Cardiovascular manifestations secondary to COVID-19: A narrative review.

The coronavirus disease 2019 (COVID-19) pandemic has spread rapidly, becoming a major threat to global health. In addition to having required the adaptation of healthcare workers for almost 2 years, it has been much talked about, both in the media and among the scientific community. Beyond lung damage and respiratory symptoms, the involvement of the cardiovascular system largely explains COVID-19 morbimortality. In this review, we emphasize that cardiovascular involvement is common and is associated with a worse prognosis, and that earlier detection by physicians should lead to better management. First, direct cardiac involvement will be discussed, in the form of COVID-19 myocarditis, then secondary cardiac involvement, such as myocardial injury, myocardial infarction and arrhythmias, will be considered. Finally, worsening of previous cardiovascular disease as a result of COVID-19 will be examined, as well as long-term COVID-19 effects and cardiovascular complications of COVID-19 vaccines.

Rearing in captivity affects spermatogenesis and sperm quality in greater amberjack, Seriola dumerili (Risso, 1810).

The greater amberjack, (Risso, 1810), is a promising candidate for the diversification of European aquaculture production, but inconsistent reproduction in captivity prevents commercial production. Recent studies showed that greater amberjack confined in sea cages exhibited scarce gonad development and early interruption of gametogenic activity during the reproductive season. The aim of the present study was to improve our understanding of the observed impairment of spermatogenesis. Adult wild and captive-reared males were sampled during 3 different phases of the reproductive cycle: early gametogenesis (EARLY; late April to early May), advanced gametogenesis (ADVANCED; late May to early June), and spawning (SPAWNING; late June to July). Spermatogonial stem cells and proliferating germ cells were identified through the immunohistochemical localization of and proliferating cell nuclear antigen, respectively. Apoptotic germ cells were identified throughout the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling method. Sperm quality of captive-reared fish was evaluated using computer-assisted sperm analysis. Captive-reared males exhibited seminiferous lobules of a smaller diameter, a precocious and progressive decrease of spermatogonial mitosis, and a high level of apoptosis at the beginning of the reproductive season, concomitant with a many-fold higher 17ß-estradiol plasma concentration. The motile spermatozoa percentage of captive greater amberjack was lower than in other teleosts, and a drastic decrease of spermatozoa motility duration, velocity, and ATP content occurred along the reproductive season. An abnormal increase of sperm concentration as well as an increase of dead spermatozoa occurred during the SPAWNING phase, probably because of lack of sperm hydration and ejaculation and consequent sperm ageing. The present study demonstrates the extreme susceptibility of greater amberjack to rearing stress and underscores the need for improvement of the rearing and handling procedures to ameliorate gametogenesis dysfunctions in commercial aquaculture production.

The Nme gene family in fish.

The Nme gene family, also known as Nm23 or NDPK, is a very ancient gene family that can be found in all kingdoms of life. In the late eighties, a gene of the Nme family, NME1, was identified as the first metastatic suppressor gene, resulting in a major interest for this family. Due to the complexity of the family, the need for a unified and evolutionary-supported gene nomenclature was recently stressed by the scientific community. Based on a complete evolutionary history study of the gene family in metazoans and vertebrates, a unified nomenclature was recently proposed and accepted by gene nomenclature consortia. In addition to its well-documented role in tumor metastasis, members of the Nme family are also involved in a wide variety of cellular and physiological processes. Available data in non-mammalian species remain, however, scarce with the noticeable exception of Drosophila in which a major role in development was reported. In fish, very few studies have specifically investigated the role of nme genes. Several transcriptomic and proteomic studies have, however, revealed the expression of nme genes in various fish organs and tissues, in mature oocytes, and during embryonic development. Altogether, interest for the Nme gene family in fish is growing and new functions/roles in fish biology are expected to be discovered in the forthcoming years. Here, we briefly review the current knowledge of the Nme family in fish.

GnRHa-mediated stimulation of the reproductive endocrine axis in captive Atlantic bluefin tuna, Thunnus thynnus.

A controlled-release implant loaded with GnRH agonist (GnRHa) was used to induce spawning in Atlantic bluefin tuna (Thunnus thynnus) during two consecutive reproductive seasons. The fish were implanted underwater and sampled between days 2 and 8 after treatment. At the time of GnRHa treatment, females were in full vitellogenesis and males in spermiation. There was a rapid burst of pituitary luteinizing hormone (LH) release at day 2 after treatment in GnRHa-treated fish, and circulating LH remained elevated up to day 8 after treatment. In contrast, control fish had significantly lower levels in the plasma, but higher LH content in the pituitary, as observed in many other cultured fishes that fail to undergo oocyte maturation, ovulation and spawning unless induced by an exogenous GnRHa. Plasma testosterone (T) and 17ß-estradiol (E(2)) were elevated in response to the GnRHa treatment in females, while 11-ketotestosterone (11-KT) but not T was elevated in males. Even though oocyte maturation and ovulation did occur in GnRHa-induced fish, no significant elevations in 17,20ß-dihydroxy-4-pregnen-3-one (17,20ß-P) or 17,20ß,21-trihydroxy-4-pregnen-3-one (20ß-S), in either the free, conjugated or 5ß-reduced,3α-hydroxylated forms was observed in fish sampled within 6 days after treatment. Interestingly, a significant peak in plasma free 17,20ß-P levels occurred in both males and females at day 8 after treatment. Histological sections of the ovaries in these females contained oocytes at the migrating germinal vesicle stage, suggesting the role of this hormone as a maturation-inducing steroid in Atlantic bluefin tuna. In conclusion, the GnRHa implants activated effectively the reproductive endocrine axis in captive Atlantic bluefin tuna broodstocks, through stimulation of sustained elevations in plasma LH, which in turn evoked the synthesis and secretion of the relevant sex steroids leading to gamete maturation and release.

The NME gene family in zebrafish oogenesis and early development.

After the recent report of the expression of several nme genes in the zebrafish gonads, the present study aimed at further analyzing the expression of nme genes in the ovary with special attention for the nme transcripts that are maternally inherited and could thus participate in the determination of oocyte developmental competence. The expression levels of all groups I and II nme genes were characterized by QPCR in a panel of zebrafish tissues. The nme genes exhibiting an ovarian expression were subsequently monitored throughout oogenesis and early development, and their expression sites characterized using in situ hybridization. Here, we show that nme2b1, nme3, nme4, and nme6 are highly expressed in the ovary and present in the zebrafish oocyte throughout oogenesis. While the four transcripts are maternally inherited, nme3 and nme6 display a typical maternal profile and are detected in the zebrafish early embryo. In contrast to nme3, nme6, abundance exhibits a sharp decrease during early embryogenesis. After zygotic genome activation, we observed an increased expression of nme2b1, nme2b2, nme3, and nme6. The present study provides a comprehensive overview of the expression of nme family members during zebrafish oogenesis and early development. In addition, the maternal origin of two nme transcripts in the early embryo is reported here for the first time in any vertebrate species. Together, our observations suggest an important role of the nme family in oocyte and embryo development in vertebrates.

Sea bass Dicentrarchus labrax nervous necrosis virus isolates with distinct pathogenicity to sea bass larvae.

Reproduction of nodavirus disease was performed by experimental infection of sea bass eggs during fertilization or at larval stage 4 with 2 genetically distinguishable nodavirus strains (Sb1 and Sb2) isolated from sea bass collected along the Atlantic and Mediterranean French coast. The pathogenicity of the virus strains was assigned after detection of the virus by ELISA and immunohistochemistry (IHC). The Atlantic (Sb1) strain was more pathogenic than the Mediterranean (Sb2) strain during the fertilization step whilst both strains were pathogenic following experimental exposure of 4 d old larvae. Virus lesions developed in the brain 4 to 6 d following experimental exposure. Experimental ELISA proved very sensitive for detecting the nodavirus in Sb1 or Sb2 experimentally infected larvae, as well as in naturally infected sea bass larvae collected in French hatcheries or in barramundi larvae reared in the Pacific area. The development of an ELISA specific for the 2 nodavirus strains isolated from the sea bass should be useful for the detection of the virus, in addition to other techniques recommended by the Office International des Epizooties (OIE).

Effects of osmolality, morphology perturbations and intracellular nucleotide content during the movement of sea bass (Dicentrarchus labrax) spermatozoa.

Sea bass spermatozoa are maintained immotile in the seminal fluid, but initiate swimming for 45 s at 20 degrees C, immediately after dispersion in a hyperosmotic medium (1100 mOsm kg-1). The duration of this motile period could be extended by a reduction of the amplitude of the hyperosmotic shock. Five seconds after the initiation of motility, 94.4 +/- 1.8% of spermatozoa were motile with a swimming velocity of 141.8 +/- 1.2 microns s-1, a flagellar beat frequency of 60 Hz and a symmetric type of flagellar swimming, resulting in linear tracks. Velocity, flagellar beat frequency, percentage of motile cells and trajectory diameter decreased concomitantly throughout the swimming phase. After 30 s of motility, the flagellar beat became asymmetric, leading to circular trajectories. Ca2+ modulated the swimming pattern of demembranated spermatozoa, suggesting that the asymmetric waves produced by intact spermatozoa after 30 s of motility were induced by an accumulation of intracellular Ca2+. Moreover, increased ionic strength in the reactivation medium induced a dampening of waves in the distal portion of the flagellum and, at high values, resulted in an arrest of wave generation in demembranated spermatozoa. In non-demembranated cells, the intracellular ATP concentration fell immediately after transfer to sea water. In contrast, the AMP content increased during the same period, while the ADP content increased slightly. In addition, several morphological changes affected the mitochondria, chromatin and midpiece. These results indicate that the short swimming period of sea bass spermatozoa is controlled by energetic and cytoplasmic ionic conditions and that it is limited by osmotic stress, which induces marked changes in cell morphology.