Nicotinamide riboside: A promising therapy for MI-induced acute kidney injury by upregulating nicotinamide phosphoribosyltransferase-mediated NAD levels.

Background: Cardiorenal syndrome (CRS) type 1 is characterized by the development of acute kidney injury (AKI) following acute cardiac illness and notably acute myocardial infarction (MI). AKI is considered an independent risk factor increasing mortality rate substantially. Nicotinamide dinucleotide (NAD) is an important coenzyme in energy metabolism and oxidative phosphorylation and in its oxidized form, a substrate for multiple NAD + -dependent enzymes such as Sirtuins and poly-ADP ribose polymerases. Decreased cardiac NAD levels along with a down-regulation of the nicotinamide phosphoribosyl transferase (NAMPT) have been reported following MI. A compensatory upregulation in nicotinamide riboside kinase (NMRK) 2, an NAD + biosynthetic enzyme that uses nicotinamide riboside (NR) to generate NAD + takes place in the heart after MI but the impact on kidney NAD metabolism and function has not been addressed before. Methods: MI was induced by ligating the left anterior descending coronary artery in 2 months old C57BL6/J mice, followed by the administration of NR (IP injection, 400mg/kg/day) for four and seven days. We hypothesized that NR treatment could be a potential promising therapy for MI-induced AKI. Results: Our findings showed no significant improvement in cardiac ejection fraction following NR treatment at days 4 and 7 post-MI, whereas kidney functions were enhanced and morphological alterations and cell death decreased. The observed renal protection seems to be mediated by an up-regulation of NAMPT-mediated increase in renal NAD levels, notably in distal tubules. Conclusion: Our findings indicate that NR could be a potential promising therapy for AKI following an early stage of MI.

Empagliflozin: Primus Inter Pares Among Sodium-Glucose Cotransporter-2 Inhibitors?

ABSTRACT: Sodium/glucose cotransporter-2 (SGLT2) inhibitors are a novel class of antidiabetic medications which have proved capable of providing breakthrough cardiovascular (CV) benefits in a variety of clinical scenarios, including patients with heart failure or obesity, irrespective of diabetic status. Several SGLT2 inhibitors are available, but the most prominent ones are canagliflozin, dapagliflozin, and empagliflozin. Several studies have focused on empagliflozin and its effects on the risk of heart failure incidence and recurrences. Most recently, empagliflozin has been recently tested in patients with recent myocardial infarction in the EMPAgliflozin on Hospitalization for Heart Failure and Mortality in Patients With aCuTe Myocardial Infarction randomized trial, with apparently ambiguous findings. The present viewpoint succinctly illustrates the main features of SGLT2 inhibitors as a pharmacologic class, their ever expanding role as a CV medication, and the comparative effectiveness of different individual SGLT2 inhibitors, explicitly commenting on the recent data on empagliflozin in patients with acute myocardial infarction. The reader will find in this article a poignant perspective on this novel avenue for CV prevention and treatment, which greatly expands the management armamentarium of CV practitioners. Indeed, we make the case that SGLT2 inhibitors have a clearly favorable class effect, with differences between individual agents mainly suitable for personalization of care and minimization of side effects.

Correction: Noureddine et al. Impact of the Renin-Angiotensin System on the Endothelium in Vascular Dementia: Unresolved Issues and Future Perspectives. Int. J. Mol. Sci. 2020, 21, 4268.

The authors would like to make the following correction to the publication dealing with Reference #3 [...].

Caloric Restriction Rejuvenates Skeletal Muscle Growth in Heart Failure With Preserved Ejection Fraction.

Heart failure with preserved ejection fraction (HFpEF) is a major clinical problem, with limited treatments. HFpEF is characterized by a distinct, but poorly understood, skeletal muscle pathology, which could offer an alternative therapeutic target. In a rat model, we identified impaired myonuclear accretion as a mechanism for low myofiber growth in HFpEF following resistance exercise. Acute caloric restriction rescued skeletal muscle pathology in HFpEF, whereas cardiac therapies had no effect. Mechanisms regulating myonuclear accretion were dysregulated in patients with HFpEF. Overall, these findings may have widespread implications in HFpEF, indicating combined dietary with exercise interventions as a beneficial approach to overcome skeletal muscle pathology.

Exploring the Promise and Challenges of Artificial Intelligence in Biomedical Research and Clinical Practice.

ABSTRACT: Artificial intelligence (AI) is poised to revolutionize how science, and biomedical research in particular, are done. With AI, problem-solving and complex tasks using massive data sets can be performed at a much higher rate and dimensionality level compared with humans. With the ability to handle huge data sets and self-learn, AI is already being exploited in drug design, drug repurposing, toxicology, and material identification. AI could also be used in both basic and clinical research in study design, defining outcomes, analyzing data, interpreting findings, and even identifying the most appropriate areas of investigation and funding sources. State-of-the-art AI-based large language models, such as ChatGPT and Perplexity, are positioned to change forever how science is communicated and how scientists interact with one another and their profession, including postpublication appraisal and critique. Like all revolutions, upheaval will follow and not all outcomes can be predicted, necessitating guardrails at the onset, especially to minimize the untoward impact of the many drawbacks of large language models, which include lack of confidentiality, risk of hallucinations, and propagation of mainstream albeit potentially mistaken opinions and perspectives. In this review, we highlight areas of biomedical research that are already being reshaped by AI and how AI is likely to affect it further in the near future. We discuss the potential benefits of AI in biomedical research and address possible risks, some surrounding the creative process, that warrant further reflection.

Potential Alternative Receptors for SARS-CoV-2-Induced Kidney Damage: TLR-4, KIM-1/TIM-1, and CD147.

Kidney damage in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur even in patients with no underlying kidney disease. Signs of kidney problems can progress to a state that demands dialysis and hampering recovery. Although not without controversy, emerging evidence implicates direct infectivity of SARS-CoV-2 in the kidney. At the early stage of the pandemic, consideration was mainly on the well-recognized angiotensin-converting enzyme 2 (ACE2) receptor as being the site for viral interaction and subsequent cellular internalization. Despite the abundance of ACE2 receptors in the kidneys, researchers have expanded beyond ACE2 and identified novel viral entry pathways that could be advantageously explored as therapeutic targets. This review presents the potential involvement of toll-like receptor 4 (TLR-4), kidney injury molecule-1/T cell immunoglobulin mucin domain 1 (KIM-1/TIM-1), and cluster of differentiation 147 (CD147) in SARS-CoV-2-associated renal damage. In this context, we address the unresolved issues surrounding SARS-CoV-2 renal infectivity.

Nicotinamide Riboside Supplementation Restores Myocardial Nicotinamide Adenine Dinucleotide Levels, Improves Survival, and Promotes Protective Environment Post Myocardial Infarction.

AIMS: Myocardial infarction (MI) is a major cause of death. Nicotinamide adenine dinucleotide (NAD+) is a coenzyme in oxidative phosphorylation and substrate of sirtuins and poly-ADP ribose polymerases, enzymes critical for cardiac remodeling post-MI. Decreased NAD+ is reported in several heart failure models with paradoxically an upregulation of nicotinamide riboside kinase 2, which uses nicotinamide riboside (NR) as substrate in an NAD+ biosynthetic pathway. We hypothesized that stimulating nicotinamide riboside kinase 2 pathway by NR supplementation exerts cardioprotective effects. METHODS AND RESULTS: MI was induced by LAD ligation in 2-3-month-old male mice. NR was administered daily (1 µmole/g body weight) over 7 days. RT-PCR showed a 60-fold increase in nicotinamide riboside kinase 2 expression 4 days post-MI with a 60% drop in myocardial NAD+ and overall survival of 61%. NR restored NAD+ levels and improved survival to 92%. Assessment of respiration in cardiac fibers revealed mitochondrial dysfunction post-MI, and NR improved complexes II and IV activities and citrate synthase activity, a measure of mitochondrial content. Additionally, NR reduced elevated PARP1 levels and activated a type 2 cytokine milieu in the damaged heart, consistent with reduced early inflammatory and pro-fibrotic response. CONCLUSION: Our data show that nicotinamide riboside could be useful for MI management.

Assessing the outcomes of prescribing angiotensin converting enzyme inhibitors and angiotensin receptor blockers for COVID-19 patients.

Background: Patients with heart failure were affected severely by COVID-19. Most heart failure patients are on guideline directed medical therapy, which includes ACE inhibitors (ACEI) and ARBs. These medications were controversial at the beginning of the pandemic due to their interplay with the receptor that SARS-CoV-2 binds in the lungs. We investigated the effect that ACEI and ARB had on patients with hypertension, coronary artery disease, and heart failure. Methods: We recruited 176 patients with COVID-19 infection and cardiovascular comorbidities at the American University of Beirut Medical Center in Lebanon. Of these, 110 patients were taking ACEI or ARB and 66 were not. We collected clinical data and looked at inflammatory markers such as CRP and IL-6 and cardiac markers such as troponin T. We also reported the incidence of ARDS, sepsis, and death of each patient, and compared the 2 groups. Results: We found that patients taking ACEI and ARB had a statistically significant decrease in levels of troponin T, IL-6, and CRP compared to patients not taking these medications (p < 0.05). We found no difference in rates of ARDS, sepsis, or death between the 2 groups. Conclusion: Inhibition of the renin-angiotensin-aldosterone-system had no effect on the mortality of patients with COVID-19 and on their overall disease progression. However, it may be beneficial not to stop these medications as they decrease inflammation in the body and the levels of troponin, which are related to increased stress on the heart.

Cooling Down Inflammation in the Cardiovascular System via the Nicotinic Acetylcholine Receptor.

ABSTRACT: Inflammation is a major player in many cardiovascular diseases including hypertension, atherosclerosis, myocardial infarction, and heart failure. In many individuals, these conditions coexist and mutually exacerbate each other's progression. The pathophysiology of these diseases entails the active involvement of both innate and adaptive immune cells. Immune cells that possess the α7 subunit of the nicotinic acetylcholine receptor on their surface have the potential to be targeted through both pharmacological and electrical stimulation of the cholinergic system. The cholinergic system regulates the inflammatory response to various stressors in different organ systems by systematically suppressing spleen-derived monocytes and chemokines and locally improving immune cell function. Research on the cardiovascular system has demonstrated the potential for atheroma plaque stabilization and regression as favorable outcomes. Smaller infarct size and reduced fibrosis have been associated with improved cardiac function and a decrease in adverse cardiac remodeling. Furthermore, enhanced electrical stability of the myocardium can lead to a reduction in the incidence of ventricular tachyarrhythmia. In addition, improving mitochondrial dysfunction and decreasing oxidative stress can result in less myocardial tissue damage caused by reperfusion injury. Restoring baroreflex activity and reduction in renal damage can promote blood pressure regulation and help counteract hypertension. Thus, the present review highlights the potential of nicotinic acetylcholine receptor activation as a natural approach to alleviate the adverse consequences of inflammation in the cardiovascular system.

Inhibiting B cell activating factor attenuates preeclamptic symptoms in placental ischemic rats.

PROBLEM: Preeclampsia (PE), new-onset hypertension during pregnancy, is associated with a pro-inflammatory state with activated T cells, cytolytic natural killer (NK) cells, dysregulated complement proteins, and B cells secreting agonistic autoantibodies to the angiotensin II type-1 receptor (AT1-AA). The reduced uterine perfusion pressure (RUPP) model of placental ischemia recapitulates these features of PE. Blocking CD40L-CD40 communication between T and B cells or B cell depletion with Rituximab prevents hypertension and AT1-AA production in RUPP rats. This suggests that T cell-dependent B cell activation contributes to the hypertension and AT1-AA associated with PE. B2 cells maturing into antibody producing plasma cells are the product of T cell-dependent B cell-interactions and B cell Activating Factor (BAFF) is an integral cytokine in the development of B2 cells specifically. Thus, we hypothesize that BAFF blockade will selectively deplete B2 cells, therefore reducing blood pressure, AT1-AA, activated NK Cells, and complement in the RUPP rat model of PE. METHOD OF STUDY: Gestational Day (GD) 14 pregnant rats underwent the RUPP procedure, and a subset were treated with 1 mg/kg Anti-BAFF antibodies via jugular catheters. On GD19, blood pressure was measured, B cells and NK cells were measured by flow cytometry, AT1-AA was measured by cardiomyocyte bioassay, and complement activation was measured by ELISA. RESULTS: Anti-BAFF therapy attenuated hypertension, AT1-AA, NK cell activation, and APRIL levels in RUPP rats without negatively impacting fetal outcomes. CONCLUSIONS: This study demonstrates that B2 cells contribute to hypertension, AT1-AA, and NK cell activation in response to placental ischemia during pregnancy.

Central role for BRAF in cardiac hypertrophy: rethinking the pathological-physiological divide.

The RAF/MEK/ERK1/2 signaling cascade has been implicated in pathological cardiac hypertrophy downstream of some Gq-coupled receptors. The RAF family of kinases consists of three isoforms (ARAF, BRAF, and CRAF) and until recently most studies on this signaling pathway in the heart have focused on RAF1 (CRAF). In a recent issue of Clinical Science, Alharbi et al. utilized an inducible cardiac myocyte targeted knockout mouse model to define the role of BRAF in pathological versus physiological hypertrophy using angiotensin II and phenylephrine (PE) infusion, respectively. They reported that loss of BRAF attenuated both pathological cardiac hypertrophy and interstitial fibrosis. BRAF knockout decreased cardiac function with PE in male mice and enhanced both interstitial and perivascular cardiac fibrosis but had no effect on hypertrophy. In contrast, loss of BRAF attenuated physiological hypertrophy in female mice but had no effect on fibrosis or contractility. These observations extend those previously made by this group assessing the consequences of expressing an inducible activating mutant of BRAF in the heart and the benefit of enhancing RAF/MEK/ERK1/2 signaling by exploiting the 'RAF paradox'. Additional studies are needed to better define the role of BRAF under conditions reflective of chronic stress on the heart due to the biomechanical stimulation exerted by hypertension. In addition, the role of BRAF and its activation in overt heart failure remains to be established. Nevertheless, the new findings highlight the potential importance of additional signaling events, perhaps related to RAF1 or ERK1/2 activation, in shaping BRAF signaling in a sex- and context-dependent manner.

Risk of thromboembolic events in non-hospitalized COVID-19 patients: A systematic review.

The risk of thromboembolism in non-hospitalized COVID-19 patients remains uncertain and was assessed in this review to better weigh benefits vs. risks of prophylactic anticoagulation in this population. A search was performed through three databases: Medline, Embase, and Cochrane Library until 2022. Self-controlled case series, case-control and cohort studies were included, and findings summarized narratively. Meta-analyses for risk of thromboembolism including deep vein thrombosis (DVT), pulmonary embolism (PE), and myocardial infarction (MI) between COVID-19 and non-COVID-19 non-hospitalized patients were conducted. Frequency, incidence rate ratio (IRR), and risk ratio (RR) of stroke were used to assess risk in non-hospitalized COVID-19 patients considering the lack of studies to conduct a meta-analysis. Ten studies met inclusion criteria characterized by adult non-hospitalized COVID-19 patients. Risk of bias was relatively low. Risk of DVT (RR: 1.98 with 95% CI: 1.03-3.83) and PE (OR: 6.72 with 95% CI: 4.81-9.39 and RR: 4.44 with 95% CI: 1.98-9.99) increased in non-hospitalized COVID-19 patients compared to controls. Risk of MI (OR: 1.91 with 95% CI: 0.89-4.09) is possibly increased in non-hospitalized COVID-19 patients with moderate certainty when compared to controls. A trend in favor of stroke was documented in the first week following infection. Our meta-analyses support the increase in risk of DVT and PE, and likely increase of MI, in non-hospitalized COVID-19 patients. The risk of stroke appears significant in the first week following infection but drops to insignificance two weeks later. More studies are needed to establish evidence-based recommendations for prophylactic anticoagulation therapy in non-hospitalized COVID-19 patients.

Sexual dimorphism in acute myocardial infarction-induced acute kidney injury: cardiorenal deteriorating effects of ovariectomy in premenopausal female mice.

Acute kidney injury (AKI) is a common complication of cardiovascular diseases (CVDs) in both males and females, increasing mortality rate substantially. Premenopausal females appear to be more protected, suggesting a potential protective role of female sex hormones. Here, we tested the hypothesis that ovariectomy (OVX) eliminates the beneficial effect of female sex on renal protection following acute myocardial infarction (MI). Seven days post-MI, both sexes exhibited worsened kidney function and a substantial decrease in total kidney NAD levels. Unlike MI female mice, MI males showed exacerbated morphological alterations with increased proinflammatory, proapoptotic, and profibrotic biomarkers. The expression of NAD+ biosynthetic enzymes NAMPT and NMRK-1 was increased in MI females only, while males showed a substantial increase in NAD+ consuming enzyme PARP-1. OVX did not eliminate the female-sex protection of glomerular morphology but was associated with swelling of proximal convoluted tubules with MI as in males. With OVX, MI females had enhanced proinflammatory cytokine release, and a further decrease in creatinine clearance and urine output was observed. Our findings suggest that MI induced AKI in both sexes with pre-menopausal female mice being more protected. Ovariectomy worsens aspects of AKI in females after MI, which may portend increased risk for development of chronic kidney disease.