[Prevalence, knowledge and control of arterial hypertension in vulnerable neighborhoods of Argentina: A Cross-sectional Study]

INTRODUCTION

Hypertension (HTN) represents the primary individual risk factor, contributing significantly to the global burden of cardiovascular diseases (CVD). In our country, epidemiological research has highlighted substantial variations in the prevalence of these risk factors across different populations. However, there is a lack of epidemiological studies assessing exclusive cardiovascular risk factors within vulnerable neighborhoods characterized by extremely limited economic resources, sociocultural challenges, and inadequate healthcare access.

METHODS

A multicenter cross-sectional observational study was conducted among individuals residing in economically deprived and marginalized communities, including informal settlements and underprivileged neighborhoods. Simple random sampling of households was employed. Blood pressure measurements, anthropometric assessments, and epidemiological, economic, and sociocultural questionnaires were administered. Results encompass prevalence rates, awareness levels, and blood pressure control across diverse regions. Logistic regression was utilized to identify independent variables influencing primary outcomes.

RESULTS

A total of 989 participants were analyzed. The overall prevalence of hypertension was 48.2%. About 82% had a body mass index (BMI) >25. Approximately 45.3% had less than 6 years of formal education. Independent association was established between education levels below 6 years and higher hypertension prevalence. Among hypertensive individuals, 44% were unaware of their condition, with only 17.2% achieving control, correlated with having health insurance and a higher educational background. Merely 24% were receiving combined therapy.

CONCLUSION

The prevalence of hypertension within vulnerable neighborhoods is alarmingly high, surpassing rates in other social strata. Knowledge, treatment, and control levels of hypertension are suboptimal, comparable to other populations. Inadequate use of combination therapy was observed. This study underscores the urgent need for targeted interventions addressing cardiovascular risk factors in poor areas to mitigate the burden of CVD.

Targeting proliferative retinopathy: Arginase 1 limits vitreoretinal neovascularization and promotes angiogenic repair

Current therapies for treatment of proliferative retinopathy focus on retinal neovascularization (RNV) during advanced disease and can trigger adverse side-effects. Here, we have tested a new strategy for limiting neurovascular injury and promoting repair during early-stage disease. We have recently shown that treatment with a stable, pegylated drug form of the ureohydrolase enzyme arginase 1 (A1) provides neuroprotection in acute models of ischemia/reperfusion injury, optic nerve crush, and ischemic stroke. Now, we have determined the effects of this treatment on RNV, vascular repair, and retinal function in the mouse oxygen-induced retinopathy (OIR) model of retinopathy of prematurity (ROP). Our studies in the OIR model show that treatment with pegylated A1 (PEG-A1), inhibits pathological RNV, promotes angiogenic repair, and improves retinal function by a mechanism involving decreased expression of TNF, iNOS, and VEGF and increased expression of FGF2 and A1. We further show that A1 is expressed in myeloid cells and areas of RNV in retinal sections from mice with OIR and human diabetic retinopathy (DR) patients and in blood samples from ROP patients. Moreover, studies using knockout mice with hemizygous deletion of A1 show worsened RNV and retinal injury, supporting the protective role of A1 in limiting the OIR-induced pathology. Collectively, A1 is critically involved in reparative angiogenesis and neuroprotection in OIR. Pegylated A1 may offer a novel therapy for limiting retinal injury and promoting repair during proliferative retinopathy.

Investigation of Retinal Metabolic Function in Type 1 Diabetic Akita Mice

Diabetic retinopathy (DR) is the leading cause of vision loss in working age adults. Understanding the retinal metabolic response to circulating high glucose levels in diabetic patients is critical for development of new therapeutics to treat DR. Measuring retinal metabolic function using the Seahorse analyzer is a promising technique to investigate the effect of hyperglycemia on retinal glycolysis and mitochondrial respiration. Here, we analyzed the retinal metabolic function in young and old diabetic and control mice. We also compared the expression of key glycolytic enzymes between the two groups. The Seahorse XF analyzer was used to measure the metabolic function of retina explants from young and old type 1 diabetic Akita (Ins2^Akita) mice and their control littermates. Rate-limiting glycolytic enzymes were analyzed in retina lysates from the two age groups by Western blotting. Retinas from young adult Akita mice showed a decreased glycolytic response as compared to control littermates. However, this was not observed in the older mice. Western blotting analysis showed decreased expression of the glycolytic enzyme PFKFB3 in the young Akita mice retinas. Measurement of the oxygen consumption rate showed no difference in retinal mitochondrial respiration between Akita and WT littermates under normal glucose conditions ex vivo despite mitochondrial fragmentation in the Akita retinas as examined by electron microscopy. However, Akita mice retinas showed decreased mitochondrial respiration under glucose-free conditions. In conclusion, diabetic retinas display a decreased glycolytic response during the early course of diabetes which is accompanied by a reduction in PFKFB3. Diabetic retinas exhibit decreased mitochondrial respiration under glucose deprivation.

Abstract P134: Peg-arginase 1 Limits Vascular Complications Of Type 2 Diabetes

Background: Distinct from its role in the urea cycle, the function of arginase 1 (A1) in regulating inflammatory responses has been demonstrated to be an intriguing target for controlling chronic, neuroinflammatory disease. Arginase competes with nitric oxide synthase (NOS) isoforms for their common substrate, L-arginine. Inflammatory cytokines increase expression of inducible NOS (iNOS) resulting in oxidant stress. Our group has recently shown that the polyethylene glycol-linked arginase 1 (PEG-A1) formulation, which provides enzyme stability, is a promising treatment that can counteract the destructive effects of neuro-inflammation and oxidative stress in ischemic retinal disease. This study assessed the efficacy of systemic PEG-A1 treatment in protecting the retinal neurovascular system from the effects of chronic hyperglycemia in a well-established murine model of type 2 diabetes.

Methods: Studies were performed using 16-week-old obese, diabetic db/db mice to examine effects of chronic hyperglycemia and dyslipidemia on the retina. Lean Db/db littermates served as controls (n= 7/group). The db/db mice (n= 8/group) were treated with PEG-A1 (25 mg/kg IP) or PEG alone (control) 7 times over 2 weeks. Activation of the inflammasome pathway was examined by Western blots. Immuno-labeling of 4-HNE was used to quantify oxidative stress. Breakdown of the blood retinal barrier (BRB) was examined via albumin extravasation.

Results: Expression of inflammasome pathway proteins, iNOS, caspase 1, IL-1β, and TNFα were upregulated in conjunction with increased cell death and breakdown of the BRB in db/db mice compared to controls. PEG-A1 treatment of the db/db mice significantly decreased the expression of iNOS, IL-1β, and TNFα, while reducing oxidative stress and preserving the BRB, as evidenced by decreased albumin leakage compared to db/db mice treated with PEG.

Conclusions: Chronic diabetes increases retinal inflammation, oxidative stress and BRB disruption. We hypothesize that systemic PEG-A1 administration provides significant anti-inflammatory and anti-oxidant protection while inhibiting BRB breakdown in the db/db obese, diabetic mouse by decreasing L-arginine availability for iNOS and thereby inhibiting its expression/activity.

Atypical phenotype and response of B cells in patients with seropositive rheumatoid arthritis

Patients with rheumatoid arthritis (RA) may be classified as seropositive or seronegative according to the presence of autoantibodies. An abnormal B cell phenotype and function could be one of the main components of the immunopathology of seropositive patients; however, there is little information regarding B cell defects in these patients. This study shows a broad characterization of the B cell phenotype and function in patients with seropositive RA. We focused mainly on the evaluation of subsets, the expression of modulatory molecules of cell activation (CD22, FcɣRIIb and FcµR), calcium mobilization, global tyrosine phosphorylation, expression of activation markers, cytokine and immunoglobulin (Ig) production, proliferation and the in-vitro generation of plasma cells. Increased frequency of CD27^- IgM^- IgD^- and CD21^- B cells was observed in patients with seropositive RA compared with healthy donors (HD). Decreased expression of CD22 was primarily found in memory B cells of patients with RA regardless of seropositivity. B cells from seropositive patients exhibited normal proliferation, calcium mobilization kinetics and global tyrosine phosphorylation, but showed an increased frequency of CD86⁺ B cells compared with HD. B cells of seropositive patients secrete less interleukin-10 after in-vitro activation and showed a decreased frequency of plasma cell differentiation and IgM production compared with HD. Our data indicate that patients with seropositive RA have an increased frequency of atypical B cell populations previously associated with chronic activation and antigen exposure. This may result in the observed low responsiveness of these cells in vitro.

110 Pregnancy rate and embryo viability in response to chorionic gonadotrophins given for oestrus induction and gonadotrophin-releasing hormone 5 days after timed laparoscope-aided insemination of lactating and non-lactating goats

Gonadotrophins are included in oestrous/ovulation synchronization (E/OS) regimens when breeding early in the transitional phase to promote follicular development. However, the time of use has been a matter of debate. Hence, the objective of this study was to determine whether equine and human chorionic gonadotrophins (eCG and hCG, respectively) given 24h before or 24h after concurrent removal of intravaginal progestagen (P4) and prostaglandin (PGF2α) delivery influences pregnancy rate (PR) and/or embryo viability (EV). Relatedly, the influence of gonadotrophin-releasing hormone (GnRH) 5 days post-breeding (dpb) on PR and/or EV was also considered. A prospective randomised control trial was conducted using lactating and non-lactating Alpine breed goats of different parity, average±s.e. age, and bodyweight (3.7±2.6), and (52.5±7), respectively. Goats were time-bred at 48h after P4 removal by laparoscopy (LAI; n=75) or by natural service (NS; n=29) during the early transitional breeding phase in mid-September through mid-December (corresponding to 12:12h daylight/darkness). E/OS used an intravaginal device containing 300mg of P4 for 12±1d. At P4 removal, 2mL of PGF2α was administered IM. Twenty-four hours before (E) or 24h after (L) P4 removal, an IM dose of 1.5mL containing 120IU of eCG and 60IU of hCG was given. A third control (C) group (n=38) was not exposed to gonadotrophins. GnRH analogue was given (n=51) 5 days after insemination, and the remaining goats (n=53) received an IM dose of 2mL of saline solution. PR was evaluated at 18 to 24 (dpb) by non-return to oestrus (NRE), at 30 dpb by pregnancy-specific protein B (PSPB), and at 40 dpb by ultrasound imaging (UI). EV was determined from the difference between pregnancy outcomes for NRE and PSPB, and PSPB and UI. Statistical analysis (JMP/SAS vs.11; SAS Institute Inc.) were obtained using logistic regression. All concomitant variables (i.e. parity, bodyweight, days of P4 exposure, and lactation were not influenced by PR or EV; P>0.07). The overall PR was 71% for LAI and 69% for NS and, as shown in Table 1, was similar (P>0.49) at all times (at 18 to 24, 30, and 40 dpb). Likewise, the breeding procedure did not influence the levels of EV at 30 or 40 dpb. E/OS protocol or the use of GnRH 5 dpb did not affect PR or EV at any of the time points evaluated. Table 1. Main effect mean comparisons and logistic model probabilities for pregnancy rate (PR) and embryo viability (EV) by main treatment effect Response variable (days post-breeding) Breeding procedure E/OS Protocol Gonadotrophin LAI NS P> Control Early Late P> GnRH Placebo P> PR at 18–24 77 72 0.49 76 73 78 0.83 78 74 0.49 PR at 30 68 66 0.65 66 65 70 0.82 71 64 0.43 PR at 40 69 69 0.78 66 69 73 0.77 73 66 0.43 EV at 30 89 90 0.94 86 94 90 0.65 92 87 0.46 EV at 40 88 95 0.42 86 89 94 0.73 92 87 0.43

112 Follicular dynamics and oestrus response of Alpine goats with oestrus/ovulation synchronized during the early transitional reproductive phase using gonadotrophin given early or late

Oestrus and ovulation synchronization (E/OS) regimens for fixed-timed breeding are useful when consistently eliciting ovulation. Early synchronization in the reproductive season promotes unreliable oestrus behavioural and physiologic response due to insufficient ovarian priming. In ruminants, equine (eCG) or human chorionic gonadotrophin (hCG) has FSH bioactivity or elicits ovulation, correspondingly. Hence, 120 and 60IU of eCG and hCG, respectively, are included in goat E/OS regimes. This experiment addresses the time when eCG/hCG (CG) is given relative to progestagen (P4) withdrawal and its effect on oestrus and ovulation. Fourteen non-lactating, Alpine breed goats, ranging from 1 to 6 kiddings, averaging±s.d. 3.9±2.0 years of age, and 56.3±5.0kg of bodyweight (BW), and body condition score (BCS) of 2.6±0.2, were evaluated early in the transitional reproductive phase (12h daylight:12h darkness). E/OS was accomplished with 12 day of P4 (200 mg) exposure by intravaginal insert. Three treatments were evaluated: Traditional (T; n=4) did not receive CG and served as the control group; early (E; n=5) received CG 24h before P4 removal; and reverse (R; n=5) received PGF2α 24h before P4 withdrawal as well as CG concurrent with P4 withdrawal. Oestrus response to E/OS was evaluated 24h after breeding using epididymectomized bucks. Ovaries were scanned by transrectal ultrasound (Aloka SSD-500V/7.5-MHz linear array probe) for 4 consecutive days starting with the first i.m. injection of 1.0mL of PGF2α or 1.5mL of CG. Images were digitized (MediCapture™) for later morphometry. The absence of effect (P>0.05) from concomitant variables age, BW, BCS, and parity was ascertained using a logistic regression model (JMP/SAS v15; SAS Institute Inc.). Ovulation, defined as the disappearance of the largest (>7mm) preovulatory follicle on a subsequent observation, was 100, 80, and 100%; and the average±s.e. number of ovulations per goat was 2±0.41, 1±0.32, and 1.3±0.49 (P>0.05). Table 1 summarises follicular size documented of 122 observations of ovulatory areas. Graafian follicle location was not different for left or right ovaries (P>0.05). Oestrus behavioural response to each E/OS treatment (T, E, or L) up to 24h after P4 removal was 50, 80, and 80% (P>0.05), respectively. In summary, oestrus response and ovulation were not affected by the variables studied. In this experience the timing of CG was not relevant. Table 1. Mean diameter (±SE; mm) of nonovulatory and preovulatory follicles on left (L) and right (R) ovaries E/OS protocol Non- and preovulatory Nonovulatory Preovulatory L R L R L R Traditional 6.4±0.6 5.5±0.6 4.8±0.4 4.5±0.4 7.7±0.4 8.9±0.3 Early 5.2±0.3 5.5±0.4 4.9±0.2 4.4±0.3 8.4±1.2 8.1±0.2 Reverse 6.6±0.5 5.3±0.6 5.1±0.4 4.4±0.5 8.7±0.3 8.1±0.2 Overall 5.7±0.19 4.7±0.14 8.3±0.14

111 Use of gonadotrophin-releasing hormone (GnRH) or equine and human chorionic gonadotrophins for oestrus synchronization and their influence on embryo viability and progesterone levels on day 16 and 30 of goats receiving GnRH 5 days after intrauterine insemination or natural service

Gonadotrophin-releasing hormone (GnRH) or equine and human chorionic gonadotrophins (eCG and hCG) were evaluated for oestrus/ovulation synchronization (E/OS), as well as the influence of GnRH 5 days post-breeding (dpb) on embryo viability (EV), and progesterone (P4) levels on Day 16 and 30 after laparoscopic AI (LAI) or natural service (NS). Fifty-four lactating/non-lactating Alpine breed goats (average of 3.82±1.2s.d. years of age) of mixed parity were E/OS during the early transitional breeding phase using 12±1 day of 300mg of P4 and 2mL of prostaglandin F2α analogue given at P4 removal. The experiment included a sub-group from a larger study in which a completely randomised design was used. The germane data were arranged as a 2×2×2 factorial. This study focused on goats receiving 120IU of eCG and 60IU of hCG (n=40), or GnRH analogue (n=14) 24h after P4 removal. At 5 dpb, 25 goats received 1mL (IM) of GnRH and the control (n=29) received 1mL of physiologic saline. Goats were time-bred 48h after P4 withdrawal by LAI (n=33) or NS (n=21). Pregnancy was diagnosed at 18 to 24, 30, and 40 dpb by non-return to oestrus, pregnancy-specific protein B, and ultrasound, respectively. EV was evaluated as the difference between pregnancy diagnosis results. Blood serum P4 was evaluated at 5, 16, and 30 dpb. A logistic regression model was used for statistical analysis. Pregnancy rate (PR) for LAI or NS, at 18–24, 30, and 40 days was 73 vs. 76%, 67 vs. 62%, and 64 vs. 67%, respectively (P>0.72). In contrast, when GnRH was used for E/OS, the 5 dpb GnRH influenced EV at 30 days (95 vs. 81%; P=0.06) but not at 40 days (89 vs. 86%; P>0.35), compared with placebo. Similarly, with the exception of PR at 40 days (43 vs. 72%; P=0.05), for the GnRH and eCG/hCG E/OS groups, respectively, PR was not affected (P>0.12) by either E/OS or GnRH 5 dpb or their interaction (P>0.35) at any pregnancy diagnosis (i.e. 18–24, 30, or 40 dpb). Likewise, levels of P4 at 5, 16, and 30 dpb did not affect PR at 18–24, 30, and 40 dpb (P>0.92, 0.71, and 0.11). As shown in Table 1, the level of P4 was not influenced for goats receiving GnRH or placebo at 5, 16, or 30 dpb. The baseline mean P4 blood serum level for goats receiving GnRH 5 dpb differed at 16 but not at 30 dpb (P<0.001). Table 1 Blood serum progesterone (P4, ng mL−1) in response to gonadotrophin-releasing hormone (GnRH) or placebo given 5 days post-breeding Sampling day GnRH Placebo P >1 Mean ±SE Mean ±SE 5 (baseline) 6.2a 0.83 5.7a 0.72 0.66 16 11.7b 1.11 11.0b 1.05 0.65 30 6.2a 0.89 7.6c 0.84 0.26 a–cMean values with different superscripts within a column signify statistical difference for GnRH (P<0.001) and placebo (P<0.02). 1Probability for mean differences in the same row.

Integrating a Sport-Based Trauma-Sensitive Program in a National Youth-Serving Organization

There is a pressing need to equip youth-serving community organizations to respond to the unique needs of trauma-exposed children. Early prevention measures can be an effective means of redirecting children to self-regulatory healing, while facilitating their transition toward strength-based thriving. Sport can offer a powerful opportunity to reach these children; however there remains little information on how to effectively develop, deliver, evaluate, and sustain trauma-sensitive sport programs in a community context. The purpose of this paper is to outline a case study of integrating sport-based trauma-sensitive practices with BGC Canada's national Bounce Back League program. An interdisciplinary partnership of academic, community, and practice experts used a community-based participatory action research approach, paired with a knowledge translational approach, to guide the process of program development. Mixed methods (e.g., surveys, logbooks, interviews, focus groups, online communications) were used to generate ongoing insights of staff's training experiences, successes and challenges of program implementation, and potential impact of program on club members. Several stages of program development are described, including: (a) collaboratively planning the program; (b) piloting the program to three clubs; (c) adapting the program using pilot insights; (d) expanding the adapted program to ten clubs; and (e) creating opportunities to maintain, sustain, and scale-out practices throughout grant duration and beyond. Lessons learned regarding the leadership team's experiences in terms of developing, adapting, and integrating trauma-sensitive practices in this community context are shared.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10560-021-00776-7.

151 Influence of chorionic gonadotrophin, breeding procedure, and gonadotrophin-releasing hormone on pregnancy, embryo viability, and kidding rate of lactating Alpine goats time inseminated during the early transitional reproductive phase

Oestrus and ovulation synchronisation (E/OS) regimens containing equine chorionic gonadotrophin (ECG) are used for follicular stimulation during the early transitional reproductive phase and goat anestrus. However, the effects of ECG when applied at different times are unknown. Thus, the objective was to evaluate the influence of ECG, breeding procedure, and gonadotrophin-releasing hormone (GnRH) on pregnancy, embryonic viability, and kidding rate in dairy goats. We used 41 alpine goats (mean±standard deviation: 3.82±1.2 years old; 57.0±6.0kg of bodyweight; 1.75-2.25 body condition score; 195±16.7 days in milk; range of 1-4 kiddings). This study took place during the transitional phase (12h of daylight, 12h of dark) in September (35.9° N, 97.3° W) using controlled internal drug release intravaginal inserts (300mg of progestagen; P4) for 11, 12, or 13 days with a 2-mL intramuscular dose containing 10mg of dinoprost tromethamine at P4 removal. The E/OS protocols differed on the time when the 1-mL intramuscular dose of P.G. 600© (Merck Animal Health; 120 and 60IU of ECG and human chorionic gonadotrophin, respectively) was given (i.e. early=24h before P4 removal; late=24h after P4 removal), and the traditional control group did not receive P.G. 600. Time breeding, either by laparoscopic-aided insemination using frozen-thawed semen (n=28) or natural (n=13), was scheduled 48h after P4 removal. To improve embryo survival, 5 days post-breeding (dpb) 21 goats received 1mL of GnRH analogue intramuscularly as 50µgmL−1 gonadorelin diacetate tetrahydrate, and 20 control goats received 1mL of placebo intramuscularly. Pregnancy rate (PR) was evaluated at d 18-24 by non-return to oestrus, d 30 by pregnancy-specific protein B, and d 40 by ultrasound. Kidding rate was determined for females with at least one newborn. Logistic regression was used to establish statistical significance. Days of P4 exposure did not influence any response variable (P>0.20). Table 1 summarises the results; age influenced all PR evaluations. The number of kiddings and administration of GnRH at 5 dpb had a significant effect on PR, whereas bodyweight, days in milk, E/OS protocol, and breeding procedure were not influential. Embryo viability and kidding rate were not influenced by any variable. In short, P.G. 600 had no bearing on any response variable analysed. Late-lactating goats can be evaluated early in the transitional breeding phase using PR at 18-24, 30, or 40 dpb. As indicated by the lack of effect on embryo viability at 30 and 40 days, the mechanism by which GnRH increases PR was not by decreasing embryo mortality. Table 1.Logistic model independent variable probabilities on response variables1 Response variable Age (years) BW Kidding DIM E/OS protocol GnRH Breeding procedure PR 18-24 d 0.02 0.65 0.15 0.52 0.37 0.21 0.30 PR 30 d 0.01 0.56 0.05 0.58 0.61 0.05 0.39 PR 40 d 0.001 0.12 0.01 0.60 0.62 0.02 0.35 EV 30 d 0.62 0.96 0.61 0.63 0.30 0.32 0.36 EV 40 d 0.44 0.90 0.26 0.36 0.46 0.17 0.40 KR 0.83 0.93 0.63 0.86 0.42 0.29 0.35 1BW=body weight; DIM=days in milk; E/OS=oestrus/ovulation synchronisation; GnRH=gonadotrophin-releasing hormone; PR=pregnancy rate; EV=embryo viability at 30 and 40 d; KR=kidding rate.

Neurofibromin Deficiency Induces Endothelial Cell Proliferation and Retinal Neovascularization

Purpose

Neurofibromatosis type 1 (NF1) is the result of inherited mutations in the NF1 tumor suppressor gene, which encodes the protein neurofibromin. Eye manifestations are common in NF1 with recent reports describing a vascular dysplasia in the retina and choroid. Common features of NF1 retinopathy include tortuous and dilated feeder vessels that terminate in capillary tufts, increased endothelial permeability, and neovascularization. Given the retinal vascular phenotype observed in persons with NF1, we hypothesize that preserving neurofibromin may be a novel strategy to control pathologic retinal neovascularization.

Methods

Nf1 expression in human endothelial cells (EC) was reduced using small hairpin (sh) RNA and EC proliferation, migration, and capacity to form vessel-like networks were assessed in response to VEGF and hypoxia. Wild-type (WT), Nf1 heterozygous (Nf1^+/−), and Nf1^flox/+;Tie2cre pups were subjected to hyperoxia/hypoxia using the oxygen-induced retinopathy model. Retinas were analyzed quantitatively for extent of retinal vessel dropout, neovascularization, and capillary branching.

Results

Neurofibromin expression was suppressed in response to VEGF, which corresponded with activation of Mek-Erk and PI3-K-Akt signaling. Neurofibromin-deficient EC exhibited enhanced proliferation and network formation in response to VEGF and hypoxia via an Akt-dependent mechanism. In response to hyperoxia/hypoxia, Nf1^+/− retinas exhibited increased vessel dropout and neovascularization when compared with WT retinas. Neovascularization was similar between Nf1^+/− and Nf1^flox/+;Tie2cre retinas, but capillary drop out in Nf1^flox/+;Tie2cre retinas was significantly reduced when compared with Nf1^+/− retinas.

Conclusions

These data suggest that neurofibromin expression is essential for controlling endothelial cell proliferation and retinal neovascularization and therapies targeting neurofibromin-deficient EC may be beneficial.

High concentrations of atorvastatin reduce in-vitro function of conventional T and regulatory T cells

Regulatory T cells (T_regs ) modulate the magnitude of immune responses and possess therapeutic potential in an array of immune diseases. Statins reduce the activation and proliferation of conventional T cells (T_cons ), and they seem to up-regulate the frequency and function of T_regs . However, there is a lack of simultaneous evaluation of the in-vitro effect of statins on the functional profile of T_regs versus T_cons . Herein, magnetically purified T_cons and T_regs were stimulated with CD3/CD28/interleukin (IL)-2 in the presence of atorvastatin (ATV) at 1 or 10 µM. The suppressive function of T_regs , the expression of markers associated with T_reg function, activation levels, cytokine production and calcium flux in both subpopulations were assessed by flow cytometry. ATV had no cytotoxic effect on T cells at the concentrations used. Interestingly, 10 µM ATV hampered the suppressive capacity of T_regs . Moreover, this higher concentration reduced the expression of forkhead box protein 3 (FoxP3), cytotoxic T lymphocyte antigen (CTLA-4) and programmed death 1 (PD-1). In T_cons , ATV at 10 µM decreased PD-1 and CD45RO expression. The expression of CD25, CD69, CD95, CD38, CD62L, CCR7 and perforin was not affected in both subpopulations or at any ATV concentrations. Remarkably, 10 µM ATV increased the percentage of tumour necrosis factor (TNF)-α-producing T_regs . Although there was a reduction of calcium flux in T_cons and T_regs , it was only significant in 10 µM ATV-treated T_cons . These results suggested that 10 µM ATV affects the cellular functions of both populations; however, this concentration particularly affected several aspects of T_reg biology: its suppressive function, cytokine production and expression of T_reg -specific markers.

Retinal Neuroprotection From Optic Nerve Trauma by Deletion of Arginase 2

Our previous studies have implicated expression of the mitochondrial isoform of the arginase enzyme arginase 2 (A2) in neurovascular injury during ischemic retinopathies. The aim of this study was to characterize the specific involvement of A2 in retinal injury following optic nerve crush (ONC). To accomplish this, wild-type (WT) or A2 knockout (A2^-/-) mice were subjected to ONC injury. The contralateral eye served as sham control. Quantitative RT-PCR and western blot were used to evaluate mRNA and protein expression. Retinal ganglion cell (RGC) survival was assessed in retinal whole mounts. Axonal sprouting was determined by anterograde transport of Cholera Toxin B (CTB). These analyses showed increased A2 expression following ONC. Numbers of NeuN-positive neurons as well as Brn3a- and RBPMS-positive RGC were decreased in the WT retinas at 14 days after ONC as compared to the sham controls. This ONC-induced neuronal loss was diminished in the A2^-/- retinas. Similarly, axonal degeneration was ameliorated by A2 deletion whereas axon sprouting was enhanced. Significant retinal thinning was also seen in WT retinas at 21 days after ONC, and this was blocked in A2^-/- mice. Cell death studies showed an increase in TUNEL positive cells in the RGC layer at 5 days after ONC in the WT retinas, and this was attenuated by A2 deletion. ONC increased glial cell activation in WT retinas, and this was significantly reduced by A2 deletion. Western blotting showed a marked increase in the neurotrophin, brain derived neurotrophic factor (BDNF) and its downstream signaling in A2^-/- retinas vs. WT after ONC. This was associated with increases in the axonal regeneration marker GAP-43 in A2^-/- retinas. Furthermore, A2^-/- retinas showed decreased NLRP3 inflammasome activation and lower interleukin (IL-) 1β/IL-18 levels as compared to WT retinas subjected to ONC. Collectively, our results show that deletion of A2 limits ONC-induced neurodegeneration and glial activation, and enhances axonal sprouting by a mechanism involving increases in BDNF and decreases in retinal inflammation. These data demonstrate that A2 plays an important role in ONC-induced retinal damage. Blockade of A2 activity may offer a therapeutic strategy for preventing vision loss induced by traumatic retinal injury.

Pain in children and adolescents hospitalized in a center of reference

INTRODUCTION

The evaluation and treatment of pain in hospitalized is still an important health pro blem.

OBJECTIVE

To know the prevalence, characteristics and approaches to pain management in children and adolescents hospitalized in the Pediatric Hospital of the Pereira Rossell Center (HP-CH- PR), a pediatric reference center in Uruguay.

PATIENTS AND METHOD

Cross-sectional study, through survey and review of clinical records on 09/13/16. All hospitalized children under the age of 19 were included.

VARIABLES

age, gender, reason for admission, presence of cognitive disorder, the prevalen ce of pain at some time during hospitalization, in the last 24 hours and during the interview, cause of maximum pain, intensity, pharmacological and non-pharmacological treatment.

RESULTS

97.4% (152/156) hospitalized children were included. Pain prevalence at some point during hospitalization: 51.3% (78/152, 95% CI: 43.2-59.3); in the previous 24 hours: 39.5% (60/152, 95% CI: 31.7-47.2); during the interview: 15.8% (24/152, 95% CI: 10-21.5). Intensity: mild 13/24, moderate-severe 11/24. Maximum pain referred during hospitalization: needle punctures 48.5% (38/78). They had some analgesic prescription 47.3% of them had some analgesic prescription. Inadequate interdose inter val: 45.8%; adequate dose 98.9%; intravenous administration: 43.7%; contraindication to oral route: 40.5%.

CONCLUSIONS

Regarding children and adolescents hospitalized, 39.5% reported pain 24 hours before being the interviewed and 15.8% reported pain during the interview. The maximum pain reported during hospitalization was due to needle punctures. Children in pain with inappropriate analgesic prescriptions are still detected.

Drivers of international variation in prevalence of disabling low back pain: Findings from the Cultural and Psychosocial Influences on Disability study

Background

Wide international variation in the prevalence of disabling low back pain (LBP) among working populations is not explained by known risk factors. It would be useful to know whether the drivers of this variation are specific to the spine or factors that predispose to musculoskeletal pain more generally.

Methods

Baseline information about musculoskeletal pain and risk factors was elicited from 11 710 participants aged 20–59 years, who were sampled from 45 occupational groups in 18 countries. Wider propensity to pain was characterized by the number of anatomical sites outside the low back that had been painful in the 12 months before baseline (‘pain propensity index’). After a mean interval of 14 months, 9055 participants (77.3%) provided follow‐up data on disabling LBP in the past month. Baseline risk factors for disabling LBP at follow‐up were assessed by random intercept Poisson regression.

Results

After allowance for other known and suspected risk factors, pain propensity showed the strongest association with disabling LBP (prevalence rate ratios up to 2.6, 95% CI: 2.2–3.1; population attributable fraction 39.8%). Across the 45 occupational groups, the prevalence of disabling LBP varied sevenfold (much more than within‐country differences between nurses and office workers), and correlated with mean pain propensity index (r = 0.58).

Conclusions

Within our study, major international variation in the prevalence of disabling LBP appeared to be driven largely by factors predisposing to musculoskeletal pain at multiple anatomical sites rather than by risk factors specific to the spine.

Significance

Our findings indicate that differences in general propensity to musculoskeletal pain are a major driver of large international variation in the prevalence of disabling low back pain among people of working age.

Mechanisms of Diabetes-Induced Endothelial Cell Senescence: Role of Arginase 1

We have recently found that diabetes-induced premature senescence of retinal endothelial cells is accompanied by NOX2-NADPH oxidase-induced increases in the ureohydrolase enzyme arginase 1 (A1). Here, we used genetic strategies to determine the specific involvement of A1 in diabetes-induced endothelial cell senescence. We used A1 knockout mice and wild type mice that were rendered diabetic with streptozotocin and retinal endothelial cells (ECs) exposed to high glucose or transduced with adenovirus to overexpress A1 for these experiments. ABH [2(S)-Amino-6-boronohexanoic acid] was used to inhibit arginase activity. We used Western blotting, immunolabeling, quantitative PCR, and senescence associated β-galactosidase (SA β-Gal) activity to evaluate senescence. Analyses of retinal tissue extracts from diabetic mice showed significant increases in mRNA expression of the senescence-related proteins p16^INK4a, p21, and p53 when compared with non-diabetic mice. SA β-Gal activity and p16^INK4a immunoreactivity were also increased in retinal vessels from diabetic mice. A1 gene deletion or pharmacological inhibition protected against the induction of premature senescence. A1 overexpression or high glucose treatment increased SA β-Gal activity in cultured ECs. These results demonstrate that A1 is critically involved in diabetes-induced senescence of retinal ECs. Inhibition of arginase activity may therefore be an effective therapeutic strategy to alleviate diabetic retinopathy by preventing premature senescence.

The CEA Family: A System in Transitional Evolution?

The CEA family consists of two structurally and functionally distinct subgroups; the group including CEA, NCA and CGM-6 which are cell surface-bound by phosphatidylinositol (PI) linkages, and the group of BGP splice variants which have transmembrane and cytoplasmic domains. Although all CEA family members mediate intercellular adhesion in vitro, the PI-linked group show Ca++ and temperature independent adhesion whereas the BGP group show rapidly reversible Ca++ and temperature dependent adhesion. From the close alignment in cDNA nucleotide sequences between family members and between repeated domains in one family member, it is apparent that the CEA family is now rapidly evolving; in fact, analogs of only the transmembrane BGP group have been found so far in the mouse. The addition of a new group of potent adhesion molecules to complex species at some time after the rodent radiation has strong evolutional implications, which are discussed.

Azithromycin Fails to Prevent Accelerated Airway Obliteration in T-bet-/- Mouse Lung Allograft Recipients

BACKGROUND

Cellular and molecular mechanisms of acute and chronic lung allograft rejection have yet to be clearly defined, and obliterative bronchiolitis (OB) remains the primary limitation to survival in lung transplant recipients (LTRs). We have previously shown that T-bet-deficient recipients of full major histocompatibility complex (MHC)-mismatched, orthotopic left lung transplants develop accelerated obliterative airway disease (OAD) in the setting of acute cellular rejection characterized by robust alloimmune CD8⁺ interleukin (IL)-17 and interferon (IFN)-γ responses that are attenuated with neutralization of IL-17. Azithromycin has been shown to be beneficial in some LTRs with bronchiolitis obliterans syndrome/OB. Here, we evaluated the effects of azithromycin on rejection pathology and T-cell effector responses in T-bet^-/- recipients of lung transplants.

METHODS

Orthotopic left lung transplantation was performed in BALB/c → B6 wild type or BALB/c → B6 T-bet^-/- strain combinations as previously described. Mice treated with azithromycin received 10 mg/kg or 50 mg/kg subcutaneously daily. Lung allograft histopathology was analyzed at day 10 or day 21 post-transplantation, and neutrophil staining for quantification was performed using anti-myeloperoxidase. Allograft mononuclear cells were isolated at day 10 for T-cell effector cytokine response assessment using flow cytometry.

RESULTS

We show that while azithromycin significantly decreases lung allograft neutrophilia and CXCL1 levels and attenuates allospecific CD8⁺ IL-17 responses early post-transplantation, OAD persists in T-bet-deficient mice.

CONCLUSIONS

Our results indicate that lung allograft neutrophilia is not essential for the development of OAD in this model and suggest allospecific T-cell responses that remain despite marked attenuation of CD8⁺ IL-17 are sufficient for obliterative airway inflammation and fibrosis.

Onset and Evolution of Southern Annular Mode-Like Changes at Centennial Timescale

The Southern Westerly Winds (SWW) are the surface expression of geostrophic winds that encircle the southern mid-latitudes. In conjunction with the Southern Ocean, they establish a coupled system that not only controls climate in the southern third of the world, but is also closely connected to the position of the Intertropical Convergence Zone and CO₂ degassing from the deep ocean. Paradoxically, little is known about their behavior since the last ice age and relationships with mid-latitude glacier history and tropical climate variability. Here we present a lake sediment record from Chilean Patagonia (51°S) that reveals fluctuations of the low-level SWW at mid-latitudes, including strong westerlies during the Antarctic Cold Reversal, anomalously low intensity during the early Holocene, which was unfavorable for glacier growth, and strong SWW since ~7.5 ka. We detect nine positive Southern Annular Mode-like events at centennial timescale since ~5.8 ka that alternate with cold/wet intervals favorable for glacier expansions (Neoglaciations) in southern Patagonia. The correspondence of key features of mid-latitude atmospheric circulation with shifts in tropical climate since ~10 ka suggests that coherent climatic shifts in these regions have driven climate change in vast sectors of the Southern Hemisphere at centennial and millennial timescales.

Maternal magnesium therapy, neonatal serum magnesium concentration and immediate neonatal outcomes

OBJECTIVE

The fetus is exposed to magnesium administered to the pregnant mother. However, there is controversy regarding magnesium-related neonatal adverse outcomes, largely driven by a limited understanding of the factors that influence neonatal serum magnesium concentrations and associated outcomes. The objective of this study was to examine the relationship between antenatal maternal magnesium dose and serum concentrations, neonatal serum magnesium concentration and immediate neonatal outcomes.

STUDY DESIGN

A retrospective study was conducted at a community-based teaching hospital. Neonatal serum magnesium concentrations within 48 h of birth were used to stratify magnesium-exposed neonates into three groups: group 1: <2.5 mg dl^-1, group 2: ⩾2.5 to <4.5 mg dl^-1, and group 3:⩾4.5 mg dl^-1. Immediate neonatal outcomes were compared between the three groups. Total maternal magnesium dose and serum magnesium concentrations before the delivery were correlated with neonatal serum magnesium concentrations and outcomes.

RESULTS

Of the 304 mother-baby dyads between 24 and 34 weeks gestation, 237 received antenatal magnesium. Neonatal serum magnesium concentration was 3.14±0.83 mg dl^-1 in exposed and 1.96±0.42 mg dl^-1 in unexposed neonates (P<0.001). Compared with group 2, neonates had higher odds of grade 3 or 4 intraventricular hemorrhage in group 1 (adjusted odds ratio (AOR) 5.95 (95% confidence interval (CI) 1.05 to 33.66)) and group 3 (AOR 8.42 (95% CI 1.35 to 52.54)). Group 3 neonates also had increased odds of periventricular leukomalacia (AOR: 5.37 (95% CI 1.02 to 28.28) compared with group 2 neonates. Predictors of neonatal serum magnesium concentrations included maternal magnesium dose (r=0.66, P<0.0001), duration of therapy (r=0.70, P<0.0001) and serum concentration (r=0.72, P<0.001).

CONCLUSION

The between-group differences highlight that there is a therapeutic range of neonatal serum magnesium concentrations for neuroprotective effects of antenatal magnesium sulfate, while concentrations outside of this range may be associated with adverse neonatal outcomes. Further studies are needed to determine the optimal dose and duration of maternal magnesium to minimize adverse neonatal outcomes.

The Lymphocytes Stimulation Induced DNA Release, a Phenomenon Similar to NETosis

The release of DNA into the extracellular milieu by neutrophil during a process called NETosis has been postulated as an additional source of autoantigens; a process believed to be important in the pathogenesis of some autoimmune disease, such as systemic lupus erythematosus (SLE). However, it is not established if the B and T cells undergo the release of DNA to the extracellular milleu, in response to different stimuli. In this study, it was observed that the treatment of B and T cells with PMA, ionomycin and the serum from patients with SLE induced the extracellular DNA presence in B and T cells. These findings suggest that the phenomenon were similar to those observed in neutrophil's Etosis; B and T cells also released their DNA into the extracellular milieu. The findings express that serum from patients with SLE and SLEDAI ≤ 8 triggers the release of extracellular DNA in neutrophils, B and T cells, that suggested the presence of soluble factors in the serum that favoured this phenomenon.

NOX2-Induced Activation of Arginase and Diabetes-Induced Retinal Endothelial Cell Senescence

Increases in reactive oxygen species (ROS) and decreases in nitric oxide (NO) have been linked to vascular dysfunction during diabetic retinopathy (DR). Diabetes can reduce NO by increasing ROS and by increasing activity of arginase, which competes with nitric oxide synthase (NOS) for their commons substrate l-arginine. Increased ROS and decreased NO can cause premature endothelial cell (EC) senescence leading to defective vascular repair. We have previously demonstrated the involvement of NADPH oxidase 2 (NOX2)-derived ROS, decreased NO and overactive arginase in DR. Here, we investigated their impact on diabetes-induced EC senescence. Studies using diabetic mice and retinal ECs treated with high glucose or H₂O₂ showed that increases in ROS formation, elevated arginase expression and activity, and decreased NO formation led to premature EC senescence. NOX2 blockade or arginase inhibition prevented these effects. EC senescence was also increased by inhibition of NOS activity and this was prevented by treatment with a NO donor. These results indicate that diabetes/high glucose-induced activation of arginase and decreases in NO bioavailability accelerate EC senescence. NOX2-generated ROS contribute importantly to this process. Blockade of NOX2 or arginase represents a strategy to prevent diabetes-induced premature EC senescence by preserving NO bioavailability.

Chlamydial infection in women along the US–Mexico border

Few studies have reported on sexually transmitted infections at the US–Mexico border, so the prevalence of Chlamydia trachomatis in this population remains uncertain. This binational project investigated the prevalence of, and risk factors for, C. trachomatis among women along the Arizona, US–Sonora, Mexico border.

Women who self-referred for routine gynaecological care were invited to complete an interviewer-administered questionnaire and to undergo a Pap smear, C. trachomatis test, and HPV test. In 2270 women, C. trachomatis prevalence overall was 8.2% as measured by hybrid capture and 2.6% by enzyme immunoassay. Infection was associated with young age, a history of new sexual partner(s) in the previous three months, HPV infection, and proximity of clinic to the international border. Antibiotic use in the previous 30 days was associated with decreased odds of infection.

Women in Arizona–Sonora border communities are at increased risk for C. trachomatis infection compared to women attending clinics in non-border locations.

Salivirus and aichivirus A infections in children with gastroenteritis in Brazil

Stool samples were obtained from healthy children and children with diarrhoea in Rio de Janeiro, Brazil, and analysed for aichivirus A and salivirus by reverse transcription PCR. Aichivirus A was detected in 5 (0.8%) and salivirus in 10 (1.7%) of the samples obtained from children with diarrhoea. None of the healthy children tested positive for these viruses. The results demonstrate that these viruses continuously circulate in the country, although at a low frequency.

Arginase inhibition enhances angiogenesis in endothelial cells exposed to hypoxia

Hypoxia-induced arginase elevation plays an essential role in several vascular diseases but influence of arginase on hypoxia-mediated angiogenesis is completely unknown. In this study, in vitro network formation in bovine aortic endothelial cells (BAEC) was examined after exposure to hypoxia for 24h with or without arginase inhibition. Arginase activity, protein levels of the two arginase isoforms, eNOS, and VEGF as well as production of NO and ROS were examined to determine the involvement of arginase in hypoxia-mediated angiogenesis. Hypoxia elevated arginase activity and arginase 2 expression but reduced active p-eNOS(Ser1177) and NO levels in BAEC. In addition, both VEGF protein levels and endothelial elongation and network formation were reduced with continued hypoxia, whereas ROS levels increased and NO levels decreased. Arginase inhibition limited ROS, restored NO formation and VEGF expression, and prevented the reduction of angiogenesis. These results suggest a fundamental role of arginase activity in regulating angiogenic function.

Arginase 2 deficiency prevents oxidative stress and limits hyperoxia-induced retinal vascular degeneration

Background

Hyperoxia exposure of premature infants causes obliteration of the immature retinal microvessels, leading to a condition of proliferative vitreoretinal neovascularization termed retinopathy of prematurity (ROP). Previous work has demonstrated that the hyperoxia-induced vascular injury is mediated by dysfunction of endothelial nitric oxide synthase resulting in peroxynitrite formation. This study was undertaken to determine the involvement of the ureahydrolase enzyme arginase in this pathology.

Methods and Findings

Studies were performed using hyperoxia-treated bovine retinal endothelial cells (BRE) and mice with oxygen-induced retinopathy (OIR) as experimental models of ROP. Treatment with the specific arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) prevented hyperoxia-induced apoptosis of BRE cells and reduced vaso-obliteration in the OIR model. Furthermore, deletion of the arginase 2 gene protected against hyperoxia-induced vaso-obliteration, enhanced physiological vascular repair, and reduced retinal neovascularization in the OIR model. Additional deletion of one copy of arginase 1 did not improve the vascular pathology. Analyses of peroxynitrite by quantitation of its biomarker nitrotyrosine, superoxide by dihydroethidium imaging and NO formation by diaminofluoroscein imaging showed that the protective actions of arginase 2 deletion were associated with blockade of superoxide and peroxynitrite formation and normalization of NOS activity.

Conclusions

Our data demonstrate the involvement of arginase activity and arginase 2 expression in hyperoxia-induced vascular injury. Arginase 2 deletion prevents hyperoxia-induced retinal vascular injury by preventing NOS uncoupling resulting in decreased reactive oxygen species formation and increased nitric oxide bioavailability.

Anti-angiogenic actions of the mangosteen polyphenolic xanthone derivative α-mangostin

Retinal neovascularization is a major cause of vision loss in diseases characterized by retinal ischemia and is characterized by the pathological growth of abnormal vessels. Vascular endothelial growth factor (VEGF) is known to play an important role in this process. Oxidative stress has been strongly implicated in up-regulation of VEGF associated with neovascularization in various tissues. Hence, compounds with anti-oxidant actions can prevent neovascularization. α-Mangostin, a component of mangosteen (Garcinia mangostana Linn), has been shown to have an anti-oxidant property in pathological conditions involving angiogenesis such as cancer. However, the effect of α-mangostin on ROS formation and angiogenic function in microvascular endothelial cells has not been studied. Hence, this study demonstrated the anti-angiogenic effects of α-mangostin in relation to ROS formation in bovine retinal endothelial cells (REC). α-Mangostin significantly and dose-dependently reduced formation of ROS in hypoxia-treated REC. α-Mangostin also significantly and dose-dependently suppressed VEGF-induced increases in permeability, proliferation, migration and tube formation in REC and blocked angiogenic sprouting in the ex vivo aortic ring assay. In addition, α-mangostin inhibited VEGF-induced phosphorylation of VEGFR2 and ERK1/2-MAPK. According to our results, α-mangostin reduces oxidative stress and limits VEGF-induced angiogenesis through a process involving abrogation of VEGFR2 and ERK1/2-MAPK activation.

Perkinsus chesapeaki observed in a new host, the European common edible cockle Cerastoderma edule, in the Spanish Mediterranean coast

Histological observations showed the presence of a Perkinsus sp. parasite in Cerastoderma edule tissues for the first time in the Spanish Mediterranean coast. ITS molecular characterization by PCR-RFLP, in situ hybridization and sequencing, identified the parasite as Perkinsus chesapeaki, with a maximum identity of 99-100% with GenBank P. chesapeaki sequences from France and 97% with P. chesapeaki sequences of North American origin when BLAST analysis was carried out. Furthermore, phylogenetic studies placed the European cockle parasite in a well defined cluster together with the other European isolates. This is the first report of P. chesapeaki in the cockle C. edule.

Requirement of NOX2 expression in both retina and bone marrow for diabetes-induced retinal vascular injury

Objective

Diabetic retinopathy, a major cause of blindness, is characterized by increased expression of vascular endothelial growth factor (VEGF), leukocyte attachment to the vessel walls and increased vascular permeability. Previous work has shown that reactive oxygen species (ROS) produced by the superoxide generating enzyme NOX2/NADPH oxidase play a crucial role in the vascular pathology. The aim of this work was to identify the cellular sources of the damaging NOX2 activity by studies using bone marrow chimera mice.

Methods

Bone marrow cells were collected from the femurs and tibias of wild type and NOX2 deficient (NOX2^-/-) donor mice and injected intravenously into lethally irradiated NOX2^-/- and wild type recipients. Following recovery from radiation, mice were rendered diabetic by streptozotocin injections. The following groups of bone marrow chimeras were studied: non-diabetic WT→WT, diabetic WT→WT, diabetic WT→NOX2^-/-, diabetic NOX2^-/-→WT. After 4 weeks of diabetes, early signs of retinopathy were examined by measuring ROS, expression of VEGF and ICAM-1, leukocyte attachment to the vessel wall and vascular permeability.

Results

The retinas of the diabetic WT→WT chimeras showed significant increases in ROS as compared with the non-diabetic chimeras. These diabetes-induced alterations were correlated with increases in expression of VEGF and ICAM-1, leukocyte adhesion and vascular permeability. Each of these diabetes-induced alterations were significantly attenuated in the diabetic WT→NOX2^-/- and NOX2^-/-→WT chimera groups (p<0.05).

Conclusion

NOX2-generated ROS produced by both bone marrow-derived cells and resident retinal cells contribute importantly to retinal vascular injury in the diabetic retina. Targeting NOX2 in bone marrow and/or retinal cells may represent a novel therapeutic strategy for the treatment/prevention of vascular injury in the diabetic retina.

Arginase in retinopathy

Ischemic retinopathies, such as diabetic retinopathy (DR), retinopathy of prematurity and retinal vein occlusion are a major cause of blindness in developed nations worldwide. Each of these conditions is associated with early neurovascular dysfunction. However, conventional therapies target clinically significant macula edema or neovascularization, which occur much later. Intra-ocular injections of anti-VEGF show promise in reducing retinal edema, but the effects are usually transient and the need for repeated injections increases the risk of intraocular infection. Laser photocoagulation can control pathological neovascularization, but may impair vision and in some patients the retinopathy continues to progress. Moreover, neither treatment targets early stage disease or promotes repair. This review examines the potential role of the ureahydrolase enzyme arginase as a therapeutic target for the treatment of ischemic retinopathy. Arginase metabolizes l-arginine to form proline, polyamines and glutamate. Excessive arginase activity reduces the l-arginine supply for nitric oxide synthase (NOS), causing it to become uncoupled and produce superoxide and less NO. Superoxide and NO react and form the toxic oxidant peroxynitrite. The catabolic products of polyamine oxidation and glutamate can induce more oxidative stress and DNA damage, both of which can cause cellular injury. Studies indicate that neurovascular injury during retinopathy is associated with increased arginase expression/activity, decreased NO, polyamine oxidation, formation of superoxide and peroxynitrite and dysfunction and injury of both vascular and neural cells. Furthermore, data indicate that the cytosolic isoform arginase I (AI) is involved in hyperglycemia-induced dysfunction and injury of vascular endothelial cells whereas the mitochondrial isoform arginase II (AII) is involved in neurovascular dysfunction and death following hyperoxia exposure. Thus, we postulate that activation of the arginase pathway causes neurovascular injury by uncoupling NOS and inducing polyamine oxidation and glutamate formation, thereby reducing NO and increasing oxidative stress, all of which contribute to the retinopathic process.

Arginase 1 mediates increased blood pressure and contributes to vascular endothelial dysfunction in deoxycorticosterone acetate-salt hypertension

Enhanced arginase (ARG) activity has been identified as a factor that reduces nitric oxide production and impairs endothelial function in vascular pathologies. Using a gene deletion model, we investigated involvement of arginase isoforms arginase 1 and 2 (ARG1 and ARG2) in hypertension and endothelial dysfunction in a mineralocorticoid-salt mouse model. Hypertension was induced in wild type (WT), partial ARG1^+/− knockout (KO), and complete ARG2^−/− KO mice by uninephrectomy and deoxycorticosterone acetate (DOCA)-salt treatment for 6-weeks. (Control uninephrectomized mice drank tap water.) After 2 weeks of DOCA-salt treatment, systolic blood pressure (SBP) was increased by ∼15 mmHg in all mouse genotypes. SBP continued to rise in DOCA-salt WT and ARG2^−/− mice to ∼130 mmHg at 5–6 weeks, whereas in ARG1^+/− mice SBP waned toward control levels by 6 weeks (109 ± 4 vs. 101 ± 3 mmHg, respectively). DOCA-salt treatment in WT mice increased vascular ARG activity (aorta by 1.5-fold; mesenteric artery (MA) by 2.6-fold and protein levels of ARG1 (aorta: 1.49-fold and MA: 1.73-fold) vs. WT Sham tissues. ARG2 protein increased in WT-DOCA MA (by 2.15-fold) but not in aorta compared to those of WT Sham tissues. Maximum endothelium-dependent vasorelaxation to acetylcholine was significantly reduced in DOCA-salt WT mice and largely or partially maintained in DOCA ARG1^+/− and ARG2^−/− mice vs. their Sham controls. DOCA-salt augmented contractile responses to phenylephrine in aorta of all mouse genotypes. Additionally, treatment of aorta or MA from WT-DOCA mice with arginase inhibitor (100 μM) improved endothelium-mediated vasorelaxation. DOCA-salt-induced coronary perivascular fibrosis (increased by 2.1-fold) in WT was prevented in ARG1^+/− and reduced in ARG2^−/− mice. In summary, ARG is involved in murine DOCA-salt-induced impairment of vascular function and hypertension and may represent a novel target for antihypertensive therapy.

Arginase as a mediator of diabetic retinopathy

We have shown previously that diabetes causes increases in retinal arginase activity that are associated with impairment of endothelial cell (EC)-dependent vasodilation and increased formation of the peroxynitrite biomarker nitrotyrosine. Arginase blockade normalizes vasodilation responses and reduces nitrotyrosine formation, suggesting that overactive arginase contributes to diabetic retinopathy by reducing NO and increasing oxidative stress. We tested this hypothesis by studies in streptozotocin-induced diabetic mice and high glucose (HG) treated retinal ECs. Our results show that arginase activity is increased in both diabetic retinas and HG-treated retinal ECs as compared with the controls. Western blot shows that both arginase isoforms are present in retinal vessels and ECs and arginase I is increased in the diabetic vessels and HG-treated retinal ECs. Nitrate/nitrite levels are significantly increased in diabetic retinas, indicating an increase in total NO products. However, levels of nitrite, an indicator of bioavailable NO, are reduced by diabetes. Imaging analysis of NO formation in retinal sections confirmed decreases in NO formation in diabetic retinas. The decrease in NO is accompanied by increased O2.− formation and increased leukocyte attachment in retinal vessels. Studies in knockout mice show that arginase gene deletion enhances NO formation, reduces O2.− and prevents leukostasis in the diabetic retinas. HG treatment of retinal ECs also reduces NO release, increases oxidative stress, increases ICAM-1, and induces EC death. Arginase inhibitor treatment reverses these effects. In conclusion, diabetes- and HG-induced signs of retinal vascular activation and injury are associated with increased arginase activity and expression, decreased bioavailable NO, and increased O2.− formation. Blockade of the arginase pathway prevents these alterations, suggesting a primary role of arginase in the pathophysiological process.

Abnormalities in cancer patients' coagulation system

e22207

Background: It is well known cancer patients may present both hemorrhagic and thrombotic abnormalities and these phenomena are difficult to diagnose and treat. Thrombotic phenomena are developed clinicly in 15% in cancer patients and it’s higher in adenocarcinomas and myeloprolipherative disorders. These complications can be the consequence of coagulations factor direct activation or chronic DIC, because of the acquired capacity of neoplastic cells for starting coagulation cascade. Methods: In this study an untreated cancer patients group were compared with another healthy controls group, older than 14 years. Patients before treatment and controls were laboratory tested. A t – test for independent samples was employed. Results: Number: patients group: 66, control group: 73. Median age: patients: 50 (17-78). Controls: 52 (18 -93). Sex: Patients: men: 35%, women: 65%. Controls: men: 52%, women: 48%. Malignancies: breast cancer 9.7%; gastric carcinoma 8.1%; cervical carcinoma 6.5%; NH lymphomas 6.5%, unknown origen metastatic carcinoma 4.8%; oral carcinoma 4.8%. Clinical stages: I: 6.3%; II: 6.3%; III: 22.9%; IV: 62.5% (metastatic) 47.9%. Thrombotic antecedents in patients group: 19.7%. There were significant differences in: Platelets count: patients: 281121, controls: 307745 (p<0.001). Protein C: 0.87 and 3.81 UI/mL, respectively (p < 0.001). Antithrombin III: 97 and 101% (p<0.001). Plasminogen: 92.9 and 101.1% (p < 0.001). Lupus anticoagulant (RVV time): 27 and 25.6” (p<0.001). There were no significant differences in PT: 18.3 and 16.9” and PTT: 31 and 34”. The same significant differences were got when the patients of every clinical stage were compared with control patients. There were no differences when the patients of every clinical stage were compared among themselves, nor between sex. Conclusions: This study shows cancer patients may have many coagulation abnormalities: anticoagulant system defects and fibrinolytic system hipoactivity, demonstrated by the significant differences found in antithrombin III, protein C and plasminogen levels between patients and controls groups. It is suggested to practice these tests to cancer patients, even without clinical coagulation disorders, to stablish prophylactic measures.

The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes

AIMS/HYPOTHESIS

A reduction in retinal blood flow occurs early in diabetes and is likely to be involved in the development of diabetic retinopathy. We hypothesise that activation of the arginase pathway could have a role in the vascular dysfunction of diabetic retinopathy.

METHODS

Experiments were performed using a mouse and rat model of streptozotocin (STZ)-induced diabetes for in vivo and ex vivo analysis of retinal vascular function. For in vivo studies, mice were infused with the endothelial-dependent vasodilator acetylcholine (ACh) or the endothelial-independent vasodilator sodium nitroprusside (SNP), and vasodilation was assessed using a fundus microscope. Ex vivo assays included pressurised vessel myography, western blotting and arginase activity measurements.

RESULTS

ACh-induced retinal vasodilation was markedly impaired in diabetic mice (40% of control values), whereas SNP-induced dilation was not altered. The diabetes-induced vascular dysfunction was markedly blunted in mice lacking one copy of the gene encoding arginase I and in mice treated with the arginase inhibitor 2(S)-amino-6-boronohexanoic acid. Ex vivo studies performed using pressure myography and central retinal arteries isolated from rats with STZ-induced diabetes showed a similar impairment of endothelial-dependent vasodilation that was partially blunted by pretreatment of the isolated vessels with another arginase inhibitor, (S)-2-boronoethyl-L-cysteine. The diabetes-induced vascular alterations were associated with significant increases in both arginase I protein levels and total arginase activity.

CONCLUSIONS/INTERPRETATION

These results indicate that, in the mouse and rat model, diabetes-induced increases in arginase I were involved in the diabetes-induced impairment of retinal blood flow by a mechanism involving vascular endothelial cell dysfunction.

Prevention of diabetes-induced arginase activation and vascular dysfunction by Rho kinase (ROCK) knockout

AIMS

We determined the role of the Rho kinase (ROCK) isoforms in diabetes-induced vascular endothelial dysfunction and enhancement of arginase activity and expression.

METHODS AND RESULTS

Studies were performed in aortic tissues from haplo-insufficient (H-I) ROCK1 and ROCK2 mice and wild-type (WT) mice rendered diabetic with streptozotocin and in bovine aortic endothelial cells (BAECs) treated with high glucose (HG, 25 mM). Protein expression of both ROCK isoforms was substantially elevated in aortas of WT mice after 8 weeks of diabetes and in BAECs after 48 h in HG. Impairment of endothelium-dependent vasorelaxation of aortas was observed in diabetic WT mice. However, there was no impairment in aortas of diabetic ROCK1 H-I mice and less impairment in aortas of diabetic ROCK2 H-I mice, compared with non-diabetic mice. These vascular effects were associated with the prevention of diabetes-induced decrease in nitric oxide (NO) production and a rise in arginase activity/expression. Acute treatment with the arginase inhibitor, BEC, improved endothelium-dependent vasorelaxation of aortas of both diabetic WT and ROCK2, but not of ROCK1 mice.

CONCLUSION

Partial deletion of either ROCK isoform, but to a greater extent ROCK1, attenuates diabetes-induced vascular endothelial dysfunction by preventing increased arginase activity and expression and reduction in NO production in type 1 diabetes. Limiting ROCK and arginase activity improves vascular function in diabetes.