Effects of l-arginine and l-ornithine supplementations on the treatment of chronic periodontitis: A preliminary randomized short-term clinical trial

The growing interest in the possibilities of modulating macrophages in inflammatory diseases with therapeutic purpose has prompted the development of new approaches for the treatment of periodontitis. This randomized add-on open preliminary clinical study evaluated the short-term effects of L-arginine or L-ornithine as an adjuvant to scaling and root planing (SRP) in patients with chronic periodontitis. MATERIALS AND METHODS: Seventy-five periodontitis patients were recruited and monitored clinically and immunologically at baseline (before SRP) and 30 ± 5 days after SRP. All patients were assigned by stratified randomization to SRP (SRP only, n = 25), Arg (SRP + L-arginine, n = 25) or Control (SRP + L-ornithine, n = 25) Group. The medicines were used according to available instructions for 10 and 15 days, respectively. During the study, all patients were on a stable diet, without changing their rations and regiments. As immunological monitoring immunohistochemical study of CD68+ and CD163 + single positive gingival macrophages for 5 patients per group in the same time-point was conducted. The data were statistically analyzed. RESULTS: Reduction of periodontal pocket depth (PPD) and bleeding on probing (BoP) was observed in all groups, with significant between-group differences for BoP in the Arg Group (p < 0.0001) at 30 days. The SRP and Arg groups demonstrated nonsignificantly increased density of CD68+ and CD163 + cells. The Orn Group showed an increase in the density of CD68+ and CD163 + macrophages at intragroup (p = 0.0066 and p < 0.0001) and between-group levels (p = 0.001 and p < 0.0001), and these changes corresponded to clinical PPD and BoP reduction. In the Arg and Orn groups at 30 days, CD163 + macrophages significantly predominated over CD68+ (p = 0.013, p < 0.0001). CONCLUSION: The use of L-arginine and L-ornithine as an adjunct to SRP promotes additional limited immunological benefit in the treatment of periodontitis. Metabolic stimulation with L-ornithine, but not L-arginine, is preferable for CD163+ Mφs subpopulation in periodontitis-affected gingiva.