Leucocyte mobilization and release of neutrophil elastase following acute insulin-induced hypoglycaemia in normal humans

Cardiogenic cerebral embolism caused by a severe hypoglycemic attack : a case report

The direct relationship between a hypoglycemic attack and cerebral infarction remains unknown. It has been reported that a hypoglycemic attack can result in takotsubo syndrome, leading to cerebral infarction. We report a case of a cardiogenic cerebral embolism caused by a hypoglycemic attack, with additional literature review. A 71-year-old woman was admitted to our hospital in a semi-comatose state due to a severe hypoglycemic attack ; she developed hemiplegia one day after admission. Magnetic resonance imaging revealed cerebral infarction in the area supplied by the left middle cerebral artery. Takotsubo syndrome was suspected based on echocardiography. We diagnosed cerebral embolism due to takotsubo syndrome, caused by the hypoglycemic attack. J. Med. Invest. 67 : 362-364, August, 2020.

Transient Intermittent Hyperglycemia Accelerates Atherosclerosis by Promoting Myelopoiesis

RATIONALE

Treatment efficacy for diabetes mellitus is largely determined by assessment of HbA1c (glycated hemoglobin A1c) levels, which poorly reflects direct glucose variation. People with prediabetes and diabetes mellitus spend >50% of their time outside the optimal glucose range. These glucose variations, termed transient intermittent hyperglycemia (TIH), appear to be an independent risk factor for cardiovascular disease, but the pathological basis for this association is unclear.

OBJECTIVE

To determine whether TIH per se promotes myelopoiesis to produce more monocytes and consequently adversely affects atherosclerosis.

METHODS AND RESULTS

To create a mouse model of TIH, we administered 4 bolus doses of glucose at 2-hour intervals intraperitoneally once to WT (wild type) or once weekly to atherosclerotic prone mice. TIH accelerated atherogenesis without an increase in plasma cholesterol, seen in traditional models of diabetes mellitus. TIH promoted myelopoiesis in the bone marrow, resulting in increased circulating monocytes, particularly the inflammatory Ly6-C^hi subset, and neutrophils. Hematopoietic-restricted deletion of S100a9, S100a8, or its cognate receptor Rage prevented monocytosis. Mechanistically, glucose uptake via GLUT (glucose transporter)-1 and enhanced glycolysis in neutrophils promoted the production of S100A8/A9. Myeloid-restricted deletion of Slc2a1 (GLUT-1) or pharmacological inhibition of S100A8/A9 reduced TIH-induced myelopoiesis and atherosclerosis.

CONCLUSIONS

Together, these data provide a mechanism as to how TIH, prevalent in people with impaired glucose metabolism, contributes to cardiovascular disease. These findings provide a rationale for continual glucose control in these patients and may also suggest that strategies aimed at targeting the S100A8/A9-RAGE (receptor for advanced glycation end products) axis could represent a viable approach to protect the vulnerable blood vessels in diabetes mellitus. Graphic Abstract: A graphic abstract is available for this article.

Asymptomatic Reactive Hypoglycemia and Inflammatory Reaction in Patients with Coronary Artery Disease

Hyperglycemia is an established risk factor of coronary artery disease (CAD). However, hyperglycemia with preserved pancreatic β cell function induces hyperinsulinemia to correct the glucose profile and may even result in reactive hypoglycemia (RH), which induces an inflammatory response. In this study, the incidence of RH and its effect on arteriosclerosis were examined in CAD patients with a lengthy oral glucose tolerance test (OGTT).We performed a prospective cross-sectional study on 116 nondiabetic CAD patients [70 ± 9 years, 70% male, HbA1c < 6.5%] using coronary angiography and a 4-hour OGTT. Blood samples were collected prior to and 4 hours after the glucose load to evaluate arteriosclerosis markers. Hypoglycemia following the glucose tolerance test was defined as blood glucose levels < 70 mg/dL. We comparatively examined markers of inflammation and arteriosclerosis between the RH group and the non-RH group.A glucose metabolism disorder was observed in 69% of the patients. Hypoglycemia was observed in 24% (28 individuals) of the patients. All showed a RH pattern with no symptoms. The RH group exhibited significantly elevated insulin levels at 1 hour. Furthermore, a significant increase in the white blood cell (WBC) count during OGTT was observed in the RH group compared with the non-RH group [delta WBC; RH: 4.84 (-4.17-20.75) versus non-RH: -2.17 (-9.23-9.09) %; P = 0.04].Asymptomatic RH and an augmentation of inflammation were observed at an incidence of 24% in CAD patients.

The Saudi Diabetic Kidney Disease study (Saudi-DKD): clinical characteristics and biochemical parameters

BACKGROUND

Saudi Arabia is facing an epidemic of type 2 diabetes that is complicated by a high rate of chronic complications such as kidney disease, which have a major impact on the healthcare system and economy. The Saudi diabetic kidney disease (SAUDI-DKD) study was launched to understand the implications of chronic diabetic kidney disease .

OBJECTIVES

Examine the hematological, biochemical and metabolic parameters of the selected cohorts to look for biomarkers of diabetic nephropathy.

DESIGN

Cross-sectional, hospital-based.

SETTING

Four general hospitals and two dialysis centers in Riyadh.

PATIENTS AND METHODS

We recruited adult type 2 diabetic patients aged between 35 and 70 years, with a duration of diabetes > 10 years, including subjects with microalbuminuria, macroalbuminuria and end stage renal disease (ESRD). They were compared with subjects with normal albumin excretion classified according to American Diabetes Association (ADA) criteria.

MAIN OUTCOME MEASURES

The effect of different stages of diabetic nephropathy on hematological and biochemical parameters.

RESULTS

Of 427 subjects with nephropathy, 184 (43%) had microalbuminuria, 83 (19%) had macroalbu.minuria and 160 (37%) had end stage renal disease (ESRD). The remaining 213 (50%) subjects did not have nephropathy. Patients with nephropathy were older with a mean age (SD) of 55.62 (6.00) years and had a longer duration of diabetes (mean [SD], 19.04 [6.33]) years), and had a lower monthly income and body mass index (BMI) than patients without nephropathy. Insulin resistance, elevated uric acid level, low red blood cells (RBCs) count and low hemoglobin level were associated with significantly increased risk of macroalbuminuria and ESRD. Elevated uric acid and LDH were associated with significantly increased risk of microalbuminuria and ESRD, while elevated red blood cell distribution width was significantly associated with an increased risk of ESRD.

CONCLUSION

Diabetic nephropathy is associated with insulin resistance, changes in liver enzymes and uric acid in addition to abnormalities in the red blood cell count and red blood cell shape that warrant frequent monitoring among patients with diabetic kidney disease.

LIMITATIONS

Cross-sectional study design and exclusion of patients with some risk factors.

Low Glucose Concentrations Induce a Similar Inflammatory Response in Monocytes from Type 2 Diabetic Patients and Healthy Subjects

This study aims to assess the proinflammatory interleukin 1β (IL-1β) and anti-inflammatory IL-10 production by monocytes from 38 patients with type 2 diabetes and 31 controls in different glucose concentrations. Monocytes were incubated in low (2.5 mmol/L)-, normal (5.0 mmol/L)-, and high (20 mmol/L)-glucose conditions in the presence and absence of lipopolysaccharide (LPS). Monocytes from both patients and controls only produced a significant increase in IL-1β in low-glucose conditions (p < 0.01), and this phenomenon was amplified in the presence of LPS, while it was not seen in normal- or high-glucose conditions, not even in the presence of LPS stimulation. There was no increase in IL-10 production by monocytes from either diabetic patients or controls using whatever glucose concentrations, except when treated with LPS in normal-glucose conditions. These findings seem to suggest that low-glucose conditions induce an inflammatory response in monocytes in all individuals, as an intrinsic capacity of this cell line. On the other hand, monocytes only retain their anti-inflammatory ability in response to known inflammatory stimuli such as LPS, under normal-glucose concentrations. In conclusion, human monocytes express an inflammatory pattern in low-glucose conditions in vitro. This response could contribute to explaining the higher cardiovascular risk induced by hypoglycemia in diabetic patients.

Prognostic value of blood glucose in emergency room and glycosylated hemoglobin in patients who have suffered an acute cerebro-vascular event

BACKGROUND AND OBJECTIVE

Stress hyperglycemia has been associated with a worse prognosis in patients hospitalized in critical care units. The aim of this study is to evaluate the impact of blood glucose and glycosylated hemoglobin (HbA1c) levels on the mortality of patients suffering a acute cerebro-vascular event, and to determine if this relationship depends on the presence of diabetes.

MATERIAL AND METHODS

A retrospective analysis of 255 patients admitted to the ER for stroke was performed. Venous plasma glucose levels in the emergency room and HbA1c levels within the first 48hours were analyzed. The presence of diabetes was defined in terms of the patients' medical history, as well as their levels of fasting plasma glucose and HbA1c. Mortality was assessed within the first 30 months after the onset of the acute event.

RESULTS

28.2% of patients had diabetes. Higher mortality was observed in patients who had been admitted with plasma glucose levels≥140mg/dl (hazard ratio [HR]=2.22, 95% CI: 1.18-4.16, P=.013) after adjusting for various factors. This relationship was not confirmed in diabetic patients (HR=2.20, 95% CI: 0.66-7.40, P=.201) and was in non-diabetics (HR=2.55, 95% CI: 1.11-5.85, P=.027). In diabetics, HbA1c≥7% was not associated with poor prognosis (HR=0.68, 95% CI: 0.23-1.98, P=.475), whereas non-diabetics with admission levels of HbA1c falling within the pre-diabetes range (5.7% -6.4%) had a higher mortality (HR=2.62, 95% CI: 1.01-6.79, P=.048).

CONCLUSION

Admission hyperglycemia is associated with a worse prognosis in patients without diabetes admitted for stroke, but this relationship was not seen in diabetics. In non-diabetic patients, HbA1c levels in the pre-diabetes range is associated with higher mortality.

Relationship between frequency of hypoglycemic episodes and changes in carotid atherosclerosis in insulin-treated patients with type 2 diabetes mellitus

The effect of hypoglycemia on the progression of atherosclerosis in patients with type 2 diabetes mellitus (T2DM) remains largely unknown. This is a post hoc analysis of a randomized trial to investigate the relationship between hypoglycemic episodes and changes in carotid intima-media thickness (IMT). Among 274 study subjects, 104 patients experienced hypoglycemic episodes. Increases in the mean IMT and left maximum IMT of the common carotid arteries (CCA) were significantly greater in patients with hypoglycemia compared to those without hypoglycemia. Classification of the patients into three groups according to the frequency of hypoglycemic episodes showed that high frequency of hypoglycemic events was associated with increases in mean IMT-CCA, and left max-IMT-CCA and right max-IMT-CCA. In addition, repetitive episodes of hypoglycemia were associated with a reduction in the beneficial effects of sitagliptin on carotid IMT. Our data suggest that frequency of hypoglycemic episodes was associated with changes in carotid atherosclerosis.

Association Between Severe Hypoglycemia and Cardiovascular Disease Risk in Japanese Patients With Type 2 Diabetes

Background

It remains unclear whether severe hypoglycemia is associated with cardiovascular disease (CVD) in Asian populations with type 2 diabetes (T2D). Furthermore, no study in Japan, where the prescription patterns differ from those in other countries, has examined this association.

Methods and Results

We retrospectively included 58 223 patients (18–74 years old) with T2D. First, we examined the potential predictors of severe hypoglycemia. Then, we investigated the association between severe hypoglycemia and CVD risk. Finally, we performed an updated systematic review and meta‐analysis to incorporate our findings and recently published studies into the previous systematic review and meta‐analysis. During 134 597 person‐years from cumulative observation periods, 128 persons experienced severe hypoglycemia and 550 developed CVD events. In a multivariate Cox proportional hazard model, severe hypoglycemia was strongly and positively associated with the risk of CVD (multivariate‐adjusted adjusted hazard ratio, 3.39; 95% CI, 1.25–9.18). In a propensity score–matched cohort that had similar baseline characteristics for patients with severe hypoglycemia and those without, severe hypoglycemia was more strongly associated with the risk of CVD. An updated systematic review and meta‐analysis that included 10 studies found that severe hypoglycemia was associated with an ≈2‐fold increased risk of CVD (pooled relative risk, 1.91; 95% CI, 1.69–2.15).

Conclusions

Our results suggest that severe hypoglycemia is strongly associated with an increased risk of CVD in Japanese patients with T2D, further supporting the notion that avoiding severe hypoglycemia may be important in preventing CVD in this patient population.

Update on strategies limiting iatrogenic hypoglycemia

The prevalence of type 2 diabetes mellitus (T2DM) is increasing all over the world. Targeting good glycemic control is fundamental to avoid the complications of diabetes linked to hyperglycemia. This narrative review is based on material searched for and obtained via PubMed up to April 2015. The search terms we used were: 'hypoglycemia, diabetes, complications' in combination with 'iatrogenic, treatment, symptoms.' Serious complications might occur from an inappropriate treatment of hyperglycemia. The most frequent complication is iatrogenic hypoglycemia that is often associated with autonomic and neuroglycopenic symptoms. Furthermore, hypoglycemia causes acute cardiovascular effects, which may explain some of the typical symptoms: ischemia, QT prolongation, and arrhythmia. With regards to the latter, the night represents a dangerous period because of the major increase in arrhythmias and the prolonged period of hypoglycemia; indeed, sleep has been shown to blunt the sympatho-adrenal response to hypoglycemia. Two main strategies have been implemented to reduce these effects: monitoring blood glucose values and individualized HbA1c goals. Several drugs for the treatment of T2DM are currently available and different combinations have been recommended to achieve individualized glycemic targets, considering age, comorbidities, disease duration, and life expectancy. In conclusion, according to international guidelines, hypoglycemia-avoiding therapy must reach an individualized glycemic goal, which is the lowest HbA1c not causing severe hypoglycemia and preserving awareness of hypoglycemia.

Myocardial Injury without Electrocardiographic Changes after a Suicide Attempt by an Overdose of Glimepiride and Zolpidem: A Case Report and Literature Review

A 40-year-old diabetic man was admitted to our hospital for poor glycemic control. During hospitalization, he took 42 mg glimepiride and 50 mg zolpidem as a suicide attempt. The following day, the creatine kinase-MB fraction and troponin I levels were elevated to 112 IU/L and 8.77 ng/mL, respectively, without any electrocardiographic abnormalities. The patient recovered completely without any complications. Four weeks later, coronary computed tomography angiography and myocardial perfusion scintigraphy revealed moderate one-vessel coronary disease without the evidence of myocardial ischemia or old infarction. Cardiac-specific markers must be considered in sulfonylurea-induced hypoglycemic patients, particularly when the patient is unconscious and does not exhibit any clinical manifestations.

Effect of Repetitive Glucose Spike and Hypoglycaemia on Atherosclerosis and Death Rate in Apo E-Deficient Mice

Epidemiological data suggest that postprandial hyperglycaemia and hypoglycaemia are potential risk factors for cardiovascular disease. However, the effects of repetitive postprandial glucose spikes, repetitive hypoglycaemia, and their combination on the progression of atherosclerosis remain largely unknown. The present study investigated the effects of rapid rises and falls in glucose, and their combination, on the progression of atherosclerosis in apolipoprotein (apo) E-deficient mice. In this study, apo E-deficient mice with forced oral administration of glucose twice daily for 15 weeks were used as a model of repetitive postprandial glucose spikes, and apo E-deficient mice given an intraperitoneal injection of insulin once a week for 15 weeks were used as a model of repetitive hypoglycaemia. In addition, we established a model of both repetitive postprandial glucose spikes and hypoglycaemia by combining the above interventions. Atherosclerosis was evaluated in all mice by oil red O staining. Administration of ipragliflozin, a selective inhibitor of sodium-glucose cotransporter 2, in the mouse model of repetitive glucose spikes inhibited the progression of atherosclerosis, whereas long-term repetitive glucose spikes, repetitive hypoglycaemia, and their combination had no significant impact on atherosclerosis. However, repetitive hypoglycaemia was associated with poor survival rate. The results showed that repetitive hypoglycaemia reduces the survival rate without associated progression of atherosclerosis in apo E-deficient mice.

The clinical impact of inpatient hypoglycemia

Hypoglycemia is common in hospitalized patients and is associated with poor outcomes, including increased mortality. Older individuals and those with comorbidities are more likely to suffer the adverse consequences of inpatient hypoglycemia. Observational studies have shown that spontaneous inpatient hypoglycemia is a greater risk factor for death than iatrogenic hypoglycemia, suggesting that hypoglycemia acts as a marker for more severe illness, and may not directly cause death. Initial randomized controlled trials of intensive insulin therapy in intensive care units demonstrated improvements in mortality with tight glycemic control, despite high rates of hypoglycemia. However, follow-up studies have not confirmed these initial findings, and the largest NICE-SUGAR study showed an increase in mortality in the tight control group. Despite these recent findings, a causal link between hypoglycemia and mortality has not been clearly established. Nonetheless, there is potential for harm from inpatient hypoglycemia, so evidence-based strategies to treat hyperglycemia, while preventing hypoglycemia should be instituted, in accordance with current practice guidelines.

Repetitive hypoglycemia increases circulating adrenaline level with resultant worsening of intimal thickening after vascular injury in male Goto-Kakizaki rat carotid artery

Hypoglycemia associated with diabetes management is a potential risk for cardiovascular diseases. However, the effect of hypoglycemic episodes including a surge of sympathetic activity on the progression of neointima formation after vascular injury remains largely unknown. In this study, insulin was injected intraperitoneally into nonobese diabetic Goto-Kakizaki (GK) rats, once every 3 days for 4 weeks after balloon injury of carotid artery to induce hypoglycemia. Then, we evaluated balloon injury-induced neointima formation. Insulin treatment enhanced neointima formation and increased the number of proliferating cell nuclear antigen (PCNA)-positive cells in the carotid artery. Injection of glucose with insulin prevented hypoglycemia and abrogated intimal thickening. Also, bunazosin, an α1 adrenergic receptor antagonist, prevented intimal thickening and accumulation of PCNA-positive cells induced by insulin treatment despite the presence of concomitant hypoglycemia and high adrenaline levels. Incubation of cultured smooth muscle cells with adrenaline resulted in a significant increase in their proliferation and G0/G1 to S phase progression, which was associated with activation of extracellular signal-regulated kinase, enhanced expression of cell cycle regulatory molecules such as cyclin D1, and cyclin E, and phosphorylation of retinoblastoma protein. These adrenaline-induced effects were abrogated by bunazosin. Our data indicated that increased adrenaline induced by repetitive hypoglycemia promotes intimal thickening and smooth muscle cell proliferation after endothelial denudation in GK rats.

Repetitive hypoglycaemia increases serum adrenaline and induces monocyte adhesion to the endothelium in rat thoracic aorta

AIMS/HYPOTHESIS

Severe hypoglycaemia associated with diabetes management is a potential risk for cardiovascular diseases. However, the effect and mechanism of hypoglycaemia on the progression of atherosclerosis remains largely unknown. As a first step towards elucidating the above, we investigated the effect of hypoglycaemia on monocyte-endothelial interaction.

METHODS

Insulin was injected intraperitoneally once every 3 days for 5 weeks in Goto-Kakizaki rats, a non-obese rat model of type 2 diabetes. We counted the number of monocytes adherent to the endothelium of thoracic aorta as an index of early atherosclerogenesis. Cultured HUVEC were used to investigate the mechanism of action.

RESULTS

Insulin treatment increased the number of monocytes adherent to the vascular endothelium. This increase was abrogated by injection of glucose with insulin. Amosulalol, an α-1 and β-adrenoreceptor antagonist, suppressed monocyte adhesion to endothelium and levels of adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in the endothelial surface, which had been enhanced by insulin-induced hypoglycaemia. In HUVEC, adrenaline (epinephrine) significantly increased nuclear translocation of nuclear factor-κB (NF-κB) p65 and levels of adhesion molecules, effects that were abrogated following addition of SQ22536, a specific adenyl cyclase inhibitor.

CONCLUSIONS/INTERPRETATION

Our data indicate that repetitive hypoglycaemia induced by insulin enhanced monocyte adhesion to endothelial cells in Goto-Kakizaki rat aorta through enhanced adrenaline activity and that the latter stimulated intracellular cAMP, leading to nuclear translocation of NF-κB with subsequent production of adhesion molecules in endothelial cells.

Vascular endothelial growth factor during hypoglycemia in patients with type 1 diabetes mellitus: relation to cognitive function and renin-angiotensin system activity

In healthy adults, levels of vascular endothelial growth factor (VEGF) increase in response to mild hypoglycemia. VEGF is implicated in glucose transport over the blood-brain barrier, and the increase during hypoglycemia has been positively correlated with preservation of cognitive function during hypoglycemia. High activity in the renin-angiotensin system (RAS) is associated with an increased risk of severe hypoglycemia in patients with type 1 diabetes mellitus. Renin-angiotensin system possibly exerts its mechanism in hypoglycemia via VEGF. We studied the impact of mild hypoglycemia on plasma VEGF in patients with type 1 diabetes mellitus and high or low RAS activity and analyzed associations between VEGF levels and cognitive function during hypoglycemia. Eighteen patients with type 1 diabetes mellitus-9 with high and 9 with low RAS activity-underwent a single-blinded, placebo-controlled, crossover study with either mild hypoglycemia or stable glycemia. Cognitive function was assessed by the California Cognitive Assessment Package and the Alzheimer Quick Test. Nadir plasma glucose was 2.2 (0.3) mmol/L. During the control study, plasma VEGF did not change. During hypoglycemia, plasma VEGF increased from 39 to 58 pg/L in the high-RAS group (P = .004) and from 76 to 109 pg/L in the low-RAS group (P = .01), with no difference between RAS groups (P = .9). A weak association between reduced preservation of cognitive function during hypoglycemia and low VEGF response was observed. Plasma VEGF levels increase during mild, short-term hypoglycemia in patients with type 1 diabetes mellitus. The VEGF response is not dependent on RAS activity and only weakly associated with preservation of cognitive function during hypoglycemia. Thus, the previously described association between low RAS activity and better cognitive performance during hypoglycemia does not seem to be mediated by VEGF.

Vascular disease and diabetes: is hypoglycaemia an aggravating factor?

Acute hypoglycaemia provokes profound physiological changes affecting the cardiovascular system and several haematological parameters, principally as a consequence of sympatho-adrenal activation and counter-regulatory hormonal secretion. Many of these responses have an important role in protecting the brain from neuroglycopenia, through altering regional blood flow and promoting metabolic changes that will restore blood glucose to normal. In healthy young adults the cardiovascular effects are transient and have no obvious detrimental consequences. However, some of the effected changes are potentially pathophysiological and in people with diabetes who have developed endothelial dysfunction, they may have an adverse impact on a vasculature that is already damaged. The acute haemodynamic and haematological changes may increase the risk of localized tissue ischaemia, and major vascular events can certainly be precipitated by acute hypoglycaemia. These include myocardial and cerebral ischaemia and occasionally infarction. Established diabetic retinopathy often deteriorates after strict glycaemic control is instituted, the latter being associated with a threefold increase in frequency of severe hypoglycaemia, and enhanced exposure to mild hypoglycaemia. The possible mechanisms underlying these hypoglycaemia-induced effects include haemorrheological changes, white cell activation, vasoconstriction, and the release of inflammatory mediators and cytokines. The concept that acute hypoglycaemia could aggravate vascular complications associated with diabetes is discussed in relation to evolving comprehension of the pathogenesis of atherosclerosis and blood vessel disease.

Plasma endothelin response to acute hypoglycaemia in adults with Type 1 diabetes

AIMS

To determine whether acute insulin-induced hypoglycaemia provokes a detectable alteration in peripheral plasma endothelin (ET) concentrations in humans with Type 1 diabetes.

METHODS

Serial plasma concentrations of ET were measured in 20 patients with Type 1 diabetes during controlled hypoglycaemia induced by intravenous infusion of soluble insulin.

RESULTS

A significant increase was observed in plasma ET concentrations, from 3.80 +/- 0.31 pg/ml at baseline to 6.72 +/- 1.47 pg/ml at 60 min after the onset of the hypoglycaemic reaction (P < 0.05).

CONCLUSIONS

Acute insulin-induced hypoglycaemia induces a rise in plasma endothelin concentrations in people with Type 1 diabetes. This finding is consistent with a putative role for ET in the mediation of hypoglycaemia-induced vasoconstriction, and the possible precipitation of macrovascular or microvascular events.

Bikunin (Urinary Trypsin Inhibitor): Structure, Biological Relevance, And Measurement

Inflammatory processes, such as phagocytosis, coagulation, and vascular dilation, promote the release of serine proteases by neutrophils, macrophages, mast cells, lymphocytes, and the epithelial or endothelial cells. These proteases further facilitate the release of inflammatory cytokines and growth factors as well as take part in signal-cell proliferation through protease-activated receptors (PARs). Controlling the action of this cascade is necessary to prevent further damage to the normal tissues. One of the main anti-inflammatory response mediators is bikunin (Bik) that is responsible for inhibiting the activity of many serine proteases such as trypsin, thrombin, chymotrypsin, kallikrein, plasmin, elastase, cathepsin, Factors IXa, Xa, XIa, and XlIa. During the acute-phase response, Bik is released into plasma from proinhibitors primarily due to increased elastase activity. Bik is a glycoprotein, also referred to as urinary trypsin inhibitor, which in plasma inhibits the trypsin family of serine proteases by binding to either of the two Kunitz-binding domains. Bik also accumulates in urine. In conditions such as infection, cancer, tissue injury during surgery, kidney disease, vascular disease, coagulation, and diabetes, the concentrations of Bik in plasma and urine are increased. Several trypsin inhibitory assays for urine and immunoassays for both blood and urine have been described for measuring Bik. In addition to presenting the synthesis, structure, and pathophysiology of Bik, we will summarize various diagnostic approaches for measuring Bik. Analysis of Bik may provide a rapid approach in assessing various conditions involving the inflammatory processes.

Insulin differentially regulates monocyte and polymorphonuclear neutrophil functions in healthy young and elderly humans

CONTEXT

Insulin can regulate immune cell function. Aging is associated with various degrees of insulin resistance together with reduced immune cell activity.

OBJECTIVE

We investigated the hypothesis that blood monocytes and polymorphonuclear neutrophils (PMNs) are less responsive to the action of insulin in elderly subjects. DESIGN-INTERVENTION: We evaluated the effect of hyperinsulinemia (0.7 mU/kg(-1) fat-free mass per minute(-1)) on monocyte and PMN activity using a 4-h euglycemic clamp technique.

PARTICIPANTS

Eight young (24 +/- 6 yr old) and nine elderly (69 +/- 4 yr old) healthy volunteers participated in the study.

MAIN OUTCOME MEASURES

Monocyte and PMN receptor expression and density were measured using flow cytometric detection. PMN chemotaxis toward formyl-Met-Leu-Phe (fMLP) was evaluated using a two-compartment chamber. PMN and monocyte phagocytosis was determined by measuring the engulfment of opsonized particles. Microbicidal functions were determined based on the production of reactive oxygen species (ROS) and bactericidal protein by stimulated cells.

RESULTS

The density of PMN and monocyte insulin receptors was not affected by age or insulin clamp treatment regardless of the age. Insulin was able to regulate the expression of receptors involved in PMN action in the young-adult group only. PMN chemotaxis was up-regulated by insulin in both groups. In contrast, although insulin stimulated phagocytosis and bactericidal activity in young-adult subjects, the ability of PMN to adapt to physiological hyperinsulinemia was blunted in the older group. The effect of insulin on monocyte bactericidal properties seemed to be limited, although a suppressive action on fMLP-induced ROS production was detected in young adults.

CONCLUSIONS

We confirmed the presence of the insulin receptor on monocyte and PMN membranes. We revealed that insulin has a limited action on monocyte function. Insulin has a priming effect on the main PMN functions. Immune cell function adapted poorly to insulin infusion in the elderly subjects.

Peripheral total and differential leukocyte count in diabetic nephropathy: the relationship of plasma leptin to leukocytosis

OBJECTIVE

Because of increasing evidence that white blood cells (WBCs) play a role in the development and progression of diabetes complications, this study aimed to investigate the relation of circulating total and differential leukocyte counts to nephropathy in patients with type 2 diabetes. Plasma leptin levels were also measured to investigate their role in peripheral leukocytosis.

RESEARCH DESIGN AND METHODS

For this study, 1,480 subjects with type 2 diabetes who were enrolled in a disease management program were stratified according to urinary microalbumin and serum creatinine measurements. The total and differential leukocyte profiles of peripheral blood were measured and plasma leptin was examined by enzyme-linked immunosorbent assay. Demographic and potential metabolic confounding factors were analyzed with linear and logistic regression to calculate the effects of leukocyte count on diabetic nephropathy.

RESULTS

The peripheral total WBC, monocyte, and neutrophil counts increased in parallel with the advancement of diabetic nephropathy. In contrast, the lymphocyte count decreased. When WBC counts were analyzed per quartile and as continuous variables after adjusting for age, sex, and other known risk factors with multiple regression analysis, peripheral total WBC, monocyte, neutrophil, and lymphocyte counts were independently and significantly associated with diabetic nephropathy. Plasma leptin levels increased in patients with nephropathy and correlated significantly with total WBC count (r = 0.194, P = 0.014).

CONCLUSIONS

Because leukocytes are activated and secrete cytokines in the diabetic state and leptin stimulates leukocyte proliferation and differentiation, our results suggest that circulating leukocytes contribute to the development and progression of nephropathy, partially through the effects of leptin, in patients with type 2 diabetes.

In vivo evidences that insulin regulates human polymorphonuclear neutrophil functions

Polymorphonuclear neutrophils (PMN) are able to destroy invasive mircoorganisms by a wide variety of functions. Whereas insulin does not stimulate hexose transport in PMN, previous reports have clearly shown that this hormone regulates glucose metabolism inside this cell, raising the question of insulin action on PMN functions in humans. It is interesting that in vitro studies established a strong relationship between specific binding of insulin to its PMN membrane receptor and the activation of the main PMN functions. Therefore, investigation in healthy subjects under strict euglycemia and physiological insulinemia was performed to understand the in vivo-specific action of insulin on PMN functions without hyperglycemia interferences. We determined numerous PMN functions before and after hyperinsulinemia (0.5 mU/kg/min) and euglycemia (0.9 g/l) clamp for 4 h in eight adult healthy volunteers (24+/-6 years). The total number of PMN and the number of PMN expressing CD11b, CD15, CD62L, and CD89 were significantly increased over baseline (P<0.001), whereas the density of these receptors was down-regulated (P<0.01) by insulin. PMN chemotaxis (+117%, P<0.05), phagocytosis (+29%, P<0.001), and bactericidal (+17-25%, P<0.001) capacities were increased during the insulin clamp (P<0.05). Therefore, insulin treatment may modulate PMN functions not only by attainment of a better metabolic control, as suggested by in vivo studies in diabetic patients, but also through a direct effect of insulin.