Nitric oxide and cardiovascular effects: new insights in the role of nitric oxide for the management of osteoarthritis

Multi-scale computational investigation of Ag-doped two-dimensional Zn-based MOFs for storage and release of small NO and CO bioactive molecules

Nitric oxide (NO) and carbon monoxide (CO) are two important gasotransmitters with critical biological roles in the human body. Due to their short lifetime and dangerous side effects at high concentrations, it is essential to find safe storage and slow release methods of these two gases. Herein, we report the multi-scale simulations of two-dimensional (Zn)MOF-470 doped with antimicrobial Ag atoms to evaluate the degree of enhancement of adsorption and dynamics of NO and CO. The results show that NO binds to Ag stronger than CO. In addition, the decoration of the benzene ring with Ag atoms on both sides has led to the effective adsorption of NO and CO with binding energies of -26.34 and -21.71 kcal mol^-1, respectively. The GCMC results show that Ag can significantly improve NO and CO storage capacity, especially in low-pressure ranges. The storage capacity of NO in (Zn)MOF-470 and Ag-doped MOFs is 6.12 and 7.21 mol kg^-1, respectively. This storage capacity for CO is 4.09 and 5.48 mol kg^-1, respectively. The heat of adsorption for NO and CO was obtained to be 31.72 and 25.64 kJ mol^-1 for (Zn)MOF-470, and 36.5 and 31.12 kJ mol^-1 for Ag-(Zn)MOF-470 at 298 K and 1 bar. Besides, the MD results indicate that when Ag is doped into the structure of MOFs, the dynamics of gases within the pores of MOFs significantly decrease. When Ag atoms are considered mobile, the dynamics of guest molecules increase and it shows that the structural and dynamical behavior of NO and CO strongly depends on the mobility or immobility of doped Ag atoms. The result from the MSD directions (x, y, and z components) indicates that the diffusion of NO and CO within the pores of (Zn)MOF-470 is anisotropic and this may be due to the 2D structural characteristics of the MOF, the dipolar nature of NO and CO molecules, and the very narrow and layered pores of (Zn)MOF-470. These promising results from the simulations suggest that (Zn)MOF-470 and doping Ag atoms into this MOF can improve the storage capacity and slow release of bioactive NO and CO along with utilization of the antimicrobial nature of Ag atoms in medical applications.

Systemic side effects of glaucoma medications

Glaucoma is a progressive loss of retinal ganglion cells leading to visual field loss. Lowering intraocular pressure is currently the only modifiable risk factor to slow glaucoma progression. Intraocular pressure-lowering options include topical and systemic medications, lasers, and surgical procedures. Glaucoma eye drops play a major role in treating this blinding disease. Similar to all medications, the glaucoma medications have their own adverse effects. The majority of glaucoma medications work by stimulating or inhibiting adrenergic, cholinergic, and prostaglandin receptors, which are distributed all over the body. Therefore, the glaucoma medications can affect organs other than the eye. This review will discuss the systemic adverse effects of carbonic anhydrase inhibitors, sympathomimetics, para-sympathomimetics, beta blockers, prostaglandin analogs, hyperosmotic agents, and novel glaucoma medications with a stress on pregnant patients, breastfeeding mothers, and paediatric patients.

Novel NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are some of the most commonly used drugs to relieve a multitude of pain symptoms.F They are readily available and used extensively. There is a lot of concern about their adverse side effects namely cardiovascular (CV) and gastrointestinal (GI) side effects. It is important to have a good grasp of the pharmacology of these drugs in order to use them safely and effectively. NSAIDs work by inhibiting the cyclooxygenase (COX) enzyme system responsible for production of prostaglandins. Prostaglandins mediate pain inflammation and temperature regulation in the body. NSAIDS can be divided into selective and non-selective types. Three isoforms of COX have been identified COX-1, COX-2 and COX-3. Selective NSAIDs act on these isoforms. COX-1 is anti-inflammatory, COX-2 pro-inflammatory and COX-3, a variant of COX-1, does not produce prostaglandins. The CV side effects of these drugs can be wide ranging and include a rise in blood pressure (BP) and a higher risk of thromboembolic events. Patients also suffer from peptic ulcer disease or bleeding in the stomach as a result of their use. NSAIDs can cause liver and kidney toxicity and should be used with caution in patients with bleeding tendencies. New NSAIDs on the market include; lornoxicam (xefo®), meloxicam (coxflam®), celecoxib (celebrex®), parecoxib (rayzon®) and etoricoxib (arcoxia®). New ways of delivering NSAIDs to the body with minimal or no side effects are being researched. Novel technology in this field includes nano formulated NSAIDs; indomethacin (tivorbex®) and dicofenac (zorvolex), prodrugs and multi action drugs; cyclooxygenase inhibiting nitric oxide donors and hydrogen sulphide releasing drugs. Further exciting innovations are in the pipeline that could change the face of how we use these drugs. Until then they must be used with careful consideration and only if the benefits of use outweigh the risks.

The placental growth factor attenuates intimal hyperplasia in vein grafts by improving endothelial dysfunction

Saphenous vein grafts (SVG) patency is limited by intimal hyperplasia (IH) caused by endothelial dysfunction. This study aimed to explore the effect of placental growth factor (PlGF) on the endothelial function of SVG. In rat models of external jugular vein-carotid artery graft treated with PlGF or saline hydrogel, PlGF inhibited vein graft IH (day 28: 12.0 ± 1.9 vs. 61.7 ± 13.1 μm, P < 0.001), promoted microvessel proliferation (day 14: 33.3% 3+ vs. 50.0% 2+, P = 0.03), and increased nitric oxide (NO) production (P < 0.05 on days 1/3/5) and NO synthase (NOS) expression by immunohistochemistry. In human umbilical vein endothelial cells (HUVECs) cultured under hypoxia and treated or not with PlGF, PlGF restored the survival (50 ng/ml PlGF, 48 h: 91.7 ± 0.6% vs. 84.9 ± 0.5%, P < 0.01), migration (by Matrigel assay), and tube formation ability (junctions, tubules, and tubule total length; all P < 0.01) of HUVECs after hypoxia. PlGF increased NO production through increased eNOS expression (P < 0.05), without changes in iNOS expression. The mRNA expression of eNOS decreased after the addition of the PI3K inhibitor LY294002 (P < 0.05). PlGF promoted the protein expression of eNOS by up-regulating AKT, and the AKT and eNOS protein levels were decreased after adding LY294002 (all P < 0.05). In conclusion, PlGF is a candidate for the inhibition of IH in SVG after coronary artery bypass graft. The effects of PlGF are mediated by the upregulation of the eNOS mRNA and protein through the PI3K/AKT signaling pathway. PlGF promotes the secretion of NO by endothelial cells and thereby reduces the occurrence and development of IH.

Nonsteroidal Anti-Inflammatory Therapy: A Journey Toward Safety

The efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs) against inflammation, pain, and fever has been supporting their worldwide use in the treatment of painful conditions and chronic inflammatory diseases until today. However, the long-term therapy with NSAIDs was soon associated with high incidences of adverse events in the gastrointestinal tract. Therefore, the search for novel drugs with improved safety has begun with COX-2 selective inhibitors (coxibs) being straightaway developed and commercialized. Nevertheless, the excitement has fast turned to disappointment when diverse coxibs were withdrawn from the market due to cardiovascular toxicity. Such events have once again triggered the emergence of different strategies to overcome NSAIDs toxicity. Here, an integrative review is provided to address the breakthroughs of two main approaches: (i) the association of NSAIDs with protective mediators and (ii) the design of novel compounds to target downstream and/or multiple enzymes of the arachidonic acid cascade. To date, just one phosphatidylcholine-associated NSAID has already been approved for commercialization. Nevertheless, the preclinical and clinical data obtained so far indicate that both strategies may improve the safety of nonsteroidal anti-inflammatory therapy.

Pharmaceutical therapy for osteoarthritis

There are a variety of oral and topical pharmaceutical agents for the treatment of osteoarthritis. To date there is no pharmacologic agent proved to prevent disease progression. This article focuses primarily on the medications used for symptomatic relief and palliation of pain. The article reviews the medications' mechanisms of action and the available efficacy literature, as well as indications, contraindications, and common adverse effects.

Managing the adverse effects of nonsteroidal anti-inflammatory drugs

Conventional medical treatment for rheumatoid arthritis and osteoarthritis includes the use of NSAIDs (traditional and selective inhibitors of cyclooxygenase [COX]-2), because they provide unmistakable and significant health benefits in the treatment of pain and inflammation. However, they are associated with an increased risk of serious gastrointestinal (GI) and cardiovascular (CV) adverse events. Both beneficial and adverse effects are due to the same mechanism of action, which is inhibition of COX-dependent prostanoids. Since CV and GI risk are related to drug exposure, a reduction in the administered dose is recommended. However, this strategy will not eliminate the hazard owing to a possible contribution of individual genetic background. Further studies will be necessary to develop genetic and/or biochemical markers predictive of the CV and GI risk of NSAIDs.

Nutritional supplementation with L-arginine prevents pelvic radiation-induced changes in morphology, density, and regulating factors of blood vessels in the wall of rat bladder

PURPOSE

To determine whether L-arginine has protective effects against radiation-induced alterations in the morphology and regulatory factors of vesical blood vessels in rats.

METHODS

Male rats aged 3-4 months were divided into groups of 10 animals each: (a) controls, consisting of non-treated animals; (b) radiated-only rats; and (c) radiated rats receiving L-arginine supplementation. Radiation was in one session of 10 Gy and was aimed at the pelvic-abdominal region. L-arginine was administered once a day (0.65 g/kg body weight), starting 7 days before radiation and continuing until killing on the 16th day after radiation. The density, relative area, and wall thickness of blood vessels were measured in the vesical lamina propria using histological methods, and the expression of vascular endothelial growth factor (VEGF) and fibroblast growth factors (FGF) in the bladder wall was assessed by RT-PCR.

RESULTS

Compared with controls, radiation alone decreased the density and relative area of blood vessels by 32 % (p < 0.01) and 25 % (p < 0.05), respectively, and reduced the arterial wall thickness by 42 % (p < 0.004). VEGF and FGF mRNA levels after radiation were diminished by 67 % (p < 0.002) and 56 % (p < 0.04), respectively. The radiated animals supplemented with L-arginine were not significantly different from controls.

CONCLUSIONS

Pelvic radiation leads to significant vesical modifications, as in the morphology of blood vessels and in VEGF and FGF expression. All these changes, however, were prevented by L-arginine treatment. These results emphasize, therefore, the potential use of this amino acid as a radioprotective drug.

Whole blood lead levels are associated with radiographic and symptomatic knee osteoarthritis: a cross-sectional analysis in the Johnston County Osteoarthritis Project

INTRODUCTION

Lead (Pb) is known to affect bone, and recent evidence suggests that it has effects on cartilage as well. As osteoarthritis (OA) is a highly prevalent disease affecting bone and cartilage, we undertook the present analysis to determine whether whole blood Pb levels are associated with radiographic and symptomatic OA (rOA and sxOA, respectively) of the knee.

METHODS

The analysis was conducted using cross-sectional data from the Johnston County Osteoarthritis Project, a rural, population-based study, including whole blood Pb levels, bilateral posteroanterior weight-bearing knee radiography and knee symptom data. rOA assessment included joint-based presence (Kellgren-Lawrence (K-L) grade 2 or higher) and severity (none, K-L grade 0 or 1; mild, K-L grade 2; moderate or severe, K-L grade 3 or 4), as well as person-based laterality (unilateral or bilateral). SxOA was deemed present (joint-based) in a knee on the basis of K-L grade 2 or higher with symptoms, with symptoms rated based on severity (0, rOA without symptoms; 1, rOA with mild symptoms; 2, rOA with moderate or severe symptoms) and in person-based analyses was either unilateral or bilateral. Generalized logit or proportional odds regression models were used to examine associations between the knee OA status variables and natural log-transformed blood Pb (ln Pb), continuously and in quartiles, controlling for age, race, sex, body mass index (BMI), smoking and alcohol drinking.

RESULTS

Those individuals with whole blood Pb data (N = 1,669) had a mean (±SD) age of 65.4 (±11.0) years and a mean BMI of 31.2 (±7.1) kg/m2, including 66.6% women and 35.4% African-Americans, with a median blood Pb level of 1.8 μg/dl (range, 0.3 to 42.0 μg/dl). In joint-based analyses, for every 1-U increase in ln Pb, the odds of prevalent knee rOA were 20% higher (aOR, 1.20; 95% CI, 1.01 to 1.44), while the odds of more severe rOA were 26% higher (aOR, 1.26; 95% CI, 1.05 to 1.50, under proportional odds). In person-based analyses, the odds of bilateral rOA were 32% higher for each 1-U increase in ln Pb (aOR, 1.32; 95% CI, 1.03 to 1.70). Similarly for knee sxOA, for each 1-U increase in ln Pb, the odds of having sxOA were 16% higher, the odds of having more severe symptoms were 17% higher and the odds of having bilateral knee symptoms were 25% higher. Similar findings were obtained with regard to ln Pb in quartiles.

CONCLUSIONS

Increases in the prevalence and severity measures for both radiographically and symptomatically confirmed knee OA (although statistically significant only for rOA) were observed with increasing levels of blood Pb, suggesting that Pb may be a potentially modifiable environmental risk factor for OA.

Intra-renal oxygenation in rat kidneys during water loading: effects of cyclooxygenase (COX) inhibition and nitric oxide (NO) donation

PURPOSE

To evaluate intra-renal oxygenation by blood oxygenation level dependent (BOLD) MRI in rat kidneys during water loading and to investigate if the NO donating moiety in naproxcinod could compensate for the effect of cyclooxygenase (COX) inhibition of naproxen.

MATERIALS AND METHODS

Nineteen male Sprague Dawley rats were divided into three groups and dosed with vehicle, naproxen or naproxcinod by gavage for two weeks. On the day of the experiment, hypotonic saline with glucose was infused intravenously to induce water diuresis. BOLD MRI data to monitor renal oxygenation and timed urine samples for estimation of prostaglandins (PGs) and urine flow were obtained.

RESULTS

The data in this study is consistent with previous experience in humans in that pre-treatment with naproxen abolished the improvement in medullary oxygenation during water loading. In addition, the inhibition of PGs by naproxcinod reached similar levels as naproxen but maintained the improvement in oxygenation in renal medulla during water loading.

CONCLUSION

This suggests that naproxcinod may have less nephrotoxicity and that the NO donating moiety partially compensates for the hemodynamic effects of prostaglandin inhibition by naproxen.

Influence of dipyridamole and its combination with NO donor or NO synthase inhibitor on adjuvant arthritis

The anti-arthritic and anti-inflammatory effects of dipyridamole and the possible involvement of NO in the dipyridamole action are not yet clear. The aim of this study was to evaluate the effects of dipyridamole alone and in combination with either the nitric oxide donor, sodium nitroprusside (SNP) or the non-selective nitric oxide synthase inhibitor, L-NG- monomethyl arginine (L-NMMA), on pathogenesis of adjuvant-induced arthritis model in rats. The results of the present work showed that prophylactic administration of dipyridamole alone and dipyridamole administration in combination with either low dose of SNP or L-NMMA significantly ameliorated pathogenesis of adjuvant arthritis in rats as evidenced by significant decrease in arthritis index, hind paws volume, loss of body weight, hyperalgesia compared with control vehicle (1% DMSO) treated adjuvant arthritic rats. Inflammatory cellular infiltrate in synovium of ankle joint and pannus formation were also markedly inhibited. Interleukin-10(IL-10) levels were significantly increased in these groups of animals. In contrast, a high dose of SNP counteracted the anti-inflammatory and anti-arthritic effects of dipyridamole. The inhibitory effect of therapeutic administration of dipyridamole alone on adjuvant arthritis syndrome was not significantly different from that of vehicle administration. In conclusion, dipyridamole has prophylactic but not therapeutic anti-arthritic and anti-inflammatory effects that appear to be dependent on inhibition of NO synthase. A synergistic combination between dipyridamole and NO synthase inhibitor or low dose of NO donor may have prophylactic and therapeutic values in autoimmune diseases like RA.

Treatment of osteoarthritis in hypertensive patients

IMPORTANCE OF THE FIELD

Osteoarthritis and hypertension commonly co-exist. Treatment of osteoarthritis in hypertensive patients is a therapeutic challenge due to the adverse effects of some analgesics, especially non-steroidal anti-inflammatory drugs (NSAIDs), on blood pressure. Even small drug-induced rises in blood pressure due to therapy may significantly increase cardiovascular risk in these patients if sustained over the long term. Patients treated with certain classes of antihypertensive agent may be at particular risk of deterioration in blood pressure control with NSAID therapy. NSAIDs may also increase cardiovascular risk due to mechanisms other than by raising blood pressure.

AREAS COVERED IN THIS REVIEW

We discuss the management of osteoarthritis in the hypertensive patient, review the evidence for the effects of paracetamol and NSAIDs on blood pressure and discuss novel therapeutic strategies for osteoarthritis that might diminish this problem. A literature search was undertaken in PubMed including the years 1980 - 2009.

WHAT THE READER WILL GAIN

Insight will be gained into the complexity of treating patients with co-existent osteoarthritis and hypertension and into possible new approaches to treating osteoarthritis symptoms effectively in these patients while minimising any adverse impact on blood pressure control.

TAKE HOME MESSAGE

There are ways to minimise the adverse impact of treatment of osteoarthritis on blood pressure control in hypertensive patients.

Adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs, aspirin and coxibs) on upper gastrointestinal tract

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most widely prescribed medication in the world. Their main benefit derives from their anti-inflammatory and analgesic effect, but the use of these agents is not innocuous since they mainly increase the risk of gastrointestinal (GI) and cardiovascular complications compared with non-NSAID users. NSAIDs injures the upper and lower gut by depleting COX-1 derived prostaglandins and causing topical injury to the mucosa. The risk of upper GI complications varies, depending on the presence of one or more risk factors. Among them, the three main risk factors are prior history of peptic ulcer, the single most important risk factor, age, the most common, and concomitant aspirin use, due to their GI and cardiovascular implications. Those individuals at-risk should be considered for alternatives to NSAID therapy and modifications of risk factors. If NSAID therapy is required, patients at risk will need prevention strategies including co-therapy of NSAID with gastroprotectants (PPI or misoprostol) or the prescription of COX-2 selective inhibitors. The probable introduction of NO-NSAIDs in the market in the near future may open a new therapeutic option for patients with hypertension who need NSAIDs.

Naproxcinod, a new cyclooxygenase-inhibiting nitric oxide donator (CINOD)

BACKGROUND

COX-inhibiting nitric oxide donators (CINODs) are a new class of drugs that combine the actions of the parent COX inhibitor with nitric oxide (NO), with the aim of reducing potential toxicity of the parent drug, while maintaining its analgesic and anti-inflammatory effects. AZD3582 (Naproxcinod) is the first in the class of CINODs.

OBJECTIVE/METHODS

To review the effects of NO donation, CINODS in general and naproxen in osteoarthritis (OA), based on literature in PubMed.

RESULTS

In preclinical and human studies, this drug produced similar analgesic and anti-inflammatory effects to its parent naproxen, with improved gastrointestinal safety in OA patients. The results of recent clinical trials, which were designed to study effects on blood pressure, are expected shortly, after peer-review.

CONCLUSIONS

As naproxen is considered the safest COX inhibitor choice from a cardiovascular perspective, AZD3582 has the potential to become a new drug treatment in patients with OA, in whom pain and function are not controlled by the use of analgesics.