, hypogonadism, obesity-induced androgen deficiency, hyperinsulinemia and inflammation are the mechanisms commonly involved and may act as potential targets for MetS-male urogenital system interrelations. Future studies are needed to evaluate the therapeutic approaches for intervention in MetS-male urogenital disease relations.

Objective: Fibrinogen is a key mediator of thrombosis and it has been implicated in the pathogenesis of atherosclerosis. Because metformin has shown a potential protective effect on different atherothrombotic risk factors, we assessed in this meta-analysis its effect on plasma fibrinogen concentrations. Methods: A systematic review and meta-analysis was carried out to identify randomized placebo-controlled trials evaluating the effect of metformin administration on fibrinogen levels. The search included PubMed-Medline, Scopus, ISI Web of Knowledge and Google Scholar databases (by June 2, 2017) and quality of studies was performed according to Cochrane criteria. Quantitative data synthesis was conducted using a random-effects model and sensitivity analysis by the leave-one-out method. Meta-regression analysis was performed to assess the modifiers of treatment response. Results: Meta-analysis of data from 9 randomized placebo-controlled clinical trials with 2302 patients comprising 10 treatment arms did not suggest a significant change in plasma fibrinogen concentrations following metformin therapy (WMD: -0.25 g/L, 95% CI: -0.53, 0.04, p = 0.092). The effect size was robust in the leave-one-out sensitivity analysis and remained non-significant after omission of each single study from the meta-analysis. Conclusion: No significant effect of metformin on plasma fibrinogen concentrations was demonstrated in the current meta-analysis.