Methods: Whole blood samples were collected from a total of 310 subjects, including 70 healthy donors (HDs), 80 patients with rheumatoid arthritis (RA), 80 with psoriatic arthritis (PsA), and 80 with spondyloarthritis (SpA). A panel of key metabolites from the NAD ⁺ pathway (NAD ⁺ , NADH, NAM, NMN, NR, NADP and Tryp) was analyzed using two-dimensional Nuclear Magnetic Resonance (DOSY-NMR) technology (Biosfer). Additionally, a longitudinal analysis was performed in 90 CIRDs patients, 30 from each disease group, before and after 6 months of anti-TNF therapy to assess therapy-induced changes in the NAD+ metabolome. Peripheral blood mononuclear cells (PBMCs) from 45 CIRD patients (15 from each disease group) were treated ex-vivo with 1 nM of established and novel NAD ⁺ boosters, including NAM, NR, NMN, NRT, NRH, and NAR, for 24 hours. Intracellular NAD ⁺ and NADH levels were measured using the NAD/NADH-Glo Assay Kit (Promega). In parallel, secreted inflammatory mediators were assessed using the Olink Target 96 Inflammation Panel (Cobiomic).

Results: RA, SpA, and PsA exhibited a significant reduction in the NAD ⁺ /NADH ratio, along with increased levels of NAM and NMN compared to healthy donors (HDs). Additionally, NAD ⁺ levels were reduced in RA, whereas NADH levels were elevated in SpA and PsA. Notably, SpA patients showed a decrease in NADP levels and an increase in Trp levels. These findings underscore disease-specific disruptions in NAD ⁺ metabolism, which may contribute to chronic inflammation and immune dysfunction. The alterations in the NAD ⁺ metabolome were directly associated with specific clinical features across diseases. In RA, a negative correlation was observed between the NAD ⁺ /NADH ratio and disease activity (DAS28), while positive correlations were found between NADH and NMN levels and CRP, as well as tender and swollen joint counts (TJC and SJC). Additionally, rheumatoid factor (RF) and anti-CCP antibodies were positively correlated with NADH levels. In PsA, the NAD ⁺ /NADH ratio showed a negative correlation with TJC and SJC, and NAD ⁺ levels were negatively correlated with disease activity, measured by the DAPSA score. Furthermore, uveitis was positively correlated with NAD levels, and psoriasis was associated with NAM levels. In SpA, axial forms exhibited a lower NAD ⁺ /NADH ratio, with positive correlations between ESR and NMN, entesitis and NADH, and dactylitis and tryptophan (Trp). Anti-TNF therapy for 6 months induced disease-specific changes in NAD ⁺ metabolites, with distinct patterns observed across different conditions. Overall, the treatment appeared to restore NAD ⁺ metabolite levels closer to those observed in HDs, suggesting a potential role in rebalancing disrupted metabolic pathways. All NAD ⁺ boosters significantly increased intracellular NAD ⁺ levels in PBMCs from patients across the three diseases, although the magnitude of the response varied depending on the specific booster and disease type. Notably, NRH demonstrated the most potent effect in raising NAD ⁺ levels. In addition, the boosters showed anti-inflammatory potential by reducing the secretion of key inflammatory mediators, with effects that also varied based on the booster and pathology, further highlighting their therapeutic potential in modulating disease-related inflammation.

Conclusion: 1- The NAD ⁺ metabolome is profoundly altered in CIRDs, with disease-specific patterns of disruption and associated to key clinical features in each disease. 2-Anti-TNF therapy partially restored NAD ⁺ metabolite levels toward those observed in HDs, suggesting a role for metabolic rebalancing in the therapeutic response. 3- Preclinical testing of NAD ⁺ boosters demonstrated their ability to effectively enhance intracellular NAD ⁺ levels and reduce inflammatory mediators, with both shared and disease-specific effects. These findings highlight the potential of targeting the NAD ⁺ pathway as a novel therapeutic strategy in CIRDs.

REFERENCES: NIL.

Acknowledgements: Supported by: CPS: RYC2021-033828-I; PID2022-141500OA-I00, Minister of Science, Innovation and Universities co-financed by the European Union; FAR2023-2024; Junta de Andalucia/Consejeria de Salud y Consumo, PIP-0149-2024; DIN2022-012766, AEI. CLP: ISCIII (PI21/0591, PI24/00959, CD21/00187 and RICOR-21/0002/0033); co-financed by European Union. JMV: RTI2018-100695-B-I00, PID2021-126280OB-I00, JA grants P18-RT-4264, 1263735-R and BIO-276, PRE2019-08743, P18-RT-4264, BIO-276 and PID2021-126280OB-I00. AEC: ICI23/00100 ISCIII. CLM, ECE and NBP: Projects “PI22/00539 and PMP21/00119”, funded by ISCIII and co-funded by the European Union, and project “PI-0243-2022” funded by the “Junta de Andalucia/Consejeria de Salud y Consumo. Project “PID2023-152503OB” funded by the Minister of Science, Innovation and Universities co-financed by the European Union. ChromaDex, Inc.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.