Impact of Cell Therapy on Myocardial Perfusion and Cardiovascular Outcomes in Patients With Angina Refractory to Medical Therapy: A Systematic Review and Meta-Analysis.

RATIONALE: The effect of stem/progenitor cells on myocardial perfusion and clinical outcomes in patients with refractory angina remains unclear because studies published to date have been small phase I-II trials. OBJECTIVE: We performed a meta-analysis of randomized controlled trials to evaluate the effect of cell-based therapy in patients with refractory angina who were ineligible for coronary revascularization. METHODS AND RESULTS: Several data sources were searched from inception to September 2015, which yielded 6 studies. The outcomes pooled were indices of angina (anginal episodes, Canadian Cardiovascular Society angina class, exercise tolerance, and antianginal medications), myocardial perfusion, and clinical end points. We combined the reported clinical outcomes (myocardial infarction, cardiac-related hospitalization, and mortality) into a composite end point (major adverse cardiac events). Mean difference (MD), standardized mean differences, or odds ratio were calculated to assess relevant outcomes. Our analysis shows an improvement in anginal episodes (MD, -7.81; 95% confidence interval [CI], -15.22 to -0.41), use of antianginal medications (standardized MD, -0.59; 95% CI, -1.03 to -0.14), Canadian Cardiovascular Society class (MD, -0.58; 95% CI, -1.00 to -0.16), exercise tolerance (standardized MD, 0.331; 95% CI, 0.08 to 0.55), and myocardial perfusion (standardized MD, -0.49; 95% CI, -0.76 to -0.21) and a decreased risk of major adverse cardiac events (odds ratio, 0.49; 95% CI, 0.25 to 0.98) and arrhythmias (odds ratio, 0.25; 95% CI, 0.06 to 0.98) in cell-treated patients when compared with patients on maximal medical therapy. CONCLUSIONS: The present meta-analysis indicates that cell-based therapies are not only safe but also lead to an improvement in indices of angina, relevant clinical outcomes, and myocardial perfusion in patients with refractory angina. These encouraging results suggest that larger, phase III randomized controlled trials are in order to conclusively determine the effect of stem/progenitor cells in refractory angina.

Stretch-activation of angiotensin II type 1a receptors contributes to the myogenic response of mouse mesenteric and renal arteries.

RATIONALE: Vascular wall stretch is the major stimulus for the myogenic response of small arteries to pressure. The molecular mechanisms are elusive, but recent findings suggest that G protein-coupled receptors can elicit a stretch response. OBJECTIVE: To determine whether angiotensin II type 1 receptors (AT1R) in vascular smooth muscle cells exert mechanosensitivity and identify the downstream ion channel mediators of myogenic vasoconstriction. METHODS AND RESULTS: We used mice deficient in AT1R signaling molecules and putative ion channel targets, namely AT1R, angiotensinogen, transient receptor potential channel 6 (TRPC6) channels, or several subtypes of the voltage-gated K+ (Kv7) gene family (KCNQ3, 4, or 5). We identified a mechanosensing mechanism in isolated mesenteric arteries and in the renal circulation that relies on coupling of the AT1R subtype a to a Gq/11 protein as a critical event to accomplish the myogenic response. Arterial mechanoactivation occurs after pharmacological block of AT1R and in the absence of angiotensinogen or TRPC6 channels. Activation of AT1R subtype a by osmotically induced membrane stretch suppresses an XE991-sensitive Kv channel current in patch-clamped vascular smooth muscle cells, and similar concentrations of XE991 enhance mesenteric and renal myogenic tone. Although XE991-sensitive KCNQ3, 4, and 5 channels are expressed in vascular smooth muscle cells, XE991-sensitive K+ current and myogenic contractions persist in arteries deficient in these channels. CONCLUSIONS: Our results provide definitive evidence that myogenic responses of mouse mesenteric and renal arteries rely on ligand-independent, mechanoactivation of AT1R subtype a. The AT1R subtype a signal relies on an ion channel distinct from TRPC6 or KCNQ3, 4, or 5 to enact vascular smooth muscle cell activation and elevated vascular resistance.

Inositol 1,4,5-trisphosphate (IP3) receptor up-regulation in hypertension is associated with sensitization of Ca2+ release and vascular smooth muscle contractility.

Resistance arteries show accentuated responsiveness to vasoconstrictor agonists in hypertension, and this abnormality relies partly on enhanced Ca(2+) signaling in vascular smooth muscle (VSM). Although inositol 1,4,5-triphosphate receptors (IP3Rs) are abundant in VSM, their role in the molecular remodeling of the Ca(2+) signaling machinery during hypertension has not been addressed. Therefore, we compared IP3R expression and function between mesenteric arteries of normotensive and hypertensive animals. Levels of IP3R transcript and protein were significantly increased in mesenteric arteries of hypertensive animals, and pharmacological inhibition of the IP3R revealed a higher contribution of IP3-dependent Ca(2+) release to vascular contraction in these arteries. Subsequently, we established cultured aortic VSM A7r5 cells as a cellular model that replicates IP3R up-regulation during hypertension by depolarizing the VSM cell membrane. IP3R up-regulation requires Ca(2+) influx through L-type Ca(2+) channels, followed by activation of the calcineurin-NFAT axis, resulting in IP3R transcription. Functionally, IP3R up-regulation in VSM is associated with enhancement and sensitization of IP3-dependent Ca(2+) release, resulting in increased VSM contraction in response to agonist stimulation.

NO-NSAIDs. Part 3: nitric oxide-releasing prodrugs of non-steroidal anti-inflammatory drugs.

In continuation of our efforts to discover novel nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) as potentially "Safe NSAIDs," we report herein the design, synthesis and evaluation of 21 new NO-NSAIDs of commonly used NSAIDs such as aspirin, diclofenac, naproxen, flurbiprofen, ketoprofen, sulindac, ibuprofen and indomethacin. These prodrugs have NO-releasing disulfide linker attached to a parent NSAID via linkages such as an ester (compounds 9-16), a double ester (compounds 17-24), an imide (compounds 25-30) or an amide (compounds 31-33). Among these NO-NSAIDs, the ester-containing NO-aspirin (9), NO-diclofenac (10), NO-naproxen (11), and the imide-containing NO-aspirin (25), NO-flurbiprofen (27) and NO-ketoprofen (28) have shown promising oral absorption, anti-inflammatory activity and NO-releasing property, and also protected rats from NSAID-induced gastric damage. NO-aspirin compound 25, on further co-evaluation with aspirin at equimolar doses, exhibited comparable dose-dependent pharmacokinetics, inhibition of gastric mucosal prostaglandin E(2) (PGE(2)) synthesis and analgesic properties to those of aspirin, but retained its gastric-sparing properties even after doubling its oral dose. These promising NO-NSAIDs could therefore represent a new class of potentially "Safe NSAIDs" for the treatment of arthritic pain and inflammation.

Postsynaptic density-95 scaffolding of Shaker-type K⁺ channels in smooth muscle cells regulates the diameter of cerebral arteries.

Postsynaptic density-95 (PSD95) is a 95 kDa scaffolding molecule in the brain that clusters postsynaptic proteins including ion channels, receptors, enzymes and other signalling partners required for normal cognition. The voltage-gated, Shaker-type K(+) (K(V)1) channel is one key binding partner of PSD95 scaffolds in neurons. However, K(V)1 channels composed of α1.2 and α1.5 pore-forming subunits also are expressed in the vascular smooth muscle cells (cVSMCs) of the cerebral circulation, although the identity of their molecular scaffolds is unknown. Since α1.2 contains a binding motif for PSD95, we explored the possibility that cVSMCs express PSD95 as a scaffold to promote K(V)1 channel expression and cerebral vasodilatation. Cerebral arteries from Sprague-Dawley rats were isolated for analysis of PSD95 and K(V)1 channel proteins. PSD95 was detected in cVSMCs and it co-immunoprecipitated and co-localized with the pore-forming α1.2 subunit of the K(V)1 channel. Antisense-mediated knockdown of PSD95 profoundly reduced K(V)1 channel expression and suppressed K(V)1 current in patch-clamped cVSMCs. Loss of PSD95 also depolarized cVSMCs in pressurized cerebral arteries and induced a strong constriction associated with a loss of functional K(V)1 channels. Our findings provide initial evidence that PSD95 is expressed in cVSMCs, and the K(V)1 channel is one of its important binding partners. PSD95 appears to function as a critical 'dilator' scaffold in cerebral arteries by increasing the number of functional K(V)1 channels at the plasma membrane.

Oral bioavailability, efficacy and gastric tolerability of P2026, a novel nitric oxide-releasing diclofenac in rat.

The present study was designed to evaluate, P2026 [(2-((2-(nitrooxy)ethyl)disulfanyl)ethyl 2-(2-(2,6-dichlorophenylamino)phenyl)acetate)], a novel NO (nitric oxide) donor prodrug of diclofenac for its ability to release NO and diclofenac, and whether P2026 provides advantage of improved activity/gastric tolerability over diclofenac. Oral bioavailability of P2026 was estimated from plasma concentration of diclofenac and nitrate/nitrite (NOx). Anti-inflammatory activity was evaluated in three different models of inflammation: acute (carrageenan-induced paw oedema), chronic (adjuvant-induced arthritis), and systemic (lipopolysaccharide-induced endotoxic shock). Gastric tolerability was evaluated from compound's propensity to cause gastric ulcers. P2026 exhibited dose-dependent diclofenac and NOx release. Similar to diclofenac, P2026 showed potent anti-inflammatory activity in acute and chronic model, whereas it improved activity in systemic model. Both diclofenac and P2026 inhibited gastric prostaglandin, but only diclofenac produced dose-dependent haemorrhagic ulcers. Thus, the results suggest that coupling of NO and diclofenac contribute to improved gastric tolerability while retaining the anti-inflammatory properties of diclofenac.

NO-NSAIDs: Gastric-sparing nitric oxide-releasable prodrugs of non-steroidal anti-inflammatory drugs.

Recently, a new class of nitric-oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) is being studied as 'Safe NSAIDs' because of their gastric-sparing properties. As an extension of our novel disulfide linker technology, we have designed, synthesized and evaluated novel NO-releasing NSAID prodrugs such as NO-Aspirin (1b-d) and NO-Diclofenac (2b-c). Although the amide-containing derivative 1d did not show any bioavailability, the remaining compounds have shown fair to excellent pharmacokinetic, anti-inflammatory and gastric-sparing properties. Among them, however, the NO-Diclofenac (2b) has shown the most promising pharmacokinetic, anti-inflammatory and NO-releasing properties and protected rats from NSAID-induced gastric damage which could be attributable to the beneficial effects of NO released from these prodrugs.

Pro-Angiogenic Actions of CMC-Derived Extracellular Vesicles Rely on Selective Packaging of Angiopoietin 1 and 2, but Not FGF-2 and VEGF.

While the fundamental mechanism by which cardiac cell therapy mitigates ventricular dysfunction in the post ischemic heart remains poorly defined, donor cell paracrine signaling is presumed to be a chief contributor to the afforded benefits. Of the many bioactive molecules secreted by transplanted cells, extracellular vesicles (EVs) and their proteinaceous, nucleic acid, and lipid rich contents, comprise a heterogeneous assortment of prospective cardiotrophic factors-whose involvement in the activation of endogenous cardiac repair mechanism(s), including reducing fibrosis and promoting angiogenesis, have yet to be fully explained. In the current study we aimed to interrogate potential mechanisms by which cardiac mesenchymal stromal cell (CMC)-derived EVs contribute to the CMC pro-angiogenic paracrine signaling capacity in vitro. Vesicular transmission and biological activity of human CMC-derived EVs was evaluated in in vitro assays for human umbilical vein endothelial cell (HUVEC) function, including EV uptake, cell survival, migration, tube formation, and intracellular pathway activation. HUVECs incubated with EVs exhibited augmented cell migration, tube formation, and survival under peroxide exposure; findings which paralleled enhanced activation of the archetypal pro-survival/pro-angiogenic pathways, STAT3 and PI3K-AKT. Cytokine array analyses revealed preferential enrichment of a subset of prototypical angiogenic factors, Ang-1 and Ang-2, in CMC EVs. Interestingly, pharmacologic inhibition of Tie2 in HUVECs, the cognate receptors of angiopoietins, efficiently attenuated CMC-EV-induced HUVEC migration. Further, in additional assays a Tie2 kinase inhibitor exhibited specificity to inhibit Ang-1-, but not Ang-2-, induced HUVEC migration. Overall, these findings suggest that the pro-angiogenic activities of CMC EVs are principally mediated by Ang-1-Tie2 signaling.

Rosiglitazone attenuates the cognitive deficits induced by high fat diet feeding in rats.

The present study was designed to test the hypothesis that insulin resistance plays a role in high fat diet feeding induced cognitive deficits. Rats consuming the high fat diet exhibited characteristic features of insulin resistance viz. mild hyperglycemia, hypertriglyceridemia, hypercholesterolemia, and hyperinsulinemia. Further, these rats showed a severe deficit in learning and memory. In contrast, rosiglitazone at the dose of 5 mg/kg, p.o. for 7 days prior to biochemical and behavioral testing significantly lowered the plasma glucose, triglycerides, cholesterol, and insulin levels. These animals also performed better on Morris water maze task, suggesting improved spatial memory. Our data demonstrate that the insulin sensitizers can overcome the cognitive deficits arising from high fat diet feeding, which may be in part mediated through the development of peripheral insulin resistance.

Chronic administration of pioglitazone attenuates intracerebroventricular streptozotocin induced-memory impairment in rats.

Memory impairment induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) in rats is associated with impaired brain glucose and energy metabolism, oxidative stress and impaired cholinergic neurotransmission. Treatment with antioxidants and cholinergic agonists has been reported to produce beneficial effect in this model. However, no reports are available on drugs that improve glucose utilization and metabolism. In the present study, we evaluated the effects of pioglitazone on cognitive performance, oxidative stress and glucose utilization in ICV STZ injected rats (3 mg/kg, on day 1 and 3). Pioglitazone (10 and 30 mg/kg) was administered per oral (p.o.) for 14 days, starting 5 days prior to STZ injection. Cognitive performance was assessed using step-through passive avoidance and Morris water maze task. Malondialdehyde (MDA) and glutathione levels in brain were estimated as parameters of oxidative stress. Glucose utilization by brain was assessed as the amount of glucose consumed from the media by the brain. ICV STZ injected rats showed a severe deficit in learning and memory associated with increased MDA levels (+67.5%), decreased glutathione levels (-29.2%) and impaired cerebral glucose utilization (-44.4%). In contrast pioglitazone treatment improved cognitive performance, lowered oxidative stress and improved cerebral glucose utilization in ICV STZ rats. The present study demonstrates the beneficial effects of pioglitazone in the ICV STZ induced cognitive deficits, which can be exploited for the dementia associated with diabetes and age-related neurodegenerative disorder, where oxidative stress and impaired glucose and energy metabolism are involved.