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Glutamine as a modulator of the immune system of critical care patients: effect on Toll-like receptor expression. A
Jon Pérez-Bárcena1, Verónica Regueiro, Pedro Marsé
1Intensive Care Unit, University Hospital Son Dureta, Palma de Mallorca, Spain. jperez@hsd.es
Objective:
We evaluated the expression of Toll-like receptors 2 and 4 (TLR-2 and TLR-4) in circulating monocytes from peripheral blood of critical care patients treated with and without glutamine. Because no research has been published to date on the effect of glutamine on TLR receptors in critical patients, it was determined in an initial sample of 30 patients.
Methods:
This was a prospective, randomized, single-blind study with 15 patients assigned to receive parenteral nutrition with a daily glutamine supplement of 0.35 g/kg. The control group received isocaloric-isonitrogenous parenteral nutrition. Blood samples were extracted before beginning the treatment and at 5 and 14 d. Expressions of CD14, TLR-2, and TLR-4 were determined by flow cytometry. Levels of TLRs were expressed as mean fluorescence intensity (mfi).
Results:
Basal characteristics were similar in both groups. The expressions of TLR-2 in the treatment group with glutamine were 4.67 +/- 3.82 mfi before treatment, 3.91 +/- 2.04 mfi at 5 d, and 4.28 +/- 2.47 mfi at 14 d. The expressions of TLR-2 in the control group were 5.49 +/- 3.20 mfi before treatment, 4.48 +/- 2.15 mfi at 5 d, and 4.36 +/- 2.36 mfi at 14 d. The expressions of TLR-4 in the treatment group were 1.65 +/- 1.89 mfi before treatment, 1.23 +/- 1.10 mfi at 5 d, and 1.77 +/- 1.97 at 14 d. The expressions of TLR-4 in the control group were 1.51 +/- 1.76 mfi before treatment, 1.36 +/- 0.99 mfi at 5 d, and 1.26 +/- 0.59 mfi at 14 d. Infections were detected in 11 patients who received glutamine and 13 control patients (P = 0.51).
Conclusion:
In critical care patients, parenteral nutrition supplemented with glutamine does not increase the expression of TLR-2 or TLR-4 in peripheral blood monocytes.
Insights
Glutamine supplementation in critical care patients receiving parenteral nutrition did not alter the expression of Toll-like receptors 2 and 4 (TLR-2 and TLR-4) on monocytes. This study found no significant effect of glutamine on these immune markers in critically ill patients.
Area of Science:
- Immunology
- Critical Care Medicine
- Nutritional Support
Background:
- Toll-like receptors (TLRs) are crucial in innate immunity and are implicated in critical illness.
- Glutamine is an amino acid that plays a role in immune function and is often supplemented in critical care.
- The effect of glutamine on TLR expression in critically ill patients remains largely unexplored.
Purpose of the Study:
- To evaluate the expression of Toll-like receptors 2 and 4 (TLR-2 and TLR-4) in monocytes of critical care patients.
- To determine if glutamine supplementation via parenteral nutrition influences TLR-2 and TLR-4 expression.
- To investigate the potential impact of glutamine on immune responses in critically ill patients.
Main Methods:
- A prospective, randomized, single-blind study involving 30 critical care patients.
- Patients received either parenteral nutrition with glutamine (0.35 g/kg/day) or standard isocaloric-isonitrogenous parenteral nutrition.
- Monocyte expression of CD14, TLR-2, and TLR-4 was measured by flow cytometry at baseline, 5 days, and 14 days.
Main Results:
- No significant differences in basal characteristics were observed between the glutamine and control groups.
- Parenteral nutrition supplemented with glutamine did not alter the mean fluorescence intensity (mfi) of TLR-2 or TLR-4 on monocytes compared to the control group at any time point.
- Infection rates were similar between the groups (11 in the glutamine group vs. 13 in the control group, P = 0.51).
Conclusions:
- Parenteral nutrition supplemented with glutamine does not increase the expression of TLR-2 or TLR-4 in peripheral blood monocytes of critical care patients.
- Glutamine supplementation does not appear to modulate these specific innate immune receptors in this patient population.
- Further research may be needed to explore other potential immunomodulatory effects of glutamine in critical illness.