L-glutamine therapy reduces endothelial adhesion of sickle red blood cells to human umbilical vein endothelial cells

Abstract

Background: We have previously demonstrated that therapy with orally administered L-glutamine improves nicotinamide adenosine dinucleotide (NAD) redox potential of sickle red blood cells (RBC). On further analysis of L-glutamine therapy for sickle cell anemia patients, the effect of L-glutamine on adhesion of sickle RBC to human umbilical vein endothelial cells (HUVEC) was examined.

Methods: The first part of the experiment was conducted with the blood samples of the 5 adult sickle cell anemia patients who had been on L-glutamine therapy for at least 4 weeks on a dosage of 30 grams per day compared to those of patient control group. In the second part of the experiment 6 patients with sickle cell anemia were studied longitudinally. Five of these patients were treated with oral L-glutamine 30 grams daily and one was observed without treatment as the control. t-test and paired t-test were used for determination of statistical significance in cross-sectional and longitudinal studies respectively.

Results: In the first study, the mean adhesion to endothelial cells with the autologous plasma incubated cells were 0.97 +/- 0.45 for the treated group and 1.91 +/- 0.53 for the nontreated group (p < 0.02). Similarly with lipopolysaccharide (LPS) incubated cells the mean adhesion to endothelial cells were 1.39 +/- 0.33 for the treated group and 2.80 +/- 0.47 for the untreated group (p < 0.001). With the longitudinal experiment, mean decrease in the adhesion to endothelial cells was 1.13 +/- 0.21 (p < 0.001) for the 5 treated patients whereas the control patient had slight increase in the adhesion to endothelial cells.

Conclusion: In these studies, oral L-glutamine administration consistently resulted in improvement of sickle RBC adhesion to HUVEC. These data suggest positive physiological effects of L-glutamine in sickle cell disease.

Figure 1

Ratios of HUVEC adhesion rates of sickle RBC to those of normal RBC for the treatment group (0.97 ± 0.45) and non-treatment group (1.91 ± 0.53) when the cells were incubated with autologous plasma alone. (p < 0.02)

Figure 2

Ratios of HUVEC adhesion rates of sickle RBC to those of normal RBC for the treatment group (1.39 ± 0.33) and non-treatment group (2.80 ± 0.47) when the cells were incubated with autologous plasma and LPS. (p < 0.001)

Figure 3

Ratios of HUVEC adhesion rates of sickle RBC to those of normal RBC before and after treatment for the five sickle cell anemia patients with one sickle cell anemia control patient who was not treated. Mean decrease of the adhesion ratios was 1.13 ± 0.21 with p < 0.001 for the five treated patients, whereas the control patient actually had slight increase in the adhesion ratio over the same period.