ABSTRACT
Objective To investigate whether AGEs stimulate human lymphocytes to produce cytokines and whether the immune response to AGEs stimulation is the same or not in diabetics and normal subjects.Methods Venous blood was collected from 55 normal subjects and 50 diabetic patients.The blood sample was mixed in 1640 culture medium with 10?g/ml PHA or 20?g/ml AGEs respectively for 24 hours incubation.TNF-? and IL-6 of the medium were determined by ELISA test kit.Results After 24 hours incubation,AGEs-induced TNF-? production in diabetic patients and normal subjects was 473.20?66.93pg/ml vs 254.62?35.14pg/ml ( P 0.05).There was no relation of higher cytokine production with course of diabetes,glycemia levels,body weight and sex.Conclusion The above results demonstrated that (1) AGEs do stimulate human lymphocytes to produce TNF-? and IL-6;(2)The immune response to AGEs and PHA was more sensitive in diabetics,at least partially,than that in normal subjects;(3)It seems that the sensitive response to AGEs stimulation has no relation with course of diabetes,glycemia levels,body weight and sex in tested individuals.Our findings imply the possibility that immune response to AGEs of diabetic individual can be studied by this method.The sensitive response to AGEs stimulation in diabetes may be an independent risk factor involved in diabetic complications.
ABSTRACT
AIM To investigate the inhibitory effect of pycnogenol on generation of advanced glycation end products (AGEs) in vitro. METHODS Advanced glycation end products were determined by fluorospectrophotometer in the medium of 1 mol?L -1 glucose and 5% bovine albumin incubated at 37℃, 50℃, and 70℃ for different times. The inhibitory effect of pycnogenol was confirmed by the same system incubated with or without pycnogenol at different concentrations. RESULTS The rate of generation of AGEs in vitro was related with incubation time and incubation temperature. The generation of AGEs was inhibited by pycnogenol in vitro. The inhibitory rate was 10%～80% dependent on concentration and incubation time of pycnogenol. The inhibitory effect of pycnogenol on generation of AGEs was almost the same as that of Aminoguanidine at the same concentration. CONCLUSION pycnogenol could significantly inhibit generation of AGEs in vitro.