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Topic Review
ZIKA Virus and Male Infertility
Zika virus (ZIKV) has been reported by several groups as an important virus causing pathological damage in the male reproductive tract. ZIKV can infect and persist in testicular somatic and germ cells, as well as spermatozoa, leading to cell death and testicular atrophy. ZIKV has also been detected in semen samples from ZIKV-infected patients. This has huge implications for human reproduction. Global scientific efforts are being applied to understand the mechanisms related to arboviruses persistency, pathogenesis, and host cellular response to suggest a potential target to develop robust antiviral therapeutics and vaccines. Here, we discuss the cellular modulation of the immunologic and physiologic properties of the male reproductive tract environment caused by arboviruses infection, focusing on ZIKV. We also present an overview of the current vaccine effects and therapeutic targets against ZIKV infection that may impact the testis and male fertility.
  • 782
  • 01 Nov 2020
Topic Review
Zeaxanthin and Lutein Across Life's Taxa
Zeaxanthin and lutein are structural isomers with zeaxanthin possessing a slightly longer system of conjugated double bonds (11) than lutein. Carotenoids also play key roles in light-independent processes, e.g., as gene regulators of human immune function. Carotenoid-derived vitamin A has a well-documented immunoregulatory role and a similar role is emerging for xanthophylls. Xanthophylls may be especially important in opposing non-resolving inflammation that can trigger a plethora of associated inflammatory diseases, disorders, and dysfunctions. Additionally, lutein and zeaxanthin are emerging as candidates for protecting cognitive function across the human lifespan, including attention, memory, learning, and executive functions.
  • 758
  • 28 Apr 2022
Topic Review
Xanthine Oxidoreductase Activities
Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid. XOR is widely distributed throughout living organisms and is highly conserved in prokaryotic, plant, and animal species. XOR activity is very versatile, generating both pro-oxidant (primarily within the cell) and anti-oxidant (primarily in plasma) products.
  • 2.9K
  • 21 Sep 2020
Topic Review
Von Willebrand Factor
The von Willebrand factor (vWF) is a plasma protein that mediates platelet adhesion and leukocyte recruitment to vascular injury sites and carries coagulation factor VIII, a building block of the intrinsic pathway of coagulation. A steep rise in shear rates, which may occur at sites of arterial stenosis and injury, is crucial for unfolding and activation of vWF. The hemostatic activity of vWF is counterbalanced by ADAMTS-13, a vWF-cleaving protease. The presence of ultra-large multimers of vWF in the bloodstream is associated with spontaneous thrombosis, whereas its deficiency leads to bleeding.
  • 994
  • 12 Nov 2020
Topic Review
VO2max Changes of Masters Athletes in Continuing Training
Elite masters endurance athletes are considered models of optimal healthy aging due to the maintenance of high cardiorespiratory fitness (CRF) until old age. Whereas a drop in VO2max in masters athletes has been broadly investigated, the modifying impact of training still remains a matter of debate. Longitudinal observations in masters endurance athletes demonstrated VO2max declines between −5% and −46% per decade that were closely related to changes in training volume.
  • 1.8K
  • 09 Sep 2022
Topic Review
Vitamin D, Oxidative-Stress and Aging
Recent advances in vitamin D research indicate that this vitamin, a secosteroid hormone, has beneficial effects on several body systems other than the musculoskeletal system. Both 25 dihydroxy vitamin D [25(OH)2D] and its active hormonal form, 1,25-dihydroxyvitamin D [1,25(OH)2D] are essential for human physiological functions, including damping down inflammation and the excessive intracellular oxidative stresses. Vitamin D is one of the key controllers of systemic inflammation, oxidative stress and mitochondrial respiratory function, and thus, the aging process in humans. In turn, molecular and cellular actions form 1,25(OH)2D slow down oxidative stress, cell and tissue damage, and the aging process. On the other hand, hypovitaminosis D impairs mitochondrial functions, and enhances oxidative stress and systemic inflammation. The interaction of 1,25(OH)2D with its intracellular receptors modulates vitamin D–dependent gene transcription and activation of vitamin D-responsive elements, which triggers multiple second messenger systems. Thus, it is not surprising that hypovitaminosis D increases the incidence and severity of several age-related common diseases, such as metabolic disorders that are linked to oxidative stress. These include obesity, insulin resistance, type 2 diabetes, hypertension, pregnancy complications, memory disorders, osteoporosis, autoimmune diseases, certain cancers, and systemic inflammatory diseases. Vitamin D adequacy leads to less oxidative stress and improves mitochondrial and endocrine functions, reducing the risks of disorders, such as autoimmunity, infections, metabolic derangements, and impairment of DNA repair; all of this aids a healthy, graceful aging process. Vitamin D is also a potent anti-oxidant that facilitates balanced mitochondrial activities, preventing oxidative stress-related protein oxidation, lipid peroxidation, and DNA damage. New understandings of vitamin D-related advances in metabolomics, transcriptomics, epigenetics, in relation to its ability to control oxidative stress in conjunction with micronutrients, vitamins, and antioxidants, following normalization of serum 25(OH)D and tissue 1,25(OH)2D concentrations, likely to promise cost-effective better clinical outcomes in humans. 
  • 1.7K
  • 29 Oct 2020
Topic Review
Vitamin D, microbiome, and IBD
Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract (GIT), including Crohn’s disease (CD) and ulcerative colitis (UC), which differ in the location and lesion extensions. Both diseases are associated with microbiota dysbiosis, with a reduced population of butyrate-producing species, abnormal inflammatory response, and micronutrient deficiency (e.g., vitamin D hypovitaminosis). Vitamin D (VitD) is involved in immune cell differentiation, gut microbiota modulation, gene transcription, and barrier integrity. Vitamin D receptor (VDR) regulates the biological actions of the active VitD (1α,25-dihydroxyvitamin D3), and is involved in the genetic, environmental, immune, and microbial aspects of IBD. VitD deficiency is correlated with disease activity and its administration targeting a concentration of 30 ng/mL may have the potential to reduce disease activity. Moreover, VDR regulates functions of T cells and Paneth cells and modulates release of antimicrobial peptides in gut microbiota-host interactions. Meanwhile, beneficial microbial metabolites, e.g., butyrate, upregulate the VDR signaling.
  • 663
  • 31 Jan 2021
Topic Review
Vitamin D against COVID-19
Many studies suggest that vitamin D improves immune function, reducing susceptibility to infection. In contrast, an extensive number of scientific studies highlight its immunosuppressive effects. Thus, it seems that vitamin D supports immune response under physiological conditions, but it also has an active role in autoimmunity prevention. In short, its effects would depend on the immunological situation of the patient.
  • 395
  • 30 Dec 2021
Topic Review
Vitamin C against COVID-19
Vitamin C is a nutrient required as a cofactor for multiple enzymatic reactions, such us norepinephrine biosynthesis, collagen hydroxylation, or amidation of peptide hormones. Additionally, it exerts a wide range of properties that could come in handy for the prevention and treatment of infections, including antioxidant, immunomodulating, as well as antiviral and antithrombotic functions.
  • 390
  • 10 Jan 2022
Topic Review
Vitamin A Transporters in Visual Function
Vitamins are essential compounds obtained through diet that are necessary for normal development and function in an organism. One of the most important vitamins for human physiology is vitamin A, a group of retinoid compounds and carotenoids, which generally function as a mediator for cell growth, differentiation, immunity, and embryonic development, as well as serving as a key component in the phototransduction cycle in the vertebrate retina. 
  • 448
  • 25 Nov 2021
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