Regulation of corneal noradrenaline release and topography of sympathetic innervation: Functional implications for adrenergic mechanisms in the human cornea.

Having established a main neuronal origin for noradrenaline (NA) in the cornea, we set out to study the physiologic determinants of its release and to correlate functional findings with sympathetic nerve density and overall topography. Whole corneas were obtained from 3 to 4 month-old rabbits and human donors. Study of prejunctional effects was carried out after incubation with radiolabelled NA (3H-NA). Corneas were superfused with warm aerated amine-free medium with cocaine and hydrocortisone to block subsequent neuronal and extraneuronal NA uptake. Samples were collected every 5 min. Four periods of transmural electrical stimulation were applied to assess evoked release of 3H-NA in the absence and in the presence of alpha-2 adrenoceptor antagonists. Catecholamines were extracted with alumina from the superfusate collected and quantified by high pressure liquid chromatography with electrochemical detection (HPLC-ED). Corneal nerve morphology was studied by immunofluorescence staining with monoclonal antibodies and subsequent confocal microscopy. Corneal lamellar sections were also produced (epithelium, stroma, endothelium) and endogenous NA and adrenaline (AD) were quantified by HPLC-ED. Results are means ±â€¯SEM. ANOVA and t-tests were used for statistical analysis. Ratios between enzymatic end products and their substrates were calculated. In both rabbit and human corneas, electrical stimulation increased the outflow of 3H-NA per minute and per shock. Addition of the alpha-2 adrenoceptor antagonist rauwolscine further increased the electrically-evoked overflow of 3H-NA in a concentration-dependent manner. Immunofluorescence revealed particular staining patterns for sensory and sympathetic fibres, epithelial cells and stromal keratocytes. In human corneal lamellar sections only NA was identified, particularly in the endothelium and epithelium. In the rabbit, concentration of NA was ten times that of AD. Electrically-evoked overflow reflects action potential-induced NA release by sympathetic nerves in the cornea and an alpha-2 adrenoceptor-mediated mechanism for its release is presented. Sympathetic innervation has similar functional relevance in both rabbit and human corneas.

Concentration gradient of noradrenaline from the periphery to the centre of the cornea - A clue to its origin.

We set out to demonstrate that the major source of corneal catecholamines is its neuronal release from intrinsic sympathetic nerves rather than circulating or non-neuronal local production. Three concentric segments (central, intermediate, peripheral) were obtained by double trephination (9.5-7.25 mm) performed on corneas harvested from 3 to 4 month old rabbits and human corneas rejected for transplantation, along with aqueous humour, full iris tissue and blood samples. Endogenous catecholamines were quantified by high pressure liquid chromatography with electrochemical detection (HPLC-ED), and comparison with the uptake of radio-labelled noradrenaline (3H-NA) before and after incubation with cocaine was performed. Results are means ±â€¯SEM. Ratios between enzymatic end products and their substrates were calculated. ANOVA was used for statistical analysis. Catecholamine levels were found to be about one log unit lower in the human cornea than in the rabbit cornea. In the rabbit, dopamine (DA), noradrenaline (NA) and adrenaline (AD) were identified by HPLC-ED in all corneal segments, whilst in the human cornea NA was identified only in the intermediate and peripheral corneal segments, and no AD was found. In the iris and aqueous humour only DA and NA were present. A concentration gradient for NA decreasing from the periphery to the centre of the cornea was identified in both species (NA/DA ratio higher than 1 in the periphery; low AD/NA ratio in all corneal segments), but not for DA or AD. After incubation with 3H-NA all corneal segments and iris tissue showed loading with the aforementioned gradient being reproduced, and a decrease in 3H-NA loading after cocaine was significant only in the peripheral corneal segment and in the iris of both species. Reduction in 3H-NA loading after incubation with cocaine shows that NA in the cornea is mostly of neuronal origin and demonstrates the presence of functional sympathetic nerves (also expectedly found in the iris); the existence of a gradient both for 3H-NA loading and loading reduction after cocaine points to a higher density of fibres in the peripheral cornea.

Probiotics for the control of obesity - Its effect on weight change.

BACKGROUND: Obesity is a growing epidemic worldwide. Evidence so far demonstrates that the bacteria that are commonly found in the human gastrointestinal tract affect nutrient acquisition and energy regulation. This suggests that an important role is played by gut microbiota in the development of obesity. OBJECTIVES: Our main goal was to assess if a probiotic diet leads to a significant difference in weight change in non-obese and obese people, and in experimental models. METHODS: Search was undertaken in PubMed, Scopus, ISI Web of knowledge, Cochrane Central Register of Controlled Trials, Google scholar, meta-Register of Controlled Trials, ClinicalTrials.gov and by scanning reference lists of articles, without publication date imposed, for randomised clinical trials studying the administration of probiotics to obese or overweight patients and experimental studies in experimental models and healthy humans. Search terms included probiotics, obesity, weight, BMI, weight gain, weight loss, weight change, probiotic diet and probiotic therapy. In an unblended standardized manner, 2 reviewers analysed the searched studies, using the defined inclusion and exclusion criteria, and performed extraction of data, in an independent way, using predefined data fields. RESULTS: We've identified, through searching databases specified in methods, 269 records. A total of 4 clinical trials and 14 experimental studies were included in the systematic review. Among the 4 randomized clinical trials only one showed statistically significant results. L. rhamnosus CGMCC 1.3724 was efficient in reducing weight in females, but not in males - Mean weight loss 12 week/24 week (kg): Males-probiotic: 4/5.4; Males-placebo: 3.05/4.43; Females-probiotic: 4.4/5.2; Females- placebo: 2.6/2.5 (P<0.05 only on females). CONCLUSIONS: In our systematic review, we found that probiotic effect in body weight is specie and strain specific. L. gasseri BNR17, reduced the weight gain compared to controls; L. gasseri L66-5 promoted weight gain, L. rhamnosus GGMCC is the only one that had a positive effect in weight loss in humans. Probiotic effect in body weight was species and strain specific. On the other hand L. plantarum LG42, L. gasseri SBT2055 and L. plantarum co-therapy with KY103 and L. curvatus HY7601 had an anti-obesity effect in animal models.