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Platelet-rich plasma (PRP) has gained popularity as an experimental tool in regenerative medicine, with potential applications in reproductive medicine. This review will assess the existing literature on the role of PRP in female fertility enhancement, focusing on ovarian rejuvenation and increased endometrial thickness. PRP is being explored as a treatment for recurrent implantation failure, primary ovarian insufficiency and poor ovarian response. While the influence of PRP on endometrial thickness and implantation success is postulated, its effectiveness remains the subject of debate due to protocol variability and unclear patient selection criteria. This narrative review includes 36 articles published before December 2022, and highlights the lack of comprehensive molecular studies examining the impact of PRP on reproductive capacity. This review underscores the importance of standardizing PRP preparation protocols in reproductive medicine. However, challenges persist, and there is a need for well-planned randomized controlled trials and a deeper understanding of the patient population that would gain the greatest benefit from PRP treatment. Clarifying these aspects is crucial to improve outcomes for low-prognosis patients undergoing assisted reproductive technology., (Copyright © 2024 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Research Question: Do morphokinetic parameters vary between male and female preimplantation embryos?, Design: This was a retrospective cohort study of 175 cycles between March 2018 and June 2021 at two reproductive centres. It included time-lapse data from 92 female and 83 male preimplantation embryos exclusively issued from fresh oocyte donation and undergoing intracytoplasmic sperm injection (ICSI). Only fresh elective single-embryo transfers on day 5 were assessed, and the sex of the embryo was confirmed at birth. The morphokinetic parameters analysed were measured in hours post-insemination (hpi). A two-tailed Student's t-test was used to compare the morphokinetics between embryo sexes and a value of P < 0.05 was considered statistically significant., Results: Following strict inclusion criteria to avoid poor-quality preimplantation embryos, no significant differences were found in morphokinetic parameters when comparing cycles that resulted in female versus male live births for the following: time to pronuclear fading (22.1 ± 2.4 versus 22.4 ± 2.9 hpi; P = 0.52); time to the 2-cell stage (24.6 ± 2.5 versus 25.0 ± 2.5 hpi; P = 0.34); time to the 3-cell stage (35.3 ± 3.3 versus 35.8 ± 3.1 hpi; P = 0.28); time to the 4-cell stage (36.3 ± 3.4 versus 36.9 ± 3.7 hpi; P = 0.20); time to the 5-cell stage (47.9 ± 4.6 versus 48.0 ± 4.8 hpi; P = 0.88); time to the 8-cell stage (54.0 ± 6.5 versus 54.1 ± 6.5 hpi; P = 0.91); time to the start of blastulation (86.3 ± 14.6 versus 85.7 ± 15.5 hpi; P = 0.78); and time to the full blastocyst stage (93.0 ± 16.9 versus 93.2 ± 17.2 hpi; P = 0.94)., Conclusions: There are no significant differences in morphokinetics between male and female preimplantation embryos., (Copyright © 2023 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.)

Epithelia grow and shape into functional structures during organogenesis. Although most of the focus on organogenesis has been drawn to the building of biological structures, the disassembly of pre-existing structures is also an important event to reach a functional adult organ. Examples of disassembly processes include the regression of the Müllerian or Wolffian ducts during gonad development and mammary gland involution during the post-lactational period in adult females. To date, it is unclear how organ disassembly is controlled at the cellular level. Here, we follow the Drosophila larval trachea through metamorphosis and show that its disassembly is a hormone-driven and precisely orchestrated process. It occurs in two phases: first, remodeling of the apical extracellular matrix (aECM), mediated by matrix metalloproteases and independent of the actomyosin cytoskeleton, results in a progressive shortening of the entire trachea and a nuclear-to-cytoplasmic relocalization of the Hippo effector Yorkie (Yki). Second, a decreased transcription of the Yki target, Diap1, in the posterior metameres and the activation of caspases result in the apoptotic loss of the posterior half of the trachea while the anterior half escapes cell death. Thus, our work unravels a mechanism by which hormone-driven ECM remodeling controls sequential tissue shortening and apoptotic cell removal through the transcriptional activity of Yki, leading to organ disassembly during animal development., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Evolution of morphogenesis is generally associated with changes in genetic regulation. Here, we report evidence indicating that dorsal closure, a conserved morphogenetic process in dipterans, evolved as the consequence of rearrangements in epithelial organization rather than signaling regulation. In Drosophila melanogaster , dorsal closure consists of a two-tissue system where the contraction of extraembryonic amnioserosa and a JNK/Dpp-dependent epidermal actomyosin cable result in microtubule-dependent seaming of the epidermis. We find that dorsal closure in Megaselia abdita, a three-tissue system comprising serosa, amnion and epidermis, differs in morphogenetic rearrangements despite conservation of JNK/Dpp signaling. In addition to an actomyosin cable, M. abdita dorsal closure is driven by the rupture and contraction of the serosa and the consecutive microtubule-dependent seaming of amnion and epidermis. Our study indicates that the evolutionary transition to a reduced system of dorsal closure involves simplification of the seaming process without changing the signaling pathways of closure progression., Competing Interests: JF, JJ, JS No competing interests declared, (© 2018, Fraire-Zamora et al.)

Epithelia have the ability to repair injuries through an evolutionary conserved wound healing mechanism. Wound healing events can be classified into the transcription-independent signals involving mobilization of ionic currents and cytoskeletal rearrangements or the transcription-dependent response with activation of repair genes. The vacuolar H + -ATPase (V-ATPase) has been implicated in the regeneration of vertebrate structures, but the underlying cellular mechanisms remain unclear. Here, we use wounding assays on the epidermis of Drosophila embryos to assess the role of the V-ATPase in the healing response. We show that a deficient V-ATPase induces a defective wound healing response by delaying re-epithelialization and preventing the ERK-dependent transcriptional activation of repair around the wound site. Our data suggests that the V-ATPase plays an evolutionary conserved role in the activation of genes necessary for the wound healing response., (© 2018 by the Wound Healing Society.)

In the amoeboid spermatozoa from Caenorhabditis elegans, motility acquisition is preceded by substantial rearrangement of the plasma membrane. The current genetic model posits a multicomponent complex of membrane and cytoplasmic proteins responsible for pseudopod extension. This model can be translated into a physiological context through the involvement of cholesterol-enriched signaling platforms. We show that discrete cholesterol-enriched microdomains are present in C. elegans spermatids. These microdomains redistributed towards the cell body upon pseudopod extension resulting in a phospholipid-enriched pseudopod. Cholesterol saturation in the spermatids prevented pseudopod extension and motility acquisition, whereas cholesterol depletion increased the rate of in vitro pseudopod extension. This work suggests that plasma membrane cholesterol plays an important role in regulating the membrane dynamics that precede pseudopod extension and motility acquisition., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Nematode spermatozoa are highly specialized cells that lack flagella and, instead, extend a pseudopod to initiate motility. Crawling spermatozoa display classic features of amoeboid motility (e.g. protrusion of a pseudopod that attaches to the substrate and the assembly and disassembly of cytoskeletal filaments involved in cell traction and locomotion), however, cytoskeletal dynamics in these cells are powered exclusively by Major Sperm Protein (MSP) rather than actin and no other molecular motors have been identified. Thus, MSP-based motility is regarded as a simple locomotion machinery suitable for the study of plasma membrane protrusion and cell motility in general. This recent focus on MSP dynamics has increased the necessity of a standardized methodology to obtain C. elegans sperm extract that can be used in biochemical assays and proteomic analysis for comparative studies. In the present work we have modified a method to reproducibly obtain relative high amounts of proteins from C. elegans sperm extract. We show that these extracts share some of the properties observed in sperm extracts from the parasitic nematode Ascaris including Major Sperm Protein (MSP) precipitation and MSP fiber elongation. Using this method coupled to immunoblot detection, Mass Spectrometry identification, in silico prediction of functional domains and biochemical assays, our results indicate the presence of phosphorylation sites in MSP of Caenorhabditis elegans spermatozoa.

Nematode spermatozoa are highly specialized amoeboid cells that must acquire motility through the extension of a single pseudopod. Despite morphological and molecular differences with flagellated spermatozoa (including a non-actin-based cytoskeleton), nematode sperm must also respond to cues present in the female reproductive tract that render them motile, thereby allowing them to locate and fertilize the egg. The factors that trigger pseudopod extension in vivo are unknown, although current models suggest the activation through proteases acting on the sperm surface resulting in a myriad of biochemical, physiological, and morphological changes. Compelling evidence shows that pseudopod extension is under the regulation of physiological events also observed in other eukaryotic cells (including flagellated sperm) that involve membrane rearrangements in response to extracellular cues that initiate various signal transduction pathways. An integrative approach to the study of nonflagellated spermatozoa will shed light on the identification of unique and conserved processes during fertilization among different taxa., ((c) 2010 Wiley-Liss, Inc.)

Human sperm are endowed with putative voltage-dependent calcium channels (VDCC) that produce measurable increases in intracellular calcium concentration ([Ca(2+)](i)) in response to membrane depolarization with potassium. These channels are blocked by nickel, inactivate in 1-2 min in calcium-deprived medium, and are remarkably stimulated by NH(4)Cl, suggesting a role for intracellular pH (pH(i)). In a previous work, we showed that calcium permeability through these channels increases approximately onefold during in vitro "capacitation," a calcium-dependent process that sperm require to fertilize eggs. In this work, we have determined the pH(i) dependence of sperm VDCC. Simultaneous depolarization and pH(i) alkalinization with NH(4)Cl induced an [Ca(2+)](i) increase that depended on the amount of NH(4)Cl added. VDCC stimulation as a function of pH(i) showed a sigmoid curve in the 6.6-7.2 pH(i) range, with a half-maximum stimulation at pH approximately 7.00. At higher pH(i) (> or =7.3), a further stimulation occurred. Calcium release from internal stores did not contribute to the stimulating effect of pH(i) because the [Ca(2+)](i) increase induced by progesterone, which opens a calcium permeability pathway that does not involve gating of VDCC, was unaffected by ammonium. The ratio of pH(i)-stimulated-to-nonstimulated calcium influx was nearly constant at different test depolarization values. Likewise, depolarization-induced calcium influx in pH(i)-stimulated and nonstimulated cells was equally blocked by nickel. In our capacitating conditions pH(i) increased 0.11 pH units, suggesting that the calcium influx stimulation observed during sperm capacitation might be partially caused by pH(i) alkalinization. Additionally, a calcium permeability pathway triggered exclusively by pH(i) alkalinization was detected.