NAMPT and NAMPT-controlled NAD Metabolism in Vascular Repair

NAD metabolic therapy in metabolic dysfunction-associated steatotic liver disease: Possible roles of gut microbiota

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly named non-alcoholic fatty liver disease (NAFLD), is induced by alterations of hepatic metabolism. As a critical metabolites function regulator, nicotinamide adenine dinucleotide (NAD) nowadays has been validated to be effective in the treatment of diet-induced murine model of MASLD. Additionally, gut microbiota has been reported to have the potential to prevent MASLD by dietary NAD precursors metabolizing together with mammals. However, the underlying mechanism remains unclear. In this review, we hypothesized that NAD enhancing mitochondrial activity might reshape a specific microbiota signature, and improve MASLD progression demonstrated by fecal microbiota transplantation. Here, this review especially focused on the mechanism of Microbiota-Gut-Liver Axis together with NAD metabolism for the MASLD progress. Notably, we found significant changes in Prevotella associated with NAD in a gut microbiome signature of certain MASLD patients. With the recent researches, we also inferred that Prevotella can not only regulate the level of NAD pool by boosting the carbon metabolism, but also play a vital part in regulating the branched-chain amino acid (BCAA)-related fatty acid metabolism pathway. Altogether, our results support the notion that the gut microbiota contribute to the dietary NAD precursors metabolism in MASLD development and the dietary NAD precursors together with certain gut microbiota may be a preventive or therapeutic strategy in MASLD management.

NAMPT mediates PDGF-induced pulmonary arterial smooth muscle cell proliferation by TLR4/NF-κB/PLK4 signaling pathway

Nicotinamide phosphoribosyltransferase (NAMPT), a pleiotropic protein, promotes the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs), which is associated with the genesis and progression of pulmonary arterial hypertension (PAH). NAMPT is highly increased in PAH patient's plasma and highly relevant to PAH severity. The mRNA and protein levels of NAMPT are elevated in PAH animal models. However, the underlying molecular mechanisms how NAMPT mediated platelet-derived growth factor (PDGF)-induced PASMCs proliferation are still unclear. The present study aimed to address these issues. Primary cultured PASMCs were attained from male Sprague-Dawley (SD) rats. Western blotting, RT-PCR, ELISA, cell transfection, Cell Counting Kit-8 (CCK-8) and EdU incorporation assays were used in the experiments. We showed that PDGF upregulated NAMPT expression through the activation of signal transducers and activators of transcription 5 (STAT5), and elevated extracellular NAMPT further promoted the activation of NF-κB through Toll-like receptor 4 (TLR4), which ultimately upregulated polo-like kinase 4 (PLK4) expression leading to PASMCs proliferation. Knockdown of STAT5, NAMPT or PLK4, and inhibition of TLR4 or NF-κB suppressed PDGF-induced PASMCs proliferation. Our study suggests that NAMPT plays an essential role in PDGF-induced PASMCs proliferation via TLR4/NF-κB/PLK4 pathway, suggesting that targeting NAMPT might be valuable in ameliorating pulmonary arterial hypertension.

NAD+ Homeostasis and NAD+-Consuming Enzymes: Implications for Vascular Health

Nicotinamide adenine dinucleotide (NAD⁺) is a ubiquitous metabolite that takes part in many key redox reactions. NAD⁺ biosynthesis and NAD⁺-consuming enzymes have been attracting markedly increasing interest since they have been demonstrated to be involved in several crucial biological pathways, impacting genes transcription, cellular signaling, and cell cycle regulation. As a consequence, many pathological conditions are associated with an impairment of intracellular NAD⁺ levels, directly or indirectly, which include cardiovascular diseases, obesity, neurodegenerative diseases, cancer, and aging. In this review, we describe the general pathways involved in the NAD⁺ biosynthesis starting from the different precursors, analyzing the actual state-of-art of the administration of NAD⁺ precursors or blocking NAD⁺-dependent enzymes as strategies to increase the intracellular NAD⁺ levels or to counteract the decline in NAD⁺ levels associated with ageing. Subsequently, we focus on the disease-related and age-related alterations of NAD⁺ homeostasis and NAD⁺-dependent enzymes in endothelium and the consequent vascular dysfunction, which significantly contributes to a wide group of pathological disorders.

Ferroptosis and Autophagy-Related Genes in the Pathogenesis of Ischemic Cardiomyopathy

Background

Obesity plays an important role in type 2 diabetes mellitus (T2DM) and myocardial infarction (MI). Ferroptosis and ferritinophagy are related to metabolic pathways, such as fatty acid metabolism and mitochondrial respiration. We aimed to investigate the ferroptosis- and autophagy-related differentially expressed genes (DEGs) that might be potential targets for MI progression.

Methods

GSE116250 was analyzed to obtain DEGs. A Venn diagram was used to obtain the overlapping ferroptosis- and autophagy-related DEGs. The enrichment pathway analysis was performed and the hub genes were obtained. Pivotal miRNAs, transcription factors, and drugs with the hub genes interactions were also predicted. The MI mice model was constructed, and qPCR analysis and single-cell sequencing were used to validate the hub genes.

Results

Utilizing the limma package and the Venn diagram, 26 ferroptosis-related and 29 autophagy-related DEGs were obtained. The list of ferroptosis-related DEGs was analyzed, which were involved in the cellular response to a toxic substance, cellular oxidant detoxification, and the IL-17 signaling pathway. The list of autophagy-related DEGs was involved in the regulation of autophagy, the regulation of JAK-STAT signaling pathway, and the regulation of MAPK cascade. In the protein-protein interaction network, the hub DEGs, such as IL-6, PTGS2, JUN, NQO1, NOS3, LEPR, NAMPT, CDKN2A, CDKN1A, and Snai1, were obtained. After validation using qPCR analysis in the MI mice model and single-cell sequencing, the 10 hub genes can be the potential targets for MI deterioration.

Conclusion

The screened hub genes, IL-6, PTGS2, JUN, NQO1, NOS3, LEPR, NAMPT, CDKN2A, CDKN1A, and Snai1, may be therapeutic targets for patients with MI and may prevent adverse cardiovascular events.

Dysregulated Immunity in Pulmonary Hypertension: From Companion to Composer

Pulmonary hypertension (PH) represents a grave condition associated with high morbidity and mortality, emphasizing a desperate need for innovative and targeted therapeutic strategies. Cumulative evidence suggests that inflammation and dysregulated immunity interdependently affect maladaptive organ perfusion and congestion as hemodynamic hallmarks of the pathophysiology of PH. The role of altered cellular and humoral immunity in PH gains increasing attention, especially in pulmonary arterial hypertension (PAH), revealing novel mechanistic insights into the underlying immunopathology. Whether these immunophysiological aspects display a universal character and also hold true for other types of PH (e.g., PH associated with left heart disease, PH-LHD), or whether there are unique immunological signatures depending on the underlying cause of disease are points of consideration and discussion. Inflammatory mediators and cellular immune circuits connect the local inflammatory landscape in the lung and heart through inter-organ communication, involving, e.g., the complement system, sphingosine-1-phosphate (S1P), cytokines and subsets of, e.g., monocytes, macrophages, natural killer (NK) cells, dendritic cells (DCs), and T- and B-lymphocytes with distinct and organ-specific pro- and anti-inflammatory functions in homeostasis and disease. Perivascular macrophage expansion and monocyte recruitment have been proposed as key pathogenic drivers of vascular remodeling, the principal pathological mechanism in PAH, pinpointing toward future directions of anti-inflammatory therapeutic strategies. Moreover, different B- and T-effector cells as well as DCs may play an important role in the pathophysiology of PH as an imbalance of T-helper-17-cells (T_H17) activated by monocyte-derived DCs, a potentially protective role of regulatory T-cells (T_reg) and autoantibody-producing plasma cells occur in diverse PH animal models and human PH. This article highlights novel aspects of the innate and adaptive immunity and their interaction as disease mediators of PH and its specific subtypes, noticeable inflammatory mediators and summarizes therapeutic targets and strategies arising thereby.

Therapeutic Potential of Emerging NAD+-Increasing Strategies for Cardiovascular Diseases

Cardiovascular diseases are the leading cause of death worldwide. Aging and/or metabolic stress directly impact the cardiovascular system. Over the last few years, the contributions of altered nicotinamide adenine dinucleotide (NAD+) metabolism to aging and other pathological conditions closely related to cardiovascular diseases have been intensively investigated. NAD+ bioavailability decreases with age and cardiometabolic conditions in several mammalian tissues. Compelling data suggest that declining tissue NAD+ is commonly related to mitochondrial dysfunction and might be considered as a therapeutic target. Thus, NAD+ replenishment by either genetic or natural dietary NAD+-increasing strategies has been recently demonstrated to be effective for improving the pathophysiology of cardiac and vascular health in different experimental models, as well as human health, to a lesser extent. Here, we review and discuss recent experimental evidence illustrating that increasing NAD+ bioavailability, particularly by the use of natural NAD+ precursors, may offer hope for new therapeutic strategies to prevent and treat cardiovascular diseases.

Identification of feature autophagy-related genes in patients with acute myocardial infarction based on bioinformatics analyses

Objective: To identify feature autophagy-related genes (ARGs) in patients with acute myocardial infarction (AMI) and further investigate their value in the diagnosis of AMI.

Methods: Gene microarray expression data of AMI peripheral blood samples were downloaded from the GSE66360 dataset. The data were randomly classified into a discovery cohort (21 AMI patients and 22 healthy controls) and a validation cohort (28 AMI patients and 28 healthy controls). Differentially expressed ARGs between patients with AMI and healthy controls in the discovery cohort were identified using a statistical software package. Feature ARGs were screened based on support vector machine-recursive feature elimination (SVM-RFE), and an SVM classifier was constructed. Receiver operating characteristic (ROC) analysis was used to investigate the predictive value of the classifier, which was further verified in an independent external cohort.

Results: A total of seven genes were identified based on SVM-RFE. The SVM classifier had an excellent discrimination ability in both the discovery cohort (area under the curve [AUC] = 0.968) and the validation cohort (AUC = 0.992), which was further confirmed in the GSE48060 dataset (AUC = 0.963). Furthermore, the SVM classifier showed outstanding discrimination between AMI patients with and without recurrent events in the independent external cohort (AUC = 0.992). The identified genes are mainly involved in the cellular response to autophagy, macroautophagy, apoptosis, and the FoxO signaling pathway.

Conclusion: Our study identified feature ARGs and indicated their potential roles in AMI diagnosis to improve our understanding of the molecular mechanism underlying the occurrence of AMI.

Lipopolysaccharide-Induced Microglial Neuroinflammation: Attenuation by FK866

Alleviating microglia-mediated neuroinflammation bears great promise to reduce neurodegeneration. Nicotinamide phosphoribosyltransferase (NAMPT) may exert cytokine-like effect in the brain. However, it remains unclear about role of NAMPT in microglial inflammation. Also, it remains unknown about effect of NAMPT inhibition on microglial inflammation. In the present study, we observed that FK866 (a specific noncompetitive NAMPT inhibitor) dose-dependently inhibited lipopolysaccharide (LPS)-induced proinflammatory mediator (interleukin (IL)-6, IL-1β, inducible nitric oxide synthase, nitric oxide and reactive species) level increase in BV2 microglia cultures. FK866 also significantly inhibited LPS-induced polarization change in microglia. Furthermore, LPS significantly increased NAMPT expression and nuclear factor kappa B (NF-κB) phosphorylation in microglia. FK866 significantly decreased NAMPT expression and NF-κB phosphorylation in LPS-treated microglia. Finally, conditioned medium from microglia cultures co-treated with FK866 and LPS significantly increased SH-SY5Y and PC12 cell viability compared with conditioned medium from microglia cultures treated with LPS alone. Our study strongly indicates that NAMPT may be a promising target for microglia modulation and NAMPT inhibition may attenuate microglial inflammation.

Nicotinamide mononucleotide (NMN) protects bEnd.3 cells against H2 O2 -induced damage via NAMPT and the NF-κB p65 signalling pathway

An increasing number of studies have shown that nicotinamide mononucleotide (NMN) can inhibit not only ageing but also oxidative stress and inflammatory reactions by improving energy metabolism. However, the role of NMN in regulating the anti‐apoptotic, antioxidative stress and inflammatory responses of brain microvascular endothelial cells is still unknown. Therefore, here we studied the effects of NMN on H₂O₂‐induced oxidative damage of bEnd.3 cells. In this study, we found that NMN could inhibit the NF‐κBp65 inflammatory signalling pathway and increase the expression of the enzymes NAMPT, VEGF and eNOS, alleviating H₂O₂‐induced apoptosis in bEnd.3 cells. Taken together, these results suggest that NMN reduces H₂O₂‐induced oxidative stress and apoptosis and improves cell functions by inhibiting the NF‐κBp65 inflammatory pathway and increasing NAMPT expression.

CTRP13 Mitigates Abdominal Aortic Aneurysm Formation via NAMPT1

Abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease characterized by localized dilation of the abdominal aorta. C1q/tumor necrosis factor (TNF)-related protein-13 (CTRP13) is a secreted adipokine that plays important roles in the cardiovascular system. However, the functional role of CTRP13 in the formation and development of AAA has yet to be explored. In this study, we determined that serum CTRP13 levels were significantly downregulated in blood samples from patients with AAA and in rodent AAA models induced by Angiotensin II (Ang II) in ApoE^-/- mice or by CaCl₂ in C57BL/6J mice. Using two distinct murine models of AAA, CTRP13 was shown to effectively reduce the incidence and severity of AAA in conjunction with reduced aortic macrophage infiltration, expression of proinflammatory cytokines (interleukin-6 [IL-6], TNF-α, and monocyte chemoattractant protein 1 [MCP-1]), and vascular smooth muscle cell (SMC) apoptosis. Mechanistically, nicotinamide phosphoribosyl-transferase 1 (NAMPT1) was identified as a new target of CTRP13. The decreased in vivo and in vitro expression of NAMPT1 was markedly reversed by CTRP13 supplementation in a ubiquitination-proteasome-dependent manner. NAMPT1 knockdown further blocked the beneficial effects of CTRP13 on vascular inflammation and SMC apoptosis. Overall, our study reveals that CTRP13 management may be an effective treatment for preventing AAA formation.

Crucial transcripts predict response to initial immunoglobulin treatment in acute Kawasaki disease

Although intravenous immunoglobulin (IVIG) can effectively treat Kawasaki disease (KD), 10–20% of KD patients show no beneficial clinical response. Developing reliable criteria to discriminate non-responders is important for early planning of appropriate regimens. To predict the non-responders before IVIG treatment, gene expression dataset of 110 responders and 61 non-responders was obtained from Gene Expression Omnibus. After weighted gene co-expression network analysis, we found that modules positively correlated with the non-responders were mainly associated with myeloid cell activation. Transcripts up-regulated in the non-responders, IL1R2, GK, HK3, C5orf32, CXCL16, NAMPT and EMILIN2, were proven to play key roles via interaction with other transcripts in co-expression network. The crucial transcripts may affect the clinical response to IVIG treatment in acute KD. And these transcripts may serve as biomarkers and therapeutic targets for precise diagnosis and treatment of the non-responders.

Genetic variation contributes to gene expression response in ischemic stroke: an eQTL study

Objective

Single nucleotide polymorphisms (SNPs) contribute to complex disorders such as ischemic stroke (IS). Since SNPs could affect IS by altering gene expression, we studied the association of common SNPs with changes in mRNA expression (i.e. expression quantitative trait loci; eQTL) in blood after IS.

Methods

RNA and DNA were isolated from 137 patients with acute IS and 138 vascular risk factor controls (VRFC). Gene expression was measured using Affymetrix HTA 2.0 microarrays and SNP variants were assessed with Axiom Biobank Genotyping microarrays. A linear model with a genotype (SNP) × diagnosis (IS and VRFC) interaction term was fit for each SNP‐gene pair.

Results

The eQTL interaction analysis revealed significant genotype × diagnosis interaction for four SNP‐gene pairs as cis‐eQTL and 70 SNP‐gene pairs as trans‐eQTL. Cis‐eQTL involved in the inflammatory response to IS included rs56348411 which correlated with neurogranin expression (NRGN), rs78046578 which correlated with CXCL10 expression, rs975903 which correlated with SMAD4 expression, and rs62299879 which correlated with CD38 expression. These four genes are important in regulating inflammatory response and BBB stabilization. SNP rs148791848 was a strong trans‐eQTL for anosmin‐1 (ANOS1) which is involved in neural cell adhesion and axonal migration and may be important after stroke.

Interpretation

This study highlights the contribution of genetic variation to regulating gene expression following IS. Specific inflammatory response to stroke is at least partially influenced by genetic variation. This has implications for progressing toward personalized treatment strategies. Additional research is required to investigate these genes as therapeutic targets.

Metabolic regulation of endothelial SK channels and human coronary microvascular function

BACKGROUND

Diabetic (DM) inactivation of small conductance calcium-activated potassium (SK) channels contributes to coronary endothelial dysfunction. However, the mechanisms responsible for this down-regulation of endothelial SK channels are poorly understood. Thus, we hypothesized that the altered metabolic signaling in diabetes regulates endothelial SK channels and human coronary microvascular function.

METHODS

Human atrial tissue, coronary arterioles and coronary artery endothelial cells (HCAECs) obtained from DM and non-diabetic (ND) patients (n = 12/group) undergoing cardiac surgery were used to analyze metabolic alterations, endothelial SK channel function, coronary microvascular reactivity and SK gene/protein expression/localization.

RESULTS

The relaxation response of DM coronary arterioles to the selective SK channel activator SKA-31 and calcium ionophore A23187 was significantly decreased compared to that of ND arterioles (p < 0.05). Diabetes increases the level of NADH and the NADH/NAD+ ratio in human myocardium and HCAECs (p < 0.05). Increase in intracellular NADH (100 μM) in the HCAECs caused a significant decrease in endothelial SK channel currents (p < 0.05), whereas, intracellular application of NAD+ (500 μM) increased the endothelial SK channel currents (p < 0.05). Mitochondrial reactive oxygen species (mROS) of HCAECs and NADPH oxidase (NOX) and PKC protein expression in the human myocardium and coronary microvasculature were increased respectively (p < 0.05).

CONCLUSIONS

Diabetes is associated with metabolic changes in the human myocardium, coronary microvasculature and HCAECs. Endothelial SK channel function is regulated by the metabolite pyridine nucleotides, NADH and NAD+, suggesting that metabolic regulation of endothelial SK channels may contribute to coronary endothelial dysfunction in the DM patients with diabetes.

Nicotinamide phosphoribosyltransferase postpones rat bone marrow mesenchymal stem cell senescence by mediating NAD+-Sirt1 signaling

In vitro replicative senescence affects MSC characteristics and functionality, thus severely restricting their application in regenerative medicine and MSC-based therapies. Previously, we found that MSC natural senescence is accompanied by altered intracellular nicotinamide adenine dinucleotide (NAD⁺) metabolism, in which Nampt plays a key role. However, whether Nampt influences MSC replicative senescence is still unclear. Our study showed that Nampt expression is down-regulated during MSC replicative senescence. Nampt depletion via a specific Nampt inhibitor FK866 or Nampt knockdown in early passage MSCs led to enhanced senescence as indicated by senescence-like morphology, reduced proliferation, and adipogenic and osteogenic differentiation, and increased senescence-associated-β-galactosidase activity and the expression of the senescence-associated factor p16^INK4a. Conversely, Nampt overexpression ameliorated senescence-associated phenotypic features in late passage MSCs. Further, Nampt inhibition resulted in reduced intracellular NAD⁺ content, NAD⁺/NADH ratio, and Sirt1 activity, whereas overexpression had the opposite effects. Exogenous intermediates involved in NAD⁺ biosynthesis not only rescued replicative senescent MSCs but also alleviated FK866-induced MSC senescence. Thus, Nampt suppresses MSC senescence via mediating NAD⁺-Sirt1 signaling. This study provides novel mechanistic insights into MSC replicative senescence and a promising strategy for the severe shortage of cells for MSC-based therapies.

Reversal of endothelial dysfunction by nicotinamide mononucleotide via extracellular conversion to nicotinamide riboside

BACKGROUND

Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are effective substrates for NAD synthesis, which may act as vasoprotective agents. Here, we characterize the effects of NMN and NR on endothelial inflammation and dysfunction and test the involvement of CD73 in these effects.

MATERIALS AND METHODS

The effect of NMN and NR on IL1β- or TNFα-induced endothelial inflammation (ICAM1 and vWF expression), intracellular NAD concentration and NAD-related enzyme expression (NAMPT, CD38, CD73), were studied in HAECs. The effect of NMN and NR on angiotensin II-induced impairment of endothelium-dependent vasodilation was analyzed in murine aortic rings. The involvement of CD73 in NMN and NR effects was tested using CD73 inhibitor-AOPCP, or CD73^-/- mice.

RESULTS

24 h-incubation with NMN and NR induced anti-inflammatory effects in HAEC stimulated by IL1β or TNFα, as evidenced by a reduction in ICAM1 and vWF expression. Effects of exogenous NMN but not NR was abrogated in the presence of AOPCP, that efficiently inhibited extracellular endothelial conversion of NMN to NR, without a significant effect on the metabolism of NMN to NA. Surprisingly, intracellular NAD concentration increased in HAEC stimulated by IL1β or TNFα and this effect was associated with upregulation of NAMPT and CD73, whereas changes in CD38 expression were less pronounced. NMN and NR further increased NAD in IL1β-stimulated HAECs and AOPCP diminished NMN-induced increase in NAD, without an effect on NR-induced response. In ex vivo aortic rings stimulated with angiotensin II for 24 h, NO-dependent vasorelaxation induced by acetylcholine was impaired. NMN and NR, both prevented Ang II-induced endothelial dysfunction in the aorta. In aortic rings taken from CD73^-/- mice NMN effect was lost, whereas NR effect was preserved.

CONCLUSION

NMN and NR modulate intracellular NAD content in endothelium, inhibit endothelial inflammation and improve NO-dependent function by CD73-dependent and independent pathways, respectively. Extracellular conversion of NMN to NR by CD73 localized in the luminal surface of endothelial cells represent important vasoprotective mechanisms to maintain intracellular NAD.

lncRNA GAS5/miR-223/NAMPT axis modulates the cell proliferation and senescence of endothelial progenitor cells through PI3K/AKT signaling

Endothelial progenitor cells (EPCs) have been reported to replace the damaged endothelial cells to repair the injured or dead endothelium. However, EPC senescence might lead to the failure in EPC function. Thus, developing an in-depth understanding of the mechanism of EPC senescence might provide novel strategies for related vascular disorders' treatments. Herein, nicotinamide phosphoribosyltransferase (NAMPT) overexpression could increase cell proliferation and suppress cell senescence in EPCs. miR-223 directly bound to the 3'-untranslated region of NAMPT to inhibit its expression, therefore modulating EPC proliferation and senescence through NAMPT and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling. Long noncoding RNA (lncRNA) GAS5 sponges miR-223, consequently downregulating miR-223 expression. GAS5 knockdown inhibited EPC proliferation and promoted senescence. GAS5 might serve as a competing endogenous RNA for miR-223 to counteract miR-223-mediated suppression on NAMPT, thus regulating EPC proliferation and senescence via the PI3K/AKT signaling pathway. In summary, our findings provide a solid experimental basis for understanding the role and mechanism of lncRNA GAS5/miR-223/NAMPT axis in EPC proliferation and senescence.

Metabolic Regulation of Angiogenesis in Diabetes and Aging

Impaired angiogenesis and endothelial dysfunction are hallmarks of diabetes and aging. Clinical efforts at promoting angiogenesis have largely focused on growth factor pathways, with mixed results. Recently, a new repertoire of endothelial intracellular molecules critical to endothelial metabolism has emerged as playing an important role in regulating angiogenesis. This review thus focuses on the emerging importance and therapeutic potential of these proteins and of endothelial bioenergetics in diabetes and aging.

The value of serum visfatin in predicting in-stent restenosis of drug-eluting stents

OBJECTIVE

This study aims to determine the association between serum visfatin level and in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) using drug-eluting stents (DES).

METHODS

A total of 460 patients with stable coronary heart disease who underwent DES placement were included. According to the results of coronary angiography 1year after PCI, 62 patients diagnosed as ISR were enrolled into the ISR group and 398 patients without ISR were recruited into the control group. Baseline clinical data were collected, and serum visfatin level was measured using ELISA method.

RESULTS

The serum visfatin levels before PCI were not different between ISR and control groups (P=0.41). However, visfatin level after PCI in the ISR group was significantly higher than in the control group [(30.2±8.6) ng/ml vs. (22.6±7.9) ng/ml, P<0.01]. In multivariate logistic regression, the independent predictors for ISR included post-procedural visfatin level (odds ratio [OR]: 2.08, 95% confidence interval [CI]: 1.19-3.65), type 2 diabetes (OR: 2.30, 95% CI: 1.10-4.79), reference vessel diameter (OR: 0.79, 95% CI: 0.63-0.98), stent length (OR: 1.52, 95% CI: 1.05-2.21) and stent diameter (OR: 0.67, 95% CI: 0.51-0.88). ROC curve analysis indicated that the area under the curve for post-procedural visfatin in predicting ISR was 0.82 (95% CI: 0.77-0.86), with the optimal cut-off value of 25.9ng/ml showing a sensitivity of 84.0% and a specificity of 69.3%.

CONCLUSION

Increased serum visfatin level after DES placement is independently associated with ISR. Serum visfatin may be useful in the prediction of ISR.

Emerging potential benefits of modulating NAD+ metabolism in cardiovascular disease

Nicotinamide adenine dinucleotide (NAD⁺) and related metabolites are central mediators of fuel oxidation and bioenergetics within cardiomyocytes. Additionally, NAD⁺ is required for the activity of multifunctional enzymes, including sirtuins and poly(ADP-ribose) polymerases that regulate posttranslational modifications, DNA damage responses, and Ca²⁺ signaling. Recent research has indicated that NAD⁺ participates in a multitude of processes dysregulated in cardiovascular diseases. Therefore, supplementation of NAD⁺ precursors, including nicotinamide riboside that boosts or repletes the NAD⁺ metabolome, may be cardioprotective. This review examines the molecular physiology and preclinical data with respect to NAD⁺ precursors in heart failure-related cardiac remodeling, ischemic-reperfusion injury, and arrhythmias. In addition, alternative NAD⁺-boosting strategies and potential systemic effects of NAD⁺ supplementation with implications on cardiovascular health and disease are surveyed.

Nicotinamide Phosphoribosyltransferase in Smooth Muscle Cells Maintains Genome Integrity, Resists Aortic Medial Degeneration, and Is Suppressed in Human Thoracic Aortic Aneurysm Disease

Rationale:

The thoracic aortic wall can degenerate over time with catastrophic consequences. Vascular smooth muscle cells (SMCs) can resist and repair artery damage, but their capacities decline with age and stress. Recently, cellular production of nicotinamide adenine dinucleotide (NAD + ) via nicotinamide phosphoribosyltransferase (Nampt) has emerged as a mediator of cell vitality. However, a role for Nampt in aortic SMCs in vivo is unknown.

Objectives:

To determine whether a Nampt-NAD + control system exists within the aortic media and is required for aortic health.

Methods and Results:

Ascending aortas from patients with dilated aortopathy were immunostained for NAMPT, revealing an inverse relationship between SMC NAMPT content and aortic diameter. To determine whether a Nampt-NAD + control system in SMCs impacts aortic integrity, mice with Nampt -deficient SMCs were generated. SMC- Nampt knockout mice were viable but with mildly dilated aortas that had a 43% reduction in NAD + in the media. Infusion of angiotensin II led to aortic medial hemorrhage and dissection. SMCs were not apoptotic but displayed senescence associated-ß-galactosidase activity and upregulated p16, indicating premature senescence. Furthermore, there was evidence for oxidized DNA lesions, double-strand DNA strand breaks, and pronounced susceptibility to single-strand breakage. This was linked to suppressed poly(ADP-ribose) polymerase-1 activity and was reversible on resupplying NAD + with nicotinamide riboside. Remarkably, we discovered unrepaired DNA strand breaks in SMCs within the human ascending aorta, which were specifically enriched in SMCs with low NAMPT. NAMPT promoter analysis revealed CpG hypermethylation within the dilated human thoracic aorta and in SMCs cultured from these tissues, which inversely correlated with NAMPT expression.

Conclusions:

The aortic media depends on an intrinsic NAD + fueling system to protect against DNA damage and premature SMC senescence, with relevance to human thoracic aortopathy.

Meat Intake and the Dose of Vitamin B3 - Nicotinamide: Cause of the Causes of Disease Transitions, Health Divides, and Health Futures?

Meat and vitamin B3 - nicotinamide - intake was high during hunter-gatherer times. Intake then fell and variances increased during and after the Neolithic agricultural revolution. Health, height, and IQ deteriorated. Low dietary doses are buffered by 'welcoming' gut symbionts and tuberculosis that can supply nicotinamide, but this co-evolved homeostatic metagenomic strategy risks dysbioses and impaired resistance to pathogens. Vitamin B3 deficiency may now be common among the poor billions on a low-meat diet. Disease transitions to non-communicable inflammatory disorders (but longer lives) may be driven by positive 'meat transitions'. High doses of nicotinamide lead to reduced regulatory T cells and immune intolerance. Loss of no longer needed symbiotic 'old friends' compounds immunological over-reactivity to cause allergic and auto-immune diseases. Inhibition of nicotinamide adenine dinucleotide consumers and loss of methyl groups or production of toxins may cause cancers, metabolic toxicity, or neurodegeneration. An optimal dosage of vitamin B3 could lead to better health, but such a preventive approach needs more equitable meat distribution. Some people may require personalised doses depending on genetic make-up or, temporarily, when under stress.

Nicotinamide Phosphoribosyltransferase Promotes Pulmonary Vascular Remodeling and Is a Therapeutic Target in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension is a severe and progressive disease, a hallmark of which is pulmonary vascular remodeling. Nicotinamide phosphoribosyltransferase (NAMPT) is a cytozyme that regulates intracellular nicotinamide adenine dinucleotide levels and cellular redox state, regulates histone deacetylases, promotes cell proliferation, and inhibits apoptosis. We hypothesized that NAMPT promotes pulmonary vascular remodeling and that inhibition of NAMPT could attenuate pulmonary hypertension.

METHODS

Plasma, mRNA, and protein levels of NAMPT were measured in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension and in the lungs of rodent models of pulmonary hypertension. Nampt^+/- mice were exposed to 10% hypoxia and room air for 4 weeks, and the preventive and therapeutic effects of NAMPT inhibition were tested in the monocrotaline and Sugen hypoxia models of pulmonary hypertension. The effects of NAMPT activity on proliferation, migration, apoptosis, and calcium signaling were tested in human pulmonary artery smooth muscle cells.

RESULTS

Plasma and mRNA and protein levels of NAMPT were increased in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension, as well as in lungs of rodent models of pulmonary hypertension. Nampt^+/- mice were protected from hypoxia-mediated pulmonary hypertension. NAMPT activity promoted human pulmonary artery smooth muscle cell proliferation via a paracrine effect. In addition, recombinant NAMPT stimulated human pulmonary artery smooth muscle cell proliferation via enhancement of store-operated calcium entry by enhancing expression of Orai2 and STIM2. Last, inhibition of NAMPT activity attenuated monocrotaline and Sugen hypoxia-induced pulmonary hypertension in rats.

CONCLUSIONS

Our data provide evidence that NAMPT plays a role in pulmonary vascular remodeling and that its inhibition could be a potential therapeutic target for pulmonary arterial hypertension.

Metrnl: a secreted protein with new emerging functions

Secreted proteins play critical roles in physiological and pathological processes and can be used as biomarkers and therapies for aging and disease. Metrnl is a novel secreted protein homologous to the neurotrophin Metrn. But this protein, unlike Metrn that is mainly expressed in the brain, shows a relatively wider distribution in the body with high levels of expression in white adipose tissue and barrier tissues. This protein plays important roles in neural development, white adipose browning and insulin sensitization. Based on its expression and distinct functions, this protein is also called Cometin, Subfatin and Interleukin 39, which refer to its neurotrophic effect, adipokine function and the possible action as a cytokine, respectively. The spectrum of Metrnl functions remains to be determined, and the mechanisms of Metrnl action need to be elucidated. In this review, we focus on the discovery, structural characteristics, expression pattern and physiological functions of Metrnl, which will assist in developing this protein as a new therapeutic target or agent.

Targeting Nicotinamide Phosphoribosyltransferase as a Potential Therapeutic Strategy to Restore Adult Neurogenesis

Adult neurogenesis is the process of generating new neurons throughout life in the olfactory bulb and hippocampus of most mammalian species, which is closely related to aging and disease. Nicotinamide phosphoribosyltransferase (NAMPT), also an adipokine known as visfatin, is the rate-limiting enzyme for mammalian nicotinamide adenine dinucleotide (NAD) salvage synthesis by generating nicotinamide mononucleotide (NMN) from nicotinamide. Recent findings from our laboratory and other laboratories have provided much evidence that NAMPT might serve as a therapeutic target to restore adult neurogenesis. NAMPT-mediated NAD biosynthesis in neural stem/progenitor cells is important for their proliferation, self-renewal, and formation of oligodendrocytes in vivo and in vitro. Therapeutic interventions by the administration of NMN, NAD, or recombinant NAMPT are effective for restoring adult neurogenesis in several neurological diseases. We summarize adult neurogenesis in aging, ischemic stroke, traumatic brain injury, and neurodegenerative disease and review the advances of targeting NAMPT in restoring neurogenesis. Specifically, we provide emphasis on the P7C3 family, a class of proneurogenic compounds that are potential NAMPT activators, which might shed light on future drug development in neurogenesis restoration.