Relationship between nutritional parameters，macrophagic polarization changes and severity of renal injury in elders with diabetic kidney disease

Objective To examine the relationship between nutritional parameters,macrophagic polarization changes and severity of renal injury in elders with diabetic kidney disease(DKD). Methods Between January 2020 and October 2021,a total of 110 DKD elders were hospitalized. According to the staging criteria of chronic kidney disease(CKD),they were divided into five groups of stage Ⅰ(n=22), stage Ⅱ(n=23),stage Ⅲ(n=28),stage Ⅳ(n=20)and stage Ⅴ(n=17). A total of 30 elders with diabetes mellitus during the same period were recruited as control group. The levels of M1 and M2 macrophage phenotypic markersnitric oxide synthase(iNOS)& mannose receptor(MR)in peripheral blood were detected by double-antibody sandwich enzyme-linked immunosorbent assay(ELISA). Estimated glomerular filtration rate(eGFR)was assayed. The nutritional parametersalbumin(Alb),total protein (TP)& transferrin(TRF)were detected by a full-automatic biochemical analyzer. Renal functionrelated parametersblood urea nitrogen(BUN),serum creatinine(Scr)& β2-microglobulin(β2-MG) and inflammatory parameterinterleukin(IL)-6were detected by ELISA. The detection results of the above parameters in different groups were compared. The relationship between nutritional parameters, macrophagic polarization changes,renal function parameters and eGFR was analyzed by Pearson's correlation analysis. And the evaluation value of nutritional parameters and macrophagic polarization for renal injury was analyzed by receiver operating characteristic(ROC)curve. Results eGFR,Alb,TP,TRF and MR in different staging groups were significantly lower than those in control group. And iNOS protein was higher than that in control group. In stages I-V groups,eGFR,Alb,TP and TRF gradually declined (P<0. 05). MR value was lower in stage Ⅱ group than that in stages Ⅰ,Ⅲ,Ⅳ and Ⅴ groups while iNOS protein was higher than that in the other groups(P<0. 05). IL-6,BUN,Scr and β2-MG in different staging groups were significantly higher than those in control group and it was significantly lower in stage I group than the other groups(P<0. 05). Pearson's correlation analysis revealed that Alb,TP, TRF and MR were correlated positively with eGFR and negatively with BUN,Scr and β2-MG. The level of iNOS protein was correlated negatively with eGFR and positively with BUN,Scr and β2-MG(P <0. 05). The results of ROC curve showed that AUC values of Alb,TP,TRF,iNOS protein and MR for evaluating the severity of renal injury in DKD elders were 0. 797,0. 971,0. 775,0. 802 and 0. 922 respectively(P<0. 05). Conclusion Severity of renal injury is greatly correlated with pro-inflammatory polarization direction of peripheral blood macrophages and nutritional status in DKD elders. Nutritional parameters and macrophagic polarization are excellent for evaluating severity of renal injury during an early assessment of DKD.