Metabolic Syndrome and Cardiac Remodeling Due to Mitochondrial Oxidative Stress Involving Gliflozins and Sirtuins.

PURPOSE OF REVIEW: To address the mechanistic pathways focusing on mitochondria dysfunction, oxidative stress, sirtuins imbalance, and other contributors in patient with metabolic syndrome and cardiovascular disease. Sodium glucose co-transporter type 2 (SGLT-2) inhibitors deeply influence these mechanisms. Recent randomized clinical trials have shown impressive results in improving cardiac function and reducing cardiovascular and renal events. These unexpected results generate the need to deepen our understanding of the molecular mechanisms able to generate these effects to help explain such significant clinical outcomes. RECENT FINDINGS: Cardiovascular disease is highly prevalent among individuals with metabolic syndrome and diabetes. Furthermore, mitochondrial dysfunction is a principal player in its development and persistence, including the consequent cardiac remodeling and events. Another central protagonist is the renin-angiotensin system; the high angiotensin II (Ang II) activity fuel oxidative stress and local inflammatory responses. Additionally, sirtuins decline plays a pivotal role in the process; they enhance oxidative stress by regulating adaptive responses to the cellular environment and interacting with Ang II in many circumstances, including cardiac and vascular remodeling, inflammation, and fibrosis. Fasting and lower mitochondrial energy generation are conditions that substantially reduce most of the mentioned cardiometabolic syndrome disarrangements. In addition, it increases sirtuins levels, and adenosine monophosphate-activated protein kinase (AMPK) signaling stimulates hypoxia-inducible factor-1ß (HIF-1 beta) and favors ketosis. All these effects favor autophagy and mitophagy, clean the cardiac cells with damaged organelles, and reduce oxidative stress and inflammatory response, giving cardiac tissue protection. In this sense, SGLT-2 inhibitors enhance the level of at least four sirtuins, some located in the mitochondria. Moreover, late evidence shows that SLGT-2 inhibitors mimic this protective process, improving mitochondria function, oxidative stress, and inflammation. Considering the previously described protection at the cardiovascular level is necessary to go deeper in the knowledge of the effects of SGLT-2 inhibitors on the mitochondria function. Various of the protective effects these drugs clearly had shown in the trials, and we briefly describe it could depend on sirtuins enhance activity, oxidative stress reduction, inflammatory process attenuation, less interstitial fibrosis, and a consequent better cardiac function. This information could encourage investigating new therapeutic strategies for metabolic syndrome, diabetes, heart and renal failure, and other diseases.

Vitamin D supplementation as a rational pharmacological approach in the COVID-19 pandemic.

The COVID-19 pandemic has reached most of the countries worldwide causing death, which often results from an inflammatory storm associated with severe acute respiratory syndrome (SARS). This has prompted researchers to seek specific novel and definitive treatments urgently. In this context, it is interesting to evaluate the preventive and therapeutic effects of existing pharmacological agents that could be useful. In this regard, vitamin D supplementation, particularly in individuals likely to be deficient, may be a promising option. Vitamin D is a hormone that modulates many of the same inflammatory and oxidative signaling pathways triggered during COVID-19. For example, vitamin D suppresses the actions of the renin-angiotensin system, which has a determining role in the pathophysiology of the inflammatory response related to COVID-19. This paper analyzes the evidence that vitamin D supplementation might be a valuable preventive/therapeutic measure in groups at risk for or infected with COVID-19. It also discusses how clinical studies could be best designed to evaluate the possible advantages of vitamin D supplementation for the benefit of public health during the pandemic.

Blood pressure control is not enough to normalize endothelial repair by progenitor cells.

Patients presenting with classical cardiovascular risk factors within acceptable or average value ranges often develop cardiovascular disease, suggesting that other risk factors need to be considered. Considering that endothelial progenitor cells (EPCs) contribute to endothelial repair, we investigated whether EPCs might be such a factor. We compared the ability of peripheral blood EPCs to attach to extracellular matrix proteins and to grow and function in culture, between controlled hypertensive patients exhibiting a Framingham score (FS) of <10% while showing severe vascular impairment (intima-media thickness/diameter, carotid-femoral pulse wave velocity, brachial artery flow-mediated dilation, carotid and femoral atherosclerotic plaque presence; vulnerable group, N = 30) and those with an FS of ≥10% and scarce vascular changes (protected group, N = 30). When compared with vulnerable patients, protected patients had significantly higher early and late-EPC and early and late-tunneling nanotube (TNT) numbers. Significant negative associations were found between vascular damage severity and early EPC, late-EPC, or late-TNT numbers, whereas EPC or TNT numbers and patient characteristics or cardiovascular risk factors were not associated. Except for protected patients, in all controlled hypertensive patients, early and late-EPC and early and late-TNT counts were significantly lower than those in the normotensive subjects studied (N = 30). We found that the disparity in vascular status between patients presenting with both an FS of ≥10% and scarce vascular changes and those presenting with both an FS of <10% and severe vascular impairment is related to differences in peripheral blood EPC and TNT numbers. These observations support the role of EPCs as contributors to vascular injury repair and suggest that EPC numbers may be a potential cardiovascular risk factor to be included in the FS calculation.NEW & NOTEWORTHY As individuals who present with risk factors within acceptable or average value ranges often develop cardiovascular (CV) disease, it has been suggested that other CV risk factors need to be considered in addition to those that are commonly combined in the Framingham score (FS) to estimate the risk of general CV disease. We investigated whether peripheral endothelial progenitor cells (EPCs) and tunneling nanotubes (TNTs) deserve to be considered. Here we report that EPCs and TNTs are significantly lower in controlled hypertensive patients versus normotensive subjects and that the disparity in vascular status between patients presenting with an FS of ≥10% with scarce vascular changes and those presenting with an FS of <10% with severe vascular impairment is related to differences in EPC and TNT numbers. These data point to EPC and TNT numbers as potential CV risk factors to be included in the FS calculation.

Angiotensin II blockade: how its molecular targets may signal to mitochondria and slow aging. Coincidences with calorie restriction and mTOR inhibition.

Caloric restriction (CR), renin angiotensin system blockade (RAS-bl), and rapamycin-mediated mechanistic target of rapamycin (mTOR) inhibition increase survival and retard aging across species. Previously, we have summarized CR and RAS-bl's converging effects, and the mitochondrial function changes associated with their physiological benefits. mTOR inhibition and enhanced sirtuin and KLOTHO signaling contribute to the benefits of CR in aging. mTORC1/mTORC2 complexes contribute to cell growth and metabolic regulation. Prolonged mTORC1 activation may lead to age-related disease progression; thus, rapamycin-mediated mTOR inhibition and CR may extend lifespan and retard aging through mTORC1 interference. Sirtuins by deacetylating histone and transcription-related proteins modulate signaling and survival pathways and mitochondrial functioning. CR regulates several mammalian sirtuins favoring their role in aging regulation. KLOTHO/fibroblast growth factor 23 (FGF23) contribute to control Ca(2+), phosphate, and vitamin D metabolism, and their dysregulation may participate in age-related disease. Here we review how mTOR inhibition extends lifespan, how KLOTHO functions as an aging suppressor, how sirtuins mediate longevity, how vitamin D loss may contribute to age-related disease, and how they relate to mitochondrial function. Also, we discuss how RAS-bl downregulates mTOR and upregulates KLOTHO, sirtuin, and vitamin D receptor expression, suggesting that at least some of RAS-bl benefits in aging are mediated through the modulation of mTOR, KLOTHO, and sirtuin expression and vitamin D signaling, paralleling CR actions in age retardation. Concluding, the available evidence endorses the idea that RAS-bl is among the interventions that may turn out to provide relief to the spreading issue of age-associated chronic disease.

Sympathetic predominance is associated with impaired endothelial progenitor cells and tunneling nanotubes in controlled-hypertensive patients.

Early endothelial progenitor cells (early EPC) and late EPC are involved in endothelial repair and can rescue damaged endothelial cells by transferring organelles through tunneling nanotubes (TNT). In rodents, EPC mobilization from the bone marrow depends on sympathetic nervous system activity. Indirect evidence suggests a relation between autonomic derangements and human EPC mobilization. We aimed at testing whether hypertension-related autonomic imbalances are associated with EPC impairment. Thirty controlled-essential hypertensive patients [systolic blood pressure/diastolic blood pressure = 130(120-137)/85(61-88) mmHg; 81.8% male] and 20 healthy normotensive subjects [114(107-119)/75(64-79) mmHg; 80% male] were studied. Mononuclear cells were cultured on fibronectin- and collagen-coated dishes for early EPC and late EPC, respectively. Low (LF)- and high (HF)-frequency components of short-term heart rate variability were analyzed during a 5-min rest, an expiration/inspiration maneuver, and a Stroop color-word test. Modulations of cardiac sympathetic and parasympathetic activities were evaluated by LF/HF (%) and HF power (ms(2)), respectively. In controlled-hypertensive patients, the numbers of early EPC, early EPC that emitted TNT, late EPC, and late EPC that emitted TNT were 41, 77, 50, and 88% lower than in normotensive subjects (P < 0.008), respectively. In controlled-hypertensive patients, late EPC number was positively associated with cardiac parasympathetic reserve during the expiration/inspiration maneuver (rho = 0.45, P = 0.031) and early EPC with brachial flow-mediated dilation (rho = 0.655; P = 0.049); also, late TNT number was inversely related to cardiac sympathetic response during the stress test (rho = -0.426, P = 0.045). EPC exposure to epinephrine or norepinephrine showed negative dose-response relationships on cell adhesion to fibronectin and collagen; both catecholamines stimulated early EPC growth, but epinephrine inhibited late EPC growth. In controlled-hypertensive patients, sympathetic overactivity/parasympathetic underactivity were negatively associated with EPC, suggesting that reducing sympathetic/increasing parasympathetic activation might favor endothelial repair.

Renin-angiotensin system inhibitors positively impact on multiple aging regulatory pathways: Could they be used to protect against human aging?

The renin-angiotensin system (RAS)-a classical blood pressure regulator-largely contributes to healthy organ development and function. Besides, RAS activation promotes age-related changes and age-associated diseases, which are attenuated/abolished by RAS-blockade in several mammalian species. RAS-blockers also increase rodent lifespan. In previous work, we discussed how RAS-blockade downregulates mTOR and growth hormone/IGF-1 signaling, and stimulates AMPK activity (together with klotho, sirtuin, and vitamin D-receptor upregulation), and proposed that at least some of RAS-blockade's aging benefits are mediated through regulation of these intermediaries and their signaling to mitochondria. Here, we included RAS-blockade's impact on other aging regulatory pathways, that is, TGF-ß, NF-kB, PI3K, MAPK, PKC, Notch, and Wnt, all of which affect mitochondria. No direct evidence is available on RAS/RAS-blockade-aging regulatory pathway-mitochondria interactions. However, existing results allow to conjecture that RAS-blockers neutralize mitochondrial dysfunction by acting on the discussed pathways. The reviewed evidence led us to propose that the foundation is laid for conducting clinical trials aimed at testing whether angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB)-even at subclinical doses-offer the possibility to live longer and in better health. As ACEi and ARB are low cost and well-tolerated anti-hypertension therapies in use for over 35 years, investigating their administration to attenuate/prevent aging effects seems simple to implement.

Cellular and Mitochondrial Pathways Contribute to SGLT2 Inhibitors-mediated Tissue Protection: Experimental and Clinical Data.

In metabolic syndrome and diabetes, compromised mitochondrial function emerges as a critical driver of cardiovascular disease, fueling its development and persistence, culminating in cardiac remodeling and adverse events. In this context, angiotensin II - the main interlocutor of the renin-angiotensin-aldosterone system - promotes local and systemic oxidative inflammatory processes. To highlight, the low activity/expression of proteins called sirtuins negatively participates in these processes, allowing more significant oxidative imbalance, which impacts cellular and tissue responses, causing tissue damage, inflammation, and cardiac and vascular remodeling. The reduction in energy production of mitochondria has been widely described as a significant element in all types of metabolic disorders. Additionally, high sirtuin levels and AMPK signaling stimulate hypoxia- inducible factor 1 beta and promote ketonemia. Consequently, enhanced autophagy and mitophagy advance through cardiac cells, sweeping away debris and silencing the orchestra of oxidative stress and inflammation, ultimately protecting vulnerable tissue from damage. To highlight and of particular interest, SGLT2 inhibitors (SGLT2i) profoundly influence all these mechanisms. Randomized clinical trials have evidenced a compelling picture of SGLT2i emerging as game-changers, wielding their power to demonstrably improve cardiac function and slash the rates of cardiovascular and renal events. Furthermore, driven by recent evidence, SGLT2i emerge as cellular supermolecules, exerting their beneficial actions to increase mitochondrial efficiency, alleviate oxidative stress, and curb severe inflammation. Its actions strengthen tissues and create a resilient defense against disease. In conclusion, like a treasure chest brimming with untold riches, the influence of SGLT2i on mitochondrial function holds untold potential for cardiovascular health. Unlocking these secrets, like a map guiding adventurers to hidden riches, promises to pave the way for even more potent therapeutic strategies.

Sodium-glucose cotransporter-2 inhibitors protect tissues via cellular and mitochondrial pathways: Experimental and clinical evidence.

Mitochondrial dysfunction is a key driver of cardiovascular disease (CVD) in metabolic syndrome and diabetes. This dysfunction promotes the production of reactive oxygen species (ROS), which cause oxidative stress and inflammation. Angiotensin II, the main mediator of the renin-angiotensin-aldosterone system, also contributes to CVD by promoting ROS production. Reduced activity of sirtuins (SIRTs), a family of proteins that regulate cellular metabolism, also worsens oxidative stress. Reduction of energy production by mitochondria is a common feature of all metabolic disorders. High SIRT levels and 5' adenosine monophosphate-activated protein kinase signaling stimulate hypoxia-inducible factor 1 beta, which promotes ketosis. Ketosis, in turn, increases autophagy and mitophagy, processes that clear cells of debris and protect against damage. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), a class of drugs used to treat type 2 diabetes, have a beneficial effect on these mechanisms. Randomized clinical trials have shown that SGLT2i improves cardiac function and reduces the rate of cardiovascular and renal events. SGLT2i also increase mitochondrial efficiency, reduce oxidative stress and inflammation, and strengthen tissues. These findings suggest that SGLT2i hold great potential for the treatment of CVD. Furthermore, they are proposed as anti-aging drugs; however, rigorous research is needed to validate these preliminary findings.

The world pandemic of vitamin D deficiency could possibly be explained by cellular inflammatory response activity induced by the renin-angiotensin system.

This review attempts to show that there may be a relationship between inflammatory processes induced by chronic overstimulation of the renin-angiotensin system (RAS) and the worldwide deficiency of vitamin D (VitD) and that both disorders are probably associated with environmental factors. Low VitD levels represent a risk factor for several apparently different diseases, such as infectious, autoimmune, neurodegenerative, and cardiovascular diseases, as well as diabetes, osteoporosis, and cancer. Moreover, VitD insufficiency seems to predispose to hypertension, metabolic syndrome, left ventricular hypertrophy, heart failure, and chronic vascular inflammation. On the other hand, inappropriate stimulation of the RAS has also been associated with the pathogenesis of hypertension, heart attack, stroke, and hypertrophy of the left ventricle and vascular smooth muscle cells. Because VitD receptors (VDRs) and RAS receptors are almost distributed in the same tissues, a possible link between VitD and the RAS is even more plausible. Furthermore, from an evolutionary point of view, both systems were developed simultaneously, actively participating in the regulation of inflammatory and immunological mechanisms. Changes in RAS activity and activation of the VDR seem to be inversely related; thus any changes in one of these systems would have a completely opposite effect on the other, making it possible to speculate that the two systems could have a feedback relationship. In fact, the pandemic of VitD deficiency could be the other face of increased RAS activity, which probably causes lower activity or lower levels of VitD. Finally, from a therapeutic point of view, the combination of RAS blockade and VDR stimulation appears to be more effective than either RAS blockade or VDR stimulation individually.

[Renal effects of GLP-1 agonists in type 2 diabetes]. / Efectos renales de los agonistas GLP-1 en la diabetes tipo 2.

The prevalence of type 2 diabetes mellitus (DM2) is increasing, generating a great impact both at individual and public health level. Nearly half of the patients with DM2 develop impaired renal function, so nephron-protection is highly important. The robust body of evidence that shifted the therapeutic focus from glycemic to cardio-renal metabolic therapy in DM2 led to the inclusion of new therapies with cardiovascular and renal benefits in international guidelines. Type 1 glucagon (GLP-1) receptor agonists have showed favorable effects on renal function and their potential protective actions are multifactorial, beyond glycemic control. These benefits have been demonstrated in efficacy and safety clinical studies, as well as in cardiovascular outcomes and real-life studies. This comprehensive review describes the direct and indirect effects of these molecules, as well as evidence obtained from pivotal clinical (LEADER, SUSTAIN 6 and REWIND) and real-life studies demonstrating their beneficial effects on renal function, and also introduces expectations of future results from ongoing studies with renal endpoints.

La prevalencia de diabetes mellitus tipo 2 (DM2) está en aumento, generando un gran impacto tanto a nivel individual como en salud pública. Cerca de la mitad de los pacientes con DM2 sufren un deterioro de la función renal, por esto la nefroprotección resulta de fundamental importancia. El conjunto de evidencia que cambió del enfoque terapéutico glucocéntrico al cardiorrenometabólico en la DM2 motivó la inclusión en las recomendaciones internacionales de nuevas terapias con beneficios cardiovasculares y renales. Los agonistas del receptor del péptido similar al glucagón tipo 1 (GLP-1) tienen efectos favorables sobre la función renal y sus posibles acciones protectoras son multifactoriales, más allá del control glucémico. Estos beneficios han sido demostrados en los estudios clínicos de eficacia y seguridad, así como también en los estudios de resultados cardiovasculares y de vida real. En esta revisión narrativa se describen los efectos directos e indirectos de estas moléculas, así como su evidencia en los principales estudios clínicos (LEADER, SUSTAIN 6 y REWIND) y de vida real que demuestran sus efectos beneficiosos sobre la función renal e introduce la expectativa de los resultados futuros de los estudios en curso con objetivos renales.

High-dose vitamin D versus placebo to prevent complications in COVID-19 patients: Multicentre randomized controlled clinical trial.

BACKGROUND: The role of oral vitamin D3 supplementation for hospitalized patients with COVID-19 remains to be determined. The study was aimed to evaluate whether vitamin D3 supplementation could prevent respiratory worsening among hospitalized patients with COVID-19. METHODS AND FINDINGS: We designed a multicentre, randomized, double-blind, sequential, placebo-controlled clinical trial. The study was conducted in 17 second and third level hospitals, located in four provinces of Argentina, from 14 August 2020 to 22 June 2021. We enrolled 218 adult patients, hospitalized in general wards with SARS-CoV-2 confirmed infection, mild-to-moderate COVID-19 and risk factors for disease progression. Participants were randomized to a single oral dose of 500 000 IU of vitamin D3 or matching placebo. Randomization ratio was 1:1, with permuted blocks and stratified for study site, diabetes and age (≤60 vs >60 years). The primary outcome was the change in the respiratory Sepsis related Organ Failure Assessment score between baseline and the highest value recorded up to day 7. Secondary outcomes included the length of hospital stay; intensive care unit admission; and in-hospital mortality. Overall, 115 participants were assigned to vitamin D3 and 105 to placebo (mean [SD] age, 59.1 [10.7] years; 103 [47.2%] women). There were no significant differences in the primary outcome between groups (median [IQR] 0.0 [0.0-1.0] vs 0.0 [0.0-1.0], for vitamin D3 and placebo, respectively; p = 0.925). Median [IQR] length of hospital stay was not significantly different between vitamin D3 group (6.0 [4.0-9.0] days) and placebo group (6.0 [4.0-10.0] days; p = 0.632). There were no significant differences for intensive care unit admissions (7.8% vs 10.7%; RR 0.73; 95% CI 0.32 to 1.70; p = 0.622), or in-hospital mortality (4.3% vs 1.9%; RR 2.24; 95% CI 0.44 to 11.29; p = 0.451). There were no significant differences in serious adverse events (vitamin D3 = 14.8%, placebo = 11.7%). CONCLUSIONS: Among hospitalized patients with mild-to-moderate COVID-19 and risk factors, a single high oral dose of vitamin D3 as compared with placebo, did not prevent the respiratory worsening. TRIAL REGISTRATION: ClincicalTrials.gov Identifier: NCT04411446.

Chronic Kidney Disease and Arterial Stiffness: A Two-Way Path.

The kidney-heart relationship has raised interest for the medical population since its vast and complex interaction significantly impacts health. Chronic kidney disease (CKD) generates vascular structure and function changes, with significant hemodynamic effects. The early arterial stiffening in CKD patients is a consequence of the interaction between oxidative stress and chronic vascular inflammation, leading to an accelerated deterioration of left ventricular function and alteration in tissue perfusion. CKD amplifies the inflammatory cascade's activation and is responsible for altering the endothelium function, increasing the vascular tone, wall thickening, and favors calcium deposits in the arterial wall. Simultaneously, the autonomic imbalance, and alteration in other hormonal systems, also favor the overactivation of inflammatory and fibrotic mediators. Thus, hormonal disarrangement also contributes to structural and functional lesions throughout the arterial wall. On the other hand, a rise in arterial stiffening and volume overload generates high left ventricular afterload. It increases the left ventricular burden with consequent myocardial remodeling, development of left ventricular hypertrophy and, in turn, heart failure. It is noteworthy that reduction in glomerular mass of renal diseases generates a compensatory glomerular filtration overdriven associated with large-arteries stiffness and high cardiovascular events. Furthermore, we consider that the consequent alterations of the arterial system's mechanical properties are crucial for altering tissue perfusion, mainly in low resistance. Thus, increasing the knowledge of these processes may help the reader to integrate them from a pathophysiological perspective, providing a comprehensive idea of this two-way path between arterial stiffness and renal dysfunction and their impact at the cardiovascular level.

High-dose vitamin D versus placebo to prevent complications in COVID-19 patients: A structured summary of a study protocol for a randomised controlled trial (CARED-TRIAL).

OBJECTIVES: To evaluate whether a single high dose of oral cholecalciferol improves the respiratory outcomes as compared with placebo among adults COVID-19 patients at moderate risk of clinical complications. TRIAL DESIGN: The CARED trial is an investigator-initiated, multicentre, randomized, parallel, two-arm, sequential, double-blind and placebo-controlled clinical trial. It was planned as a pragmatic trial since the inclusion criteria are broad and the study procedures are as simple as possible, in order to be implemented in the routine clinical practice in general wards in the pandemic setting and a middle-income country context. The sequential design involves two stages. The first stage will assess the effects of vitamin D supplementation on blood oxygenation (physiological effects). The second stage will assess the effects on clinical outcomes. PARTICIPANTS: Participants of either gender admitted to general adult wards in 21 hospital sites located in four provinces of Argentina are invited to participate in the study if they meet the following inclusion criteria and none of the exclusion criteria: Inclusion criteria SARS-CoV-2 confirmed infection by RT-PCR; Hospital admission at least 24 hours before; Expected hospitalization in the same site ≥24 hours; Oxygen saturation ≥90% (measured by pulse oximetry) breathing ambient air; Age ≥45 years or at least one of the following conditions: ○ Hypertension; ○ Diabetes; ○ At least moderate COPD or asthma; ○ Cardiovascular disease (history of myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting or valve replacement surgery); ○ Body mass index ≥30; Willingness to sign informed consent (online supplementary material 1 and 2). EXCLUSION CRITERIA: Age <18 years; Women in childbearing age; >= 72 hs since current admission; Requirement for a high dose of oxygen (>5 litres/minute) or mechanical ventilation (non-invasive or invasive); History of chronic kidney disease requiring haemodialysis or chronic liver failure; Inability for oral intake. Chronic supplementation with pharmacological vitamin D; Current treatment with anticonvulsants; History of: ○ Sarcoidosis; ○ Malabsorption syndrome; ○ Known hypercalcemia or serum calcium >10.5 mg/dL; Life expectancy <6 months; Known allergy to study medication; Any condition at discretion of investigator impeding to understand the study and give informed consent. INTERVENTION AND COMPARATOR: The intervention consists in a single oral dose of 500.000 IU of commercially available cholecalciferol soft gel capsules (5 capsules of 100.000 IU) or matching placebo MAIN OUTCOMES: The primary outcome for the first stage is the change in the respiratory Sepsis-related Organ Failure Assessment (SOFAr) score between pre-treatment value and the worst value recorded during the first 7 seven days of hospitalization, the death or discharge, whichever occurs first. The SOFAr score measured as the ratio between the pulse oximetry saturation (SpO2) and FiO2 (27, 28) is used instead of the arterial partial pressure of oxygen (PaO2). SOFAr score is a 4-points scale, with higher values indicating deeper respiratory derangement as follows: 1 PaO2 <400; 2 PaO2 <300; 3 PaO2 <200; 4 PaO2 <100. The primary outcome for the second stage is the combined occurrence of requirement ≥40% of FiO2, invasive or non-invasive ventilation, up to 30 days or hospital discharge. RANDOMISATION: A computer-generated random sequence and the treatment assignment is performed through the web-based randomization module available in the electronic data capture system (Castor®). A randomization ratio 1:1, stratified and with permuted blocks was used. Stratification variables were diabetes (yes/no), age (≤60/>60 years) and the site. BLINDING (MASKING): Double-blind was achieved by using placebo soft gel capsules with the same organoleptic properties as the active medication. Central management of the medication is carried out by a pharmacist in charge of packaging the study drug in unblinded fashion, who have no contact with on-site investigators. Medication is packaged in opaque white bottles, each containing five soft gel capsules of the active drug or matching placebo, corresponding to complete individual treatment. Treatment codes are kept under the pharmacist responsibility, and all researchers are unaware of them. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): The first stage is planned to include 200 patients (100 per group), the second stage is planned to include 1064 additional patients. The total sample size is 1264 patients. TRIAL STATUS: Currently the protocol version is the number 1.4 (from October 13th, 2020). The recruitment is ongoing since August 11th, 2020, and the first subject was enrolled on August 14th. Since then, 21 sites located in four provinces of Argentina were initiated, and 167 patients were recruited by January 11th, 2021. We anticipate to finish the recruitment for the first stage in mid-February, 2021, and in August, 2021 for the second stage. TRIAL REGISTRATION: The study protocol is registered in ClinicalTrials.gov (identifier number NCT04411446 ) on June 2, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).

The role of high-fructose corn syrup in metabolic syndrome and hypertension.

Obesity and related diseases are an important and growing health concern in the United States and around the world. Soft drinks and other sugar-sweetened beverages are now the primary sources of added sugars in Americans' diets. The metabolic syndrome is a cluster of common pathologies, including abdominal obesity linked to an excess of visceral fat, fatty liver, insulin resistance, hyperinsulinemia, dyslipidemia, and hypertension. Trends in all of these alterations are related to the consumption of dietary fructose and the introduction of high-fructose corn syrup (HFCS) as a sweetener in soft drinks and other foods. Experimental and clinical evidence suggests a progressive association between HFCS consumption, obesity, and the other injury processes. However, experimental HFCS consumption seems to produce some of the changes associated with metabolic syndrome even without increasing the body weight. Metabolic damage associated with HFCS probably is not limited to obesity-pathway mechanisms.

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection. / El suplemento con altas dosis de vitaminaD podría representar una alternativa promisoria para prevenir o tratar la infección por COVID-19.

Although we lack enough evidence to justify supplementing with vitaminD in the prevention and treatment of COVID-19 infection, it is increasingly feasible that this hypothesis is valid. Two general underlying mechanisms should be considered. One would be the anti-infectious and immunomodulatory action that it exerts by improving intercellular barriers by stimulating innate immunity, as well as by modulating adaptive immunity. Also, vitaminD reduces the production of inflammatory cytokines, such as IL-2 and interferon-gamma (INF-γ). More recently, multiple pleiotropic effects have been demonstrated on the actions of vitaminD at the anti-inflammatory and immunomodulatory level with positive results in studies with influenza, coronavirus, and other respiratory infections. An inverse relationship between serum vitaminD levels and the prevalence of the respiratory infectious disease has been described. Of interest, another mechanistic approach responds to considering the inhibition of the renin-angiotensin-aldosterone system (RAAS), which is exacerbated in COVID-19 infection because the virus binds to the enzyme ACE2, making more angiotensinII available to cause damage. VitaminD inhibits mediators of RAAS - present in all cells of the body - and by inhibiting ACE activity and increasing ACE2, it lowers angiotensinII levels. We present studies with proposals for recommended doses of vitaminD, and although a single guideline is not specified, the possible benefits are promising. Finally, the purpose of this review is to share this idea with health professionals to ignite the debate and call for critical reflection, so that it can contribute to the undertaking of more and better clinical designs to validate the benefits of using high doses of vitaminD for the benefit of public health and especially in times of crisis for COVID-19.

Differences in RAAS/vitamin D linked to genetics and socioeconomic factors could explain the higher mortality rate in African Americans with COVID-19.

COVID-19 is said to be a pandemic that does not distinguish between skin color or ethnic origin. However, data in many parts of the world, especially in the United States, begin to show that there is a sector of society suffering a more significant impact from this pandemic. The Black population is more vulnerable than the White population to infection and death by COVID-19, with hypertension and diabetes mellitus as probable predisposing factors. Over time, multiple disparities have been observed between the health of Black and White populations, associated mainly with socioeconomic inequalities. However, some mechanisms and pathophysiological susceptibilities begin to be elucidated that are related directly to the higher prevalence of multiple diseases in the Black population, including infection and death by COVID-19. Plasma vitamin D levels and evolutionary adaptations of the renin-angiotensin-aldosterone system (RAAS) in Black people differ considerably from those of other races. The role of these factors in the development and progression of hypertension and multiple lung diseases, among them SARS-CoV-2 infection, is well established. In this sense, the present review attempts to elucidate the link between vitamin D and RAAS ethnic disparities and susceptibility to infection and death by COVID-19 in Black people, and suggests possible mechanisms for this susceptibility.

Lungs as target of COVID-19 infection: Protective common molecular mechanisms of vitamin D and melatonin as a new potential synergistic treatment.

COVID-19 pandemic has a high mortality rate and is affecting practically the entire world population. The leading cause of death is severe acute respiratory syndrome as a consequence of exacerbated inflammatory response accompanied by uncontrolled oxidative stress as well as the inflammatory reaction at the lung level. Until now, there is not a specific and definitive treatment for this pathology that worries the world population, especially the older adults who constitute the main risk group. In this context, it results in a particular interest in the evaluation of the efficacy of existing pharmacological agents that may be used for overcoming or attenuating the severity of this pulmonary complication that has ended the lives of many people worldwide. Vitamin D and melatonin could be good options for achieving this aim, taking into account that they have many shared underlying mechanisms that are able to modulate and control the immune adequately and oxidative response against COVID-19 infection, possibly even through a synergistic interaction. The renin-angiotensin system exaltation with consequent inflammatory response has a leading role in the physiopathology of COVID-19 infection; and it may be down-regulated by vitamin D and melatonin in many organs. Therefore, it is also essential to analyze this potential therapeutic association and their relation with RAS as part of this new approach.

Thiazide diuretics do not protect against changes that accompany renal aging.

BACKGROUND: During the normal aging process, changes are produced in renal structure that are indistinguishable from those provoked by uncomplicated elevated arterial pressure. Our objective was to evaluate whether long-term treatment with thiazide diuretics (hydrochlorothiazide [HCT]) prevented the changes that occur during kidney aging. METHODS: Fifty CF1 female mice were divided into 2 groups: control group without treatment and HCT group which received 25 mg/L HCT in their drinking water, after weaning and during their entire existence. Mean arterial pressure (MAP) was evaluated per semester, and proteinuria at end of study. At months 6, 12, 18 and 24 of treatment, 5 animals were sacrificed per group. Aortic blood samples were taken to measure plasma creatinine and urea concentrations. Morphometric analysis of glomeruli measured number per mm(2), diameter, percentage of mesangial area and percentage glomerulosclerosis (%GS). Using immunolabeling with anti- alpha-SM-actin percentage, we evaluated percentage glomerular alpha-SM-actin as a marker for early GS. Through electron microscopy we evaluated podocytes and thickness of the glomerular basement membrane. RESULTS: MAP was lower in the HCT group in all periods, while proteinuria was higher in the HCT group during month 24. Progressive decline in number of glomeruli and %GS was not modified by treatment. Expansion of mesangial matrix and alpha-SM-actin immunolabeling was greater in the HCT group. CONCLUSIONS: GS and loss of renal function are changes produced during aging. Although thiazide diuretics do help reduce arterial pressure, they do not prevent and, furthermore, appear to favor these changes in the normal CF1 mouse.

Zinc deficiency during growth: influence on renal function and morphology.

This study was designed to investigate the effects of moderate zinc deficiency during growth on renal morphology and function in adult life. Weaned male Wistar rats were divided into two groups and fed either a moderately zinc-deficient diet (zinc: 8 mg/kg, n=12) or a control diet (zinc: 30 mg/kg, n=12) for 60 days. We evaluated: renal parameters, NADPH-diaphorase and nitric oxide synthase activity in kidney, renal morphology and apoptotic cells in renal cortex. Zinc-deficient rats showed a decrease in glomerular filtration rate and no changes in sodium and potassium urinary excretion. Zinc deficiency decreased NADPH diaphorase activity in glomeruli and tubular segment of nephrons, and reduced activity of nitric oxide synthase in the renal medulla and cortex, showing that zinc plays an important role in preservation of the renal nitric oxide system. A reduction in nephron number, glomerular capillary area and number of glomerular nuclei in cortical and juxtamedullary areas was observed in zinc deficient kidneys. Sirius red staining and immunostaining for alpha-smooth muscle-actin and collagen III showed no signs of fibrosis in the renal cortex and medulla. An increase in the number of apoptotic cells in distal tubules and cortical collecting ducts neighboring glomeruli and, to a lesser extent, in the glomeruli was observed in zinc deficient rats. The major finding of our study is the emergence of moderate zinc deficiency during growth as a potential nutritional factor related to abnormalities in renal morphology and function that facilitates the development of cardiovascular and renal diseases in adult life.