NR supplementation blunts Th1 and Th17 immune responsiveness in healthy volunteers and in psoriasis...This study has expanded our understanding of NAD+ boosting in the adaptive immune system with the focus on NR blunting Th17 immune activity...The finding from this study that NR blunts Th1 and Th17 immune responsiveness in an ex vivo study supports that the utilization of NAD+ boosting could potentially be employed as a supplemental therapy in this disease. The concept is now being explored in vivo, where mild to moderate psoriasis patients are being investigated in a placebo-controlled study...

Overall, we show that the increased myelin production that follows NAM treatment in vivo is accompanied by a decrease in both astrocyte and microglia accumulation at the lesion site. Our data indicate that NAM influences astrocytes and microglia directly, in favor of the remyelination process by promoting a less inflammatory environment.

This study demonstrated that...NAD+ metabolism governs the anti-inflammatory function of mesenchymal stem cells during inflammation.

Diabetes mellitus is the leading cause of cardiovascular and renal disease in the United States...Overall, these data show that NR supplementation boosted NAD metabolism to augment mitochondrial function, reducing inflammation and thereby preventing the progression of diabetic kidney disease.

Recent studies have revealed the significant contribution of mitochondrial dysfunction and disrupted energy metabolism to the pathogenesis of osteoarthritis. Impaired mitochondrial function leads to the accumulation of reactive oxygens species, which contribute to cartilage degradation and chondrocyte apoptosis...Compounds capable of modulating mitochondrial metabolism and improving mitochondrial function, such as nicotinamide riboside and pyrroloquinoline quinone, have also been investigated in the context of osteoarthritis. These compounds promote mitochondrial biogenesis, enhance mitochondrial respiration, and reduce oxidative stress and inflammation in chondrocytes, ultimately preserving the integrity of the cartilage matrix...

NAM supplementation prevented brain inflammation and microglial activation inthe brains of diabetic mice.

We report the first study examining [extracellular vesicles enriched for neuronal origin or "NEV"] NEV biomarkers in response to oral NR supplementation. Our primary analysis of NAD+ and NADH in NEVs suggests an increase in neuronal NAD+ concentration in response to oral NR supplementation....We demonstrate that oral NR supplementation [in humans] increases NAD+ levels in NEVs ...These findings support the ability of orally administered NR to augment neuronal NAD+ levels and modify biomarkers related to neurodegenerative pathology in humans.

Mitochondrial dysfunction, insulin resistance, metabolic dysregulation and neuroinflammation that contribute to cognitive decline in Alzheimer's Disease...The findings of this study suggest that SIRT3 is a potential therapeutic target for the treatment of AD. Sirtuins, including SIRT3, require NAD+ as a cosubstrate. Administration of NR, a precursor of NAD+, leads to increase in the cellular level of NAD+. In this study, we demonstrate that NR increases the levels of IDE as well as neprilysin and decreases the levels of BACE1 in vivo. Interestingly, NR also increases the levels of SIRT3, probably by autoregulation. NR has been reported to reverse insulin resistance and glucose intolerance in a mouse model for type 2 diabetes. NR has been shown to be effective in reducing neuroinflammation and improve cognition in Alzheimer’s mouse models. Therefore, NR-based treatment can be considered for the treatment of AD with comorbidities.

...We found that NR supplementation could ameliorate high-fructose-induced lipid metabolism disorder by improving FGF21 resistance in the liver and WAT, which may be related to the regulation of inflammation mediated by the SIRT1/NF-κB signaling pathway.

Our data showed that NR supplementation boosted the NAD metabolism to modulate inflammation and mitochondrial function and prevent progression of diabetic kidney disease.

The objective of this study was to investigate the clinical evidence of NR's mitigation of inflammation in humans. We identified 5 clinical trials of oral NR supplementation that measured inflammation. There was substantial heterogeneity in inflammatory endpoints evaluated. NR dose and treatment duration ranged from 1–2 g/day and 5-d– 6-wks, respectively. Participants varied in age (18–78 years) and health status. In one study, NR was given as part of a nutritional cocktail, while NR was the sole intervention in the remaining studies. Of the 3 studies assessing circulating inflammatory markers, two investigated IL-6 and reported significant reductions in its levels with NR treatment, while effects on MCP-1 and TNF-α were inconsistent. NR significantly lowered gene expression of IL-6 and IL-18, but not NLRP3 or IL-1B in peripheral blood mononuclear cells in one study...Preliminary evidence suggests that NR may improve some inflammatory measures, with potential for more robust effects among populations with compromised NAD + and higher inflammation status, e.g., elderly or diseased...

...We previously reported that NR supplementation prevented the development of liver fibrosis in male mice. However, whether NR exerts a similar effect in females is unknown. Therefore, we determined whether NR supplementation can prevent obesity-induced inflammation and fibrosis in the liver and white adipose tissue (WAT) by providing NAD+ in obese female mice...Our results indicated that NR supplementation exerted an anti-obesity effect and prevented the development of inflammation and fibrosis in the white adipose tissue of old, but not young, female mice with diet-induced obesity.

Fasting and NAD+-boosting compounds, including NAD+ precursor nicotinamide riboside (NR), confer antiinflammatory effects. However, the underlying mechanisms and therapeutic potential are incompletely defined. We explored the underlying biology in myeloid cells from healthy volunteers following in vivo placebo or NR administration and subsequently tested the findings in vitro in monocytes extracted from patients with systemic lupus erythematosus (SLE)...We conclude that NR, in an NAD+-dependent manner and in part via inosine signaling, mediated suppression of autophagy and attenuated type I IFN in myeloid cells, and we identified NR as a potential adjunct for systemic lupus erythematosus management.

Our data suggest that NR administration in compromised hematopoietic systems (NAD+ depleted system) drives cell-intrinsic changes of the HSC compartment together with an overall reduction in circulating inflammatory cytokines. However, once the aged system has been exposed to NR, the effects of removing the supplementation may have undesirable consequences. Thus, once a deficient system is exposed to NAD+ supplementation, to maintain the benefits we have demonstrated, the regimen may need to be sustained long-term...Our results showed significant alterations in lineage commitment of HSCs after NR treatment, with enhanced lymphoid potential. This correlated with changes in inflammatory cytokines and transcriptional alterations of the HSCs. While transplantation of aged NR-treated HSCs reproduced the enhanced lymphoid output seen in the transcriptional profiles, the changes in potential are not sustained after NR withdrawal in the aged mice, and the rebound phenotype appear to exacerbate aging phenotypes. Our results highlight the importance of the duration of NR exposure and the timing of initial exposure to derive robust, balanced lineage outputs from HSCs.

Neuroinflammation is initiated by activation of the brain’s innate immune system in response to an inflammatory challenge. Insufficient control of neuroinflammation leads to enhanced or prolonged pathology in various neurological conditions including multiple sclerosis and Alzheimer’s disease. Nicotinamide adenine dinucleotide (NAD+) plays critical roles in cellular energy metabolism and calcium homeostasis. Our previous study demonstrated that deletion of CD38, which consumes NAD+, suppressed cuprizone-induced demyelination, neuroinflammation and glial activation. However, it is still unknown whether CD38 directly affects neuroinflammation through regulating brain NAD+ level...These results suggest that CD38-mediated neuroinflammation is linked to NAD+ consumption and that boosting NAD+ by CD38 inhibition and NR supplementation directly suppress neuroinflammation in the brain.

These results link the accumulation of senescent cells with age to the age-related NAD decline…Our study demonstrates that increased expression of CD38 in macrophages is an important source of increased NADase activity during ageing.

While mitochondria play an important role in innate immunity, the relationship between mitochondrial dysfunction and inflammation in heart failure is poorly understood. In this study we aimed to investigate the mechanistic link between mitochondrial dysfunction and inflammatory activation in peripheral blood mononuclear cells (PBMCs), and the potential antiinflammatory effect of boosting the NAD level. ...Oral nicotinamide riboside (NR) administration enhanced PBMC respiration and reduced proinflammatory cytokine gene expression in 4 subjects with heart failure. These findings suggest that systemic inflammation in patients with heart failure is causally linked to mitochondrial function of the PBMCs. Increasing NAD levels may have the potential to improve mitochondrial respiration and attenuate proinflammatory activation of PBMCs in heart failure.

Extracellular NAD is degraded by three main classes of specific ectoenzymes: CD38 and CD157, ARTs, ENPP1 and CD73. NADase, ENPP1 and CD73 can lead to the formation of adenosine (ADO), a potent immunosuppressant factor, independently of the activity of CD39. Beside generating ADO, eNAD can be degraded to nicotinamide mononucleotide (NMN) by CD38, generating Nam which can cross plasma membranes and be re-converted to NAD through NAMPT and NMN adenylyltransferase (NMNAT)...

Damage-associated molecular patterns (DAMPs) are molecules that can be actively or passively released by injured tissues and that activate the immune system. Here we show that nicotinate phosphoribosyltransferase (NAPRT), detected by antibody-mediated assays and mass spectrometry, is an extracellular ligand for Toll-like receptor 4 (TLR4) and a critical mediator of inflammation, acting as a DAMP. Exposure of human and mouse macrophages to NAPRT activates the inflammasome and NF-κB for secretion of inflammatory cytokines. Furthermore, NAPRT enhances monocyte differentiation into macrophages by inducing macrophage colony-stimulating factor. These NAPRT-induced effects are independent of NAD-biosynthetic activity, but rely on NAPRT binding to TLR4. In line with our finding that NAPRT mediates endotoxin tolerance in vitro and in vivo, sera from patients with sepsis contain the highest levels of NAPRT, compared to patients with other chronic inflammatory conditions. Together, these data identify NAPRT as a endogenous ligand for TLR4 and a mediator of inflammation.

...We aimed to establish whether oral NR supplementation in aged participants can increase the skeletal muscle NAD+ metabolome and if it can alter muscle mitochondrial bioenergetics...Targeted metabolomics showed that NR elevated the muscle NAD+ metabolome, evident by increased nicotinic acid adenine dinucleotide and nicotinamide clearance products. Muscle RNA sequencing revealed NR-mediated downregulation of energy metabolism and mitochondria pathways, without altering mitochondrial bioenergetics. NR also depressed levels of circulating inflammatory cytokines. Our data establish that oral NR is available to aged human muscle and identify anti-inflammatory effects of NR.