Establishment and functional characterization of an in vitro model of the blood-brain barrier, comprising a co-culture of brain capillary endothelial cells and astrocytes.

OBJECTIVE: The aim was to establish a flexible, abundantly available, reproducible and functionally characterized in vitro model of the blood-brain barrier (BBB). METHODS: In a first step, bovine brain capillaries and newborn rat astrocytes were isolated. Subsequently, a co-culture of primary brain capillary endothelial cells (BCEC) on semi-permeable filter inserts, with astrocytes on the bottom of the filter was established. The cell material was characterized on the basis of specific cell-type properties and (functional expression of) specific BBB properties. RESULTS: BCEC displayed: (1) characteristic endothelial cell morphology; (2) expression of endothelial cell markers (i.e., CD51, CD62P, CD71 and cadherin 5); (3) marginal F-actin localization; (4) tight junction formation between the cells; (5) expression of gamma-glutamyl-transpeptidase (gamma-GTP); (6) expression of P-glycoprotein (Pgp); (7) functional transendothelial transferrin transport and uptake; (8) restriction of paracellular transport; and (9) high transendothelial electrical resistance (TEER). Astrocytes displayed characteristic astrocyte morphology and expressed glial fibrillary acidic protein (GFAP). Co-culture with astrocytes increased TEER and decreased paracellular transport. In addition, expression of the glucocorticoid receptor (GR) was demonstrated in the endothelial cells of the BBB, while no expression of the mineralocorticoid receptor (MR) was found. CONCLUSIONS: A high quality and mass-production in vitro BBB model was established in which experiments with physiological (e.g., regulation of BBB permeability), pharmacological (e.g., pharmacokinetics and pharmacodynamics) and pathophysiological (e.g., disease influence on BBB permeability) objectives can be reproducibly performed.     

Maternal undernutrition induces neuroendocrine immune dysfunction in male pups at weaning.

The present study was designed to assess the effect of maternal undernutrition, during gestation and lactation, on the neuroendocrine [hypothalamo-pituitary-adrenal (HPA)]-immune axis response to endotoxin (LPS) administration. For this purpose, 21-day-old male rats from both well-nourished (WN) and undernourished (UN) mothers were examined 2 h after injection (i.p.) of vehicle alone (VEH) or containing LPS (130 microg/kg BW). Circulating levels of glucose (GLU), ACTH, corticosterone (B), tumor necrosis factor-alpha (TNFalpha) and leptin were explored. The results indicate that: (a) mother body weight was significantly (p < 0.05) reduced, as a consequence of UN, at the second and third weeks of pregnancy; (b) no differences in basal glycemia were found in the two groups of pups, and LPS treatment did not induce hypoglycemia, in either group; (c) basal plasma ACTH, B and TNFalpha levels were similar in the two groups, and LPS-induced ACTH, B and TNFalpha secretions, although severalfold higher than respective VEH values (p < 0.05) in pups from WN mothers, were fully (ACTH and B) and partially (TNFalpha) abolished in products from UN mothers; (d) both mean body weights and basal plasma leptin levels were significantly (p < 0.05) lower in pups from UN than from WN mothers, and LPS administration did not modify plasma leptin values in products from both groups. In addition, results of dispersed total adrenal cells incubated in vitro indicate that: (a) both basal and ACTH (22 pM)-induced B secretion were significantly (p < 0.05) lower in cells from UN than WN pups, and (b) leptin (100 nM) was able to inhibit partially ACTH-stimulated B output by adrenal gland (AG) cells from WN pups; however, it failed to inhibit ACTH-stimulated glucocorticoid release by AG cells from UN pups. The present results indicate that undernutrition in mothers, during the very critical periods of gestation and lactation, induces in their male pups at weaning: (a) reduced circulating leptin levels and body weight values; (b) metabolic adaptation to normal carbohydrate metabolism; (c) hyporesponsiveness of the HPA and immune (TNFalpha) axes during endotoxemia, and (d) leptin resistance at the adrenocortical level. This study strongly supports that undernutrition of mothers results in neuroendocrine immune dysfunction of their pups; however, adrenal resistance to the inhibitory effect of leptin on glucocorticoid output is developed, probably as an adaptive mechanism to counteract unfavorable metabolic conditions.     

Influence of wall compliance on hemodynamics in models of abdominal aortic aneurysm.

PURPOSE: To determine complementary criteria to existing morphological criteria, which are not reliable but are used to justify surgical intervention to treat abdominal aortic aneurysm (AAA). METHODS: An experimental study was conducted in which 2 models of AAA, 1 rigid and 1 soft, were used to study the influence of compliance on aneurysm dynamics. The heart rate was 70 beats per minute, and the mean flow rate was 1.02 L/min. Velocity measurements were made with particle image velocimetry in 2 planes parallel to flow (1 vertical and 1 horizontal). RESULTS: The general flow patterns generated in the rigid AAA model were in agreement with the literature. In both models, a vortex occurred at the beginning of systolic deceleration in the proximal part of the AAA, near the anterior wall. The vortex remained confined to the proximal part during the entire cycle in the rigid model, whereas in the soft model, the vortex migrated to the distal segment during the cycle and impacted the AAA walls. This impact generated a local pressure increase on the wall. In the soft model, another vortex was created near the posterior wall. These vortices eroded and weakened the walls of the distal segment, which can cause rupture. CONCLUSION: Compliance of the aneurysm wall might become another criterion to justify surgical intervention.     

Human main plant poisoning: revue of the literature]

The authors have reviewed the main toxic plants responsible for human deaths throughout the world. Forty plants (genera or species) were listed in order to establish an inventory of the botany of the plant, its use, the active molecules that could be identified, the already published analytical methods and the reported human fatal cases.     

10A multi-component model can predict outcome of restrictive surgery for obesity at baseline and 3 months

Introduction:  We previously reported that a multi-component model of autonomic and enteric factors may correlate with ultimate weight loss or gain after restrictive obesity surgery (NGM 2005; 17:472).
Patients:  We report on 39 patients, 4 male, 35 female, mean age 37.2 years, followed for up to 16 years post-operatively after vertical banded gastroplasty.
Methods:  Two autonomic measures (adrenergic: PAR and VC and cholinergic: RRI) and one enteric measure (electrogastrogram: EGG) were recorded at baseline as previously described (DDS 44: 74s–78s, 1999). We performed a discriminant function analysis to investigate whether a patient's EGG, PAR, RRI, and VC values could be used to classify that patient as a loser or gainer following weight control surgery. The patients were divided into two categories (10 gainers, 29 losers), depending on the latest weight compared to baseline; discriminant criterion derived from the patient's data was applied to each patient's autonomic and enteric values to determine whether these measurements separated the patients into their true weight category.
Results:  A discriminate model based on baseline measures successfully predicted ultimate weight gain in 8/10 (80%) of patients who subsequently gained weight and weight loss in 24/29 (83%) of patients who in subsequently lost weight for a total correct classification rate of 32/39 (82%). The same model with data at 3 months post-operatively predicted weight gain in 9 of 10 (90%) of patients and weight loss in 24 of 29 (83%) of patients, for a total correct classification rate of 34/39 pts (87%) (See table).
Conclusions:  A multi-component model demonstrates that baseline and 3 months post-operative measures can predict ultimate weight outcome from restrictive obesity surgery.
 

     

Beneficial metabolic effects of chronic glipizide in obese African Americans with impaired glucose tolerance: implications for primary prevention of type 2 diabetes

We examined the long-term metabolic effects of glipizide gastrointestinal therapeutic system (GITS), a potent sulfonylurea (SU), in impaired glucose-tolerant (IGT), first-degree relatives of African American patients with type 2 diabetes. To this end, we assessed glucose homeostasis, beta-cell function, insulin sensitivity (Si), and glucose effectiveness (Sg) in patients with IGT before and at yearly intervals for 24 months of GITS or an identical placebo in a randomized, double-blind manner. Eighteen IGT patients were randomized to receive either glipizide GITS (GITS, 5 mg/d, n = 9; mean age, 43.3 +/- 8.7 years; mean body mass index [BMI], 32.9 +/- 6.3 kg/m(2)) or identical placebo (PLAC, n = 9; mean age, 41.5 +/- 5.7 years; mean BMI, 39 +/- 4.2 kg/m(2)) for 24 months. Each of the subjects underwent oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIGT) at baseline and yearly intervals for 2 years. Si and Sg were determined by Bergman's minimal model method. The ability of beta cell to compensate for peripheral insulin resistance was calculated as the disposition index (DI). Chronic administration of glipizide GITS attenuated serum glucose responses to oral glucose challenge at 12 and 24 months when compared to baseline (0 months). In contrast, serum glucose levels at fasting and during OGTT tended to increase in the IGT/PLAC group at 12 and 24 months when compared to baseline. Serum insulin (P <.05 to 0.01) and serum C-peptide levels progressively increased in the GITS group at 12 and 24 months versus 0 months. In contrast, serum insulin and C-peptide responses remained unchanged in the IGT/PLAC group. During FSIGT, chronic GITS was associated with significant improvement in the blunted acute first insulin release in the IGT patients at 12 and 24 months. These parameters remained blunted in the IGT/PLAC group. We found that Si increased in the IGT/GITS group at 12 months (P <.01) and 24 months(P <.05) versus baseline, but deteriorated in the IGT/PLAC group. Similarly, the DIs significantly (P <.01) increased following GITS therapy at 12 and 24 months when compared to baseline. In contrast, DI did not change from baseline values in the IGT/PLAC group throughout the study period. Chronic GITS partially restored the ability of beta cells to compensate for peripheral insulin resistance (as assessed by DIs). GITS was well tolerated without any symptoms suggestive of either hypoglycemia or significant weight gain. In summary, long-term chronic glipizide GITS administration improved glucose homeostasis by increasing beta-cell responsiveness to glucose, improving Si, as well as significantly improved DI, but not Sg, in high-risk, obese African Americans with IGT. Our study demonstrated that GITS appears to prime beta cells to intravenous glucose stimulation resulting in restoration of physiologic acute first- and second-phase insulin secretion in African Americans with IGT. We conclude that GITS might be considered as a useful agent in the primary prevention of type 2 diabetes in high-risk, obese African American patients with IGT.