Treatment of male and female spontaneously hypertensive rats with TNF-α inhibitor etanercept increases markers of renal injury independent of an effect on blood pressure.

Hypertension remains the leading risk factor for cardiovascular disease. Young females tend to be protected from hypertension compared with age-matched males. Although it has become increasingly clear that the immune system plays a key role in the development of hypertension in both sexes, few studies have examined how cytokines mediate hypertension in males versus females. We previously published that there are sex differences in the levels of the cytokine tumor necrosis factor (TNF)-α in spontaneously hypertensive rats (SHR). The goal of this study was to test the hypothesis that TNF-α inhibition with etanercept will lower BP in male and female SHR. However, as male SHR have a more pro-inflammatory status than female SHR, we further hypothesize that males will have a greater decrease in BP with TNF-α inhibition than females. Young adult male and female SHR were administered increasing doses of the TNF-α inhibitor etanercept or vehicle twice weekly for 31 days and BP was continuously measured via telemetry. Following treatment, kidneys and urine were collected and analyzed for markers of inflammation and injury. Despite significantly decreasing renal TNF-α levels, renal phospho-NFκB and urinary MCP-1 excretion, etanercept did not alter BP in either male or female SHR. Interestingly, treatment with etanercept increased urinary excretion of protein, creatinine and KIM-1 in both sexes. These results indicate that TNF-α does not contribute to sex differences in BP in SHR but may be vital in the maintenance of renal health.

Sexual Dimorphism in the Polarization of Cardiac ILCs through Elabela.

Elabela is a component of the apelinergic system and may exert a cardioprotective role by regulating the innate immune responses. Innate lymphoid cells (ILCs) have a significant role in initiating and progressing immune-inflammatory responses. While ILCs have been intensively investigated during the last decade, little is known about their relationship with the apelinergic system and their cardiac diversity in a gender-based paradigm. In this study, we investigated the polarization of cardiac ILCs by Elabela in males versus females in a mouse model. Using flow cytometry and immunohistochemistry analyses, we showed a potential interplay between Elabela and cardiac ILCs and whether such interactions depend on sexual dimorphism. Our findings showed, for the first time, that Elabela is expressed by cardiac ILCs, and its expression is higher in females' ILC class 3 (ILC3s) compared to males. Females had higher frequencies of ILC1s, and Elabela was able to suppress T-cell activation and the expression of co-stimulatory CD28 in a mixed lymphocyte reaction assay (MLR). In conclusion, our results suggest, for the first time, a protective role for Elabela through its interplay with ILCs and that it can be used as an immunotherapeutic target in the treatment of cardiovascular disorders in a gender-based fashion.

Hypertensive female Sprague-Dawley rats require an intact nitric oxide synthase system for compensatory increases in renal regulatory T cells.

We have previously shown that hypertensive female rats have more regulatory T cells (Tregs), which contribute more to blood pressure (BP) control in female versus male rats. Based on known protective properties of Tregs, the goal of the present study was to investigate the mechanisms by which female rats maintain Tregs. The present study was designed to 1) compare the impact of three hypertension models on the percentage of renal Tregs and 2) test the hypothesis that nitric oxide synthase (NOS) inhibition prevents increases in renal Tregs and exacerbates renal damage in female Sprague-Dawley rats. Rats (11-14 wk old) were randomized to one of the following four groups: control, norepinephrine (NE) infusion, angiotensin II infusion, or the NOS inhibitor Nω-nitro-l-arginine methyl ester (l-NAME) in drinking water. BP was measured via tail cuff. After 2 wk of treatment, kidneys were isolated and processed to measure Tregs via flow cytometric analysis and renal injury via urinary albumin excretion, plasma creatinine, and histological analyses. Hypertensive treatments increased BP in all experimental animals. Increases in BP in norepinephrine-and angiotensin II-treated rats were associated with increases in renal Tregs versus control. In contrast, l-NAME treatment decreased Tregs compared with all groups. l-NAME treatment modestly increased albumin excretion. However, plasma creatinine was comparable among the groups, and there was no histological evidence of glomerular or tubular injury. This study provides insights into the mechanisms regulating renal Tregs and supports that an intact NOS system is crucial for female rats to have BP-related increases in renal Tregs.

Tooth Decay Prevention: Knowledge and Practices Survey of Dental Students.

OBJECTIVES: This study aimed to assess the level of knowledge, attitudes, and practices fissure sealants among undergraduate Saudi dental students. METHODS: A modified questionnaire consisted of 24-items was distributed among 226 undergraduate dental students, males and females of different years at Al-Farabi Colleges, Riyadh, Saudi Arabia. Chi-square/Fisher's exact tests were used for descriptive statistical analyses. RESULTS: The response rate was 100%. Most of the respondents were male (60.2) and (39.8%) were female. With regard to the level of study, 20.8% were in the fourth year, 43.8% in the fifth year, and 16.8% were in the sixth year. The respondents showed a sensible level of learning about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. Furthermore, respondents demonstrated inadequate learning about sealants clinical practice. CONCLUSION: Despite a high proportion of undergraduate dental students' showed sufficient knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. The findings suggest an urgent need of dental colleges to additionally and/or update their curriculum regarding fissure sealants to reflect advance dental education that concentrates on evidence-based practice (EBP) in Pediatric Dentistry and Dental Public Health need for regular continuing education courses for the dental professional. HOW TO CITE THIS ARTICLE: Al-Sabri FA, Ba-Salamah M, et al. Tooth Decay Prevention: Knowledge and Practices Survey of Dental Students. Int J Clin Pediatr Dent 2019;12(2):92-95.

Tetrahydrobiopterin improves endothelial function in patients with cystic fibrosis.

Cystic fibrosis (CF) is a genetic disorder associated with vascular endothelial dysfunction. Nitric oxide (NO) plays a major role in maintaining vascular function, and tetrahydrobiopterin (BH4) is a critical determinant of NO bioavailability. Thus the purpose of this study was to investigate the effects of oral administration of BH4 on endothelial function in patients with CF. Twenty-nine patients with CF (18 ± 8 yr old) and 29 healthy matched controls were recruited. Patients with CF participated in a randomized trial where they received a 5 mg/kg dose of oral BH4 (BH4-5; n = 17) or a 20 mg/kg dose of oral BH4 (BH4-20; n = 12). On a separate visit, a subset of patients from each group was retested following a placebo (PLC; n = 9). Brachial artery flow-mediated dilation (FMD) was used to evaluate vascular endothelial function, and a plasma sample was obtained before and 3 h after treatment. Cultured endothelial cells were treated with plasma to assess NO bioavailability. Baseline FMD was lower in patients compared with controls (5.7 ± 3.4 vs. 8.4 ± 3.5%, respectively, P = 0.005). No change in FMD was observed following PLC or BH4-5 (∆FMD: -0.8 ± 1.9% and -0.5 ± 2.5%; P = 0.273 and 0.132, respectively). Treatment with BH4-20, however, resulted in significant improvements in FMD (∆FMD: 1.1 ± 1.4%) compared with BH4-5 ( P = 0.023) and PLC ( P = 0.017). Moreover, BH4-20 significantly decreased endothelial cell superoxide production and increased NO production. These data suggest that a single oral dose of BH4 at 20 mg/kg improves vascular endothelial function in patients with CF, likely via increased endothelial NO synthase coupling. These findings support the hypothesis that loss of BH4 bioactivity contributes, in part, to endothelial dysfunction in patients with CF. NEW & NOTEWORTHY For the first time, the present study documents that a single dose of oral BH4 can improve vascular endothelial function in patients with cystic fibrosis (CF), and our in vitro data suggest this is via decreasing uncoupled nitric oxide. These data provide insight into the important role of BH4 bioactivity in vascular dysfunction and provide the foundation for further investigation into the chronic effects of BH4 treatment in patients with CF.

Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.

Traditional bone regeneration strategies relied on supplementation of biomaterials constructs with stem or progenitor cells or growth factors. By contrast, cell homing strategies employ chemokines to mobilize stem or progenitor cells from host bone marrow and tissue niches to injured sites. Although silica-based biomaterials exhibit osteogenic and angiogenic potentials, they lack cell homing capability. Stromal cell-derived factor-1 (SDF-1) plays a pivotal role in mobilization and homing of stem cells to injured tissues. In this work, we demonstrated that 3-dimensional collagen scaffolds infiltrated with intrafibrillar silica are biodegradable and highly biocompatible. They exhibit improved compressive stress-strain responses and toughness over nonsilicified collagen scaffolds. They are osteoconductive and up-regulate expressions of osteogenesis- and angiogenesis-related genes more significantly than nonsilicified collagen scaffolds. In addition, these scaffolds reversibly bind SDF-1α for sustained release of this chemokine, which exhibits in vitro cell homing characteristics. When implanted subcutaneously in an in vivo mouse model, SDF-1α-loaded silicified collagen scaffolds stimulate the formation of ectopic bone and blood capillaries within the scaffold and abrogate the need for cell seeding or supplementation of osteogenic and angiogenic growth factors. Intrafibrillar-silicified collagen scaffolds with sustained SDF-1α release represent a less costly and complex alternative to contemporary cell seeding approaches and provide new therapeutic options for in situ hard tissue regeneration.

Peroxisome Proliferator Activated Receptor-α Agonist Slows the Progression of Hypertension, Attenuates Plasma Interleukin-6 Levels and Renal Inflammatory Markers in Angiotensin II Infused Mice.

The anti-inflammatory properties of PPAR-α plays an important role in attenuating hypertension. The current study determines the anti-hypertensive and anti-inflammatory role of PPAR-α agonist during a slow-pressor dose of Ang II (400 ng/kg/min). Ten to twelve week old male PPAR-α KO mice and their WT controls were implanted with telemetry devices and infused with Ang II for 12 days. On day 12 of Ang II infusion, MAP was elevated in PPAR-α KO mice compared to WT (161 ± 4 mmHg versus 145 ± 4 mmHg) and fenofibrate (145 mg/kg/day) reduced MAP in WT + Ang II mice (134 ± 7 mmHg). Plasma IL-6 levels were higher in PPAR-α KO mice on day 12 of Ang II infusion (30 ± 4 versus 8 ± 2 pg/mL) and fenofibrate reduced plasma IL-6 in Ang II-treated WT mice (10 ± 3 pg/mL). Fenofibrate increased renal expression of CYP4A, restored renal CYP2J expression, reduced the elevation in renal ICAM-1, MCP-1 and COX-2 in WT + Ang II mice. Our results demonstrate that activation of PPAR-α attenuates Ang II-induced hypertension through up-regulation of CYP4A and CYP2J and an attenuation of inflammatory markers such as plasma IL-6, renal MCP-1, renal expression of ICAM-1 and COX-2.

Peroxisome Proliferator-Activated Receptor-α Activation Decreases Mean Arterial Pressure, Plasma Interleukin-6, and COX-2 While Increasing Renal CYP4A Expression in an Acute Model of DOCA-Salt Hypertension.

Peroxisome proliferator-activated receptor-alpha (PPAR-α) activation by fenofibrate reduces blood pressure and sodium retention during DOCA-salt hypertension. PPAR-α activation reduces the expression of inflammatory cytokines, such as interleukin-6 (IL-6). Fenofibrate also induces cytochrome P450 4A (CYP4A) and increases 20-hydroxyeicosatetraenoic acid (20-HETE) production. This study tested whether the administration of fenofibrate would reduce blood pressure by attenuating plasma IL-6 and renal expression of cyclooxygenase-2 (COX-2), while increasing expression of renal CYP4A during 7 days of DOCA-salt hypertension. We performed uni-nephrectomy on 12-14 week old male Swiss Webster mice and implanted biotelemetry devices in control, DOCA-salt (1.5 mg/g) treated mice with or without fenofibrate (500 mg/kg/day in corn oil, intragastrically). Fenofibrate significantly decreased mean arterial pressure and plasma IL-6. In kidney homogenates, fenofibrate increased CYP4A and decreased COX-2 expression. There were no differences in renal cytochrome P450, family 2, subfamily c, polypeptide 23 (CYP2C23) and soluble expoxide hydrolase (sEH) expression between the groups. Our results suggest that the blood pressure lowering effect of PPAR-α activation by fenofibrate involves the reduction of plasma IL-6 and COX-2, while increasing CYP4A expression during DOCA-salt hypertension. Our results may also suggest that PPAR-α activation protects the kidney against renal injury via decreased COX-2 expression.

Mitochondrial complex I and NAD(P)H oxidase are major sources of exacerbated oxidative stress in pressure-overloaded ischemic-reperfused hearts.

We tested the hypothesis that pressure overload exacerbates oxidative stress associated with augmented mitochondrial permeability transition (MPT) pore opening and cell death in ischemic-reperfused hearts. Pressure overload decreased the level of reduced glutathione but increased nitrotyrosine and 8-hydroxydeoxyguanosine levels in ischemic-reperfused hearts. The activity of catalase, but not superoxide dismutase (SOD), was lower in ischemic-reperfused hearts perfused at higher pressure. Mitochondria from ischemic-reperfused hearts subjected to higher perfusion pressure displayed significantly greater [³H]-2-deoxyglucose-6-P entrapment suggestive of greater MPT pore opening and consistent with greater necrosis and apoptosis. Tempol (SOD mimetic) reduced infarct size in both groups but it remained greater in the higher pressure group. By contrast, uric acid (peroxynitrite scavenger) markedly reduced infarct size at higher pressure, effectively eliminating the differential between the two groups. Inhibition of xanthine oxidase, with allopurinol, reduced infarct size but did not eliminate the differential between the two groups. However, amobarbital (inhibitor of mitochondrial complex I) or apocynin [inhibitor of NAD(P)H oxidase] reduced infarct size at both pressures and also abrogated the differential between the two groups. Consistent with the effect of apocynin, pressure-overloaded hearts displayed significantly higher NAD(P)H oxidase activity. Furthermore, pressure-overloaded hearts displayed increased nitric oxide synthase activity which, along with increased propensity to superoxide generation, may underlie uric acid-induced cardioprotection. In conclusion, increased oxidative and nitrosative stress, coupled with lack of augmented SOD and catalase activities, contributes importantly to the exacerbating impact of pressure overload on MPT pore opening and cell death in ischemic-reperfused hearts.

Increased expression and activity of 12-lipoxygenase in oxygen-induced ischemic retinopathy and proliferative diabetic retinopathy: implications in retinal neovascularization.

OBJECTIVE: Arachidonic acid is metabolized by 12-lipoxygenase (12-LOX) to 12-hydroxyeicosatetraenoic acid (12-HETE) and has an important role in the regulation of angiogenesis and endothelial cell proliferation and migration. The goal of this study was to investigate whether 12-LOX plays a role in retinal neovascularization (NV). RESEARCH DESIGN AND METHODS: Experiments were performed using retinas from a murine model of oxygen-induced ischemic retinopathy (OIR) that was treated with and without the LOX pathway inhibitor, baicalein, or lacking 12-LOX. We also analyzed vitreous samples from patients with and without proliferative diabetic retinopathy (PDR). Western blotting and RT-PCR were used to assess the expression of 12-LOX, vascular endothelial growth factor (VEGF), and pigment epithelium-derived factor (PEDF). Liquid chromatography-mass spectrometry was used to assess the amounts of HETEs in the murine retina and human vitreous samples. The effects of 12-HETE on VEGF and PEDF expression were evaluated in Müller cells (rMCs), primary mouse retinal pigment epithelial cells, and astrocytes. RESULTS: Retinal NV during OIR was associated with increased 12-LOX expression and 12-, 15-, and 5-HETE production. The amounts of HETEs also were significantly higher in the vitreous of diabetic patients with PDR. Retinal NV was markedly abrogated in mice treated with baicalein or mice lacking 12-LOX. This was associated with decreased VEGF expression and restoration of PEDF levels. PEDF expression was reduced in 12-HETE-treated rMCs, astrocytes, and the retinal pigment epithelium. Only rMCs and astrocytes showed increased VEGF expression by 12-HETE. CONCLUSIONS: 12-LOX and its product HETE are important regulators of retinal NV through modulation of VEGF and PEDF expression and could provide a new therapeutic target to prevent and treat ischemic retinopathy.

Submandibular gland and caries susceptibility in the obese Zucker rat.

BACKGROUND: Obesity is a prevalent disorder characterized as marked insulin resistance and low grade inflammation. We tested the hypothesis that obesity upregulates inflammatory markers in the submandibular gland in association with derangements of its architecture and pre-disposition to caries in obese Zucker rats (OZR). We also examined the potential impact of chromium picolinate (Cr(Pic)3), a nutritional supplement suggested to improve glycemic control, on the aforementioned parameters. DESIGN: Male OZR were treated with diets lacking and containing 5 or 10 mg/kg chromium (as Cr(Pic)3) from 6 weeks to about 6 months of age; lean Zucker rats (LZR) served as controls. Thereafter, glycemic status, salivary tissue architecture, and the levels of several inflammatory markers were determined in association with caries susceptibility. RESULTS: OZR showed reduced insulin sensitivity, increased ratio of phospho-nuclear factor-kappa B (NF-κB) to total NF-κB, and increased intercellular adhesion molecule-1 level but similar histological features compared to LZR. Importantly, compared to LZR, OZR displayed rampant caries and a tendency for reduced dentin mineral density. Treatment of OZR with Cr(Pic)3 attenuated upregulation of these proinflammatory indicators in association with reduced severity of caries without improving insulin sensitivity. CONCLUSIONS: Obesity promotes proinflammatory changes within the submandibular gland, without affecting glandular architecture, in association with rampant caries; Cr(Pic)3 treatment provided some protective effects.

Effects of chromium picolinate on glycemic control and kidney of the obese Zucker rat.

BACKGROUND: Chromium picolinate (Cr(pic)3) is advocated as adjuvant therapy for impaired glycemic control, despite concerns for DNA damage. Potential toxicity of Cr(pic)3 should be greater for the kidney that accumulates chromium. Therefore, we tested the hypothesis that Cr(pic)3 treatment of obese Zucker rats (OZR) exacerbates renal abnormalities associated with dysglycemia. METHODS: Male OZR were treated with diets lacking or containing 5 and 10 mg/kg of chromium, as Cr(pic)3, for 20 weeks; lean Zucker rats (LZR) served as controls. Glycemic and renal effects of Cr(pic)3 were determined in the context of indices of oxidative stress and inflammation. RESULTS: The OZR displayed increased fasting plasma glucose and insulin in association with enlarged pancreatic islets exhibiting collagen and periodic acid Schiff-positive deposits compared to LZR; Cr(pic)3 treatment did not affect these parameters. The OZR, irrespective of Cr(pic)3, excreted more albumin than LZR. Also, other indices of renal function or histopathology were not affected by Cr(pic)3 treatment. Urinary excretion of 8-hydroxydeoxyguanosine (8-OHdG), an index of oxidative DNA damage, was greater in the OZR than LZR; dietary Cr(pic)3 treatment attenuated 8-OHdG excretion. However, immunostaining of kidney for 8-OHdG revealed similar staining pattern and intensity, despite significant renal accumulation of chromium in Cr(pic)3-treated groups. Finally, increased renal nitrotyrosine and cyclooxygenase-2 levels and urinary excretion of monocyte chemoattractant protein-1 of OZR were partially reversed by Cr(pic)3 treatment. CONCLUSION: Dietary Cr(pic)3 treatment of OZR does not beneficially influence glycemic status or increase the risk for oxidative DNA damage; rather, the treatment attenuates indices of oxidative stress and inflammation.