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Inhibitory effects of elevated glucose and insulin levels on phagocytosis of C3b-opsonized particles in normal human neutrophils
S365
Track 4. Basic Research
(p < 0.01) that that in control (80.3 f 4.5 SE%). The HMPS activity in the uncontrolled diabetics at 0.47 & 0.04 SE nrnoVL per IO6 neutrophils was lower (p ~0.005) that that in the control (0.64 f 0.04). Following satisfactory glycemic control, the various parameters studied improved (p < 0.05)to near the control data. These findings suggest defects in handling infective organisms by PMN leucocytes in uncontrolled diabetes that is reversed with good glycemic control. (Supported by research funding from PGI and Indian Council of Medical Research)
P1437 Inhibitory
Effects of Elevated Glucose and Insulin Levels on Phagocytosis of C3b-Opsonized Particles in Normal Human Neutruphils JANOVE SEHLIN, Daniel Saiepour, Oldenborg Per-Ame. Departmenr of Integrative Medical Biology, Section for Histology and Cell Biology, Umea University, Umea, Sweden
Increased sensitivity to infections, due to reduced function of neutrophil granulocytes, is an important complication in diabetes mellitus. Defective neutrophil function may in part be the result of elevated glucose and/or insulin concentrations. Here, we studied the role of glucose and insulin on phagocytotic activity in normal human neutrophils using a microscopic assay. Phagocytosis of C3b-opsonized yeast particles (C3bY) in non-adherent neutrophils was dose-dependently inhibited by increasing the glucose concentration from 5 mM to 15 or 25 mM (27% and 58% inhibition respectively). In neutrophils adherent to BSA, or the extracellular matrix proteins fibronectin or vitronectin, phagocytosis was also inhibited by 15 or 25 mM glucose although to a lesser extent (17% and 27% inhibition respectively). Insulin, at concentrations above a normal physiological level (i.e. at 80 and 160 pU/ml) also showed a pronounced inhibitory effect on neutrophil phagocytosis of C3bY (37% and 30% inhibition respectively). Importantly, this inhibitory effect of insulin was only seen at a normal physiological glucose concentration (5 mM) and not at 15 or 25 mM glucose. Thus, elevated glucose concentrations per se inhibit complement receptor-mediated phagocytosis in normal human neutrophils. Elevated insulin concentrations can also inhibit this phagocytosis mechanism in neutrophils but only at a normal, physiological glucose concentration. In conclusion, defective phagocytotic activity of neutrophil granulocytes in diabetes can be directly related to elevated glucose or insulin levels and the insulin effect can be counteracted by hyperglycemia.
P1438 TheInvolvement of Peripheral Polymotphonuclear
Leukocytes in Oxidative Stress and Inflammation in Type 2 Diabetic Patients A.T. HERSKOVITS, S. Sela, R. Shurtz-Swirski, S.M. Shasha, G. Shapiro, L. Nasser, B. K&al. Western Galilee Hospital, Nahariya, Israel
Endothelial dysfunction precedes the occurrence of microangiopathy and appears to have a central role in the pathogenesis of atherosclerosis in diabetes. Oxidative stress and inflammation are among the mechanisms recently associated with endothelial dysfunction in diabetes. In the present study, we determined the extent of oxidative stress and inflammation contributed by polymorphonuclears (PMNs) in diabetic patients. Primed PMNs release reactive oxygen species that in the face of depleted endogenous antioxidant levels will end in oxidative stress. At the same time, primed PMNs die by necrosis that starts a cycle of inflammation with ongoing chemotaxis and PMNs recruitment. PMNs and plasma were separated from blood withdrawn from 16 untreated type 2 diabetic patients without end-organ damage and from 15 age and sex-matched healthy subjects. The rate of superoxide release and the plasma levels of the ubiquitous endogenous antioxidant glutathione were determined for assessment of the extent of oxidative stress. Peripheral blood PMN counts were determined to assess recruitment. PMN necrosis relied on
measurements sera.
of their in vitro survival in autologous and heterologous
Supmxide release (nmoles/106 cells/l0 min) Plasma GSH (MM) PMN co”nf ( IO9 cellsA) In virm survival of PMNs in autologous sera (%)
COIlEd
Diabetes
Significance
13.8f3.5 1.21*0.0!9
20.4fO.S 0.6f0.12
5.0f0.3 67f3.9
4.2fO.l 89ztl.9
These data suggest that PMNs from untreated type 2 diabetic patients are primed. This priming ends in oxidative stress with concomitant evidence of inflammation and increased self-necrosis. Necrosis starts a loop of inflammatory reactions accompanied by cell recruitment, and in the long run, together with oxidative stress, may account for the endothelial dysfunction that has been described in these patients.
P1439 Diabetes-Linked Immunoregulatory Defects from ‘D-apical Infections GODWIN 0. IFERE’, Clement 0. Odigwe*, lames Epoke3.
’ Biochemistq College of Medical Sciences, University of Calabac Calabar, Cross River State, Nigeria; ‘Internal Medicine, College of Medical Sciences, Universiry of C&bar; Calabar; Cross River State, Nigeria: 3 Medical Microbiolgy and Parasitology, College of Medical Sciences, University of C&bar; Calabar; Cmss River State, Nigeria There is now evidence that the immunoregulatory
defects resulting in the preponderance of infection in diabetes may be associated with glycation of proteins of the immune system. Infection-induced Cachexia, which results in the release of large amount of CachectiflNF by immunocompetent cells, may complement the glycation-induced immunosuppression. Here, we investigate the synergistic immunoregulatory defects arising from diabetes-linked glycation of the immune system and also from its increased microbial infection. One hundred stable or controlled diabetic and age and sex-matched non-diabetic patients serving as controls were studied. Serum antibody levels using ELISA Test Kits confirmed the extent of various infections. Oral Glucose Tolerance Test (OG’lT), and Glycated Haemoglobin (Hb) (Sigma Diagnostic) diagnosed diabetes and glycaemic control respectively. Glycation of immunoglobulin and lymphocyte membrane protein was assessed by Biorad’s new glycoanalysis Kits and Spectrophotometry respectively. Cell count in the subjects was done with a haemocytometer. CachectirJINF (tumor necrosis factor) in serum of subjects was detected with Sigma Immunoassay Kits. Fifteen each of the 60 diabetic patients presented respectively with Escherichia coli and Klebsiella spp. Infections. Ten of the remaining 20 diabetic Patients had staphylococcus aureus and Salmonella Spp infections respectively. No infection was found in 10 of the diabetic patients. Twenty of the non-diabetic patients had various cases of the listed infections, while the remaining 20 were without any infection. Diabetes was confirmed with OGTT levels z160mg/lOOml. There was a significant (PiO.01) increase in glycation of Hb, immunoglobulin and Lymphocyte membrane protein of all diabetics as compared with non-diabetic subjects. There was no significant difference (P>0.5) in these glycation values in infected and non-infected diabetics. Lymphocytes showed a significant (PeO.01) inhibited proliferation in infected diabetics as compared with non-infected diabetics and non-diabetics. Cachectin/TNFshowed a significant (P
Track 4. Basic Research
(p < 0.01) that that in control (80.3 f 4.5 SE%). The HMPS activity in the uncontrolled diabetics at 0.47 & 0.04 SE nrnoVL per IO6 neutrophils was lower (p ~0.005) that that in the control (0.64 f 0.04). Following satisfactory glycemic control, the various parameters studied improved (p < 0.05)to near the control data. These findings suggest defects in handling infective organisms by PMN leucocytes in uncontrolled diabetes that is reversed with good glycemic control. (Supported by research funding from PGI and Indian Council of Medical Research)
P1437 Inhibitory
Effects of Elevated Glucose and Insulin Levels on Phagocytosis of C3b-Opsonized Particles in Normal Human Neutruphils JANOVE SEHLIN, Daniel Saiepour, Oldenborg Per-Ame. Departmenr of Integrative Medical Biology, Section for Histology and Cell Biology, Umea University, Umea, Sweden
Increased sensitivity to infections, due to reduced function of neutrophil granulocytes, is an important complication in diabetes mellitus. Defective neutrophil function may in part be the result of elevated glucose and/or insulin concentrations. Here, we studied the role of glucose and insulin on phagocytotic activity in normal human neutrophils using a microscopic assay. Phagocytosis of C3b-opsonized yeast particles (C3bY) in non-adherent neutrophils was dose-dependently inhibited by increasing the glucose concentration from 5 mM to 15 or 25 mM (27% and 58% inhibition respectively). In neutrophils adherent to BSA, or the extracellular matrix proteins fibronectin or vitronectin, phagocytosis was also inhibited by 15 or 25 mM glucose although to a lesser extent (17% and 27% inhibition respectively). Insulin, at concentrations above a normal physiological level (i.e. at 80 and 160 pU/ml) also showed a pronounced inhibitory effect on neutrophil phagocytosis of C3bY (37% and 30% inhibition respectively). Importantly, this inhibitory effect of insulin was only seen at a normal physiological glucose concentration (5 mM) and not at 15 or 25 mM glucose. Thus, elevated glucose concentrations per se inhibit complement receptor-mediated phagocytosis in normal human neutrophils. Elevated insulin concentrations can also inhibit this phagocytosis mechanism in neutrophils but only at a normal, physiological glucose concentration. In conclusion, defective phagocytotic activity of neutrophil granulocytes in diabetes can be directly related to elevated glucose or insulin levels and the insulin effect can be counteracted by hyperglycemia.
P1438 TheInvolvement of Peripheral Polymotphonuclear
Leukocytes in Oxidative Stress and Inflammation in Type 2 Diabetic Patients A.T. HERSKOVITS, S. Sela, R. Shurtz-Swirski, S.M. Shasha, G. Shapiro, L. Nasser, B. K&al. Western Galilee Hospital, Nahariya, Israel
Endothelial dysfunction precedes the occurrence of microangiopathy and appears to have a central role in the pathogenesis of atherosclerosis in diabetes. Oxidative stress and inflammation are among the mechanisms recently associated with endothelial dysfunction in diabetes. In the present study, we determined the extent of oxidative stress and inflammation contributed by polymorphonuclears (PMNs) in diabetic patients. Primed PMNs release reactive oxygen species that in the face of depleted endogenous antioxidant levels will end in oxidative stress. At the same time, primed PMNs die by necrosis that starts a cycle of inflammation with ongoing chemotaxis and PMNs recruitment. PMNs and plasma were separated from blood withdrawn from 16 untreated type 2 diabetic patients without end-organ damage and from 15 age and sex-matched healthy subjects. The rate of superoxide release and the plasma levels of the ubiquitous endogenous antioxidant glutathione were determined for assessment of the extent of oxidative stress. Peripheral blood PMN counts were determined to assess recruitment. PMN necrosis relied on
measurements sera.
of their in vitro survival in autologous and heterologous
Supmxide release (nmoles/106 cells/l0 min) Plasma GSH (MM) PMN co”nf ( IO9 cellsA) In virm survival of PMNs in autologous sera (%)
COIlEd
Diabetes
Significance
13.8f3.5 1.21*0.0!9
20.4fO.S 0.6f0.12
5.0f0.3 67f3.9
4.2fO.l 89ztl.9
These data suggest that PMNs from untreated type 2 diabetic patients are primed. This priming ends in oxidative stress with concomitant evidence of inflammation and increased self-necrosis. Necrosis starts a loop of inflammatory reactions accompanied by cell recruitment, and in the long run, together with oxidative stress, may account for the endothelial dysfunction that has been described in these patients.
P1439 Diabetes-Linked Immunoregulatory Defects from ‘D-apical Infections GODWIN 0. IFERE’, Clement 0. Odigwe*, lames Epoke3.
’ Biochemistq College of Medical Sciences, University of Calabac Calabar, Cross River State, Nigeria; ‘Internal Medicine, College of Medical Sciences, Universiry of C&bar; Calabar; Cross River State, Nigeria: 3 Medical Microbiolgy and Parasitology, College of Medical Sciences, University of C&bar; Calabar; Cmss River State, Nigeria There is now evidence that the immunoregulatory
defects resulting in the preponderance of infection in diabetes may be associated with glycation of proteins of the immune system. Infection-induced Cachexia, which results in the release of large amount of CachectiflNF by immunocompetent cells, may complement the glycation-induced immunosuppression. Here, we investigate the synergistic immunoregulatory defects arising from diabetes-linked glycation of the immune system and also from its increased microbial infection. One hundred stable or controlled diabetic and age and sex-matched non-diabetic patients serving as controls were studied. Serum antibody levels using ELISA Test Kits confirmed the extent of various infections. Oral Glucose Tolerance Test (OG’lT), and Glycated Haemoglobin (Hb) (Sigma Diagnostic) diagnosed diabetes and glycaemic control respectively. Glycation of immunoglobulin and lymphocyte membrane protein was assessed by Biorad’s new glycoanalysis Kits and Spectrophotometry respectively. Cell count in the subjects was done with a haemocytometer. CachectirJINF (tumor necrosis factor) in serum of subjects was detected with Sigma Immunoassay Kits. Fifteen each of the 60 diabetic patients presented respectively with Escherichia coli and Klebsiella spp. Infections. Ten of the remaining 20 diabetic Patients had staphylococcus aureus and Salmonella Spp infections respectively. No infection was found in 10 of the diabetic patients. Twenty of the non-diabetic patients had various cases of the listed infections, while the remaining 20 were without any infection. Diabetes was confirmed with OGTT levels z160mg/lOOml. There was a significant (PiO.01) increase in glycation of Hb, immunoglobulin and Lymphocyte membrane protein of all diabetics as compared with non-diabetic subjects. There was no significant difference (P>0.5) in these glycation values in infected and non-infected diabetics. Lymphocytes showed a significant (PeO.01) inhibited proliferation in infected diabetics as compared with non-infected diabetics and non-diabetics. Cachectin/TNFshowed a significant (P