Jean-Michel Warnet

Hypertriglyceridaemia as a risk factor of coronary heart disease mortality in subjects with impaired glucose tolerance or diabetes

SummaryThe Paris Prospective Study is a long-term investigation of the incidence of coronary heart disease in a large population of working men. The first follow-up examination involved 7,038 men, aged 43–54 years. Subjects with impaired glucose tolerance or diabetes (n=943) were selected from the total population for a separate analysis of coronary heart disease mortality risk factors. During a mean follow-up of 11 years, 26 of these 943 subjects with abnormal glucose tolerance died from coronary heart disease. Univariate analysis showed that plasma triglyceride level (p<0.006), plasma cholesterol level (p<0.02), and plasma insulin level both fasting and 2-h post-glucose load (p<0.02), were significantly higher in subjects who died from coronary heart disease compared to those who did not. In multivariate regression analysis using the Cox model, plasma triglyceride level was the only factor positively and significantly associated with coronary death. The distribution of plasma triglyceride levels was clearly higher for the subjects who died from coronary heart disease compared to those who did not die from this cause or were alive at the end of the follow-up. This new epidemiological evidence that hypertriglyceridaemia is an important predictor of coronary heart disease mortality in subjects with impaired glucose tolerance or diabetes suggests a possible role of dyslipidaemia in the excessive occurrence of atherosclerotic vascular disease in this category of subjects.

Hyperinsulinaemia as a predictor of coronary heart disease mortality in a healthy population: the Paris Prospective Study, 15-year follow-up

SummaryThe Paris Prospective Study is a long-term, largescale study of the factors predicting coronary heart disease. The first follow-up examination included, for subjects not known as having diabetes mellitus, a 75 g oral glucose tolerance test with measurement of plasma insulin and glucose levels, fasting and 2 h post-load. Between 1968 and 1973, 6903 men aged 43–54 years were thus examined. Causes of death were ascertained within this group after 15 years of mean follow-up. The baseline variables were tested as predictors of death from coronary heart disease by a Cox regression analysis. Significant independent predictors of coronary heart disease death were: systolic blood pressure, number of cigarettes per day, plasma cholesterol level, and 2 h post-load plasma insulin level when entered as a categorical variable (below or above 452 pmol/l, i.e. the lower limit of the fifth quintile of the distribution). This dichotomization was performed to account for the non-linear univariate distribution of deaths with increasing post-load insulin values. Fasting plasma insulin level was not an independent predictor of death by coronary heart disease over this long-term follow-up. Levels of blood glucose were not significant independent predictors of death by coronary heart disease when plasma insulin levels were included in the model. The same applied to abnormalities of glucose tolerance when the 125 men with known non-insulin-treated diabetes at baseline were added to the group. Under the assumption that hyperinsulinaemia is a marker of insulin resistance, the results are consistent with the hypothesis that insulin resistance is associated with a higher risk of coronary heart disease mortality. However, it is doubtful that circulating insulin per se is a direct cause of arterial complications.

Risk Factors for NIDDM in White Population: Paris Prospective Study

Risk factors for non-insulin-dependent diabetes mellitus (NIDDM) were assessed in a population of 5042 middle-aged white men, initially nondiabetic, who were followed 3 yr. The subjects were participants in the Paris Prospective Study I. Sixty-three subjects developed diabetes during the follow-up. Plasma glucose concentration in the years before the occurrence of the disease was a major risk factor. Subjects with normal glucose tolerance but elevated fasting plasma glucose exhibited a similar risk of developing NIDDM as did subjects classified as having impaired glucose tolerance on the basis of 2-h postload glucose. In a multiple logistic regression, a high fasting plasma insulin concentration and a low 2-h plasma insulin concentration after a glucose load in association with a high body mass index were independent predictors of conversion to NIDDM from impaired glucose tolerance. Previously, this result had been found only in Nauruans, Pima Indians, and Japanese. This demonstrates for the first time in a white population that a high fasting and low 2-h insulin concentration is predictive of conversion to NIDDM from impaired glucose tolerance.

The role of non-esterified fatty acids in the deterioration of glucose tolerance in Caucasian subjects: results of the Paris Prospective Study

Summary Although an increased plasma non-esterified fatty acid (NEFA) concentration has been shown to increase insulin resistance (Randle cycle), decrease insulin secretion and increase hepatic gluconeogenesis, the effect of NEFA on the deterioration of glucose tolerance has not been studied prospectively in Caucasian subjects. Therefore, we investigated whether plasma NEFA may be regarded as predictors of deterioration of glucose tolerance in subjects with normal (NGT, n = 3671) or impaired (IGT, n = 418) glucose tolerance who were participants in the Paris Prospective study. The subjects were first examined between 1967 and 1972 and underwent two 75-g oral glucose tolerance tests 2 years apart with measurements of plasma glucose, insulin and NEFA concentrations. Glucose tolerance deteriorated from NGT to IGT or non-insulin-dependent diabetes (NIDDM) in 177 subjects and from IGT to NIDDM in 32 subjects. In multivariate analysis, high fasting plasma NEFA in NGT subjects and high 2-h plasma NEFA and low 2-h plasma insulin concentrations in IGT subjects were significant independent predictors of deterioration along with older age, high fasting and 2-h plasma glucose concentrations and high iliac to thigh ratio. When subjects were divided by tertiles of plasma NEFA concentration at baseline, there was an increase in 2-h glucose concentration with increasing NEFA in the subjects who did not deteriorate, but no effect of plasma NEFA in those who deteriorated. In subjects with IGT who deteriorated compared with those who did not 2-h plasma insulin concentration was lower but there was no evidence that this resulted from an effect of plasma NEFA. Our data suggest that a high plasma NEFA concentration is a risk marker for deterioration of glucose tolerance independent of the insulin resistance or the insulin secretion defect that characterize subjects at risk for NIDDM. [Diabetologia (1997) 40: 1101–1106]

Flow cytometric analysis of conjunctival epithelium in Ocular rosacea and keratoconjunctivitis sicca

PURPOSE To investigate by flow cytometry and impression cytology (IC) specimens the inflammatory status of the conjunctival epithelium and goblet cell density in two series of patients with rosacea and dry eye syndrome compared with a population of healthy subjects. DESIGN Nonrandomized, prospective, comparative case series. PARTICIPANTS Twenty-six eyes of 13 patients with rosacea, 26 eyes of 13 patients with dry eye syndrome, and 24 eyes of 12 control subjects were included in this study. METHODS IC specimens were collected after clinical examination of the ocular surface and analyzed by flow cytometry, using antibodies directed to human lymphocyte antigen-DR (HLA-DR), intercellular adhesion molecule-1 (ICAM-1) (CD 54), and the peptidic core of the conjunctival mucin (M1/MUC5AC). The percentage of positive cells was calculated and levels of fluorescence expression quantified and compared with those obtained in a series of 12 healthy subjects. MAIN OUTCOME MEASURES Tear break-up time (TBUT), Schirmer test, fluorescein and lissamin green stainings, and IC were realized in this study. RESULTS A significant increase of HLA-DR and ICAM-1 expressions by epithelial cells was consistently found in the two pathologic groups compared with levels calculated in normal eyes. The two markers were well correlated with each other and inversely with TBUT and Schirmer test. The percentage of goblet cells was significantly decreased in rosacea patients and in dry eye patients compared with the normal group with a significant negative correlation with both HLA DR and ICAM-1 markers. CONCLUSIONS Ocular rosacea and keratoconjunctivitis sicca were associated with severe ocular surface changes, such as an overexpression of inflammatory markers and a significant decrease in the number of goblet cells.

Body mass, blood pressure, glucose, and lipids. Does plasma insulin explain their relationships?

Obesity, hypertension, a high plasma level of glucose, and some llpid abnormalities (high plasma levels of cholesterol and triglycerides) often occur in the same individuals. Some authors have postulated that the elevated levels of plasma insulin in obese individuals may explain this association. To explore this hypothesis further, the relationships between body mass index, fasting plasma glucose and insulin, blood pressure, serum lipids, and apoproteins were Investigated in a group of 2144 healthy middle-aged men. Analysis of the data show that the associations between body mass index and blood pressure or lipid variables are largely independent of plasma glucose and Insulin. Plasma glucose is strongly related to blood pressure in nonobese subjects. Plasma Insulin is not associated with blood pressure independently of body mass index and plasma glucose; however, the simultaneous elevation of body mass index, plasma glucose, and insulin is strongly associated with blood pressure. The results also confirm that plasma insulin is positively related to triglycerides and negatively related to high density Iipoprotein cholesterol independently of plasma glucose and body mass index.

Multiple Endpoint Analysis of the 3D-Reconstituted Corneal Epithelium after Treatment with Benzalkonium Chloride: Early Detection of Toxic Damage

PURPOSE To investigate the effects of benzalkonium chloride (BAK) on the human reconstituted corneal epithelial model (HCE) and to optimize the operating potential of this model in the field of ophthalmic toxicology. METHODS The HCEs were treated with 0.001% to 0.5% BAK for 24 hours followed or not by a 24-hour postincubation period. To complete the histologic analysis, the authors designed a new MTT procedure to assess cellular viability. Frozen sections were analyzed by using fluorescence confocal microscopy for the presence of TUNEL, activated caspase-3, Ki67, ICAM-1, HLA-DR, E-cadherin, and occludin. Occludin gene expression was also investigated by using quantitative RT-PCR. RESULTS The MTT test revealed a dose-dependent response of BAK with significant toxic effects for concentrations as low as 0.005%. Increasing BAK concentrations induced an increased number of apoptotic cells, found from the superficial to the deeper layers, with the activation of caspase-3 at 0.01% and 0.02% concentrations. The number of Ki67- and ICAM-1-positive cells increased with 0.01% BAK and with 0.001% to 0.01% BAK, respectively. BAK induced the dose-dependent disappearance of occludin in the superficial layers while increasing its gene expression up to the 0.02% BAK concentration. CONCLUSIONS Fluorescence techniques conjugated with confocal microscopy on 3D-reconstructed corneal epithelia were well suited for the investigation of toxicological markers such as cell junction alteration, apoptosis, cell activation, and proliferation and gave relevant results compared with the known human data. They complement the new sensitive MTT test and improve the operating potential of this new, valuable 3D model in ophthalmic toxicology.

In Vitro Effects of Preservative-Free Tafluprost and Preserved Latanoprost, Travoprost, and Bimatoprost in a Conjunctival Epithelial Cell Line

Purpose: This study compared the toxicity profiles of three antiglaucoma prostaglandin F2α analogs, latanoprost, travoprost, and bimatoprost which contain benzalkonium chloride (BAK), with tafluprost, a new preservative-free prostaglandin analog. Methods: IOBA-NHC cells were exposed to BAK-containing prostanoid solutions, their respective BAK concentrations, and preservative-free tafluprost solution for 30 min. Membrane integrity, apoptosis, oxidative stress, and cells morphology were evaluated. Results: Preservative-free tafluprost resulted in significantly higher membrane integrity and lower pro-apoptotic and pro-oxidative effects than preservative-containing prostaglandin analog preparations. Conclusions: These results suggest that tafluprost, a new preservative-free prostaglandin analog, has very low or no pro-apoptotic, pro-necrotic, or pro-oxidative effects in vitro compared to preservative-containing formulations.

Upper-body fat distribution: a hyperinsulinemia-independent predictor of coronary heart disease mortality. The Paris Prospective Study.

The Paris Prospective Study is a long-term investigation of the factors predicting coronary heart disease in a large population of middle-aged men. The first follow-up examination involved 7,152 subjects, who were natives of metropolitan France and were free of any cardiovascular history. At that time, the usual cardiovascular risk factors and plasma insulin levels were recorded. An index of body fat distribution, the iliac-to-thigh ratio, was entered into the list of predictive variables, despite the fact that it had been measured 1 year before the first follow-up examination. After 11 years of mean follow-up, 129 of the men had died of coronary heart disease. Univariate analysis showed that the iliac-to-thigh ratio (p < 0.0001) and plasma insulin level (both fasting [p < 0.003] and 2-hour postload [p < 0.02]), as well as the four major risk factors of coronary heart disease (age, smoking, blood pressure, and plasma cholesterol level) were significantly higher in subjects who died of coronary heart disease compared with those who had died of another cause or were alive at the end of follow-up. In multivariate stepwise logistic regression, the iliac-to-thigh ratio appeared as an independent predictor of coronary heart disease death, thereby causing the removal of fasting insulin level from the list of significant independent predictors. Nevertheless, in a model that entered 2-hour postload insulin in two classes (high or low), both the insulin level and iliac-to-thigh ratio were found as significant independent predictors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute systemic inflammation induces central mitochondrial damage and mnesic deficit in adult Swiss mice

The aim of this study was to investigate how the brain is affected during systemic inflammation. For this purpose, Swiss mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 250microg/mouse) to mimic aspects of systemic infection. Spatial learning in Y-maze test demonstrated a differential learning profile during the training test between control and LPS-treated mice, with an alteration in the latter group. We show that systemic LPS-induced inflammation and oxidative injury as assessed by reactive oxygen species (ROS) and nitrites/nitrates (NOx) production associated with reduced glutathione (GSH) depletion, cyclooxygenase-2 (COX-2) expression, and lipid peroxidation. LPS also induced a loss in mitochondrial integrity as shown by a significant decrease in membrane potential and impairment in mitochondrial redox activity. Thus, peripheral inflammation by producing brain inflammation and oxidative injury causes mnesic deficits. It remains to determine whether such events can induce neuronal dysfunction/degeneration and, with time, lead to cholinergic deficiency, amyloid deposits and cognitive impairments as they occur in Alzheimers disease.