Thrombosis of the vasa vasorum of the large and medium size pulmonary artery and vein leads to pulmonary thromboembolism in COVID-19.

The vasa vasorum of the large pulmonary vessels is involved in the pathology of COVID-19. This specialized microvasculature plays a major role in the biology and pathology of the pulmonary vessel walls. We have evidence that thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels during severe COVID-19 causes ischemia and subsequent death of the pulmonary vasculature endothelium. Subsequent release of thrombi from the vasa interna into the pulmonary circulation and pulmonary embolism generated at the ischemic pulmonary vascular endothelium site, are the central pathophysiological mechanisms in COVID-19 responsible for pulmonary thromboembolism. The thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels is an internal event leading to pulmonary thromboembolism in COVID-19.

Thrombosis of the vasa vasorum of the large and medium size pulmonary artery and vein leads to pulmonary thromboembolism in COVID-19

ABSTRACT The vasa vasorum of the large pulmonary vessels is involved in the pathology of COVID-19. This specialized microvasculature plays a major role in the biology and pathology of the pulmonary vessel walls. We have evidence that thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels during severe COVID-19 causes ischemia and subsequent death of the pulmonary vasculature endothelium. Subsequent release of thrombi from the vasa interna into the pulmonary circulation and pulmonary embolism generated at the ischemic pulmonary vascular endothelium site, are the central pathophysiological mechanisms in COVID-19 responsible for pulmonary thromboembolism. The thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels is an internal event leading to pulmonary thromboembolism in COVID-19.

In vitro Fertilization: An Alert for the Association of Placenta Previa and Vasa Previa - Ultrasound and Magnetic Resonance Imaging Findings.

A 33-year-old woman, gravida 2 para 0, with a history of two previous miscarriages, underwent an investigation for recurrent miscarriage. After genetic counseling, the couple were submitted to the karyotype, which resulted in 45, X/46, XX mosaicism (mosaic Turner syndrome) in the wife result, while the husband chromosomal resulted in 46, XY (normal). After evaluating the options, the couple opted for in vitro fertilization. During prenatal follow-up, placenta and vasa previa were identified, considerably increasing the maternal-fetal mortality rate in this case. However, despite being a delicate and challenging case, the early diagnose was possible due to transvaginal ultrasound using color Doppler. Due to good care in obstetric follow-up, involving a multidisciplinary team, a therapeutic program and a successful outcome were possible. The patient underwent a cesarean section at 35 weeks of pregnancy, without complications, with a newborn in good general condition, despite the prematurity.

Vasa Vasorum in Saphenous Vein for CABG: A Review of Morphological Characteristics.

This short article discusses selected scanning electron microscope and transmission electron microscope features of vasa vasorum including pericytes and basement membrane of the human saphenous vein (SV) harvested with either conventional (CON) or no-touch (NT) technique for coronary artery bypass grafting. Scanning electron microscope data shows the general damage to vasa vasorum of CON-SV, while the transmission electron microscope data presents ultrastructural features of the vasa in more detail. Hence there are some features suggesting pericyte involvement in the contraction of vasa blood vessels, particularly in CON-SV. Other features associated with the vasa vasorum of both CON-SV and NT-SV preparations include thickened and/or multiplied layers of the basement membrane. In some cases, multiple layers of basement membrane embrace both pericyte and vasa microvessel making an impression of a "unit" made by basement membrane-pericyte-endothelium/microvessel. It can be speculated that this structural arrangement has an effect on the contractile and/or relaxing properties of the vessels involved. Endothelial colocalization of immunoreactive inducible nitric oxide synthase and endothelin-1 can be observed (with laser confocal microscope) in some of the vasa microvessels. It can be speculated that this phenomenon, particularly of the expression of inducible nitric oxide synthase, might be related to structurally changed vasa vessels, e.g., with expanded basement membrane. Fine physiological relationships between vasa vasorum endothelium, basement membrane, pericyte, and perivascular nerves have yet to be uncovered in the detail needed for better understanding of the cells'specific effects in SV preparations for coronary artery bypass grafting.

Manejo de embarazos únicos con diagnóstico antenatal de vasa previa / Management of singleton pregnancies with prenatal diagnosis of vasa previa

Introducción: vasa previa (VP) corresponde al paso de los vasos umbilicales por las membranas amnióticas, sin protección de gelatina de Wharton o placenta, antes de la presentación fetal, sobre el orificio cervical interno. Pese a su baja incidencia, el diagnóstico prenatal es relevante por las graves consecuencias que puede tener esta patología en caso de no ser diagnosticada. El objetivo de esta revisión es presentar la evidencia disponible para el manejo de embarazadas con diagnóstico antenatal de VP. Materiales y métodos: analizamos todos los estudios publicados (prospectivos, retrospectivos y reporte de casos) entre los años 1999 y 2023, con diagnóstico VP en embarazo único, reportando la edad gestacional de interrupción y el resultado neonatal. Resultados: incluimos 19 investigaciones (18 en la búsqueda primera y una adicional por relevancia). Las pacientes con manejo intrahospitalario desde las 34 semanas tuvieron mayor latencia al parto, mejores resultados neonatales y menor tasa de cesárea de urgencia que las pacientes con manejo ambulatorio. La edad gestacional de interrupción es variable entre los estudios, sin embargo, no se evidenció beneficio de interrupción a las 34 semanas comparado con manejo expectante hasta las 37 semanas de edad gestacional. Conclusión: existiría beneficio de hospitalización entre las 32-34 semanas en mujeres con diagnóstico de VP, siendo razonable la interrupción cercana a las 37 semanas por cesárea electiva.

Introduction: vasa previa (VP) corresponds to the passage of the umbilical vessels through the amniotic membranes, without the protection of Wharton's gelatin or placenta, in front of the fetal presentation, over the internal cervical os. Despite its low incidence, prenatal diagnosis is relevant due to the severe consequences of this pathology if the diagnosis is missed. This review presents the available evidence for pregnant women's management with an antenatal diagnosis of VP. Materials and methods: we analyzed all the studies published (prospective, retrospective, and case reports) between 1999 and 2023, with a diagnosis of VP in a single pregnancy, reporting gestational age at delivery and neonatal outcome. Results: We included 19 investigations (18 in the first search and another for relevance). Patients with in-hospital management from 34 weeks had a more extended latency period until delivery, better neonatal outcomes, and a lower rate of emergency cesarean section than patients with outpatient management. The gestational age at birth is variable between the studies; however, no benefit of delivery at 34 weeks was evidenced compared with expectant management until 37 weeks of gestational age. Conclusion: there would be a benefit of hospitalization between 32-34 weeks in women diagnosed with VP, being reasonable to schedule the delivery close to 37 weeks by elective cesarean section.

Silencing of the Vasa gene by RNA Interference Affects Embryonic Development and Reproductive Output in the Sea Louse Caligus rogercresseyi.

The sea louse Caligus rogercresseyi is a major ectoparasitic copepod that causes significant economic losses in the salmon farming industry. Despite recent advancements, the mechanisms underlying germline and embryo development in this species remain poorly understood. The Vasa gene encodes a highly conserved DEAD box helicase that is required for germ cell formation and function in many species. In this study, the Vasa gene was characterized in C. rogercresseyi, and its expression and function were analyzed. Phylogenetic analysis showed that the Cr-Vasa gene product formed clusters in clades with Vasa proteins from closely related species of crustaceans. Cr-Vasa gene expression patterns were assessed by qPCR, and the results showed a significantly higher relative expression level in adult females compared to copepodid, chalimus, and adult male stages. Tissue-specific localization of Cr-Vasa mRNA in C. rogercresseyi was determined using chromogenic in situ hybridization, and strong positive signal was observed in male testes, but also in the intestine and cuticle, while in females, it was observed in the ovaries, oocytes, cuticle, intestine, and egg strings. RNAi-mediated gene silencing of Cr-Vasa impacted embryonic development and reproductive output in adult female lice. Females from the dsVasa-treated group displayed unusual phenotypes, including shorter egg strings with numerous extra-embryonic inclusions, irregularly shaped abnormal embryos, and aborted egg strings. This study provides insights into the role of the Vasa gene in C. rogercresseyi embryonic development and reproductive output, which may have implications for the control of this parasitic copepod in the salmon farming industry.

Diagnóstico prenatal de vasa previa tipo 3, comunicación de un caso

La vasa previa es una patología poco frecuente en la que los vasos umbilicales se encuentran transcurriendo en las cercanías del orificio cervical interno. Habitualmente está asociada a inserción velamentosa del cordón, placenta succenturiata, inserción baja placentaria y fertilización in vitro. Tiene importantes implicancias perinatales el lograr un diagnóstico precoz en el segundo trimestre, porque se logra disminuir la mortalidad neonatal. Presentamos el primer caso de diagnóstico prenatal de vasa previa tipo 3 (una variante poco conocida) comunicado en el Perú en una gestante con placenta previa y sin diagnóstico hasta el tercer trimestre.

Vasa previa is a rare condition in which the umbilical vessels are found to run in the vicinity of the internal cervical os. It is usually associated with velamentous insertion of the umbilical cord, placenta succenturiata, low placenta insertion and in vitro fertilization. Early diagnosis in the second trimester has important perinatal implications because it reduces neonatal mortality. We present the first case of prenatal diagnosis of vasa previa type 3 (a little known variant) reported in Peru in a pregnant woman with placenta previa and undiagnosed until the third trimester.

Vasa previa con inserción velamentosa de cordón: comunicación de un caso

La afección vasa previa es un hallazgo prenatal raro y poco frecuente de hemorragia en la segunda mitad del embarazo, en la que los vasos umbilicales desprovistos de la gelatina de Wharton se interponen entre la presentación fetal y el orificio cervical interno. Cuando no se la detecta y se produce la rotura de los vasos, se asocia a una alta tasa de mortalidad perinatal. Se describen 3 tipos; el caso presentado se trata de vasa previa de tipo 1 secundaria a inserción velamentosa de cordón. Fue diagnosticada prenatalmente mediante ecografía por vía transvaginal asociada a Doppler color. Se practicó una cesárea con evolución materno perinatal favorable.

Vasa previa is a rare and infrequent prenatal finding of hemorrhage in the second half of pregnancy, in which umbilical vessels devoid of Wharton's jelly interpose between the fetal presentation and the internal cervical os. When undetected and rupture of the vessels occurs, it is associated with a high perinatal mortality rate. Three types are described; the case presented is type 1 vasa previa secondary to velamentous insertion of the cord. It was diagnosed prenatally by transvaginal ultrasound associated with color Doppler. A cesarean section was performed with favorable maternal and perinatal evolution.

Vasa Vasorum in Saphenous Vein for CABG: A Review of Morphological Characteristics

ABSTRACT This short article discusses selected scanning electron microscope and transmission electron microscope features of vasa vasorum including pericytes and basement membrane of the human saphenous vein (SV) harvested with either conventional (CON) or no-touch (NT) technique for coronary artery bypass grafting. Scanning electron microscope data shows the general damage to vasa vasorum of CON-SV, while the transmission electron microscope data presents ultrastructural features of the vasa in more detail. Hence there are some features suggesting pericyte involvement in the contraction of vasa blood vessels, particularly in CON-SV. Other features associated with the vasa vasorum of both CON-SV and NT-SV preparations include thickened and/or multiplied layers of the basement membrane. In some cases, multiple layers of basement membrane embrace both pericyte and vasa microvessel making an impression of a "unit" made by basement membrane-pericyte-endothelium/microvessel. It can be speculated that this structural arrangement has an effect on the contractile and/or relaxing properties of the vessels involved. Endothelial colocalization of immunoreactive inducible nitric oxide synthase and endothelin-1 can be observed (with laser confocal microscope) in some of the vasa microvessels. It can be speculated that this phenomenon, particularly of the expression of inducible nitric oxide synthase, might be related to structurally changed vasa vessels, e.g., with expanded basement membrane. Fine physiological relationships between vasa vasorum endothelium, basement membrane, pericyte, and perivascular nerves have yet to be uncovered in the detail needed for better understanding of the cells'specific effects in SV preparations for coronary artery bypass grafting.

Prenatal Diagnosis of Vasa Previa by Routine Transvaginal Color Doppler.

The prenatal diagnosis of vasa previa is essential to achieving a safe delivery in patients who suffer from the condition. Transvaginal ultrasound with color Doppler performed at the time of a routine mid-trimester ultrasound is a valuable tool in terms of achieving a timely and accurate diagnosis of vasa previa.

Lost and Found: Piwi and Argonaute Pathways in Flatworms.

Platyhelminthes comprise one of the major phyla of invertebrate animals, inhabiting a wide range of ecosystems, and one of the most successful in adapting to parasitic life. Small non-coding RNAs have been implicated in regulating complex developmental transitions in model parasitic species. Notably, parasitic flatworms have lost Piwi RNA pathways but gained a novel Argonaute gene. Herein, we analyzed, contrasted and compared the conservation of small RNA pathways among several free-living species (a paraphyletic group traditionally known as 'turbellarians') and parasitic species (organized in the monophyletic clade Neodermata) to disentangle possible adaptations during the transition to parasitism. Our findings showed that complete miRNA and RNAi pathways are present in all analyzed free-living flatworms. Remarkably, whilst all 'turbellarians' have Piwi proteins, these were lost in parasitic Neodermantans. Moreover, two clusters of Piwi class Argonaute genes are present in all 'turbellarians'. Interestingly, we identified a divergent Piwi class Argonaute in free living flatworms exclusively, which we named 'Fliwi'. In addition, other key proteins of the Piwi pathways were conserved in 'turbellarians', while none of them were detected in Neodermatans. Besides Piwi and the canonical Argonaute proteins, a flatworm-specific class of Argonautes (FL-Ago) was identified in the analyzed species confirming its ancestrallity to all Platyhelminthes. Remarkably, this clade was expanded in parasitic Neodermatans, but not in free-living species. These phyla-specific Argonautes showed lower sequence conservation compared to other Argonaute proteins, suggesting that they might have been subjected to high evolutionary rates. However, key residues involved in the interaction with the small RNA and mRNA cleavage in the canonical Argonautes were more conserved in the FL-Agos than in the Piwi Argonautes. Whether this is related to specialized functions and adaptations to parasitism in Neodermatans remains unclear. In conclusion, differences detected in gene conservation, sequence and structure of the Argonaute family suggest tentative biological and evolutionary diversifications that are unique to Platyhelminthes. The remarkable divergencies in the small RNA pathways between free-living and parasitic flatworms indicate that they may have been involved in the adaptation to parasitism of Neodermatans.

A brief comment on vasa vasorum of human saphenous vein: relevance for coronary artery bypass surgery

Abstract The importance of the vasa vasorum and blood supply to the wall of human saphenous vein (hSV) used for coronary artery bypass grafting (CABG) is briefly discussed. This is in the context of the possible physical link of the vasa vasorum connecting with the lumen of hSV and the anti-ischaemic impact of this microvessel network in the hSV used for CABG.

Presence of the matrix metalloproteinases during the migration of the primordial germ cells in zebrafish gonadal ridge.

In vertebrates, the primordial germ cells (PGCs) differentiate from extragonadal regions, migrating to gonadal ridge during the embryonic development. However, recent studies in mammals indicate that the PGCs originate from the epiblast and subsequently migrate into the yolk sac. Cell and molecular bases involved in routes during the migration of these cells are still not well understood. Thus, in an attempt to evaluate the participation of matrix metalloproteinases (MMPs) during the gonadal primordium formation in Danio rerio (zebrafish), the route of migration of PGCs was analyzed. In zebrafish, during the migration of the PGCs to the forming gonad, they bind by cytoplasmic processes to the extracellular matrix and migrate through amoeboid movements until they reach the gonadal ridge. During the epiboly, MMPs were not detected. However, after organogenesis, three MMP types were expressed in the somatic cells that were located ahead of the PGCs in the migration route. This expression was maintained throughout the mesentery and was not detected in the PGCs. Upon reaching the gonadal ridge, the PGCs and somatic cells express MMPs and epithelium begins to be formed. After the formation of the basement membrane, the germinal epithelium is delineated by the somatic cells, which remodeling the extracellular matrix. So, a PGC organization occurs through the tissue, forming the gonadal primordium. Concomitantly, granulocytes expressing different MMPs are present. This data in exposing the role of MMPs during the PGC migration to the forming gonad, may point a new way in understanding the reproductive biology of the vertebrates in general.

A Brief Comment on Vasa Vasorum of Human Saphenous Vein: relevance for Coronary Artery Bypass Surgery.

The importance of the vasa vasorum and blood supply to the wall of human saphenous vein (hSV) used for coronary artery bypass grafting (CABG) is briefly discussed. This is in the context of the possible physical link of the vasa vasorum connecting with the lumen of hSV and the anti-ischaemic impact of this microvessel network in the hSV used for CABG.

Saphenous Vein Vasa Vasorum as a Potential Target for Perivascular Fat-Derived Factors.

Perivascular adipose tissue (PVAT) is a source of factors affecting vasomotor tone with the potential to play a role in the performance of saphenous vein (SV) bypass grafts. As these factors have been described as having constrictor or relaxant effects, they may be considered either beneficial or detrimental. The close proximity of PVAT to the adventitia provides an environment whereby adipose tissue-derived factors may affect the vasa vasorum, a microvascular network providing the vessel wall with oxygen and nutrients. Since medial ischaemia promotes aspects of graft occlusion the involvement of the PVAT/vasa vasorum axis in vein graft patency should be considered.

Saphenous vein vasa vasorum as a potential target for perivascular fat-derived factors

Abstract Perivascular adipose tissue (PVAT) is a source of factors affecting vasomotor tone with the potential to play a role in the performance of saphenous vein (SV) bypass grafts. As these factors have been described as having constrictor or relaxant effects, they may be considered either beneficial or detrimental. The close proximity of PVAT to the adventitia provides an environment whereby adipose tissue-derived factors may affect the vasa vasorum, a microvascular network providing the vessel wall with oxygen and nutrients. Since medial ischaemia promotes aspects of graft occlusion the involvement of the PVAT/vasa vasorum axis in vein graft patency should be considered.

Rotura de vasa previa en una inserción velamentosa del cordón umbilical / Ruptured vasa previa in a velamentous umbilical cord insertion

RESUMEN La rotura de vasa previa es una afección infrecuente que aparece cuando el cordón umbilical tiene una inserción velamentosa y los vasos fetales desprotegidos, que al carecer de la gelatina de Wharton, discurren a través de las membranas, lo que los hace especialmente vulnerables a la rotura o desgarros. Los factores de riesgo más relevantes son: la gestación gemelar monocorial, las gestaciones conseguidas mediante técnicas de reproducción asistida y las anomalías de inserción placentaria. La rotura de la vasa previa puede llevar a: una hemorragia fetal aguda, un choque hipovolémico, una asfixia fetal y a la muerte perinatal. El estudio ecográfico de la placenta y el empleo del Doppler color tienen gran importancia para lograr el diagnóstico precoz de las pacientes en riesgo, el cual constituye la premisa fundamental para lograr disminuir la morbilidad y mortalidad fetal y neonatal.

ABSTRACT Ruptured vasa previa is an uncommon condition that appears when the umbilical cord has a velamentous insertion and the unprotected fetal vessels, which, in the absence of Wharton's jelly, run through membranes making them especially vulnerable to rupture or tears. The most relevant risk factors are: monochorionic twin pregnancy, pregnancies achieved through assisted reproductive techniques and abnormal placental cord insertion. Ruptured vasa previa can lead to: acute fetal hemorrhage, hypovolemic shock, fetal asphyxia and perinatal death. The ultrasound study of the placenta and the use of color Doppler ultrasound are of great importance to achieve early diagnosis of patients at risk, which is the fundamental premise to achieve lower fetal and neonatal morbidity and mortality.

Primordial Germ Cell Migration and Histological and Molecular Characterization of Gonadal Differentiation in Pachón Cavefish Astyanax mexicanus.

The genetic regulatory network governing vertebrate gonadal differentiation appears less conserved than previously thought. Here, we investigated the gonadal development of Astyanax mexicanus Pachón cavefish by looking at primordial germ cells (PGCs) migration and proliferation, gonad histology, and gene expression patterns. We showed that PGCs are first detected at the 80% epiboly stage and then reach the gonadal primordium at 1 day post-fertilization (dpf). However, in contrast to the generally described absence of PGCs proliferation during their migration phase, PGCs number in cavefish doubles between early neurula and 8-9 somites stages. Combining both gonadal histology and vasa (germ cell marker) expression patterns, we observed that ovarian and testicular differentiation occurs around 65 dpf in females and 90 dpf in males, respectively, with an important inter-individual variability. The expression patterns of dmrt1, gsdf, and amh revealed a conserved predominant male expression during cavefish gonadal development, but none of the ovarian differentiation genes, i. e., foxl2a, cyp19a1a, and wnt4b displayed an early sexually dimorphic expression, and surprisingly all these genes exhibited predominant expression in adult testes. Altogether, our results lay the foundation for further research on sex determination and differentiation in A. mexicanus and contribute to the emerging picture that the vertebrate sex differentiation downstream regulatory network is less conserved than previously thought, at least in teleost fishes.