Thrombospondin-4 (TSP-4) expression increases dramatically in hypertrophic and failing hearts in rodent models and in humans. The aim of this study was to address the function of TSP-4 in the heart. TSP-4-knockout (Thbs4(-/-)) and wild-type (WT) mice were subjected to transverse aortic constriction (TAC) to increase left ventricle load. After 2 wk, Thbs4(-/-) mice had a significantly higher heart weight/body weight ratio than WT mice. The additional increase in the heart weight in TAC Thbs4(-/-) mice was due to increased deposition of extracellular matrix (ECM). The levels of interstitial collagens were higher in the knockout mice, but the size of cardiomyocytes and apoptosis in the myocardium was unaffected by TSP-4 deficiency, suggesting that increased reactive fibrosis was the primary cause of the higher heart weight. The increased ECM deposition in Thbs4(-/-) mice was accompanied by changes in functional parameters of the heart and decreased vessel density. The expression of inflammatory and fibrotic genes known to be influential in myocardial remodeling changed as a result of TSP-4 deficiency in vivo and as a result of incubation of cells with recombinant TSP-4 in vitro. Thus, TSP-4 is involved in regulating the adaptive responses of the heart to pressure overload, suggesting its important role in myocardial remodeling. Our study showed a direct influence of TSP-4 on heart function and to identify the mechanism of its effects on heart remodeling.

Objective To investigate the modified frailty index (mFI) as a pre-operative predictor of post-operative complications following radical cystectomy in bladder cancer patients. Materials and Methods Patients undergoing radical cystectomy (RC) were identified from the National Surgical Quality Improvement Program (NSQIP) participant use files (2011-2013). The mFI was defined in prior studies with 11 variables based on mapping the Canadian Study of Health and Aging Frailty Index to NSQIP comorbidities and activities of daily living (ADL)s. Modified frailty index groups were determined by the number of risk factors per patient (0, 1, 2, ≥3). Univariate, χ2, independent sample t-test, and logistic regression analyses were performed when appropriate. A sensitivity analysis was performed to determine the mFI value at which Clavien 4 and 5 complications would reach significance. Results Of the 2679 cystectomy patients identified, 31% percent of patients had a mFI of 0, 44% had a mFI of 1, 21% had a mFI of 2, and 4% had a mFI ≥ 3. Overall, 59% of patients experienced a Clavien complication. When stratified at a cutoff of mFI >=2, the overall complication rate was not different (61.7% vs. 58.3%, p=0.1319), but the mFI2 or greater group had a significantly higher rate of Clavien grade 4 or 5 complications (14.6% vs. 8.3%, p<0.001) and overall mortality rate (3.5% vs. 1.8%, p=0.0128) in the 30-day post-operative period. The multivariate logistic regression model showed independent predictors of Clavien grade 4 or 5 complications were age >80 years old (OR, 1.58 [1.11-2.27]), mFI2 (odds ratio [OR], 1.84 [1.28-2.64]), and mFI3 (OR, 2.58 [1.47-4.55]). Conclusions Among patients undergoing radical cystectomy, the mFI can identify those patients at greatest risk for severe complications and mortality. Given that bladder cancer is increasing in prevalence particularly among the elderly, pre-operative risk stratification is crucial to inform decision making about surgical candidacy.

Myocardial remodeling is a major contributor in the development of heart failure (HF) after myocardial infarction (MI). Integrin-linked kinase (ILK), LIM-only adaptor PINCH-1, and α-parvin are essential components of focal adhesions (FAs), which are highly expressed in the heart. ILK binds tightly to PINCH-1 and α-parvin, which regulates FA assembly and promotes cell survival via the activation of the kinase Akt. Mice lacking ILK, PINCH or α-parvin have been shown to develop severe defects in the heart, suggesting that these proteins play a critical role in heart function. Utilizing failing human heart tissues (dilated cardiomyopathy, DCM), we found a 2.27-fold (p<0.001) enhanced expression of PINCH, 4 fold for α-parvin, and 10.5 fold (p<0.001) for ILK as compared to non-failing (NF) counterparts. No significant enhancements were found for the PINCH isoform PINCH-2 and parvin isoform β-parvin. Using a co-immunoprecipitation method, we also found that the PINCH-1-ILK-α-parvin (PIP) complex and Akt activation were significantly up-regulated. These observations were further corroborated with the mouse myocardial infarction (MI) and transaortic constriction (TAC) model. Thymosin beta4 (Tβ4), an effective cell penetrating peptide for treating MI, was found to further enhance the level of PIP components and Akt activation, while substantially suppressing NF-κB activation and collagen expression—the hallmarks of cardiac fibrosis. In the presence of an Akt inhibitor, wortmannin, we show that Tβ4 had a decreased effect in protecting the heart from MI. These data suggest that the PIP complex and activation of Akt play critical roles in HF development. Tβ4 treatment likely improves cardiac function by enhancing PIP mediated Akt activation and suppressing NF-κB activation and collagen-mediated fibrosis. These data provide significant insight into the role of the PIP-Akt pathway and its regulation by Tβ4 treatment in post-MI.

Two-dimensional (2-D) speckle tracking echocardiography (STE) accurately quantifies circumferential strain (S(circ)) and radial strain (S(rad)) in humans and in large and small animals. This study was performed to assess sensitivity of S(circ) and S(rad) to left ventricular (LV) dysfunction in mouse models. We performed 2-D and M-mode echocardiography 1) in 6 mice during superficial and profound isoflurane anesthesia, 2) serially in 12 mice to monitor the development of heart failure induced by transverse aortic constriction (TAC) and in 8 corresponding control mice, and 3) in 26 mice with varying degrees of TAC-induced heart failure and 12 corresponding control mice immediately before euthanasia. Fractional shortening (FS) and LV mass were measured from standard M-mode tracings, whereas S(circ) and S(rad) were derived by STE. Percent fibrosis and myocyte diameters were assessed from whole heart cross-sectional specimens stained by Masson trichrome. Profound isoflurane anesthesia decreased S(circ) (P = 0.027) but not S(rad) (P > 0.05). Mice subjected to TAC showed an immediate and sustained decrease in FS (P = 0.035), S(circ) (P = 0.016), and S(rad) (P = 0.012). S(circ) showed better correlation with FS (r = 0.56 and P < 0.0001) and LV mass (r = 0.42 and P = 0.0003) than S(rad) (r = 0.54 and P < 0.0001 for FS and r = 0.37 and P = 0.014 for LV mass, respectively). Percent fibrosis correlated better with S(circ) (r = 0.46 and P = 0.004) than with S(rad) (r = -0.32 and P = 0.05), whereas myocyte diameter showed similar correlation with both strains (r = 0.45 and r = -0.44, respectively, and P = 0.006 for both). STE correctly identifies LV dysfunction and histological changes in mice and can be used for the serial assessment of cardiac remodeling in murine models.

Erectile dysfunction (ED) is a common disorder that affects a quarter of US men, and has many causes, including endothelial impairment, low testosterone levels, prior surgical manipulation, and/or psychogenic components. Penile erection is a complex process requiring neurally mediated relaxation of arteriolar smooth muscle and engorgement of cavernosal tissues, mediated by nitric oxide (NO). Current medical therapies for ED largely seek to maximize endogenous NO signalling. Certain aetiologies, including diabetes, are difficult to treat with current modalities, emphasizing the need for new molecular targets. Research has demonstrated the importance of RhoA–Rho-associated protein kinase (ROCK) signalling in maintaining a flaccid penile state, and inhibition of RhoA–ROCK signalling potentiates smooth-muscle relaxation in an NO-independent manner. The mechanisms and effects of RhoA–ROCK signalling and inhibition suggest that the RhoA–ROCK pathway could prove to be a new therapeutic target for the treatment of ED.