Reversible female contraceptives: historical, current, and future perspectives†.

Contraception is a practice with extensive and complicated social and scientific histories. From cycle tracking, to the very first prescription contraceptive pill, to now having over-the-counter contraceptives on demand, family planning is an aspect of healthcare that has undergone and will continue to undergo several transformations through time. This review provides a comprehensive overview of current reversible hormonal and non-hormonal birth control methods as well as their mechanism of action, safety, and effectiveness specifically for individuals who can become pregnant. Additionally, we discuss the latest Food and Drug Administration (FDA)-approved hormonal method containing estetrol and drospirenone that has not yet been used worldwide as well as the first FDA-approved hormonal over-the-counter progestin-only pills. We also review available data on novel hormonal delivery through microchip, microneedle, and the latest FDA-approved non-hormonal methods such as vaginal pH regulators. Finally, this review will assist in advancing female contraceptive method development by underlining constructive directions for future pursuits. Information was gathered from the NCBI and Google Scholars databases using English and included publications from 1900 to present. Search terms included contraceptive names as well as efficacy, safety, and mechanism of action. In summary, we suggest that investigators consider the side effects and acceptability together with the efficacy of contraceptive candidate towards their development.

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

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.

Sequence determinants of human-cell entry identified in ACE2-independent bat sarbecoviruses: A combined laboratory and computational network science approach.

BACKGROUND: The sarbecovirus subgenus of betacoronaviruses is widely distributed throughout bats and other mammals globally and includes human pathogens, SARS-CoV and SARS-CoV-2. The most studied sarbecoviruses use the host protein, ACE2, to infect cells. Curiously, the majority of sarbecoviruses identified to date do not use ACE2 and cannot readily acquire ACE2 binding through point mutations. We previously screened a broad panel of sarbecovirus spikes for cell entry and observed bat-derived viruses that could infect human cells, independent of ACE2. Here we further investigate the sequence determinants of cell entry for ACE2-independent bat sarbecoviruses. METHODS: We employed a network science-based approach to visualize sequence and entry phenotype similarities across the diversity of sarbecovirus spike protein sequences. We then verified these computational results and mapped determinants of viral entry into human cells using recombinant chimeric spike proteins within an established viral pseudotype assay. FINDINGS: We show ACE2-independent viruses that can infect human and bat cells in culture have a similar putative receptor binding motif, which can impart human cell entry into other bat sarbecovirus spikes that cannot otherwise infect human cells. These sequence determinants of human cell entry map to a surface-exposed protrusion from the predicted bat sarbecovirus spike receptor binding domain structure. INTERPRETATION: Our findings provide further evidence of a group of bat-derived sarbecoviruses with zoonotic potential and demonstrate the utility in applying network science to phenotypic mapping and prediction. FUNDING: This work was supported by Washington State University and the Paul G. Allen School for Global Health.

Central serotonin and autoresuscitation capability in mammalian neonates.

Autoresuscitation is an important cardiorespiratory protective mechanism that allows neonatal mammals to recover from primary apnea. It begins with hypoxia-induced gasping and ends, if successful, with the recovery of rhythmic breathing and normal heart rate. Many factors influence the efficacy of autoresuscitation, including the availability of serotonin (5-HT) in the brain. Since the early 2000's, there has been mounting interest in the role of 5-HT in promoting autoresuscitation, driven in large part by the recognition that both failed autoresuscitation and a deficiency of central 5-HT correlate with Sudden Infant Death Syndrome in humans. Within this timeframe, newly developed animal models with a central 5-HT deficiency have examined experimentally the role of 5-HT in autoresuscitation capability. The purpose of this review is to discuss some of the methodological considerations associated with 5-HT-deficient animal models, to summarize major findings arising from their use, and to highlight several key issues related to 5-HT involvement in gasping and the autoresuscitation response.

Autoresuscitation responses to hypoxia-induced apnea are delayed in newborn 5-HT-deficient Pet-1 homozygous mice.

Autoresuscitation is a critical survival-promoting mechanism in mammals that allows recovery from primary apnea via hypoxia-induced gasping. Here we show, using head-out plethysmography, that gasping behavior is altered during autoresuscitation, and the autoresuscitation response is delayed, in neonatal 5-hydroxytryptamine (5-HT) neuron-deficient Pet-1 homozygous (Pet-1(-/-)) mice. When exposed to 97% N(2)-3% CO(2) on postnatal day 4.5, unanesthetized Pet-1(-/-) mice required over four times longer than age-matched wild-type controls to initiate gasping following primary apnea. When oxygen was made available before the first gasp, allowing autoresuscitation to occur, gasping frequency was decreased and the duration of the gasping period was extended in the Pet-1 mutants compared with wild type, resulting in a nearly threefold increase in the time needed for successful autoresuscitation. However, when the exposure to anoxia was unrelenting, gasping frequency, the form of the gasps, the total number of gasps produced, the duration of the gasping period, and time to last gasp were comparable to controls. Plethysmographic testing of the same mutants on postnatal day 9.5 revealed that their autoresuscitation responses, although improved compared with day 4.5, remained significantly longer than in wild-type controls. Our data indicate that despite a severe deficiency of central 5-HT neurons, Pet-1(-/-) neonatal mice are capable of gasping, but their gasping pattern is altered during autoresuscitation, leading to a prolongation of the time required to recover from hypoxia-induced apnea.

Arrest of 5HT neuron differentiation delays respiratory maturation and impairs neonatal homeostatic responses to environmental challenges.

Serotonin (5HT) is a powerful modulator of respiratory circuitry in vitro but its role in the development of breathing behavior in vivo is poorly understood. Here we show, using 5HT neuron-deficient Pet-1 (Pet-1(-/-)) neonates, that serotonergic function is required for the normal timing of postnatal respiratory maturation. Plethysmographic recordings reveal that Pet-1(-/-) mice are born with a depressed breathing frequency and a higher incidence of spontaneous and prolonged respiratory pauses relative to wild type littermates. The wild type breathing pattern stabilizes by postnatal day 4.5, while breathing remains depressed, highly irregular and interrupted more frequently by respiratory pauses in Pet-1(-/-) mice. Analysis of in vitro hypoglossal nerve discharge indicates that instabilities in the central respiratory rhythm generator contribute to the abnormal Pet-1(-/-) breathing behavior. In addition, the breathing pattern in Pet-1(-/-) neonates is susceptible to environmental conditions, and can be further destabilized by brief exposure to hypoxia. By postnatal day 9.5, however, breathing frequency in Pet-1(-/-) animals is only slightly depressed compared to wild type, and prolonged respiratory pauses are rare, indicating that the abnormalities seen earlier in the Pet-1(-/-) mice are transient. Our findings provide unexpected insight into the development of breathing behavior by demonstrating that defects in 5HT neuron development can extend and exacerbate the period of breathing instability that occurs immediately after birth during which respiratory homeostasis is vulnerable to environmental challenges.

Mechanochemotransduction during cardiomyocyte contraction is mediated by localized nitric oxide signaling.

Cardiomyocytes contract against a mechanical load during each heartbeat, and excessive mechanical stress leads to heart diseases. Using a cell-in-gel system that imposes an afterload during cardiomyocyte contraction, we found that nitric oxide synthase (NOS) was involved in transducing mechanical load to alter Ca(2+) dynamics. In mouse ventricular myocytes, afterload increased the systolic Ca(2+) transient, which enhanced contractility to counter mechanical load but also caused spontaneous Ca(2+) sparks during diastole that could be arrhythmogenic. The increases in the Ca(2+) transient and sparks were attributable to increased ryanodine receptor (RyR) sensitivity because the amount of Ca2(+) in the sarcoplasmic reticulum load was unchanged. Either pharmacological inhibition or genetic deletion of nNOS (or NOS1), but not of eNOS (or NOS3), prevented afterload-induced Ca2(+) sparks. This differential effect may arise from localized NO signaling, arising from the proximity of nNOS to RyR, as determined by super-resolution imaging. Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) and nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) also contributed to afterload-induced Ca(2+) sparks. Cardiomyocytes from a mouse model of familial hypertrophic cardiomyopathy exhibited enhanced mechanotransduction and frequent arrhythmogenic Ca(2+) sparks. Inhibiting nNOS and CaMKII, but not NOX2, in cardiomyocytes from this model eliminated the Ca2(+) sparks, suggesting mechanotransduction activated nNOS and CaMKII independently from NOX2. Thus, our data identify nNOS, CaMKII, and NOX2 as key mediators in mechanochemotransduction during cardiac contraction, which provides new therapeutic targets for treating mechanical stress-induced Ca(2+) dysregulation, arrhythmias, and cardiomyopathy.

The effects of hypoxia-ischemia on neutral amino acid transporters in the developing rat brain.

The neutral amino acid transporters SNAT1-3 and ASCT1 play critical roles in the recycling of glutamine, and subsequently glutamate, via the glutamine-glutamate cycle. Hypoxia-ischemia was induced in rat pups using the Rice-Vannucci model. Brains were harvested at 1 h, 24 h and 7 days after ischemia. The expression of NAATs was evaluated using immunoblotting, real-time PCR, and immunohistochemistry. Results were compared with age-matched controls and shams. SNAT1 mRNA decreased at 1 h after injury in both hemispheres when compared with the control animals and correlated with a decrease in protein expression at 24 h in the hippocampus and cortex. SNAT1 protein expression increased globally at 7 days after injury and specifically in the hippocampus. Finally, SNAT2 and 3 demonstrated subtle changes in various brain regions after injury. These data suggest that neutral amino acid transporters remain largely intact after hypoxia-ischemia.