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Cold-induced brown adipose tissue (BAT) activation is considered to improve metabolic health. In murine BAT, cold increases the fundamental molecule for mitochondrial function, nicotinamide adenine dinucleotide (NAD+), but limited knowledge of NAD+ metabolism during cold in human BAT metabolism exists. We show that cold increases the serum metabolites of the NAD+ salvage pathway (nicotinamide and 1-methylnicotinamide) in humans. Additionally, individuals with cold-stimulated BAT activation have decreased levels of metabolites from the de novo NAD+ biosynthesis pathway (tryptophan, kynurenine). Serum nicotinamide correlates positively with cold-stimulated BAT activation, whereas tryptophan and kynurenine correlate negatively. Furthermore, the expression of genes involved in NAD+ biosynthesis in BAT is related to markers of metabolic health. Our data indicate that cold increases serum tryptophan conversion to nicotinamide to be further utilized by BAT. We conclude that NAD+ metabolism is activated upon cold in humans and is probably regulated in a coordinated fashion by several tissues.

Results of several studies have confirmed the presence of brown adipose tissue among health human adults. The results are also indicative of the fact that activated brown adipose tissue has the potential to contribute substantially to energy expenditure, and thus, may be further researched as a means of treating obesity.

Background: Breast cancer-related lymphedema (BCRL) is a common complication lacking medical treatment. Lymfactin® is an adenovirus type 5-based gene therapy and prolymphangiogenic growth factor vector that induces vascular endothelial growth factor C (VEGF-C) expression. Our aim was to evaluate the therapeutic effect of Lymfactin® with vascularized lymph node transfer (VLNT)., Methods: This Phase II, double-blind, placebo-controlled, randomized multicenter study evaluated the efficacy and safety of Lymfactin® in combination with VLNT. The primary endpoints were edema volume, quality of life (LyQoLI), and lymphoscintigraphy. All adverse events were recorded. A mixed model of repeated measures analysis of covariance was performed. This study was a continuation of a previous Phase I Lymfactin® study., Results: Thirty-nine patients with BCRL were recruited between June 2018 and December 2019 and randomized to receive either Lymfactin® (n = 20) or placebo (n = 19). The primary endpoints showed a positive effect of VLNT in both groups compared to the baseline, but without statistical differences between groups at 12 months. Additionally, greater improvements were observed in the tissue dielectric constant ratios measuring skin interstitial fluid levels in the Lymfactin® group compared to the placebo group (p = 0.020). No differences in adverse events were detected between the groups., Conclusions: This study was one of the few studies to objectively show a positive effect of VLNT in a prospective clinical multicenter setting. It was also the first-ever randomized prospective clinical study showing a quantitatively positive effect of a medical therapy on the edema of lymphedema although failing to show differences between groups in primary outcome measures., Competing Interests: Statement of Financial Disclosures, Conflicts of Interest, and Products: SS, JK, IK, AS, and PH have received honoraria for participating in advisory boards of Herantis Pharma Plc. (Espoo, Finland), which was responsible for trial management and has reviewed this manuscript. Authors do not have financial disclosures to report., (Copyright © 2024 by the American Society of Plastic Surgeons.)

Cold-induced brown adipose tissue (BAT) activation is considered to improve metabolic health. In murine BAT, cold increases the fundamental molecule for mitochondrial function, nicotinamide adenine dinucleotide (NAD + ), but limited knowledge of NAD + metabolism during cold in human BAT metabolism exists. We show that cold increases the serum metabolites of the NAD + salvage pathway (nicotinamide and 1-methylnicotinamide) in humans. Additionally, individuals with cold-stimulated BAT activation have decreased levels of metabolites from the de novo NAD + biosynthesis pathway (tryptophan, kynurenine). Serum nicotinamide correlates positively with cold-stimulated BAT activation, whereas tryptophan and kynurenine correlate negatively. Furthermore, the expression of genes involved in NAD + biosynthesis in BAT is related to markers of metabolic health. Our data indicate that cold increases serum tryptophan conversion to nicotinamide to be further utilized by BAT. We conclude that NAD + metabolism is activated upon cold in humans and is probably regulated in a coordinated fashion by several tissues., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Human brown adipocytes are able to burn fat and glucose and are now considered as a potential strategy to treat obesity, type 2 diabetes and metabolic disorders. Besides their thermogenic function, brown adipocytes are able to secrete adipokines. One of these is visfatin, a nicotinamide phosphoribosyltransferase involved in nicotinamide dinucleotide synthesis, which is known to participate in the synthesis of insulin by pancreatic β cells. In a therapeutic context, it is of interest to establish whether a potential correlation exists between brown adipocyte activation and/or brite adipocyte recruitment, and adipokine expression. We analyzed visfatin expression, as a pre-requisite to its secretion, in rodent and human biopsies and cell models of brown/brite adipocytes. We found that visfatin was preferentially expressed in mature adipocytes and that this expression was higher in brown adipose tissue of rodents compared to other fat depots. However, using various rodent models we were unable to find any correlation between visfatin expression and brown or brite adipocyte activation or recruitment. Interestingly, the situation is different in humans where visfatin expression was found to be equivalent between white and brown or brite adipocytes in vivo and in vitro. In conclusion, visfatin can be considered only as a rodent brown adipocyte biomarker, independently of tissue activation.