Effect of N-acetylglucosamine administration on cartilage metabolism and safety in healthy subjects without symptoms of arthritis: A case report

Abstract

Abstract. N-acetylglucosamine (GlcNAc) is a widely accepted treatment for osteoarthritis (OA); however, its effect on healthy individuals is poorly understood. To evaluate the effect of GlcNAc administration on healthy subjects that do not exhibit symptoms of arthritis, the present randomized, double-blind, placebo-controlled study was performed. In the present study, 68 male and female Japanese participants, without symptomatic and radiographic evidence of OA, were enrolled and randomly allocated to receive placebo or GlcNAc (500 or 1,000 mg/day) for 16 weeks. Effects were evaluated using biomarkers for type II collagen degradation and synthesis, collagen type II cleavage (C2C), procollagen type II carboxy-terminal propeptide (PIICP) and their ratio (C2C/PIICP). Furthermore, safety assessments were performed via physical parameters, hematology, blood biochemistry and urinalysis. The results indicated that there was no significant change in the biomarkers for type II collagen degeneration and synthesis during and after the intervention with the placebo and two GlcNAc groups. However, subgroup analysis using subjects with impaired cartilage metabolism (who exhibited enhanced type II collagen degradation and reduced type II collagen synthesis) indicated that the C2C levels were significantly decreased at 8 (P<0.05) and 16 (P<0.01) weeks during the intervention in the two GlcNAc (500 mg and 1,000 mg/day) groups, compared with the placebo group. In contrast, PIICP levels were not notably different in the placebo and two GlcNAc groups. The C2C/PIICP ratio was markedly decreased at 12 and 16 weeks during the intervention in the two GlcNAc groups, compared with the placebo group. Moreover, no supplement-related adverse events were observed during and after the intervention. In conclusion, these observations indicate that oral administration of GlcNAc at doses of 500 and 1,000 mg/day improves cartilage metabolism in healthy subjects without apparent adverse effects.

Alphavirus nsP2 protease structure and cleavage prediction: Possible relevance to the pathogenesis of viral arthritis

“…[85] Cleavage of ER degradationenhancing alpha-mannosidase-like protein 2 (EDEM2) [86] may disrupt host ERAD of viral glycoproteins [87] or redirect viral glycoproteins away from the cell membrane for internal budding as in SINV-infected mosquito cells. [88,89] Cleavage of phosphoacetylglucosamine mutase (PAGM) may contribute to disruption of glycosaminoglycan polymers in cartilage and contribute to arthritic symptoms, [90] however N-acetylglucosamine (GlcNAc) supplementation sometimes used to treat osteoarthritis (OA) may be counterproductive given (1) it makes up some alphavirus glycans, [91] (2) it promotes replication of many other viruses in vitro and in vivo, [92] and (3) O-linked GlcNAc glycosylation of p65 aggravates TNF-α-mediated inflammation in rheumatoid arthritis (RA). [93] Other predicted cleavages involved in protein degradation include the SUMO-specific E1 enzyme SAE1, the E2 enzyme UBE2Q1, the E3 enzyme UBR4, ubiquitin-1, and tripeptidyl peptidase 2 (TPP2).…”

Ingredients, Functionality, and Safety of the Japanese Traditional Sweet Drink Amazake

“…Rice syrup was prepared using rice, which is the raw material of rice-koji, and a saccharifying enzyme that has the same composition as koji amazake (Table 1). GlcNAc has been reported to improve cartilage metabolism via the intake of 500 and 1000 mg/day [41]. However, GlcNAc in koji amazake has a lower content than these effect sizes, as mentioned in the section on skin barrier function.…”

N-Acetyl-D-Glucosamine Acts as Adjuvant that Re-Sensitizes Starvation-Induced Antibiotic-Tolerant Population of E. Coli to β-Lactam

“…GlcNAc and GlcN are known to exhibit beneficial pharmacological effects in treatment of osteoarthritis (Kubomura et al, 2017). The therapeutic potential of GlcNAc is mainly attributed to its anti-inflammatory and chondroprotective effects (Dalirfardouei et al, 2016).…”