Study on intestinal mucosal barrier dysfunction induced by postthoracotomyand and protection of alanyl-glutamine dipeptide in aged patients

Objective To investigate the changes of intestinal mucosal barrier function and protection of alanyl-glutamine(Alm-Gln) dipeptide during early stage of postthoracotomy in aged patients.Methods A prospective,randomized and controlled trial was conducted and 20 aged patients who underwent non-digestive thoracotomy were randomized into two groups,experimental group (intravenous administration of Aln-Gln dipeptide,0.5 g/(kg · d),for 4 days,n =10) and control group(equal amount saline as placebo,for 4 days,n =10).The indices of boby temperatures,heart rates,respiration and white blood cell count of all patients were daily recorded during administration.Serum concentrations of glutamine (Gln),D-lactate,diamine oxidase (DAO) and tumor necrosis factor-α(TNF-α) were measured before and after operation.Results There were no statistically significant differences in the patients' general information between experimental group and control group including age,gender and body weight.Plasma Gln concentration in postoperative 5 days was higher than that of pre-operation of experiment group ((478.32 ± 47.42) μmol/L vs.(372.67 ± 29.14) μmol/L,P =0.021).The plasma Gln level of control group at 5th day after operation was higher than that in pre-operation ((431.12 ± 42.27) μmol/L vs.(386.29 ± 19.73) μmol/L,P =0.017).The plasma level of Gln in experimental group was significantly higher than that in control group after operation((478.32±47.42) μmol/L vs.(386.29 ± 19.73) μmol/L,P =0.012).There were no significantly differences between the two groups in terms of the plasma level of DAO and D-lactate before operation (P ＞ 0.05).Meanwhile the levels of DAO and D-lactate in both group at 5th day after operation were significantly higher than that at before operation(DAO:(2.53 ±0.47) U/ml vs.(1.66±0.32) U/ml,P =0.003;D-lactate:(6.82 ±1.91) mg/L vs.(4.92 ±1.57) mg/L,P =0.024),and the levels of them in experimental group were significantly lower than that in control group(DAO:(1.10 ± 0.23) U/ml vs.(2.53 ± 0.47) U/ml,P =0.013 ; D-lactate:(4.87 ± 1.33) mg/L vs.(6.82 ± 1.91) mg/L,P =0.019).The concentration of TNF-α was significant increase in both two groups at first day after operation,but decreased at the third day.The concentration of TNF-α in experimental group at 5th day after operation was lower than that in control group ((6.89 ± 5.21) pg/L vs.(13.04 ± 4.46) pg,/L,P =0.003).The morbidity of systemic inflammatory response syndrome (SIRS) was significantly decreased in experimental group and the rate of SIRS was also lower than that in the control group(P ＜ 0.01).Conclusion Intestinal mucosal barrier function was damaged after thoracotomy in aged patients.Administration of Aln-Gln dipeptide could increase the level of serum Gln,protect the intestinal barrier and attenuate the systemic inflammatory response.Aln-Gln dipeptide can be used to help aged patients recover rapidly. Key words: Aged; Patients; Thoracotomy; Intestinal; Mucosal; Barrier; Alanyl-glutamine; dipeptide