7970 C3 and C4 Levels Decrease Post-prandial in Adolescents with type 1 Diabetes

Abstract Disclosure: C.P. Damilano: None. C. Yu: None. D. Zhou: None. R.P. Hoffman: None. Introduction: Cardiovascular disease will be the primary cause of future death for adolescents with type 1 diabetes (T1D) and its origins are likely to occur in this age group. Adolescents with T1D have increased systemic inflammation which is likely to play a significant role in the pathogenesis of cardiovascular disease. The complement system, in particular, components C3 and C4 are part of the innate immune system that regulates inflammation. Increased C3 and C4 levels are associated with increased cardiometabolic risk. Objective: Most studies of inflammation are done while fasting but TNFα and IL6 increase postprandially in adolescent T1D following both high and low glycemic index (GI) meals. The goal of this study was to determine whether there are similar post-prandial changes in C3 and C4 levels. Methodology: Twelve, non-obese children and adolescents, 10-18 years old, with T1D were recruited from the Diabetes Clinic of Nationwide Children's Hospital. A randomized cross-over design for their two subsequent visits was used. After an overnight fast baseline blood samples were taken to measure plasma glucose, C3, total C4 protein, and total C4. Rapid acting insulin was given to cover meal carbohydrate without glucose correction, and blood samples were repeated (30, 60, 90, and 120 minutes) to measure glucose and C3 and C4 levels. Visits 1 and 2 were identical except for GI of the given meal. Visits were rescheduled if the fasting glucose was greater than 200 mg/dl. Repeated measures ANOVA and Spearman’s correlation were used. Results: Glucose response was significantly greater following high GI meal (Δglucose: high 52±12 vs low 6±5 mg/dl, mean±SE, p<0.001). For C3 levels, there was a significant post-prandial decrease (time effect p=0.049), but no meal effect or meal x time interaction. No specific time differences were found. C4 levels were also suppressed postprandially (p<0.001) and there was again no meal effect or meal by time interaction. Post hoc analysis found that C4 levels were lower at 60 min than at 0 min (p=0.007), 90 min (p=0.002) or 120 min (p<0.001). Conclusions: C3 and C4 levels decrease post-prandially in adolescents with T1D in contrast to increases in TNFα and IL6. Future research is clearly needed to clarify the postprandial interactions between the complement and inflammatory systems and potential pathogenic role in cardiovascular disease. Presentation: 6/3/2024