Citations

Background — The role of load versus angiotensin II (Ang II) and endothelin-1 (ET) in the pathogenesis of hypertensive heart disease is controversial. We sought to determine whether alterations in cardiac structure and function due to hypertension (HTN) were dependent on Ang II or ET activation. Methods and Results — Bilateral renal wrapping to produce HTN (n=12) or sham surgery (n=6) was performed in adult dogs. Weekly blood pressure, plasma renin activity, Ang II, ET, and catecholamines were measured. Systolic (end-systolic elastance, Ees) and diastolic (τ) function were assessed in sham and HTN dogs at 5 (HTN-5wk) or 12 (HTN-12wk) weeks. Ang II and ET were assayed in the left ventricle (LV) and kidney. Mean arterial pressure was higher in renal wrap dogs at week 1 (* P <0.05 versus controls: 139±4* versus 123±4 mm Hg), week 5 (174±7* versus 124±4 mm Hg), and week 12 (181±12* versus 124±4 mm Hg). LV mass index was increased in HTN-5wk (22%*) and HTN-12wk (39%*). LV fibrosis was increased in HTN-12wk. Ees was preserved in HTN-5wk and HTN-12wk. τ was increased in HTN-5wk (50±3* ms) and HTN-12wk (62±10* ms) dogs compared with sham (41±2 ms). Plasma Ang II, ET, catecholamines, and plasma renin activity were unchanged during the progressive HTN. Ang II and ET in LV and kidney were not different from controls. Conclusions — Systemic HTN induces LV hypertrophy, myocardial fibrosis, and isolated diastolic dysfunction in the absence of local or systemic activation of Ang II or ET. These findings suggest that load is the prevailing stimulus for the structural and functional changes associated with early hypertensive heart disease.

Regulation of cytosolic Ca2+ concentration ([Ca2+]cyt) in airway smooth muscle (ASM) is a key aspect of airway contractility and can be modulated by inflammation. Mitochondria have tremendous potential for buffering [Ca2+]cyt, helping prevent Ca2+ overload, and modulating other intracellular events. Here, compartmentalization of mitochondria to different cellular regions may subserve different roles. In the present study, we examined the role of Ca2+ buffering by mitochondria and mitochondrial Ca2+ transport mechanisms in the regulation of [Ca2+]cyt in enzymatically dissociated human ASM cells upon exposure to the proinflammatory cytokines TNF-α and IL-13. Cells were loaded simultaneously with fluo-3 AM and rhod-2 AM, and [Ca2+]cyt and mitochondrial Ca2+ concentration ([Ca2+]mito) were measured, respectively, using real-time two-color fluorescence microscopy in both the perinuclear and distal, perimembranous regions of cells. Histamine induced a rapid increase in both [Ca2+]cyt and [Ca2+]mito, with a significant delay in the mitochondrial response. Inhibition of the mitochondrial Na+/Ca2+ exchanger (1 μM CGP-37157) increased [Ca2+]mito responses in perinuclear mitochondria but not distal mitochondria. Inhibition of the mitochondrial uniporter (1 μM Ru360) decreased [Ca2+]mito responses in perinuclear and distal mitochondria. CGP-37157 and Ru360 significantly enhanced histamine-induced [Ca2+]cyt. TNF-α and IL-13 both increased [Ca2+]cyt, which was associated with decreased [Ca2+]mito in the case of TNF-α but not IL-13. The effects of TNF-α on both [Ca2+]cyt and [Ca2+]mito were affected by CGP-37157 but not by Ru360. Overall, these data demonstrate that in human ASM cells, mitochondria buffer [Ca2+]cyt after agonist stimulation and its enhancement by inflammation. The differential regulation of [Ca2+]mito in different parts of ASM cells may serve to locally regulate Ca2+ fluxes from intracellular sources versus the plasma membrane as well as respond to differential energy demands at these sites. We propose that such differential mitochondrial regulation, and its disruption, may play a role in airway hyperreactivity in diseases such as asthma, where [Ca2+]cyt is increased.

Background— The clinical significance of incomplete coronary revascularization (ICR) after percutaneous coronary intervention in patients with acute coronary syndromes is unknown. Methods and Results— We performed quantitative angiography of the entire coronary tree in 2954 patients with acute coronary syndromes in the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. ICR was variably defined if any lesion with diameter stenosis (DS) cutoffs ranging from ≥30% to ≥70% with reference vessel diameter ≥2.0 mm remained after percutaneous coronary intervention. The primary outcome was 1-year composite rate of major adverse cardiac events (death, myocardial infarction, or ischemia-driven unplanned revascularization). With the use of DS cutoffs ≥30%, ≥40%, ≥50%, ≥60%, and ≥70%, the prevalence of ICR after percutaneous coronary intervention was 75%, 55%, 37%, 25%, and 17%, respectively. The 1-year major adverse cardiac event rate was increased among patients with ICR using all of the DS cutoffs. ICR (≥50% DS) was associated with higher 1-year rates of myocardial infarction (12.0% versus 8.2%; hazard ratio, 1.50; 95% confidence interval, 1.18–1.89; P =0.0007) and ischemia-driven unplanned revascularization (15.7% versus 10.2%; hazard ratio, 1.58; 95% confidence interval, 1.28–1.96; P <0.0001), with a trend toward increased mortality (3.1% versus 2.2%; hazard ratio, 1.43; 95% confidence interval, 0.90–2.27; P =0.13). By multivariable analysis, ICR (≥50% DS) was an independent predictor of 1-year major adverse cardiac events (hazard ratio, 1.36; 95% confidence interval, 1.12–1.64; P =0.002). The impact of ICR on major adverse cardiac events was similar regardless of chronic total occlusion presence, but it was more pronounced with a greater number of nonrevascularized lesions. Conclusions— Depending on the threshold of percent DS, ICR was present in 17% to 75% of patients with acute coronary syndromes after percutaneous coronary intervention. Regardless of the threshold, ICR was strongly associated with 1-year myocardial infarction, ischemia-driven unplanned revascularization, and major adverse cardiac events. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00093158.

AbstractChronic neuropathic pain arising from peripheral nerve damage is a severe clinical issue where there is a major unmet medical need. We previously demonstrated that both neurotensin (NT) receptor subtypes 1 (NTS1) and 2 (NTS2) are involved in mediating the naloxone‐insensitive antinociceptive effects of neurotensin in different analgesic tests including hotplate, tail‐flick, and tonic pain. However, the role of these receptors in neuropathic pain management has been poorly investigated. In the present study, we therefore examined whether intrathecal delivery ofNTS1 agonists was effective in reducing neuropathic pain symptoms in rats. Neuropathy was induced by sciatic nerve constriction (CCImodel), and the development of mechanical allodynia and thermal hyperalgesia on the ipsi‐ and contralateral hind paws was examined 3, 7, 14, 21, and 28 days post‐surgery.CCI‐operated rats exhibited significant increases in thermal and mechanical hypersensitivities over a 28‐day testing period. Spinal injection ofNTtoCCIrats alleviated the behavioral responses to radiant heat and mechanical stimuli, with a maximal reversal of 91% of allodynia at 6 μg/kg. Intrathecal administration of theNTS1‐selective agonist,PD149163 (30–90 μg/kg) also produced potent anti‐allodynic and anti‐hyperalgesic effects in nerve‐injured rats. Likewise, heat hyperalgesia and tactile allodynia produced byCCIof the sciatic nerve were fully reversed by theNTS1 agonist,NT69L(5–25 μg/kg). Altogether, these results support the idea that theNTS1 receptor subtype is involved in pain modulation, and the potential use ofNTS1 agonists for the treatment of painful neuropathies.