Collagen gel contraction by ARPE-19 cells is mediated by a FAK-Src dependent pathway

Proliferative vitreoretinopathy (PVR) may result in part from de-differentiation of retinal pigment epithelium (RPE) in an aberrant wound-healing strategy. An in vitro model of PVR, collagen gel contraction by RPE, likely requires integrin engagement and activation as an important initial step. The purpose of this study was to identify the important associated integrins and signal transduction pathway. The retinal pigment epithelial cell line ARPE-19 was used in these studies. Cell surface integrin expression was assessed using flow cytometry. An in vitro contraction assay was performed and the percent contraction quantified at specific time intervals using image capture (Gel Doc) and NIH Image software. Cells were pretreated with either small molecule inhibitors of signal transduction pathways or monoclonal antibodies with specificity for specific integrin isoforms. Transient transfections with a FAK siRNA were used to decrease FAK expression. ARPE-19 cells express alpha1, alpha2, and alpha3 integrin, isoforms involved in collagen ligation. Cell surface integrin blockade using anti-integrin alpha2 (P=0.02), alpha3 (P=0.01), or a combination of alpha1, alpha2, and alpha3 (P=0.001) antibodies significantly reduced collagen gel contraction. Inhibition of the FAK-Src complex, but not MEK or PI3K, significantly decreased contraction (P=0.0001). FAK siRNA transient transfection significantly reduced FAK protein expression by 71% (P=0.02) and concordantly decreased gel contraction (P=0.0001). RPE-mediated collagen gel contraction is a multi-step process. Integrin ligation and FAK-Src activation is necessary for collagen gel contraction produced by the ARPE-19 cell line. Validation of these observations in primary RPE cells may suggest new targets for therapeutic intervention in PVR.     

Inhibition of corneal angiogenesis by ascorbic acid in the rat model

Purpose To evaluate the effect of topically administered ascorbic acid on experimentally induced corneal neovascularization in the rat model. Materials and methods Corneal chemical cauterization of 72 eyes in Long-Evans male rats was performed using silver nitrate/potassium nitrate sticks. Nine groups of eight eyes were used to evaluate eight concentrations of ascorbic acid with one group of eight eyes serving as a control. Topical instillation of 100 mg/ml non-pH-neutralized ascorbic acid was performed in one group while the remaining seven groups were evaluated using pH-neutralized ascorbic acid in concentrations of 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 μg/ml, and 250 μg/ml. Results The percentage of corneal neovascularization and burn stimulus score was determined for all the eyes. The means of percent of corneal neovascularization in ascorbic acid 100 mg/ml (non-neutralized), 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 μg/ml, 250 μg/ml, and control group were 17.50 ± 12.80 (p = 0.001), 17.00 ± 19.30 (p = 0.001), 15.25 ± 13.26 (p = 0.001), 17.62 ± 11.89 (p = 0.001), 28.87 ± 23.08 (p = 0.001), 29.62 ± 16.91 (p = 0.001), 60.12 ± 8.50 (p = 0.04), 65.62 ± 2.26 (p = 0.185), and 68.25 ± 4.06, respectively (Tables 1 and 2). All animals had a burn score of 2+ or higher (Table 1). Conclusion Ascorbic acid applied in a topical solution appears to inhibit corneal neovascularization in the rat model of inflammatory neovascularization in concentrations in a dose-dependent manner. The optimal dose-effect relation was in our model found in concentrations between 1 mg and 500 μg/ml. At concentrations below 500 μg/ml there was no statistically significant inhibition in the degree of corneal neovascularization compared to control. None of the authors has any proprietary interest in any technique or product described herein.     

Peritoneal and intestinal tuberculosis: an ancestral disease that poses new challenges in the technological era. Case report and review of the literature

Tuberculosis is a public health problem. The most common presentation is pulmonary disease. The diagnosis of any extrapulmonary forms are quite difficult. Clinical manifestations of gastrointestinal tuberculosis are non-specific and compatible with pathologies such as inflammatory bowel disease, advanced ovarian cancer, deep mycosis, yersinia infection and amebomas. Abdominal form is located at 6th place of the extrapulmonary forms, after lymphatic, genitourinary, osteoarticular, miliary and meningeal infections. Eventually, 25 to 75% of patients with abdominal tuberculosis will require surgery. These procedures should be limitated with the purpose to preserve small bowel. Resection should be limitated for complicated cases. The surgical indications include: Intestinal occlusion (15-60%), perforation (1-15%), abscesses and fistulas (2-30%) and hemorrhage (2%). CONCLUSIONS: In most of the cases, the diagnosis of peritoneal or intestinal tuberculosis is made during a laparoscopy or laparotomy even during surgery performed by different purposes. Excessive manipulation of the intraabdominal organs may produced unexpected bowel lesions, increasing morbidity and mortality. Medical treatment is highly effective in the resolution of moderate complications such as bowel obstruction. Resectional procedures should be reserved for complications like perforation, bleeding or stenosis non-suitable for stricturoplasty.     

Urinary tract infection due to Corynebacterium urealyticum in kidney transplant recipients: an underdiagnosed etiology for obstructive uropathy and graft dysfunction-results of a prospective cohort study.

BACKGROUND: Corynebacterium urealyticum is a cause of urinary tract infection and encrusting cystitis or pyelitis. Information about this infection in renal transplant recipients is based on case reports. We communicate the first prospective epidemiological study for this population. METHODS: We selected a cohort of 163 renal transplant recipients who were screened for urinary tract infection due to C. urealyticum. Long-term incubation and special media were used for culture of C. urealyticum. The cohort was observed for a mean of 26.2 months (standard deviation, 8.7; range, 1-36 months). Risk factors and outcomes were assessed. RESULTS: At baseline, 16 (9.8%) of 163 patients had C. urealyticum bacteriuria (6 were asymptomatic, 9 had acute cystitis, and 1 had encrusting pyelitis). Independent risk factors (assessed by multivariate analysis) for urinary tract C. urealyticum infection were: antibiotic administration during the previous month (odds ratio, 8.04; 95% confidence interval, 1.57-41.06; P = .012), history of nephrostomy (odds ratio, 51.59; 95% confidence interval, 3.62-736.06; P = .004), and skin colonization (odds ratio, 208.35; 95% confidence interval, 21.54-2015.22; P< .001). Presence of urinary tract infection symptoms for >1 month (odds ratio, 27.7; 95% confidence interval, 2.55-300.5; P = .006) and obstructive uropathy (odds ratio 25.9; 95% confidence interval, 4.43-152.31; P < .001) were more frequent during follow-up in patients with C. urealyticum bacteriuria. CONCLUSIONS: When specifically tested for, C. urealyticum bacteriuria is more prevalent than previously thought in renal transplant recipients, and it is closely related to obstructive uropathy. Future studies are necessary to establish the relevance of treating the infection during follow-up after renal transplantation.     

Population-level seasonality in cardiovascular mortality,blood pressure,BMI and inflammatory cells in UK biobank

Introduction: The risk of mortality from cardiovascular disease (CVD) is higher in wintertime throughout the world, but it is not known if this reflects annual changes in diet or lifestyle, or an endogenous photoperiodic mechanism that is sensitive to changes in day length.

Methods: Phenotypic data on cardiometabolic and lifestyle factors were collected throughout a 4 year time period from 502,642 middle-aged participants in UK Biobank. To assess the impact of seasonal environmental changes on cardiovascular risk factors, we linked these data to the outdoor temperature and day length at the time of assessment. Self-reported information on physical activity, diet and disease status were used to adjust for confounding factors related to health and lifestyle.

Results: Mortality related to CVD was higher in winter, as were risk factors for this condition including blood pressure, markers of inflammation and body mass index (BMI). These seasonal rhythms were significantly related to day length after adjustment for other factors that might affect seasonality including physical activity, diet and outdoor temperature.

Conclusions: The risk of CVD may be modulated by day length at temperate latitudes, and the implications of seasonality should be considered in all studies of human cardiometabolic health.

• Key messages

• In this cross-sectional study in UK Biobank, we report annual variations in cardiovascular risk factors and mortality that were associated with day length independent of environmental and lifestyle factors.

• These seasonal changes in day length might contribute to annual patterns in cardiovascular disease and mortality.