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[Reduced phagocytic capacity of circulating granulocytes in diabetes mellitus]
W Marhoffer1, M Stein, E Mäser
1Medizinische Klinik III und Poliklinik, Universität Giessen.
Abstract:
Impaired PMN function is regarded as a major cause for infectious complications in diabetes mellitus (d.m.). The aim of this study was to investigate the phagocytic PMN functions "ingestion" (IN) and "bacterial killing" (BK) with regard to metabolic control parameters and influences of variable glucose concentrations on these PMN functions in vitro. Our findings demonstrated a significant reduction of IN and BK in diabetic subjects compared to controls (p less than 0.001 resp.). The differences between type I and type II d.m. did not reach statistical significance. Linear regression analysis showed significantly negative correlations for fasting blood-glucose concentrations as well as glycosylated hemoglobin (HbA1) and IN (r = -0.34, p 0.03; r = -0.67, p = 0.001) and a highly positive for BK (r = 0.73, p = 0.0001). In vitro there was a significant decrease in IN and BK both in diabetic subjects and controls for glucose concentrations greater than 27.7 mmol/l (p = 0.01 resp.). These data clearly demonstrated impaired PMN ingestion and bacterial killing in diabetic patients, and the degree of PMN dysfunction is inversely related to the degree of metabolic control of diabetes. These findings suggest inhibitory effects of hyperglycemia on PMN functions, thus contributing at least partly to altered host defense in diabetes mellitus.
Insights
Diabetic patients show impaired neutrophil (PMN) ingestion and bacterial killing, crucial for fighting infections. Poor metabolic control in diabetes worsens these immune cell dysfunctions, increasing infection risk.
Area of Science:
- Immunology
- Endocrinology
- Metabolic Disorders
Background:
- Neutrophil (PMN) dysfunction is a key factor in infectious complications associated with diabetes mellitus (DM).
- Understanding the impact of metabolic control on PMN phagocytic functions is crucial for managing diabetes-related infections.
Purpose of the Study:
- To investigate neutrophil (PMN) ingestion (IN) and bacterial killing (BK) functions in diabetic patients.
- To correlate PMN function with metabolic control parameters (fasting blood glucose, HbA1).
- To assess the in vitro effect of varying glucose concentrations on PMN functions.
Main Methods:
- Comparative analysis of PMN IN and BK between diabetic subjects and healthy controls.
- Linear regression analysis to determine correlations between PMN function and metabolic parameters (fasting blood glucose, HbA1).
- In vitro experiments exposing PMNs to different glucose concentrations.
Main Results:
- Diabetic subjects exhibited significantly reduced PMN IN and BK compared to controls (p < 0.001).
- Negative correlations were found between fasting blood glucose/HbA1 and IN; positive correlation with BK.
- High glucose concentrations (>27.7 mmol/l) in vitro impaired PMN IN and BK in both diabetic and control groups.
Conclusions:
- Diabetes mellitus is associated with impaired neutrophil phagocytic functions (ingestion and bacterial killing).
- The degree of PMN dysfunction is inversely related to the level of metabolic control in diabetes.
- Hyperglycemia appears to inhibit PMN functions, contributing to the compromised host defense observed in diabetes.