Neopharma Japan Co. Ltd.

5-Aminolevulinic acid (5-ALA) is an endogenous amino acid in mammalian cells; it is the first amino acid in the heme biosynthesis pathway occurring in the mitochondria. 5-ALA with sodium ferrous citrate (SFC) possesses anti-inflammatory properties by inducing heme oxygenase (HO)-1 expression and releasing heme metabolites in humans and mice. Supplements containing 5-ALA and divalent iron is available in veterinary medicine. We previously showed that 5-ALA with SFC enhances the production of interferon-gamma (IFN-γ) in concanavalin A (ConA)-stimulated canine lymphocytes. However, the effects of 5-ALA/SFC on feline lymphocytes remain to be investigated. This study demonstrated that 5-ALA/SFC-induced HO-1 expression and decreased IFN-γ production in ConA-stimulated feline lymphocytes. Comprehensive RNA sequencing analysis revealed that the activating transcription factor 4 (ATF4) signaling pathway was inhibited by adding 5-ALA/SFC. Moreover, we confirmed that 5-ALA/SFC decreased ATF4 protein expression. Furthermore, separate analyses of the effects of 5-ALA and SFC on feline lymphocytes revealed that SFC, but not 5-ALA, induced AKT dephosphorylation and mitochondrial dysfunction in activated lymphocytes. Thus, SFC in 5-ALA supplements may suppress the effector function of feline lymphocytes via mitochondrial metabolism, thereby representing a novel mechanism in 5-ALA/SFC research.

The study aimed to investigate the therapeutic effects of 5-aminolevulinic acid/sodium ferrous citrate (5-ALA/SFC) on adult-onset Still's disease (AOSD), specifically focusing on arthritis and macrophage activation syndrome (MAS). We used mouse models to assess the impact of 5-ALA/SFC on collagen-induced arthritis (CIA) and MAS induced by synthetic oligonucleotides containing CpG motifs (CpG-S-ODN). Additionally, we conducted a pilot study with AOSD patients receiving prednisolone (PSL) treatment and 5-ALA/SFC administration to evaluate its efficacy and safety. The 5-ALA/SFC group exhibited significantly lower joint scores in CIA mice. In CpG-S-ODN-treated mice, 5-ALA/SFC administration led to reduced hemophagocytosis and splenomegaly. The anti-inflammatory properties of 5-ALA/SFC were attributed to the suppression of CCL4 and CXCL10 production in monocytes and the induction of M2 macrophages. AOSD patients treated with 5-ALA/SFC demonstrated successful PSL tapering without adverse events. Collectively, the administration of 5-ALA/SFC showed promising potential in ameliorating arthritis and MAS in AOSD patients.

5-aminolevulinic acid (5-ALA), a natural amino acid that is marketed alongside sodium ferrous citrate (SFC) as a functional food, blocks severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proliferation in vitro and exerts anti-inflammatory effects. In this phase II open-label, prospective, parallel-group, randomized trial, we aimed to evaluate the safety and efficacy of 5-ALA in patients with mild-to-moderate coronavirus disease 2019.

This trial was conducted in patients receiving 5-ALA/SFC (250/145 mg) orally thrice daily for 7 days, followed by 5-ALA/SFC (150/87 mg) orally thrice daily for 7 days. The primary endpoints were changes in SARS-CoV-2 viral load, clinical symptom scores, and 5-ALA/SFC safety (adverse events [AE] and changes in laboratory values and vital signs).

A total of 50 patients were enrolled from 8 institutions in Japan. The change in SARS-CoV-2 viral load from baseline was not significantly different between the 5-ALA/SFC (n = 24) and control (n = 26) groups. The duration to improvement was shorter in the 5-ALA/SFC group than in the control group, although the difference was not significant. The 5-ALA/SFC group exhibited faster improvement rates in “taste abnormality,” “cough,” “lethargy,” and “no appetite” than the control group. Eight AEs were observed in the 5-ALA/SFC group, with 22.7% of patients experiencing gastrointestinal symptoms (decreased appetite, constipation, and vomiting). AEs occurred with 750/435 mg/day in 25.0% of patients in the first phase and with 450/261 mg/day of 5-ALA/SFC in 6.3% of patients in the second phase.

5-ALA/SFC improved some symptoms but did not influence the SARS-CoV-2 viral load or clinical symptom scores over 14 days. The safety of 5-ALA/SFC in this study was acceptable. Further evaluation using a larger sample size or modified method is warranted.