Connective Tissue Growth Factor Is Involved in Structural Retinal Vascular Changes in Long-Term Experimental Diabetes

Early retinal vascular changes in the development of diabetic retinopathy (DR) include capillary basal lamina (BL) thickening, pericyte loss and the development of acellular capillaries. Expression of the CCN (connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed) family member CCN2 or connective tissue growth factor (CTGF), a potent inducer of the expression of BL components, is upregulated early in diabetes. Diabetic mice lacking one functional CTGF allele (CTGF^+/−) do not show this BL thickening. As early events in DR may be interrelated, we hypothesized that CTGF plays a role in the pathological changes of retinal capillaries other than BL thickening. We studied the effects of long-term (6-8 months) streptozotocin-induced diabetes on retinal capillary BL thickness, numbers of pericytes and the development of acellular capillaries in wild type and CTGF^+/− mice. Our results show that an absence of BL thickening of retinal capillaries in long-term diabetic CTGF^+/− mice is associated with reduced pericyte dropout and reduced formation of acellular capillaries. We conclude that CTGF is involved in structural retinal vascular changes in diabetic rodents. Inhibition of CTGF in the eye may therefore be protective against the development of DR.     

Angiogenesis in gynecological cancers and the options for anti-angiogenesis therapy

Angiogenesis is required in cancer, including gynecological cancers, for the growth of primary tumors and secondary metastases. Development of anti-angiogenesis therapy in gynecological cancers and improvement of its efficacy have been a major focus of fundamental and clinical research. However, survival benefits of current anti-angiogenic agents, such as bevacizumab, in patients with gynecological cancer, are modest. Therefore, a better understanding of angiogenesis and the tumor microenvironment in gynecological cancers is urgently needed to develop more effective anti-angiogenic therapies, either or not in combination with other therapeutic approaches. We describe the molecular aspects of (tumor) blood vessel formation and the tumor microenvironment and provide an extensive clinical overview of current anti-angiogenic therapies for gynecological cancers. We discuss the different phenotypes of angiogenic endothelial cells as potential therapeutic targets, strategies aimed at intervention in their metabolism, and approaches targeting their (inflammatory) tumor microenvironment.     

Erythropoietic Defect Associated with Reduced Cell Proliferation in Mice Lacking the 26S Proteasome Shuttling Factor Rad23b

Rad23a and Rad23b proteins are linked to nucleotide excision DNA repair (NER) via association with the DNA damage recognition protein xeroderma pigmentosum group C (XPC) are and known to be implicated in protein turnover by the 26S proteasome. Rad23b-null mice are NER proficient, likely due to the redundant function of the Rad23b paralogue, Rad23a. However, Rad23b-null midgestation embryos are anemic, and most embryos die before birth. Using an unbiased proteomics approach, we found that the majority of Rad23b-interacting partners are associated with the ubiquitin-proteasome system (UPS). We tested the requirement for Rad23b-dependent UPS activity in cellular proliferation and more specifically in the process of erythropoiesis. In cultured fibroblasts derived from embryos lacking Rad23b, proliferation rates were reduced. In fetal livers of Rad23b-null embryos, we observed reduced proliferation, accumulation of early erythroid progenitors, and a block during erythroid maturation. In primary wild-type (WT) erythroid cells, knockdown of Rad23b or chemical inhibition of the proteasome reduced survival and differentiation capability. Finally, the defects linked to Rad23b loss specifically affected fetal definitive erythropoiesis and stress erythropoiesis in adult mice. Together, these data indicate a previously unappreciated requirement for Rad23b and the UPS in regulation of proliferation in different cell types.     

Socioeconomic status and incidence of sudden cardiac arrest

Background:

Low socioeconomic status is associated with poor cardiovascular health. We evaluated the association between socioeconomic status and the incidence of sudden cardiac arrest, a condition that accounts for a substantial proportion of cardiovascular-related deaths, in seven large North American urban populations.

Methods:

Using a population-based registry, we collected data on out-of-hospital sudden cardiac arrests occurring at home or at a residential institution from Apr. 1, 2006, to Mar. 31, 2007. We limited the analysis to cardiac arrests in seven metropolitan areas in the United States (Dallas, Texas; Pittsburgh, Pennsylvania; Portland, Oregon; and Seattle–King County, Washington) and Canada (Ottawa and Toronto, Ontario; and Vancouver, British Columbia). Each incident was linked to a census tract; tracts were classified into quartiles of median household income.

Results:

A total of 9235 sudden cardiac arrests were included in the analysis. For all sites combined, the incidence of sudden cardiac arrestin the lowest socioeconomic quartile was nearly double that in the highest quartile (incidence rate ratio [IRR] 1.9, 95% confidence interval [CI] 1.8–2.0). This disparity was greater among people less than 65 years old (IRR 2.7, 95% CI 2.5–3.0) than among those 65 or older (IRR 1.3, 95% CI 1.2–1.4). After adjustment for study site and for population age structure of each census tract, the disparity across socioeconomic quartiles for all ages combined was greater in the United States (IRR 2.0, 95% CI 1.9–2.2) than in Canada (IRR 1.8, 95% CI 1.6–2.0) (p < 0.001 for interaction).

Interpretation:

The incidence of sudden cardiac arrest at home or at a residential institution was higher in poorer neighbourhoods of the US and Canadian sites studied, although the association was attenuated in Canada. The disparity across socioeconomic quartiles was greatest among people younger than 65. The association between socioeconomic status and incidence of sudden cardiac arrest merits consideration in the development of strategies to improve survival from sudden cardiac arrest, and possibly to identify opportunities for prevention.An estimated 250 000–300 000 sudden cardiac arrests occur each year in the United States,¹ accounting for up to 63% of cardiac-related deaths annually.² Despite advances in resuscitation, more than 95% of people who experience sudden cardiac arrest die,³ and up to 50% of sudden cardiac arrests occur in people who do not have a history of coronary artery disease.⁴Socioeconomic status has been shown to predict many health outcomes, including all-cause mortality,⁵ prevalence of risk factors for cardiovascular disease⁶ and incidence of cardiovascular disease.^7–9 Despite this substantial literature, we found only three studies that examined the potential association between socioeconomic status and sudden cardiac arrest. Although the studies were small and conducted in single communities, each showed that the incidence of sudden cardiac arrest was significantly higher in lower socioeconomic areas.^10–12 The Oregon Sudden Unexplained Death Study (Ore-SUDS) reported a 30%–80% higher incidence of sudden cardiac arrest in poorer neighbourhoods. A stronger association was observed among people less than 65 years old, a group for whom basic health care funding is not guaranteed in the United States.¹¹Low socioeconomic status may be linked to an increased risk of sudden cardiac arrest by a variety of mechanisms related to individual risk factors or health-promoting behaviours or neighbourhood characteristics. Individuals of lower socioeconomic status have been found to have a greater burden of risk factors for cardiovascular disease,¹³ poorer control of established cardiovascular risk factors¹⁴ and longer delays in seeking hospital care for acute myocardial infarction.¹⁵ Numerous studies have also shown that disparities in health outcomes are apparent across the spectrum of socioeconomic status.¹⁶A better understanding of community-level patterns in the distribution of sudden cardiac arrest may identify opportunities for improving survival, such as effective targeting of community training for cardiopulmonary resuscitation and placement of automated external defibrillators in lower-income communities. We tested the hypothesis that disparities in the incidence of sudden cardiac arrest by level of socioeconomic status would be evident in a variety of urban communities in the United States and Canada, and that this association would be most prominent among people less than 65 years old residing in US communities.     

Identification of a sudden cardiac death susceptibility locus at 2q24.2 through genome-wide association in European ancestry individuals

Sudden cardiac death (SCD) continues to be one of the leading causes of mortality worldwide, with an annual incidence estimated at 250,000–300,000 in the United States and with the vast majority occurring in the setting of coronary disease. We performed a genome-wide association meta-analysis in 1,283 SCD cases and >20,000 control individuals of European ancestry from 5 studies, with follow-up genotyping in up to 3,119 SCD cases and 11,146 controls from 11 European ancestry studies, and identify the BAZ2B locus as associated with SCD (P = 1.8×10⁻¹⁰). The risk allele, while ancestral, has a frequency of ∼1.4%, suggesting strong negative selection and increases risk for SCD by 1.92–fold per allele (95% CI 1.57–2.34). We also tested the role of 49 SNPs previously implicated in modulating electrocardiographic traits (QRS, QT, and RR intervals). Consistent with epidemiological studies showing increased risk of SCD with prolonged QRS/QT intervals, the interval-prolonging alleles are in aggregate associated with increased risk for SCD (P = 0.006).     

Mechanics of toe and heel landing in stepping down in ongoing gait

When stepping down from a height difference in ongoing gait, subjects are known to use a heel landing at small height differences and switch to toe landing for larger height differences. We hypothesized that in toe landing, the leading leg can perform more negative work, to control the momentum gained during the descent, than in heel landing. Ten young male participants walked over a 10-m walkway at 5km/h to step down a height difference of 10cm halfway, using a heel or toe landing in five trials each. Kinematic data and ground reaction forces under the leading and trailing legs were recorded. Inverse dynamical analysis of both strategies showed that the leading leg performed more negative work in toe landing, while the vertical velocity at ground contact was lower. In addition, the impact forces were lower in toe landing than in heel landing. Toe landing was found to reduce gait velocity in the first step on the lower level and required higher moments and negative power around the ankle joint than heel landing. Our results indicate that heel landing may be preferred when stepping down small height differences, because it is less demanding especially for the plantar flexor muscles, while toe landing may be preferred for stepping down larger height differences, because it improves control over the momentum gained during the descent.     

Cellular microcytotoxicity in a human bladder cancer system: Analysis of in vitro lymphocyte-mediated cytotoxicity against cultured target cells

Summary The microcytotoxicity test (MCT) has been used to determine the cytotoxic effects of purified peripheral blood lymphocytes from patients with carcinoma of the urinary bladder (BT), tumor control patients (TC) (tested after therapy), and healthy donors (HD) against cultured bladder tumor cells, melanoma cells, and normal bladder cells. Lymphocytes from all three donor groups were tested in parallel. Disease-specific cytotoxicity (CTX) is defined as statistically significant and selective destruction of disease-related tumor target cells by the test lymphocytes in comparison with the baseline controls. Nonspecific CTX is defined as statistically significant destruction of a proportion (selective) or all (nonselective) disease unrelated target cells by the effector cells.Within the different donor groups, an enormous variation in non-disease related cytotoxic effects against the different cell lines was seen. It appeared that the selection of the baseline control influences the level of CTX and the specificity of the reaction.In order to determine whether a disease-specific cytotoxic effect was superimposed on the nonspecific cytotoxicity, the overall cytotoxic effects of the lymphocytes from the BT, TC patients and HD were compared statistically. The analysis of results revealed that effector cells from BT, TC patients and HD showed the same pattern of reactivity, but the CTX of lymphocytes from BT patients tested before therapy was stronger in comparison with the CTX of lymphocytes from the same group of BT patients after therapy and in comparison with the CTX of lymphocytes from HD and TC patients.     

Connective tissue growth factor is necessary for retinal capillary basal lamina thickening in diabetic mice.

Experimental prevention of basal lamina (BL) thickening of retinal capillaries ameliorates early vascular changes caused by diabetes. Connective tissue growth factor (CTGF) is upregulated early in diabetes in the human retina and is a potent inducer of expression of BL components. We hypothesize that CTGF is causally involved in diabetes-induced BL thickening of retinal capillaries. To test this hypothesis, we compared the effects of streptozotocin (STZ)-induced diabetes on retinal capillary BL thickness between wild-type mice (CTGF+/+) and mice lacking one functional CTGF allele (CTGF+/-). Differences in BL thickness were calculated by quantitative analysis of electron microscopic images of transversally sectioned capillaries in and around the inner nuclear layer of the retina. We show that BL thickening was significant in diabetic CTGF+/+ mice compared with control CTGF+/+ mice, whereas diabetes did not significantly induce BL thickening in CTGF+/- mice. We conclude that CTGF expression is necessary for diabetes-induced BL thickening and suggest that reduction of CTGF levels may be protective against the development of diabetic retinopathy.     

Distinct Transmission Networks of Chlamydia trachomatis in Men Who Have Sex with Men and Heterosexual Adults in Amsterdam,The Netherlands

Background

Genovar distributions of Chlamydia trachomatis based on ompA typing differ between men who have sex with men (MSM) and heterosexuals. We investigated clonal relationships using a high resolution typing method to characterize C. trachomatis types in these two risk groups.

Methods

C. trachomatis positive samples were collected at the STI outpatient clinic in Amsterdam between 2008 and 2010 and genotyped by multilocus sequence typing. Clusters were assigned using minimum spanning trees and these were combined with epidemiological data of the hosts.

Results

We typed 526 C. trachomatis positive samples: 270 from MSM and 256 from heterosexuals. Eight clusters, containing 10–128 samples were identified of which 4 consisted of samples from MSM (90%–100%), with genovars D, G, J, and L2b. The other 4 clusters consisted mainly of samples from heterosexuals (87%–100%) with genovars D, E, F, I, and J. Genetic diversity was much lower in the MSM clusters than in heterosexual clusters. Significant differences in number of sexual partners and HIV-serostatus were observed for MSM–associated clusters.

Conclusions

C. trachomatis transmission patterns among MSM and heterosexuals were largely distinct. We hypothesize that these differences are due to sexual host behavior, but bacterial factors may play a role as well.