Platelet activation in subjects with impaired glucose tolerance

Impaired glucose tolerance (IGT), a prediabetic state, is associated with an increased risk of cardiovascular disease. Mean platelet volume (MPV), a determinant of platelet activation, is a newly emerging risk factor for atherothrombosis. This study was designed to answer the following questions: (i) Do MPV levels change in IGT? (ii) Is there any relation between MPV levels and 2 h plasma glucose levels after 75 g oral glucose tolerance test. We selected 48 subjects with IGT, and 48 healthy subjects with normal glucose tolerance matched for age, gender, and body mass index. MPV was significantly higher in IGT group than in control group (9.06 +/- 1.5 fl vs. 8.28 +/- 0.8 fl, p = 0.002). Also, MPV was positively correlated with 2 h plasma glucose concentration in IGT group (r = 0.39, p = 0.006). In conclusion, our results suggest that subjects with IGT tend to have increased platelet activation. Increased platelet activity could contribute to increasing the risk of cardiovascular disease in IGT.     

The effect of weight loss on the mean platelet volume in obese patients

Obesity is a chronic metabolic disorder associated with cardiovascular disease and atherosclerosis. Platelet activation and aggregation are central processes in the pathophysiology of cardiovascular disease. Mean platelet volume (MPV), a determinant of platelet activation, is a newly emerging risk marker for atherothrombosis. Our objective was to evaluate the effect of weight loss on the MPV in obese patients. We selected 30 obese women patients and 30 non-obese healthy women subjects. All obese patients took the same content and caloric diet treatment for 3 months. Body mass index (BMI), metabolic parameters and MPV were measured at baseline and after 3 months diet treatment. Before diet treatment, obese group had significantly higher MPV levels than in the non-obese control group (8.18?±?1.09 fl vs. 8.01?±?0.95 fl, p?=?0.004). MPV showed positive correlations with BMI level in the obese group (r?=?0.43, p?=?0.017). BMI significantly decreased after diet treatment (36.2?±?3.2?kg/m² vs. 34.7?±?3.6?kg/m², p?<?0.001), in the obese group. MPV significantly decreased after diet treatment in the obese group (8.18?±?1.09 fl vs. 8.08?±?1.02 fl, p?=?0.013). There was a positive correlation between weight loss and reduction in MPV (r?=?0.41, p?=?0.024). In addition to its well-known positive effects on cardiovascular disease risk, weight loss may also possess significant anti-platelet activation properties that can contribute its antiatherogenic effects in obese patients.     

Platelet activation in patients with Familial Mediterranean Fever

Increased platelet activation and aggregation are central processes in the pathophysiology of atherosclerosis. Increased platelet activity is associated with increased platelet volume. Mean platelet volume (MPV), a determinant of platelet function, is a newly emerging risk factor for atherothrombosis. Familial Mediterranean Fever (FMF) is an autosomal recessive disease characterized by recurrent inflammatory febrile attacks of serosal and synovial membranes. Recently few studies have shown that FMF is associated with increased atherosclerosis risk. The present study was designed to evaluate levels of MPV in FMF patients compared with healthy subjects. We selected 35 FMF patients and 35 healthy control subjects matched for age, gender, and body mass index. Metabolic parameters and MPV levels were measured in all groups. Metabolic parameters were not different among the study groups (p > 0.05). The levels of MPV were significantly higher in the FMF group than in the control group (8.6 ± 0.9 fl vs 7.8 ± 0.5 fl, p = 0.001). The MPV levels were negatively correlated with duration of colchicine treatment (r = ?0.40, p = 0.017). Also MPV levels showed positive correlation with delay of diagnosis (r = 0.58, p = 0.001). In conclusion, our results suggest that patients with FMF tend to have an increased platelet activation. Increased platelet activity could contribute to increasing the atherosclerotic risk in FMF patients.     

The association of mean platelet volume levels with hypertensive retinopathy

The pathophysiological mechanism of hypertensive retinopathy (HR) is not fully established. Elevated blood pressure alone does not fully account for the extent of retinopathy so other pathogenic mechanisms may be involved, such as increased platelet activation. Mean platelet volume (MPV) is a marker of platelet activation. Therefore, this study was designed to answer the following questions: Do MPV levels change in HR? and is there any relation between degree of HR and MPV levels? This study included newly diagnosed and 57 untreated essential hypertensive patients with HR. The hypertensive patients were divided into two groups according to the Keith, Wagener classification. Group 1 comprised 29 hypertensive patients with grade 1 HR with a mean age of 56.8 ± 9.7 years. Group 2 comprised 28 hypertensive patients with grade 2 HR with a mean age of 58.1 ± 10.3 years. Twenty-seven normotensive subjects who were the healthy participants and had undergone the check-up program were used as the control group. Fundoscopic examination, metabolic parameters and MPV levels were measured in all groups. The level of MPV in group 2 was significantly higher than in group 1 (8.9 ± 0.8 fl vs.8.3 ± 0.8 fl, p = 0.02) and the normotensive control group (8.9 ± 0.8 fl vs 7.8 ± 0.7 fl, p < 0.001). It was also higher in group 1 than in normotensive control group (8.3 ± 0.8 fl vs.7.8 ± 0.7 fl, p < 0.01). In addition, MPV showed a positive correlation with the degree of HR in the hypertensive group (r = 0.41, p = 0.015). Our study suggests that platelet activation, a mechanism known to be involved in vascular lesions, may promote the development of HR.     

Lifestyle modification decreases the mean platelet volume in prehypertensive patients

Mean platelet volume (MPV) is an indicator of platelet activation. The present study was designed to investigate platelet function by measuring MPV, platelet count (PLC) and platelet mass (PLM) in prehypertensive (PHT) subjects. Additionally, we also evaluated the effects of lifestyle modification on platelet functions by measuring MPV, PLC and PLM. We selected 36 newly diagnosed PHT patients and 21 control subjects (BP < 120/80 mmHg) matched for age and sex. Lifestyle modifications (weight loss, reduced sodium intake, increased physical activity, limited alcohol consumption and the Dietary Approaches to Stop Hypertension (DASH) diet) were recommended to PHT individuals for 20 weeks. At entry into the study, although PLM and PLC values were similar between study groups, MPV values were significantly higher in the PHT group than in the control group (respectively, 10.41 ± 0.93 fl vs. 9.56 ± 1.04 fl, p < 0.01). Additionally, MPV was positively correlated with the systolic blood pressure (BP), body mass index (BMI) and insulin resistance (IR) in the PHT group (r: 0.41; p < 0.02, r: 0.37; p < 0.04, r: 0.35; p < 0.05, respectively). Only age and PHT were found to be independent predictors of MPV after regression analysis. The program substantially lowered BP (net reductions in systolic and diastolic BPs of 16.2 and 8.7 mmHg, p < 0.001, p < 0.001, respectively). In addition, BMI, waist circumference (WC) and IR were significantly reduced in the PHT group (p < 0.01, p < 0.01, p < 0.05, respectively). At the end of study, although PLM, PLC values were reduced in the PHT group, only the decrease in MPV reached statistical significance (respectively, 10.41 ± 0.93 fl vs. 9.67 ± 1.2 fl, p < 0.01). In closing, to our best notice, our study is the first to display a significant increase in MPV in PHT subjects and to show a decrease in MPV by lifestyle modification after 20 weeks. As a result, we consider that decreased platelet activation with multi-aspect effects of lifestyle modification therapy might play an important role in reducing thrombotic risk in PHT patients.     

The mean platelet volume in subjects with impaired fasting glucose

Mean platelet volume (MPV), a determinant of platelet function, is a newly emerging risk factor for atherothrombosis. Impaired fasting glucose (IFG) is probably a frequent glycemic disorder in the general population and is considered as a prediabetic state. The present study was designed to evaluate MPV in subjects with IFG compared with diabetic patients and normoglycemic control subjects. We selected 50 patients with type 2 diabetes mellitus, 50 subjects with IFG, and 50 normoglycemic healthy subjects matched for age, gender, and body mass index. MPV was very significantly higher in diabetic and IFG groups than in control group (p?<?0.00, p?<?0.05, respectively); it was also higher in diabetic group than in IFG group (p?<?0.05). Platelet counts were not different among the study groups (p?>?0.05). Platelet mass was significantly higher in diabetic and IFG groups than in normotensives (p?<?0.00, p?<?0.05, respectively); and it was also higher in diabetic group than in IFG group (p?<?0.05). MPV and platelet mass were positively correlated with fasting glucose and HbA1c in diabetic and IFG groups (p?<?0.05). In conclusion, our data suggests one possible mechanism by which subjects with IFG may be at increased cardiovascular risk.     

Effects of cesarean section on mean platelet volume

Mean platelet volume (MPV) is a risk factor for cardiovascular complications, cerebrovascular disorders, and low-grade inflammatory conditions prone to arterial and venous thromboses. Cesarean delivery is the most important risk factor for pulmonary embolism, stroke, and intracranial venous thrombosis. The hypothesis is that increase in the prevalence of cesarean section and high MPV may be associated with cardiovascular complications such as stroke along with intracranial complications in addition to known systemic and surgical complications. In this study, platelet counts and MPV for postpartum women who delivered by cesarean section and normal vaginal parturition are compared. The subjects were divided in two groups, one was study group consisting of 118 patients giving birth by cesarean section and the other was the control group consisting 94 patients giving birth by normal vaginal parturition. Peripheral venous blood samples in EDTA tubes were collected from all the subjects 1 week before and after the delivery for their prenatal and postpartum periods, respectively. The values were compared between the groups and also before and after the delivery. In the cesarean group, while the MPV level was 8.60 (1.64) fl in the prenatal period, it increased to 9.10 (2.00) fl in the postnatal period (p?<?0.001). Group effect, time effect (independent from group effect), and group*time interaction effect were statistically significant for MPV variable (p?=?0.032, p?<?0.001, and p?=?0.012, respectively). This study concluded that MPV, along with several other factors, may be used as a prognostic, independent, and therapeutic marker in patients who are inclined to thrombotic events after cesarean section.     

Mean platelet volume and left ventricular geometry in patients with aortic valve stenosis

Abstract

Background: Mean platelet volume (MPV) is a well-established marker of platelet activation. In the current study, we compared MPV between patients with aortic valve stenosis (AS) and control subjects. We also assessed the association between MPV and left ventricular geometry in patients with AS. Methods and results: The study population consisted of 75 patients with AS and 38 age- and sex-matched control subjects. In patients with AS, peak pressure gradient was 83.0?±?30.8?mm?Hg. MPV was significantly larger in patients with AS than control subjects (10.57?±?1.05 fl versus 9.72?±?0.66 fl, p?<?0.001). There was a significant association between peak pressure gradient and MPV in 75 patients with AS and 38 control subjects (r?=?0.35, p?<?0.001). Among the patients with AS, there were 12 patients with normal geometry, 10 patients with concentric remodeling, 14 patients with eccentric hypertrophy and 39 patients with concentric hypertrophy. There was no significant difference in MPV among the four groups. There was no significant association between MPV and LVM index. Conclusions: Our data suggested that MPV increased in patients with AS, but did not reflect left ventricular geometry.     

Evidence for Impaired Pancreatic Beta Cell Function in South African Indians with Impaired Glucose Tolerance

In a prospective study of South African Indians with impaired glucose tolerance (IGT), the serum insulin response during a 75 g oral glucose tolerance test (OGTT) was examined in 128 subjects who were classified as IGT 1 year previously (year 0) and in 60 matched control subjects. Based on the results at year 1, study subjects were divided into three groups, using World Health Organization criteria for glucose tolerance: IGT (n = 47), diabetes (n = 41), and transient IGT (normal glucose tolerance) (n = 40). When compared with the control group, despite higher plasma glucose concentrations, the IGT group showed similar fasting insulin, but lower 30-min insulin response (57.4 ± 1.9 mUI^?1 vs 86.5 ± 1.8, p<0.001) and lower 30-min insulin/glucose ratio (7.4 ± 5.2 vs 13.3 ± 8.7, p < 0.001). The insulinogenic index was lower in the IGT group than in the control group at 30, 60, 90, and 120 min (p < 0.01, p < 0.001, p < 0.001, p < 0.001, respectively). The 2-h insulin response was higher in the IGT group (106.7 ± 1.9 mUI^?1 vs 59.2 ± 1.9, p < 0.01). The IGT group displayed a delayed pattern of insulin response with maximum levels only at 2-h. Insulin area was similar in the two groups. In the transient IGT group, despite similar plasma glucose levels, the insulin responses at 0, 15, 30, and 60 min (p < 0.01, p < 0.001, p < 0.001, p < 0.001, respectively) were lower than in the control group; the 30-min insulin/glucose ratio (7.1 ± 5.1 vs 13.3 ± 8.7, p < 0.001) and 60-min insulinogenic index (46.9 ± 86.3 vs 123.4 ± 206.3, p < 0.001) were also lower in the transient IGT group. This study has shown that IGT in South African Indians is characterized by a diminished early phase insulin response and delayed (2-h) hyperinsulinaemia during OGTT. Such findings would suggest that in this population group impaired early beta cell function is an important pathophysiological abnormality underlying IGT.     

Mean platelet volume: An important predictor of coronary collateral development

Collaterals, which develop in response to ischemic stimuli derived from coronary artery disease (CAD), contribute to reduction of infarct size, left ventricular dysfunction, and mortality. However, there is considerable variation among patients with coronary heart disease regarding the extent of coronary collateral development (CCD). In this study, we aimed to investigate the association of the degree of platelet activation via mean platelet volume (MPV) with coronary collateral circulation. Therefore, 210 patients who underwent coronary angiography and had coronary stenosis ≥50 % in at least one coronary artery were included in the study. Clinical information and analyses of blood samples were obtained from a review of the patients’ chart. Blood samples for MPV were analyzed by K3 EDTA and collateral vessels were graded according to the Rentrop classification. In the study group, 150 of the 210 patients were found to have inadequate CCD. Although there was no difference between the two groups with regard to platelet count, MPV levels were significantly higher in the patients who had inadequate CCD (11.3?±?1.0 fl vs. 9.5?±?1.5 fl, p?<?0.001). Furthermore, the Gensini score was significantly lower in patients who had inadequate CCD (45?±?46 vs. 91?±?35, p?<?0.001). MPV, Gensini score, age, female gender, total cholesterol, red cell distribution width, triglyceride, and fasting glucose levels were found to have univariate association with poor CCD. In multivariate logistic regression model, MPV (OR?=?2.45, p?<?0.001) and Gensini score (OR?=?0.98, p?<?0.001) were found to be the independent predictors of impaired CCD. In receiver operator characteristic curve analysis, optimal cut-off value of MPV to predict inadequate CCD was found as >9.6 fl, with 96% sensitivity and 84.7% positive predictive value. In conclusion, we can say that MPV is an important, simple, effortless, and cost effective tool and can be useful in predicting the CCD in patients with significant CAD.     

Mean platelet volume in patients with subclinical hypothyroidism

Subclinical hypothyroidism (SCH) is frequently encountered in the general population. Since it is generally asymptomatic, these patients are mostly identified through routine screening or evaluation of non-specific symptoms. It has been suggested as a risk factor for cardiovascular disease. On the other hand, mean platelet volume (MPV), which is a determinant of platelet function, is an independent risk factor for cardiovascular disease. The aim of this study was to evaluate MPV values in subclinical hypothyroidic patients when they were subclinical hypothyroidic and became euthyroidic after 12 weeks of levothyroxine replacement therapy. Sixty patients with subclinical hypothyroidism and 78 euthyroid healthy subjects matched for age, gender and body mass index were enrolled in the study. None of the study subject had diabetes, hypertension or dyslipidemia. All the study subjects were evaluated by biochemical and platelet parameters. Subclinical hypothyroidic patients were then reevaluated with the same parameters when they became euthyroid after 12 weeks of levothyroxine treatment. Platelet counts and metabolic parameters, except serum triglyceride and high density lipoprotein cholesterol (HDLC) levels, were similar between the two groups. Serum triglyceride and MPV values were significantly higher (pTG?=?0.007 and pMPV?<?0.001) while HDLC levels were lower (pHDLC?=?0.008) in the subclinical hypothyroidic group. MPV was found to be correlated with only antithyroid peroxidase (anti-TPO) antibody levels (P?<?0.001). MPV values were decreased after subclinical hypothyroidic patients became eythyroid. However, post-treatment MPV values were still higher (p?=?0.035) in the patient group than in control group. These results suggest that subjects with SCH are susceptible to increased platelet activation and increased MPV values which contribute to increased risk of cardiovascular complications.     

Coronary heart disease is associated with mean platelet volume in type 2 diabetic patients

Background: Mean platelet volume (MPV) is an indicator of platelet activation which is a central process in the pathophysiology of coronary heart disease (CHD). The aim of the study was twofold; first to determine whether MPV values is increased in patients with DM, and secondly to evaluate the relation between diabetic complications and MPV. Methods: The study population included 258 patients divided into two groups. Group A composed of 158 type 2 diabetic patients with coexistent coronary artery disease (stenotic lesions of 50%) (78 women, 80 men; mean age 53.9_10.8; mean diabetes duration 13.1_6.0). One hundred subjects (48 women, 52 men; mean age 53.9_11) without type 2 diabetes with normal coronary angiographies were taken as the control group (group B). To evaluate the extension of CHD, Gensini scoring system was used. Results: The MPV was significantly different in the patient group compared to the controls (9.79 ± 1.5 fl vs 8.3 ± 0.9 fl, P<0.001). The existence of CHD was associated with MPV with odds ratio (95% CI) of 2.31 (1.55–4.42, p50.001). Conclusion: We have found that diabetic patients with coronary heart disease have significantly higher MPV values compared to control subjects without diabetes and with angiographically normal coronary arteries.     

The mean platelet volume in gestational diabetes

Objective: To compare the platelet count and mean platelet volume (MPV) values of pregnancies diagnosed with gestational diabetes with those of healthy pregnancies. Material—method: Between June 2003 and September 2004, 100 healthy pregnancies and 100 pregnancies with gestational diabetes were studied at Gazi University, Department of Obstetrics and Gynecology. Results: While no statistically significant difference was observed in the platelet count between the two groups, the MPV of the gestational diabetes group (9.4 ± 1.6 fl) was evaluated to be significantly higher than the MPV of the healthy pregnancy group (8.3 ± 1.1 fl). Additionally, when linear regression analysis was performed an inverse relationship was observed between platelet number and MPV. Conclusion: There is a need for further research focusing on the platelet function in the observation and treatment of gestational diabetes, which can pose the risk of developing Type 2 diabetes for the mother and has negative consequences for the fetus.     

Assessment of mean platelet volume and soluble CD40 ligand levels in patients with non-dipper hypertension,dippers and normotensives

Abstract

Objective: Patients with a lack of nocturnal decline in blood pressure (BP) are at an increased risk for cardiovascular events. Mean platelet volume (MPV) and soluble CD40 ligand (sCD40L) are accepted biomarkers of platelet activation and considered as a risk factor for cardiovascular disease. The aim of this study was to determine whether MPV and sCD40L levels are higher in non-dipper hypertensive (NDHT) patients than in dipper hypertensive (DHT) patients and healthy controls.

Methods: 124 consecutive patients were included to this study. Patients were divided into three groups: NDHT patient group [n?=?43; mean age 51.8?±?6.6; 31?males (72.1%)]; DHT patient group [n?=?41; mean age 50.2?±?7.3; 22?males (53.7%)]; and normotensive group [n?=?40; mean age 49.9?±?6.7; 22?males (55%)]. Physical examination, laboratory work-up and 24-h ABPM were performed for all participants.

Results: The sCD40L and MPV levels were significantly higher in the NDHT group than in the DHT and normotensive groups (p?<?0.05). In correlation analysis, MPV, 24-h systolic blood pressure (SBP), 24-h diastolic blood pressure (DBP), night-time SBP and night-time DBP were positively correlated with sCD40L.

Conclusion: Our study demonstrated that MPV and sCD40L levels were significantly higher in NDHT patients compared to DHT and normotensive patients. sCD40L levels were positively correlated with MPV, 24-h SBP, 24-h DBP, night-time SBP and night-time DBP.     

Mean platelet volume in psoriasis and psoriatic arthritis

Mean platelet volume (MPV), an indicator of platelet activation, is a newly emerging risk factor for atherothrombosis. There is evidence of platelet activation in psoriasis and psoriatic arthritis (PsA). The association between psoriasis, PsA, and atherosclerosis is well documented, yet, the underlying mechanisms remain unclear. The aim of this study was to investigate the differences of MPV values in patients with psoriasis, PsA, and healthy subjects and the correlation between MPV and the clinical disease activity. A total of 106 patients with psoriasis were included in this study. The study population grouped as 48 patients with PsA (group 1) and 58 patients without PsA (group 2) and 95 healthy controls (group 3). MPV was measured in psoriasis and PsA patients. MPV values were collected from standard complete blood count samples. Clinical features and PASI scores in group 1 and 2 were also recorded. MPV in patients with psoriasis 8.7 ± 0.9 fL was significantly higher than that of control subjects 7.3 ± 0.8 fL (p < 0.001). There was also statistical difference between MPV levels of patients with (9.5 ± 0.8) and without (8.0 ± 0.7) arthritis (p < 0.001). MPV levels were positively correlated with psoriasis area and severity index score (p = 0.000, r = +0.735). MPV levels showed positive correlation with disease duration (p = 0.01, r = 0.518). MPV levels are increased in patients with psoriasis and PsA. MPV may be a marker for the severity of psoriasis. This study may confirm previous observation indicating increased platelet activation in psoriasis. Increased platelet activity could contribute to increasing the atherosclerotic risk in patients with psoriasis and PsA.     

The effect of weight loss on the mean platelet volume in obese patients

Obesity is a chronic metabolic disorder associated with cardiovascular disease and atherosclerosis. Platelet activation and aggregation are central processes in the pathophysiology of cardiovascular disease. Mean platelet volume (MPV), a determinant of platelet activation, is a newly emerging risk marker for atherothrombosis. Our objective was to evaluate the effect of weight loss on the MPV in obese patients. We selected 30 obese women patients and 30 non-obese healthy women subjects. All obese patients took the same content and caloric diet treatment for 3 months. Body mass index (BMI), metabolic parameters and MPV were measured at baseline and after 3 months diet treatment. Before diet treatment, obese group had significantly higher MPV levels than in the non-obese control group (8.18 +/- 1.09 fl vs. 8.01 +/- 0.95 fl, p = 0.004). MPV showed positive correlations with BMI level in the obese group (r = 0.43, p = 0.017). BMI significantly decreased after diet treatment (36.2 +/- 3.2 kg/m(2) vs. 34.7 +/- 3.6 kg/m(2), p < 0.001), in the obese group. MPV significantly decreased after diet treatment in the obese group (8.18 +/- 1.09 fl vs. 8.08 +/- 1.02 fl, p = 0.013). There was a positive correlation between weight loss and reduction in MPV (r = 0.41, p = 0.024). In addition to its well-known positive effects on cardiovascular disease risk, weight loss may also possess significant anti-platelet activation properties that can contribute its antiatherogenic effects in obese patients.     

Increased platelet activation in young patients with prehypertension

Mean platelet volume (MPV) and sP-selectin levels are considered as indicators of platelet activation. In this study, we assessed platelet activation in prehypertensive patients by comparing MPV and sP-selectin levels of these patients with healthy conrols. The study population consisted of 25 newly diagnosed prehypertensive individuals (18 men, mean age = 34 ± 6 y) and 25 healthy control subjects (16 men, mean age = 33 ± 6 y) eligible for the current study. Blood pressure (BP) , lipid profile, plasma glucose, HOMA-IR values, sP-selectin levels, platelet counts, and MPV were measured in both groups. Other than systolic blood pressure (SBP) and diastolic blood pressure (DBP), baseline demographic characteristics of both groups were similar. No significant difference was found between the platelet counts of the two groups. Despite comparable platelet counts, platelet activation parameters were found significantly higher in the prehypertensives. Prehypertensives had larger a MPV value compared to that of the control group (8.24 ± 0.46 fl vs. 7.70 ± 0.64 fl; P = 0.001) and plasma sP-selectin levels were also significantly higher in the prehypertensive patients (163.60 ± 41.21 ng/ml vs. 132.80 ± 36.46; P = 0.007). Spearman correlation analysis revealed moderate positive correlation between SBP and platelet activation parameters (for SBP and MPV, r = 0.60, p = 0.001; for SBP and sP-selectin r = 0.51, p = 0.009). Prehypertension causes platelet activation as evidenced by increased MPV and plasma sP-selectin levels. Increased platelet activation might be related to increased vascular thrombotic risk in those patients.     

The effects of continuous positive airway pressure therapy on mean platelet volume in patients with obstructive sleep apnea

Previous studies have reported increased platelet activation and aggregation in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) treatment has been shown to decrease platelet activation. We aimed to study the effects of nasal CPAP therapy has on MPV values in patients with severe OSA. Thirty-one patients (21 men; mean age 53.8?±?9.2 years) with severe OSA (AHI?>?30 events/hour) constituted the study group. An age, gender and body mass index (BMI) matched control group was composed 25 subjects (14 men; mean age 49.6?±?8.5 years) without OSA (AHI?<?5 events/hour). We measured MPV values in patients with severe OSA and control subjects and we measured MPV values after 6 months of CPAP therapy in severe OS patients. The median (IQR) MPV values were significantly higher in patients with severe OSA than in control group (8.5 [8.3–9.1] vs. 8.3 [7.5–8.8] fL; p?=?0.03). The platelet counts were significantly lower in patients with severe OSA than in control group (217.8?±?45.9 vs. 265.4?±?64.0?×?10⁹/L; p?=?0.002). The six months of CPAP therapy caused significant reductions in median (IQR) MPV values in patients with severe OSA (8.5 [8.3–9.1] to 7.9 [7.4–8.2] fL; p?<?0.001). Six months of CPAP therapy caused significant increase in platelet counts when compared with baseline values (217.8?±?45.9 to 233.7?±?60.6?×?10⁹/L; p?<?0.001). We have found that the MPV values of patients with severe OSA were significantly higher than those of the control subjects and 6 months CPAP therapy caused significant reductions in the MPV values in patients with severe OSA.     

Plasminogen Activator Inhibitor (PAI-1) Activity is Elevated in Asian and Caucasian Subjects with Non-insulin-dependent (Type 2) Diabetes but not in Those with Impaired Glucose Tolerance (IGT) or Non-diabetic Asians

In order to study the plasminogen activator inhibitor activity (PAI-1) in subjects at different risk of non-insulin-dependent diabetes and ischaemic heart disease we examined 89 subjects with diet controlled NIDDM (49 Caucasian, 40 Asian), 29 with impaired glucose tolerance (IGT) (13 Caucasian, 16 Asian), and 149 with normal glucose tolerance (67 Caucasian, 82 Asian). Diabetes was diagnosed by WHO criteria and highly specific, monoclonal antibody-based assays were used to measure insulin, intact proinsulin, and des 31,32 proinsulin. Subjects with NIDDM were significantly more obese, had more central distribution of obesity, higher fasting plasma specific insulin concentrations (NIDDM median 74 pmol l⁻¹ vs IGT 41 pmol l⁻¹, p < 0.01 and vs normals 34 pmol l⁻¹, p < 0.001) and higher PAI-1 activity than normals and those with IGT (NIDDM 23.0 ± 6.9 vs IGT 16.8 ± 5.0, p < 0.001 and vs normals 17.1 ± 6.9 AU ml⁻¹, p < 0.001). However, PAI-1 activity was not significantly different between Asian and Caucasian normals (17.5 ± 7.3 vs 16.5 ± 6.4 AU ml⁻¹, p = ns) and diabetic (22.8 ± 7.3 vs 23.1 ± 6.6 AU ml⁻¹, p = ns) subjects. In addition to relationships with obesity and plasma triglyceride, PAI-1 activity, after controlling for age, sex, body mass index, and waist–hip ratio, was related to fasting insulin (partial r = 0.22, p < 0.001), intact proinsulin (partial r = 0.36, p < 0.001), and des 31,32 proinsulin concentrations (partial r = 0.33, p < 0.001) as measured by highly specific assays. The association of PAI-1 with diabetes was weakened but remained statistically significant (p = 0.042) after controlling for age, sex, ethnicity, obesity, plasma triglyceride, and all insulin-like molecules. We conclude that, although PAI-1 activity is raised in subjects with diet-treated NIDDM, it is normal in subjects with IGT and non-diabetic Asians, populations at high risk of NIDDM and ischaemic heart disease. Raised PAI-1 activity may play an important role in the pathogenesis of macrovascular disease in subjects with NIDDM, but is unlikely to explain excess risk of ischaemic heart disease in Asians and those with impaired glucose tolerance.     

A Higher Proinsulin Response to Glucose Loading Predicts Deteriorating Fasting Plasma Glucose and Worsening to Diabetes in Subjects with Impaired Glucose Tolerance

To evaluate the clinical significance of proinsulin determination, we measured glucose, insulin, C-peptide and proinsulin during 75-g oral glucose loading in 59 patients. In a 2.5-year follow-up study of 37 subjects with impaired glucose tolerance (IGT) at the initial test, 11 patients changed from IGT to a normal state and 5 patients showed worsening to overt Type 2 diabetes with elevation of fasting plasma glucose; 21 patients remained unchanged. Although our data showed that both fasting (IGT: p = 0.4523) and 120-min plasma glucose (IGT: p = 0.8168) values at the initial test were not significantly correlated with increased fasting plasma glucose levels in a 2.5-year follow-up study, subjects with a higher 120-min proinsulin response to glucose during the initial OGTT showed a significant correlation (IGT: p <0.0001) with increased fasting plasma glucose levels after follow-up period and developed Type 2 diabetes. The present findings suggest that the proinsulin response to glucose loading might be a useful indicator for predicting worsening to diabetes in subjects with impaired glucose tolerance.