Role of SIRT1 in Modulating Acetylation of the Sarco-Endoplasmic Reticulum Ca2+-ATPase in Heart Failure.

RATIONALE: SERCA2a, sarco-endoplasmic reticulum Ca2+-ATPase, is a critical determinant of cardiac function. Reduced level and activity of SERCA2a are major features of heart failure. Accordingly, intensive efforts have been made to develop efficient modalities for SERCA2a activation. We showed that the activity of SERCA2a is enhanced by post-translational modification with SUMO1 (small ubiquitin-like modifier 1). However, the roles of other post-translational modifications on SERCA2a are still unknown. OBJECTIVE: In this study, we aim to assess the role of lysine acetylation on SERCA2a function and determine whether inhibition of lysine acetylation can improve cardiac function in the setting of heart failure. METHODS AND RESULTS: The acetylation of SERCA2a was significantly increased in failing hearts of humans, mice, and pigs, which is associated with the reduced level of SIRT1 (sirtuin 1), a class III histone deacetylase. Downregulation of SIRT1 increased the SERCA2a acetylation, which in turn led to SERCA2a dysfunction and cardiac defects at baseline. In contrast, pharmacological activation of SIRT1 reduced the SERCA2a acetylation, which was accompanied by recovery of SERCA2a function and cardiac defects in failing hearts. Lysine 492 (K492) was of critical importance for the regulation of SERCA2a activity via acetylation. Acetylation at K492 significantly reduced the SERCA2a activity, presumably through interfering with the binding of ATP to SERCA2a. In failing hearts, acetylation at K492 appeared to be mediated by p300 (histone acetyltransferase p300), a histone acetyltransferase. CONCLUSIONS: These results indicate that acetylation/deacetylation at K492, which is regulated by SIRT1 and p300, is critical for the regulation of SERCA2a activity in hearts. Pharmacological activation of SIRT1 can restore SERCA2a activity through deacetylation at K492. These findings might provide a novel strategy for the treatment of heart failure.

The matricellular protein CCN5 prevents adverse atrial structural and electrical remodelling.

Atrial structural remodelling including atrial hypertrophy and fibrosis is a key mediator of atrial fibrillation (AF). We previously demonstrated that the matricellular protein CCN5 elicits anti-fibrotic and anti-hypertrophic effects in left ventricles under pressure overload. We here determined the utility of CCN5 in ameliorating adverse atrial remodelling and arrhythmias in a murine model of angiotensin II (AngII) infusion. Advanced atrial structural remodelling was induced by AngII infusion in control mice and mice overexpressing CCN5 either through transgenesis (CCN5 Tg) or AAV9-mediated gene transfer (AAV9-CCN5). The mRNA levels of pro-fibrotic and pro-inflammatory genes were markedly up-regulated by AngII infusion, which was significantly normalized by CCN5 overexpression. In vitro studies in isolated atrial fibroblasts demonstrated a marked reduction in AngII-induced fibroblast trans-differentiation in CCN5-treated atria. Moreover, while AngII increased the expression of phosphorylated CaMKII and ryanodine receptor 2 levels in HL-1 cells, these molecular features of AF were prevented by CCN5. Electrophysiological studies in ex vivo perfused hearts revealed a blunted susceptibility of the AAV9-CCN5-treated hearts to rapid atrial pacing-induced arrhythmias and concomitant reversal in AngII-induced atrial action potential prolongation. These data demonstrate the utility of a gene transfer approach targeting CCN5 for reversal of adverse atrial structural and electrophysiological remodelling.

Role of the PRC2-Six1-miR-25 signaling axis in heart failure.

The reduced expression of cardiac sarco-endoplasmic reticulum Ca2+ ATPase (SERCA2a) is a hallmark of heart failure. We previously showed that miR-25 is a crucial transcriptional regulator of SERCA2a in the heart. However, the precise mechanism of cardiac miR-25 regulation is largely unknown. Literatures suggested that miR-25 is regulated by the transcriptional co-factor, sine oculis homeobox homolog 1 (Six1), which in turn is epigenetically regulated by polycomb repressive complex 2 (PRC 2) in cardiac progenitor cells. Therefore, we aimed to investigate whether Six1 and PRC2 are indeed involved in the regulation of the miR-25 level in the setting of heart failure. Six1 was up-regulated in the failing hearts of humans and mice. Overexpression of Six1 led to adverse cardiac remodeling, whereas knock-down of Six1 attenuated pressure overload-induced cardiac dysfunction. The adverse effects of Six1 were ameliorated by knock-down of miR-25. The epigenetic repression on the Six1 promoter by PRC2 was significantly reduced in failing hearts. Epigenetic repression of Six1 is relieved through a reduction of PRC2 activity in heart failure. Six1 up-regulates miR-25, which is followed by reduction of cardiac SERCA2a expression. Collectively, these data showed that the PRC2-Six1-miR-25 signaling axis is involved in heart failure. Our finding introduces new insight into potential treatments of heart failure.

Primary ceramic-on-ceramic total hip arthroplasty using a 32-mm ceramic head with a titanium-alloy sleeve.

BACKGROUND: Modern ceramic-on-ceramic bearings have become attractive alternatives to conventional polyethylene in total hip arthroplasty (THA) as a result of their low wear and minimal particle production. However, 28-mm heads in ceramic-on-ceramic bearing couples have been associated with ceramic fracture. To address these issues, 32-mm and larger ceramic heads with a titanium-alloy sleeve have been introduced, although limited data are available on their durability and clinical outcomes. QUESTIONS/PURPOSES: We determined (1) the survivorship of the primary ceramic-on-ceramic THA using a 32-mm ceramic head with a titanium-alloy sleeve at a minimum followup of 5 years; (2) Harris hip scores; (3) the incidence of ceramic fracture and noisy hip; and (4) the proportion of hips showing radiographic evidence of osteolysis. METHODS: From November 2005 to August 2009, we performed 301 ceramic-on-ceramic THAs using a 32-mm ceramic head with a titanium-alloy sleeve in 270 patients. Of these, 12 patients (12 hips [4%]) died from problems unrelated to surgery and 13 patients (15 hips [5%]) were lost during followup before a minimum of 5 years had been reached, leaving 245 patients who had 274 THAs with a minimum followup of 5 years (mean, 6.5 years; range, 5-9 years) in this retrospective analysis. During the study period, 30% (301 of 997 hips) were performed with this articulation based on the operating surgeon's discretion. The mean patient age at the time of surgery was 55 years (range, 16-82 years). All operations were performed at a single center. All of the ceramic implants were hot isostatic-pressed, laser-marked, proof-tested third-generation alumina. We determined the implant survival, Harris hip scores, incidence of ceramic fracture or noisy hips (based on a questionnaire), and presence of osteolysis. RESULTS: The survival rate of ceramic-on-ceramic bearings in primary THA using a 32-mm ceramic head with a titanium-alloy sleeve was 98% (95% confidence interval, 96%-100%) at 9 years. The Harris hip score improved from a mean of 47 points preoperatively to 93 points at last followup. One ceramic head fractured at 6 years postoperatively. No ceramic liners fractured. Audible hip clicking and squeaking were identified in four hips and one hip, respectively. Osteolysis was detected in three hips, but none had symptoms. CONCLUSIONS: Primary ceramic-on-ceramic THA using a 32-mm ceramic head with a titanium-alloy sleeve has a survivorship of 98% at 9-year followup. Nevertheless, surgeons should be aware of the potential risks of ceramic fracture, noise, and osteolysis associated with the use of a ceramic head with a titanium-alloy sleeve. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Massive intercalary reconstruction of lower limb after wide excision of malignant tumors: an alternative to amputation or rotationplasty.

In this study, we present the feasibility of intercalary limb resection and massive reconstruction for malignant tumors of lower extremity. Ten cases of lower extremity malignancies that had undergone concomitant bone (and/or joint) and soft-tissue reconstruction after wide excision exceeding two-thirds of the cross-sectional area of the affected limb were reviewed. All cases were indicated for amputation because of an expansive tumor, hematoma from a pathologic fracture, or previous unplanned excision, with or without critical structure involvement. Bone was reconstructed with either an allograft or a tumor prosthesis. Soft-tissue reconstruction was performed to achieve critical structure and coverage, which was required in all cases. The resection margin was clear in all cases, and no soft-tissue graft failure was encountered. During a mean follow-up of 26 months (range, 9-42 months), no patient developed local recurrence in the resection-reconstruction site. Of the 10 patients, 8 patients were able to walk independently, and two were ambulatory but needed crutch support outdoors. Massive intercalary resection and reconstruction can be an effective treatment option for locally progressed or complicated lower extremity malignancies. Considering patient preference and the fair functional outcomes observed, it may be a useful alternative to amputation or rotationplasty.

Decoy peptides targeted to protein phosphatase 1 inhibit dephosphorylation of phospholamban in cardiomyocytes.

Cardiac sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) plays a crucial role in Ca(2+) handling in cardiomyocytes. Phospholamban (PLB) is an endogenous inhibitor of SERCA2a and its inhibitory activity is enhanced via dephosphorylation by protein phosphatase 1 (PP1). Therefore, the inhibition of PP1-mediated dephosphorylation of PLB might be an efficient strategy for the restoration of reduced SERCA2a activity in failing hearts. We sought to develop decoy peptides that would mimic phosphorylated PLB and thus competitively inhibit the PP1-mediated dephosphorylation of endogenous PLB. The phosphorylation sites Ser16 and Thr17 are located within the flexible loop region (amino acids 14-22) of PLB. We therefore synthesized a 9-mer peptide derived from this region (ΨPLB-wt) and two pseudo-phosphorylated peptides where Ser16 was replaced with Glu (ΨPLB-SE) or Thr17 was replaced with Glu (ΨPLB-TE). These peptides were coupled to the cell-permeable peptide TAT to facilitate cellular uptake. Treatment of adult rat cardiomyocytes with ΨPLB-SE or ΨPLB-TE, but not with ΨPLB-wt, significantly elevated the phosphorylation levels of PLB at Ser16 and Thr17. This increased phosphorylation of PLB correlated with an increase in contractile parameters in vitro. Furthermore, the perfusion of isolated rat hearts with ΨPLB-SE or ΨPLB-TE, but not with ΨPLB-wt, significantly improved left ventricular developed pressure that had been previously impaired by ischemia. These data indicate that ΨPLB-SE and ΨPLB-TE efficiently prevented dephosphorylation of PLB by serving as decoys for PP1. Therefore, these peptides may provide an effective modality to regulate SERCA2a activity in failing hearts.

The matricellular protein CCN5 induces apoptosis in myofibroblasts through SMAD7-mediated inhibition of NFκB.

We previously showed that the matricellular protein CCN5 reverses established cardiac fibrosis (CF) through inducing apoptosis in myofibroblasts (MyoFBs) but not in cardiomyocytes or fibroblasts (FBs). In this study, we set out to elucidate the molecular mechanisms underlying CCN5-mediated selective apoptosis of MyoFBs. We first observed that the apoptotic protein p53 and the anti-apoptotic protein NFκB are simultaneously induced in MyoFBs. When the expression level of p53 was suppressed using a siRNA, CCN5 did not induce apoptosis in MyoFBs. By contrast, when NFκB signaling was inhibited using IKK VII, an IκB inhibitor, MyoFBs underwent apoptosis even in the absence of CCN5. SMAD7 is one of the downstream targets of CCN5 and it was previously shown to potentiate apoptosis in epithelial cells through inhibition of NFκB. In accordance with these reports, when the expression of SMAD7 was suppressed using a siRNA, NFκB signaling was enhanced, and CCN5 did not induce apoptosis. Lastly, we used a luciferase reporter construct to show that CCN5 positively regulated SMAD7 expression at the transcriptional level. Collectively, our data suggest that a delicate balance between the two mutually antagonistic proteins p53 and NFκB is maintained for MyoFBs to survive, and CCN5 tips the balance in favor of the apoptotic protein p53. This study provides insight into the anti-fibrotic activity of CCN5 during the regression of CF.

Does Transection of the Superficial MCL During HTO Result in Progressive Valgus Instability? [Formula: see text].

BACKGROUND: During high tibial osteotomy (HTO), the superficial medial collateral ligament (sMCL) is cut or released at any degree to expose the osteotomy site and achieve the targeted alignment correction according to the surgeon's preference. However, it is still unclear whether transection of sMCL increases valgus laxity. PURPOSE: We aimed to assess the outcomes and safety of sMCL transection, especially focusing on iatrogenic valgus instability. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Seventy-two patients (89 knees) who underwent medial open wedge HTO (MOWHTO) with transection of the sMCL between October 2013 and September 2018 were retrospectively investigated. Clinical evaluations, including the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Tegner and Lysholm scores, were performed preoperatively and at 2 years postoperatively. The radiographic parameters hip-knee-ankle (HKA) angle, joint line convergence angle on standing radiographs (standing JLCA), and weightbearing line (WBL) ratio were assessed preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. To evaluate valgus laxity, we assessed the valgus JLCA and medial joint opening (MJO) at the aforementioned time points using valgus stress radiographs. RESULTS: All clinical results at the 2-year follow-up were significantly improved compared with those obtained at the preoperative assessment (P < .001). The postoperative HKA angle significantly differed from the preoperative one, and no significant valgus progression was observed during follow-up (preoperative, 8.5°± 2.7°; 3 months, -3.5°± 2.0°; 6 months, -3.2°± 2.3°; 1 year, -3.1°± 2.3°; 2 years, -2.9°± 2.5°; P < .001) The mean WBL ratio was 62.5% ± 9.0% at 2 years postoperatively. The postoperative valgus JLCA at all follow-up points did not significantly change compared with the preoperative valgus JLCA (preoperative, -0.1°± 2.1°; 3 months, -0.2°± 2.4°; 6 months, -0.1°± 2.5°; 1 year, 0.1°± 2.5°; 2 years, 0.2°± 2.2°) The postoperative MJO at all follow-up points did not significantly change compared with the preoperative MJO (preoperative, 7.1 ± 1.7 mm; 3 months, 7.0 ± 1.7 mm; 6 months, 6.9 ± 1.9 mm; 1 year, 6.7 ± 1.8 mm; 2 years, 6.8 ± 1.8 mm). CONCLUSION: Transection of the sMCL during MOWHTO does not increase valgus laxity and could yield desirable clinical and radiographic results.

Mast4 determines the cell fate of MSCs for bone and cartilage development.

Mesenchymal stromal cells (MSCs) differentiation into different lineages is precisely controlled by signaling pathways. Given that protein kinases play a crucial role in signal transduction, here we show that Microtubule Associated Serine/Threonine Kinase Family Member 4 (Mast4) serves as an important mediator of TGF-ß and Wnt signal transduction in regulating chondro-osteogenic differentiation of MSCs. Suppression of Mast4 by TGF-ß1 led to increased Sox9 stability by blocking Mast4-induced Sox9 serine 494 phosphorylation and subsequent proteasomal degradation, ultimately enhancing chondrogenesis of MSCs. On the other hand, Mast4 protein, which stability was enhanced by Wnt-mediated inhibition of GSK-3ß and subsequent Smurf1 recruitment, promoted ß-catenin nuclear localization and Runx2 activity, increasing osteogenesis of MSCs. Consistently, Mast4-/- mice demonstrated excessive cartilage synthesis, while exhibiting osteoporotic phenotype. Interestingly, Mast4 depletion in MSCs facilitated cartilage formation and regeneration in vivo. Altogether, our findings uncover essential roles of Mast4 in determining the fate of MSC development into cartilage or bone.

The opposing effects of CCN2 and CCN5 on the development of cardiac hypertrophy and fibrosis.

CCN family members are matricellular proteins with diverse roles in cell function. The differential expression of CCN2 and CCN5 during cardiac remodeling suggests that these two members of the CCN family play opposing roles during the development of cardiac hypertrophy and fibrosis. We aimed to evaluate the role of CCN2 and CCN5 in the development of cardiac hypertrophy and fibrosis. In isolated cardiomyocytes, overexpression of CCN2 induced hypertrophic growth, whereas the overexpression of CCN5 inhibited both phenylephrine (PE)- and CCN2-induced hypertrophic responses. Deletion of the C-terminal (CT) domain of CCN2 transformed CCN2 into a CCN5-like dominant negative molecule. Fusion of the CT domain to the Carboxy-terminus of CCN5 transformed CCN5 into a CCN2-like pro-hypertrophic molecule. CCN2 transgenic (TG) mice did not develop cardiac hypertrophy at baseline but showed significantly increased fibrosis in response to pressure overload. In contrast, hypertrophy and fibrosis were both significantly inhibited in CCN5 TG mice. CCN2 TG mice showed an accelerated deterioration of cardiac function in response to pressure overload, whereas CCN5 TG mice showed conserved cardiac function. TGF-beta-SMAD signaling was elevated in CCN2 TG mice, but was inhibited in CCN5 TG mice. CCN2 is pro-hypertrophic and -fibrotic, whereas CCN5 is anti-hypertrophic and -fibrotic. CCN5 lacking the CT domain acts as a dominant negative molecule. CCN5 may provide a novel therapeutic target for the treatment of cardiac hypertrophy and heart failure.

Atypical Femoral Shaft Fractures in Female Bisphosphonate Users Were Associated with an Increased Anterolateral Femoral Bow and a Thicker Lateral Cortex: A Case-Control Study.

The purpose of our study was to investigate the radiographic characteristics of atypical femoral shaft fractures (AFSFs) in females with a particular focus on femoral bow and cortical thickness. We performed a fracture location-, age-, gender-, and ethnicity-matched case-control study. Forty-two AFSFs in 29 patients and 22 typical osteoporotic femoral shaft fractures in 22 patients were enrolled in AFSF group and control group, respectively. With comparing demographics between two groups, radiographically measured femoral bow and cortical thicknesses of AFSF group were compared with control group. All AFSF patients were females with a mean age of 74.4 years (range, 58-85 years). All had a history of bisphosphonate (BP) use with a mean duration of 7.3 years (range 1-17 years). Femoral bow of AFSF group was significantly higher than control group on both anteroposterior (AP) and lateral radiographs after age correction. Mean femoral bow on an AP radiograph was 12.39° ± 5.38° in AFSF group and 3.97 ± 3.62° in control group (P < 0.0001). Mean femoral bow on the lateral radiograph was 15.71° ± 5.62° in AFSF group and 10.72° ± 4.61° in control group (after age correction P = 0.003). And cortical thicknesses of AFSF group demonstrated marked disparity between tensile and compressive side of bowed femurs in this study. An adjusted lateral cortical thickness was 10.5 ± 1.4 mm in AFSF group and 8.1 ± 1.3 mm in control group (after age correction P < 0.0001) while medial cortical thickness of AFSF group was not statistically different from control group. Correlation analysis showed that the lateral femoral bow on the AP radiograph was solely related to lateral CTI (R = 0.378, P = 0.002). AFSFs in female BP users were associated with an increased anterolateral femoral bow and a thicker lateral cortex of femurs.

YAP/TAZ regulates sprouting angiogenesis and vascular barrier maturation.

Angiogenesis is a multistep process that requires coordinated migration, proliferation, and junction formation of vascular endothelial cells (ECs) to form new vessel branches in response to growth stimuli. Major intracellular signaling pathways that regulate angiogenesis have been well elucidated, but key transcriptional regulators that mediate these signaling pathways and control EC behaviors are only beginning to be understood. Here, we show that YAP/TAZ, a transcriptional coactivator that acts as an end effector of Hippo signaling, is critical for sprouting angiogenesis and vascular barrier formation and maturation. In mice, endothelial-specific deletion of Yap/Taz led to blunted-end, aneurysm-like tip ECs with fewer and dysmorphic filopodia at the vascular front, a hyper-pruned vascular network, reduced and disarranged distributions of tight and adherens junction proteins, disrupted barrier integrity, subsequent hemorrhage in growing retina and brain vessels, and reduced pathological choroidal neovascularization. Mechanistically, YAP/TAZ activates actin cytoskeleton remodeling, an important component of filopodia formation and junction assembly. Moreover, YAP/TAZ coordinates EC proliferation and metabolic activity by upregulating MYC signaling. Overall, these results show that YAP/TAZ plays multifaceted roles for EC behaviors, proliferation, junction assembly, and metabolism in sprouting angiogenesis and barrier formation and maturation and could be a potential therapeutic target for treating neovascular diseases.

Recurrence of a Unicameral Bone Cyst in the Femoral Diaphysis.

Diaphyseal unicameral bone cysts of the long bone are generally known to originate near the growth plate and migrate from the metaphysis to the diaphysis during skeletal growth. In the case of unicameral bone cysts of diaphyseal origin, recurrence at the same location is extremely rare. We report a case of recurrence of a unicameral bone cyst in the diaphysis of the femur that developed 8 years after treatment with curettage and bone grafting. We performed bone grafting and lengthening of the affected femur with an application of the Ilizarov apparatus over an intramedullary nail to treat the cystic lesion and limb length discrepancy simultaneously.

A Decoy Peptide Targeted to Protein Phosphatase 1 Attenuates Degradation of SERCA2a in Vascular Smooth Muscle Cells.

Neointimal growth in the injured vasculature is largely facilitated by the proliferation of vascular smooth muscle cells (VSMC), which associates with reduced sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) activity. The gene transfer-mediated restoration of the SERCA2a level thus attenuates neointimal growth and VSMC proliferation. We previously reported that a peptide targeted to protein phosphatase 1, ψPLB-SE, normalizes SERCA2a activity in cardiomyocytes. In this study, we found that ψPLB-SE attenuated neointimal growth in balloon-injured rat carotid arteries, and the proliferation and migration of VSMC cultured in high-serum media (synthetic conditions). In parallel, ψPLB-SE inhibited the degradation of SERCA2a in the injured carotid arteries and VSMC under synthetic conditions. The calpain inhibitor MDL28170 also attenuated SERCA2a degradation and VSMC proliferation under synthetic conditions, indicating that calpain degrades SERCA2a. The Ca2+ ionophore A23187 induced SERCA2a degradation in VSMC, which was blocked by either ψPLB-SE or MDL28170. Additionally, ψPLB-SE normalized the cytosolic Ca2+ level in VSMC that was increased by either A23187 or synthetic stimulation. Collectively, these data indicate that ψPLB-SE corrects the abnormal Ca2+ handling by activating SERCA2a, which further protects SERCA2a from calpain-dependent degradation in VSMC. We conclude that ψPLB-SE may form the basis of a therapeutic strategy for vascular proliferative disorders.

Is Total Knee Arthroplasty a Viable Treatment Option in Octogenarians with Advanced Osteoarthritis?

PURPOSE: This study directly compared clinical assessment scores and short-term systemic complications after total knee arthroplasty (TKA) between a group of patients aged 80 or older (141 patients) and another group of patients aged between 65 and 70 years (616 patients) with advanced osteoarthritis. MATERIALS AND METHODS: We retrospectively investigated 757 osteoarthritic patients who underwent primary TKA from January 2007 to January 2011 with a follow-up of 1 year. The surgery was performed using an extramedullary alignment guide instrument without invasion of the intramedullary canal to decrease embolic load and blood loss. RESULTS: At 1 year after surgery, the mean Knee Society knee score was improved in both groups (from 63.6 to 83.2 in octogenarians and from 68.3 to 89.0 in the younger group) and the level of satisfaction was excellent in both groups (8 in octogenarians and 8.3 in the younger group), even though there was no notable change in function score in the octogenarians (from 61.0 to 61.9 in the octogenarians and from 62.3 to 73.6 in the younger group). The total incidence of systemic complications (3.4% vs. 1.2%, p=0.400) and surgical complications (2.1% vs. 0.5%, p=0.229) showed no significant difference between groups. CONCLUSIONS: TKA yielded favorable clinical outcomes with a comparatively low postoperative complication rate in octogenarians despite the negligible functional improvement.

NQO1 activation regulates angiotensin-converting enzyme shedding in spontaneously hypertensive rats.

AIMS: Angiotensin-converting enzyme (ACE) plays a key role in blood pressure (BP) homeostasis via regulation of angiotensin II. Active ACE ectodomain is enzymatically cleaved and released into body fluids, including plasma, and elevated plasma ACE levels are associated with increased BP. ß-lapachone (ßL) has been shown to increase cellular NAD(+)/NADH ratio via activation of NAD(P)H:quinone oxidoreductase 1 (NQO1). In this study, we evaluated whether NQO1 activation by ßL modulates BP through regulation of ACE shedding in an animal model of hypertension. METHODS AND RESULTS: Spontaneously hypertensive rats (SHR) and a human ACE-overexpressing rat lung microvascular endothelial cell line (RLMVEC-hACE) were used to investigate the mechanism by which ßL exerts a hypotensive effect. In vitro studies revealed that ßL significantly increased intracellular Ca(2+) ([Ca(2+)]i) levels and CaMKII Thr(286) phosphorylation, followed by diminished ACE cleavage secretion into culture media. Inhibition of ßL-induced [Ca(2+)]i level changes through intracellular Ca(2+) chelation, Nqo1-specific siRNA or ryanodine receptor blockade abolished not only ßL-induced increase in [Ca(2+)]i levels and CaMKII phosphorylation, but also ßL-mediated decrease in ACE shedding. The effect of ßL on ACE shedding was also blocked by inhibition of CaMKII. In SHR, ßL reduced BP following increase of CaMKII Thr(286) phosphorylation in the lung and decrease of ACE activity and angiotensin II levels in plasma. CONCLUSION: This is the first study demonstrating that ACE shedding is regulated by NQO1 activation, which is possibly correlated with relieving hypertension in SHR. These findings provide strong evidence suggesting that NQO1 might be a new target for ACE modulation and BP control.

Feasibility of whole-body MRI for detecting metastatic myxoid liposarcoma: a case series.

No feasible method currently exists to evaluate systemic metastasis in patients with myxoid liposarcoma. The purpose of this study was to determine the feasibility of performing whole-body magnetic resonance imaging (MRI) to detect metastatic myxoid liposarcoma. From June 2008 to May 2010, all patients who were newly diagnosed with myxoid liposarcomas at our institution underwent whole-body MRI along with other conventional imaging methods. We divided the whole body into 38 sections (7 soft tissue sections and 31 bone tissue sections). In total, there were 570 regions (105 soft tissue regions and 465 bony regions) in 15 patients (10 men and 5 women) who underwent whole-body MRI.Of 105 soft tissue regions, there were 4 true positives, 3 false positives, 1 false negative, and 97 true positives. Of 465 bone tissue regions, there were 11 true positives, 5 false positives, 2 false negatives, and 447 true negatives. In soft tissue, whole-body MRI for the detection of metastatic lesion showed a sensitivity of 80%, a specificity of 97.0%, a positive predictive value of 57.1%, and a negative predictive value of 99.0%. In bone tissue, whole-body MRI had a sensitivity of 84.6%, a specificity of 98.9%, a positive predictive value of 68.8%, and a negative predictive value of 99.6%.Whole-body MRI is feasible and effective for detecting bone and soft tissue metastasis in patients with myxoid liposarcoma.

Parathyroid hormone accelerates decompensation following left ventricular hypertrophy.

Parathyroid hormone (PTH) treatment was previously shown to improve cardiac function after myocardial infarction by enhancing neovascularization and cell survival. In this study, pressure overload-induced left ventricular hypertrophy (LVH) was induced in mice by transverse aortic banding (TAB) for 2 weeks. We subsequently evaluated the effects of a 2-week treatment with PTH or saline on compensated LVH. After another 4 weeks, the hearts of the mice were analyzed by echocardiography, histology, and molecular biology. Echocardiography showed that hearts of the PTH-treated mice have more severe failing phenotypes than the saline-treated mice following TAB with a greater reduction in fractional shortening and left ventricular posterior wall thickness and with a greater increase in left ventricular internal dimension. Increases in the heart weight to body weight ratio and lung weight to body weight ratio following TAB were significantly exacerbated in PTH-treated mice compared to saline-treated mice. Molecular markers for heart failure, fibrosis, and angiogenesis were also altered in accordance with more severe heart failure in the PTH-treated mice compared to the saline-treated mice following TAB. In addition, the PTH-treated hearts were manifested with increased fibrosis accompanied by an enhanced SMAD2 phosphorylation. These data suggest that the PTH treatment may accelerate the process of decompensation of LV, leading to heart failure.