Citations

Mitochondrial injury contributes to renal dysfunction in several models of renal disease, but its involvement in human hypertension remains unknown. Fragments of the mitochondrial genome released from dying cells are considered surrogate markers of mitochondrial injury. We hypothesized that hypertension would be associated with increased urine mitochondrial DNA (mtDNA) copy numbers. We prospectively measured systemic and urinary copy number of the mtDNA genes cytochrome-c oxidase-3 and NADH dehydrogenase subunit-1 by quantitative polymerase chain reaction in essential (n=25) and renovascular (RVH, n=34) hypertensive patients and compared them with healthy volunteers (n=22). Urinary kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin served as indices of renal injury. Renal blood flow and oxygenation were assessed by multidetector computed tomography and blood oxygen level–dependent magnetic resonance imaging. Blood pressure, urinary neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 were similarly elevated in essential hypertension and RVH, and estimated glomerular filtration rate was lower in RVH versus healthy volunteers and essential hypertension. Renal blood flow was lower in RVH compared with essential hypertension. Urinary mtDNA copy number was higher in hypertension compared with healthy volunteers, directly correlated with urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 and inversely with estimated glomerular filtration rate. In RVH, urinary mtDNA copy number correlated directly with intrarenal hypoxia. Furthermore, in an additional validation cohort, urinary mtDNA copy number was higher in RVH compared with healthy volunteers (n=10 each). The change in serum creatinine levels and estimated glomerular filtration rate 3 months after medical therapy without or with revascularization correlated with the change in urinary mtDNA. Therefore, elevated urinary mtDNA copy numbers in hypertensive patients correlated with markers of renal injury and dysfunction, implicating mitochondrial injury in kidney damage in human hypertension.

Obesity associated with metabolic derangements (ObM) worsens the prognosis of patients with coronary artery stenosis (CAS), but the underlying cardiac pathophysiologic mechanisms remain elusive. We tested the hypothesis that ObM exacerbates cardiomyocyte loss distal to moderate CAS. Obesity-prone pigs were randomized to four groups ( n = 6 each): lean-sham, ObM-sham, lean-CAS, and ObM-CAS. Lean and ObM pigs were maintained on a 12-wk standard or atherogenic diet, respectively, and left circumflex CAS was then induced by placing local-irritant coils. Cardiac structure, function, and myocardial oxygenation were assessed 4 wk later by computed-tomography and blood oxygenation level dependent (BOLD) MRI, the microcirculation with micro-computed-tomography, and injury mechanisms by immunoblotting and histology. ObM pigs showed obesity, dyslipidemia, and insulin resistance. The degree of CAS (range, 50–70%) was similar in lean and ObM pigs, and resting myocardial perfusion and global cardiac function remained unchanged. Increased angiogenesis distal to the moderate CAS observed in lean was attenuated in ObM pigs, which also showed microvascular dysfunction and increased inflammation (M1-macrophages, TNF-α expression), oxidative stress (gp91), hypoxia (BOLD-MRI), and fibrosis (Sirius-red and trichrome). Furthermore, lean-CAS showed increased myocardial autophagy, which was blunted in ObM pigs (downregulated expression of unc-51-like kinase-1 and autophagy-related gene-12; P < 0.05 vs. lean CAS) and associated with marked apoptosis. The interaction diet xstenosis synergistically inhibited angiogenic, autophagic, and fibrogenic activities. ObM exacerbates structural and functional myocardial injury distal to moderate CAS with preserved myocardial perfusion, possibly due to impaired cardiomyocyte turnover.

Obesity-metabolic disorders (ObM) often accompany renal artery stenosis (RAS). We hypothesized that the coexistence of ObM and RAS magnifies inflammation and microvascular remodeling in the stenotic kidney (STK) and aggravates renal scarring. Twenty-eight obesity-prone Ossabaw pigs were studied after 16 wk of a high-fat/high-fructose diet or standard chow including ObM-sham, ObM-RAS, Lean-RAS, or Lean-sham (normal control) groups. Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were assessed by multidetector computed tomography (CT), renal oxygenation and tubular transport capability by blood-oxygen-level-dependent MRI, and microcirculation by micro-CT for vessel density, and Western blotting for protein expressions of angiogenic factors (VEGF/FLK-1). Renal vein and inferior vena cava levels of inflammatory cytokines were measured to evaluate systemic and kidney inflammation. Macrophage (MØ) infiltration and subpopulations, fat deposition in the kidney, and inflammation in perirenal and abdominal fat were also examined. GFR and RBF were decreased in Lean-STK but relatively preserved in ObM-STK. However, ObM-STK showed impaired tubular transport function, suppressed microcirculation, and stimulated glomerulosclerosis. ObM diet interacted with RAS to blunt angiogenesis in the STK, facilitated the release of inflammatory cytokines, and led to greater oxidative stress than Lean-STK. The ObM diet also induced fat deposition in the kidney and infiltration of proinflammatory M1-MØ, as also in perirenal and abdominal fat. Coexistence of ObM and RAS amplifies renal inflammation, aggravates microvascular remodeling, and accelerates glomerulosclerosis. Increased adiposity and MØ-accentuated inflammation induced by an ObM diet may contribute to structural injury in the post-STK kidney.

Objective— Endothelial outgrowth cells (EOC) decrease inflammation and improve endothelial repair. Inflammation aggravates kidney injury in renal artery stenosis (RAS), and may account for its persistence upon revascularization. We hypothesized that EOC would decrease inflammatory (M1) macrophages and improve renal recovery in RAS. Approach and Results— Pigs with 10 weeks of RAS were studied 4 weeks after percutaneous transluminal renal angioplasty (PTRA+stenting) or sham, with or without adjunct intrarenal delivery of autologous EOC (10×10 6 ), and compared with similarly treated normal controls (n=7 each). Single-kidney function, microvascular and tissue remodeling, inflammation, oxidative stress, and fibrosis were evaluated. Four weeks after PTRA, EOC were engrafted in injected RAS-kidneys. Stenotic-kidney glomerular filtration rate was restored in RAS+EOC, RAS+PTRA, and RAS+PTRA+EOC pigs, whereas stenotic-kidney blood flow and angiogenesis were improved and fibrosis attenuated only in EOC-treated pigs. Furthermore, EOC increased cell proliferation and decreased the ratio of M1 (inflammatory)/M2 (reparative) macrophages, as well as circulating levels and stenotic-kidney release of inflammatory cytokines. Cultured-EOC released microvesicles in vitro and induced phenotypic switch (M1-to-M2) in cultured monocytes, which was inhibited by vascular endothelial growth factor blockade. Finally, a single intrarenal injection of rh-vascular endothelial growth factor (0.05 μg/kg) in 7 additional RAS pigs also restored M1/M2 ratio 4 weeks later. Conclusions— Intrarenal infusion of EOC after PTRA induced a vascular endothelial growth factor–mediated attenuation in macrophages inflammatory phenotype, preserved microvascular architecture and function, and decreased inflammation and fibrosis in the stenotic kidney, suggesting a novel mechanism and therapeutic potential for adjunctive EOC delivery in experimental RAS to improve PTRA outcomes.

Background— The selection of patients with renal artery stenosis (RAS) likely to improve glomerular filtration rate (GFR) after percutaneous transluminal renal angioplasty is difficult. We examined basal hemodynamic and inflammatory factors linked to improved stenotic kidney (STK) function after percutaneous transluminal renal angioplasty in swine RAS. Methods and Results— Fifteen pigs after 6 weeks of hemodynamically significant RAS were studied before and 4 weeks after technically successful percutaneous transluminal renal angioplasty+stenting. STK and contralateral kidney hemodynamics and function were evaluated by multidetector computed-tomography before and after acetylcholine challenge. Single-kidney deoxyhemoglobin (R2*, reciprocal to blood relaxation) and energy-dependent tubular function were assessed using blood-oxygen-level–dependent magnetic resonance imaging before and after furosemide. Baseline renal vein and inferior vena cava levels of inflammatory markers were measured and their gradient and net release calculated. Baseline parameters were compared with normal (n=7) and sham-RAS (n=7) pigs and correlated with the change in STK-GFR after revascularization (ΔGFR). Four weeks after percutaneous transluminal, renal angioplasty blood pressure was normalized in all animals, but STK-GFR improved in 10 of 15 (ΔGFR =+22.0±8.5 mL/min). ΔGFR correlated inversely with basal STK-GFR, renal release of inflammatory markers, and medullary R2* response to furosemide, but directly with GFR response to acetylcholine. Basal contralateral kidney GFR correlated directly with ΔGFR. Conclusions— Low basal STK-GFR with preserved response to acetylcholine may predict benefit from revascularization in RAS, whereas renal inflammation and robust STK-R2* responses to furosemide (possibly reflecting avid tubular oxygen consumption) are associated with less favorable outcomes. These tools may be useful for identification of patients likely to improve renal function after revascularization.

Revascularization improves blood pressure but not renal function in most patients with atherosclerotic renal artery stenosis (ARAS), possibly related to injury incurred during renal reperfusion. Bendavia, a novel tetrapeptide that inhibits mitochondrial permeability transition pore opening, reduces apoptosis, oxidative stress, and ischemia-reperfusion injury in experimental models. However, its potential for improving renal response to revascularization of chronic ARAS is unknown. We hypothesized that adjunct Bendavia would improve renal structure and function after percutaneous transluminal renal angioplasty (PTRA). Pigs were treated after 6 weeks of ARAS or control with PTRA+stenting (or sham), adjunct continuous 4-hour infusion of Bendavia (0.05 mg/kg IV) or vehicle (n=7 each) during PTRA. Single-kidney renal blood flow and glomerular filtration rate were studied 4 weeks later and renal mitochondrial biogenesis, microvascular architecture, and injurious pathways evaluated ex vivo. Monocyte chemoattractant protein-1 levels rose after PTRA, suggesting inflammatory injury. Bendavia did not immediately affect inflammatory cytokine levels, yet 4 weeks later, stenotic kidney renal blood flow and glomerular filtration rate both improved (44.00 ± 0.21% and 36.40 ± 10.21%, respectively) in ARAS+PTRA+Bendavia compared with ARAS+PTRA+vehicle. Renal mitochondrial biogenesis was restored after PTRA+Bendavia, and microvascular rarefaction, apoptosis, oxidative stress, tubular injury, and fibrosis decreased. Infusion of Bendavia during PTRA preserved mitochondrial biogenesis, renal hemodynamics, and function, and attenuated tissue injury in swine ARAS. Thus, functional mitochondrial injury during renal reperfusion may sustain renal inflammatory injury and limit kidney recovery after PTRA. Potent antiapoptotic and antioxidant effects provide Bendavia a novel therapeutic potential for improving kidney outcomes after PTRA in experimental ARAS.

Abstract Lung cancer is the most common cause of smoking-related mortality in worldwide. However, approximately 10 to 25 % cases are not attributable to smoking. Cumulative evidence suggests that lung cancer from never smokers (&lt;100 cigarettes lifetime) may develop via molecular mechanisms that are different from lung cancers in smokers. Recently, miRNAs have been identified as a new class of regulatory molecules that participate in a variety of biological processes. Because each miRNAs can potentially target a large set of mRNA making and therefore may play a critical role in lung tumorigenesis and patient outcome, we sought to examine the role of miRNA in lung adenocarcinoma among never smokers. A total of 298 samples were analyzed in this study including 168 fresh frozen (FF) tissues from 88 lung adenocarcinomas and 80 adjacent non-involved lung tissues; and 132 formalin-fixed paraffin embedded (FFPE) tissues from 68 tumors and 64 normal lung samples. Gene expression profiling was performed for miRNA and mRNA using Illumina Whole Genome DASL platform. We identified 20 miRNAs with the most significant expression changes between the tumor and normal in both FF and FFPE samples (Fold change &gt; 1.5, p &lt;0.01, FDR &lt;0.05). We also examined mRNA expression signature using 56 matched FF tumors and normal lung tissues. Cox proportional hazard analysis was performed independently for both FF and FFPE cohorts and showed that increased expression of mir-708 was strongly associated with an increased risk of patient death after adjusting for age, sex and tumor stage (FF cohort, HR =1.92; 95% CI =1.02–3.63; p &lt; 0.05 and FFPE cohort, HR=1.90; 95% CI=1.08–3.34; P &lt; 0.05). Candidate biological targets of mir-708 were identified using TargetScan and MicroCosm Targets databases. A total of 13 candidate genes were found and one of these genes, CMT11 (Candidate Mir-708 Target), was down-regulated 1.6 fold on average in tumors that were high in mir-708 expression. Based on the sequence, CMT11 is a novel transmembrane protein. In Cox analysis, reduced CMT11 expression was strongly correlated with an increased risk of death in patients (HR = 2.43, 95% CI = 1.17 − 5.26; P &lt;0.01). Functionally, overexpression of mir-708 in A549 and HEK293T cells significantly increased the rate of cellular proliferation and migration. Over expression of mir-708 in HEK293T cells also repressed ∼70% of the luciferase activity when the reporter RNA contained the 3′ UTR of CMT11. Recently, several studies have showed mir-708 is a potential squamous cell lung cancer marker and one of miRNAs that may predict the recurrence of Stage I lung cancer after surgical resection. Additional evidence also suggests that CMT11 is a negative regulator of Wnt-signaling pathway. Our data provides clinical and functional evidence supporting an important role of mir-708 in lung cancer progression and identifies CMT11 as a down stream target gene mediating this process. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-346. doi:10.1158/1538-7445.AM2011-LB-346