The identification of 7-[(R)-2-((1S,2S)-2-benzyloxycyclopentylamino)-1-hydroxyethyl]-4-hydroxybenzothiazolone as an inhaled long-acting β2-adrenoceptor agonist

The optimisation of two series of 4-hydroxybenzothiazolone derived β₂-adrenoceptor agonists, bearing α-substituted cyclopentyl and β-phenethyl amino-substituents, as inhaled long-acting bronchodilators is described. Analogues were selected for synthesis using a lipophilicity based hypothesis to achieve the targeted rapid onset of action in combination with a long duration of action. The profiling of the two series led to identification of the α-substituted cyclopentyl analogue 2 as the optimal compound with a comparable profile to the inhaled once-daily long-acting β₂-adrenoceptor agonist indacaterol. On the basis of these data 2 was promoted as the backup development candidate to indacaterol from the Novartis LABA project.     

Computational analysis of pediatric ventricular assist device implantation to decrease cerebral particulate embolization

Stroke is the most devastating complication after ventricular assist device (VAD) implantation with a 19% incidence and 65% mortality in the pediatric population. Current pediatric VAD technology and anticoagulation strategies alone are suboptimal. VAD implantation assisted by computational methods (CFD) may contribute reducing the risk of cerebral embolization. Representative three-dimensional aortic arch models of an infant and a child were generated. An 8 mm VAD outflow-graft (VAD-OG) anastomosed to the aorta was rendered and CFD was applied to study blood flow patterns. Particle tracks, originating in the VAD, were computed with a Lagrangian phase model and the percentage of particles entering the cerebral vessels was calculated. Eight implantation configurations (infant = 5 and child = 3) and 5 particle sizes (0.5, 1, 2, 3, and 4 mm) were considered. For the infant model, percentage of particles entering the cerebral vessels ranged from 15% for a VAD-OG anastomosed at 90° to the aorta, to 31% for 30° VAD-OG anastomosis (overall percentages: X² = 10,852, p < 0.0001). For the child model, cerebral embolization ranged from 9% for the 30° VAD-OG anastomosis to 15% for the 60° anastomosis (overall percentages: χ² = 10,323, p < 0.0001). Using detailed CFD calculations, we demonstrate that the risk of stroke depends significantly on the VAD implantation geometry. In turn, the risk probably depends on patient-specific anatomy. CFD can be used to optimize VAD implantation geometry to minimize stroke risk.     

Design and synthesis of sulfonamidophenylethylamides as novel cardiac myosin activator

The sulfonamidophenylethylamide analogues were explored for finding novel and potent cardiac myosin activators. Among them, N-(4-(N,N-dimethylsulfamoyl)phenethyl-N-methyl-5-phenylpentanamide (13, CMA at 10 µM = 48.5%; FS = 26.21%; EF = 15.28%) and its isomer, 4-(4-(N,N-dimethylsulfamoyl)phenyl-N-methyl-N-(3-phenylpropyl)butanamide (27, CMA at 10 µM = 55.0%; FS = 24.69%; EF = 14.08%) proved to be efficient cardiac myosin activators both in in vitro and in vivo studies. Compounds 13 (88.2 + 3.1% at 5 µM) and 27 (46.5 + 2.8% at 5 µM) showed positive inotropic effect in isolated rat ventricular myocytes. The potent compounds 13 and 27 were highly selective for cardiac myosin over skeletal and smooth muscle myosin, and therefore these potent and selective amide derivatives could be considered a new class of cardiac myosin activators for the treatment of systolic heart failure.     

Exercise training in chronic heart failure: mechanisms and therapies

Decreased exercise capacity negatively affects the individuals’ ability to adequately perform activities required for normal daily life and, therefore, the independence and quality of life. Regular exercise training is associated with improved quality of life and survival in healthy individuals and in cardiovascular disease patients. Also in patients with stable heart failure, exercise training can relieve symptoms, improve exercise capacity and reduce disability, hospitalisation and probably mortality. Physical inactivity can thus be considered a major cardiovascular risk factor, and current treatment guidelines recommend exercise training in patients with heart failure in NYHA functional classes II and III. Exercise training is associated with numerous pulmonary, cardiovascular, and skeletal muscle metabolic adaptations that are beneficial to patients with heart failure. This review discusses current knowledge of mechanisms by which exercise training is beneficial in these patients.     

p38α MAPK regulates myocardial regeneration in zebrafish

Although adult mammals are unable to significantly regenerate their heart, this is not the case for a number of other vertebrate species. In particular, zebrafish are able to fully regenerate their heart following amputation of up to 20% of the ventricle. Soon after amputation, cardiomyocytes dedifferentiate and proliferate to regenerate the missing tissue. More recently, identical results have also been obtained in neonatal mice. Ventricular amputation of neonates leads to a robust regenerative response driven by the proliferation of existing cardiomyocytes in a similar manner to zebrafish. However, this ability is progressively lost during the first week of birth. The fact that adult zebrafish retain the capacity to regenerate their heart suggests that they either possess a unique regenerative mechanism, or that adult mammals lose/ inhibit this process. p38α ΜAPK has previously been shown to negatively regulate the proliferation of adult mammalian cardiomyocytes. We sought to determine whether a similar mechanism exists in adult zebrafish, and whether this needs to be overcome to allow regeneration to proceed. To determine whether p38α ΜAPK also regulates zebrafish cardiomyocytes in a similar manner, we generated conditional transgenic zebrafish in which either dominant-negative or active p38α ΜAPK are specifically expressed in cardiomyocytes. We found that active p38α ΜAPK but not dominantnegative p38α ΜAPK blocks proliferation of adult zebrafish cardiomyocytes and, consequently, heart regeneration as well. It appears that adult zebrafish cardiomyocytes share many characteristics with adult mammalian cardiomyocytes, including p38α MAPK-mediated cell cycle inhibition. These findings raise the possibility that zebrafish-like heart regeneration could be achieved in adult mammals.     

Tetraploid cells from cytokinesis failure induce aneuploidy and spontaneous transformation of mouse ovarian surface epithelial cells

Most ovarian cancers originate from the ovarian surface epithelium and are characterized by aneuploid karyotypes. Aneuploidy, a consequence of chromosome instability, is an early event during the development of ovarian cancers. However, how aneuploid cells are evolved from normal diploid cells in ovarian cancers remains unknown. In the present study, cytogenetic analyses of a mouse syngeneic ovarian cancer model revealed that diploid mouse ovarian surface epithelial cells (MOSECs) experienced an intermediate tetraploid cell stage, before evolving to aneuploid (mainly near-tetraploid) cells. Using long-term live-cell imaging followed by fluorescence in situ hybridization (FISH), we demonstrated that tetraploid cells originally arose from cytokinesis failure of bipolar mitosis in diploid cells, and gave rise to aneuploid cells through chromosome mis-segregation during both bipolar and multipolar mitoses. Injection of the late passage aneuploid MOSECs resulted in tumor formation in C57BL/6 mice. Therefore, we reveal a pathway for the evolution of diploid to aneuploid MOSECs and elucidate a mechanism for the development of near-tetraploid ovarian cancer cells.     

Polo-like kinase 1 (Plk1) is expressed by cutaneous T-cell lymphomas (CTCLs), and its downregulation promotes cell cycle arrest and apoptosis

Polo-like kinases are serine/threonine kinases crucial for mitosis and DNA integrity. Plk1, the most well studied member of this family, is upregulated in several cancers, as well as in dividing cells with peak expression during G2/M phase. Recently, employing lesional skin from patients with cutaneous T-cell lymphoma (CTCL), we showed that Plk1 was increased mainly in advanced lesions. In this study, employing western blot and quantitative RT-PCR analyses, we demonstrated that Plk1 was overexpressed in multiple CTCL cell lines (HH, Hut78, MyLa, SeAx and SZ4). Further, a genetic knockdown (by short hairpin RNA) or enzyme activity inhibition (via a small molecule inhibitor, GW843682X) was found to result in a decrease in cell growth, viability and proliferation. Plk1 inhibition in CTCL cells also resulted in: (1) increased G2/M phase cell cycle arrest, (2) alteration in key mitotic proteins, (3) apoptosis and (4) multiple mitotic errors. Given our findings, clinical trials of Plk1 inhibitors in CTCL may be a promising area for further translational investigation. We speculate that overexpression of Plk1 may prove to be relevant to the progression and prognosis of CTCL through its direct impact on the regulation of tumor cell proliferation and indirect influence on the acquisition of somatic mutations by proliferating tumor cells.     

Bone remodelling around the tibia due to total ankle replacement: effects of implant material and implant–bone interfacial conditions

Abstract

One of the major causes of implant loosening is due to excessive bone resorption surrounding the implant due to bone remodelling. The objective of the study is to investigate the effects of implant material and implant–bone interface conditions on bone remodelling around tibia bone due to total ankle replacement. Finite element models of intact and implanted ankles were developed using CT scan data sets. Bone remodelling algorithm was used in combination with FE analysis to predict the bone density changes around the ankle joint. Dorsiflexion, neutral, and plantar flexion positions were considered, along with muscle force and ligaments. Implant–bone interfacial conditions were assumed as debonded and bonded to represent non-osseointegration and fully osseointegration at the porous coated surface of the implant. To investigate the effect of implant material, three finite element models having different material combinations of the implant were developed. For model 1, tibial and talar components were made of Co–Cr–Mo, and meniscal bearing was made of UHMWPE. For model 2, tibial and talar components were made of ceramic and meniscal bearing was made of UHMWPE. For model 3, tibial and talar components were made of ceramic and meniscal bearing was made of CFR-PEEK. Changes in implant material showed no significant changes in bone density due to bone remodelling. Therefore, ceramic appears to be a viable alternative to metal and CFR-PEEK can be used in place of UHMWPE. This study also indicates that proper bonding between implant and bone is essential for long-term survival of the prosthetic components.     

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR_60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR_60s (p <0.05) and in the non linear analysis of HRV from SD1_30-45s (p <0.05) and SD1_45-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.     

Effect of MCI-186 on Postischemic Reperfusion Injury in Isolated Rat Heart

MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-one) is a newly developed antioxidant which has been shown to reduce brain edema in cerebral ischemia through inhibition of the lipoxygenase pathway of arachidonic acid. However, its effect on myocardial reperfusion injury after prolonged ischemia has not yet been demonstrated. We compared the mode of the effect of MCI-186 and recombinant human CuZn superoxide dismutase (rh-SOD) in isolated perfused rat hearts subjected to 60-min ischemia followed by 60-min reperfusion. Left ventricular developed pressure (LVDP), necrotic area and the release of creatine phosphokinase (CPK) and endogenous CuZn superoxide dismutase (endoge-SOD) were measured to evaluate myocardial damage. The decrease in left coronary flow (CBF) was measured as an index of the damage of left coronary circulation. MCI-186 (17.5 mg/L) was perfused for 10 min in the MCI group and rh-SOD (70 mg/L) was perfused during the reperfusion period in the SOD group starting 5 min prior to reperfusion. The release patterns of CPK and endoge-SOD were analyzed to elucidate the difference in the mode of protection of MCI-186 and rh-SOD. The LVDP remained higher in both MCI and SOD groups than that of control (76 ± 1, 77 ± 2 and 69 ± 1% of preischemic value, respectively). The necrotic area was significantly attenuated in both MCI and SOD groups compared with that in the control group (16 ± 1,14 ± 1 and 32 ± 170, respectively, p<0.05). Total CPK release was lower in both MCI and SOD groups thfn in the control (78 ± 7, 100 ± 2 and 116 ± 4 × 10³ units/g myocardium respectively). The decrease in CPK release was more marked in the MCI group than that in the SOD group (p<0.05). The reduction in CBF was significantly attenuated by the treatment with rh-SOD or MCI-186, but the effect was much higher in the SOD group than in the MCI group (69 ± 5, 58 ± 2, and 48 ± 2% in SOD, MCI and control groups, respectively). The release pattern of endoge-SOD was identical to that of CPK and thus this did not distinguish the mode of effect of MCI-186 from that of rh-SOD. These results indicate that MCI-186 reduces reperfusion injury in isolated perfused hearts with prolonged ischemia and the effect is more closely related to the reduction of myocyte damage than the preservation of the coronary circulation.