Inhibition of CaMKII Attenuates Progressing Disruption of Ca2+ Homeostasis Upon Left Ventricular Assist Device Implantation in Human Heart Failure

In heart failure, left ventricular assist device (LVAD) implantation is performed to ensure sufficient cardiac output. Whereas some patients are subsequently weaned from LVAD support, other patients still need heart transplantation. To elucidate underlying mechanisms, we assessed the arrhythmogenic SR‐Ca²⁺ leak at the time of LVAD implantation (HF‐Im) and heart transplantation (HF‐Tx) and evaluated the effects of CaMKII‐inhibition. Human left‐ventricular cardiomyocytes were isolated, paced at 1 Hz for 10 beats to ensure SR‐Ca²⁺ loading and scanned for diastolic Ca²⁺ sparks (confocal microscopy). In HF‐Im, the high diastolic spark frequency (CaSpF) of 0.76 ± 0.12 × 100 μm^?1 × s^?1 could be reduced to 0.48 ± 0.10 × 100 μm^?1 × s^?1 by CaMKII inhibition (AIP, 1 μM). The amplitude of Ca²⁺ sparks, width, and length was not significantly altered. In sum, CaMKII inhibition yielded a clear tendency toward a reduction of the SR‐Ca²⁺ leak (n cells/patients = 76/6 vs. 108/6, P = 0.08). In HF‐Tx, we detected an even higher CaSpF of 1.00 ± 0.10 100 μm^?1 × s^?1 and a higher SR‐Ca²⁺ leak compared with HF‐Im (increase by 81 ± 33%, n cells/patients = 156/7 vs. 130/7, P < 0.05), which fits to the further decreased LV function. Here, CaMKII inhibition likewise reduced CaSpF (0.35 ± 0.09 100 μm^?1 × s^?1, P = 0.06) and significantly reduced spark duration (n sparks/patients = 58/3 vs. 159/3, P < 0.05). Conclusively, the SR‐Ca²⁺ leak was reduced by 69 ± 12% in HF‐Tx upon CaMKII inhibition (n cells/patients = 53/3 vs. 91/3, P < 0.05). These data show that the SR‐Ca²⁺ leak correlates with the development of LV function after LVAD implantation and may represent an important pathomechanism. The fact that CaMKII inhibition reduces the SR‐Ca²⁺ leak in HF‐Tx suggests that CaMKII inhibition may be a promising option to beneficially influence clinical course after LVAD implantation.     

Physical Activity,Decision-Making Abilities,and Eating Disturbances in Pre- and Postbariatric Surgery Patients

Background

Physical activity (PA) is considered to have a beneficial influence on executive functioning, including decision-making. Enhanced decision-making after bariatric surgery may strengthen patients’ ability to delay gratification, helping to establish appropriate eating behavior. The objectives of this study were to (1) compare a preoperative group with a postoperative group with regard to daily PA, decision-making, and eating disturbances; and (2) investigate the relationship between these variables.

Methods

The study included 71 bariatric surgery candidates (55 % women, BMI [kg/m²] M?=?46.9, SD?=?6.0) and 73 postoperative patients (57 % women, BMI M?=?32.0, SD?=?4.1; 89 % Roux-en-Y gastric bypass, 11 % sleeve gastrectomy; months postoperative M?=?8.2, SD?=?3.5; total weight loss [%] M?=?33.2, SD?=?8.9) who completed SenseWear Pro₂ activity monitoring. Decision-making was assessed using a computerized version of the Iowa Gambling Task and eating disorder psychopathology using the Eating Disorder Examination-Questionnaire.

Results

The number of patients who were classified as physically inactive was similarly high in the pre- and postoperative groups. No group differences emerged with regard to decision-making, but the postoperative group exhibited less eating disturbances than the preoperative group. No significant associations were found between PA, decision-making, and eating behavior.

Conclusions

Patients after bariatric surgery were not more physically active than bariatric surgery candidates, which should be considered in care programs. Additionally, future research is needed to explore the possible link between PA, patients’ decision-making abilities, and eating disturbances concerning dose-response questions.

     

Tissue thiamine deficiency as potential cause of delayed graft function after kidney transplantation: thiamine supplementation of kidney donors may improve transplantation outcome

Delayed graft function is an important medical problem after renal transplantation. It occurs in approximately 30% of cases, and is not only associated with more prolonged and complicated hospitalisation, but also with earlier graft loss on the long-term. Delayed graft function is the consequence of acute tubular necrosis caused by ischaemia-reperfusion injury, with insufficiently opposed toxic effects of reactive oxygen species and insufficient ATP regeneration. An optimal tissue thiamine status is pivotal for scavenging of reactive oxygen species and regeneration of ATP. There are several reasons to suppose that tissue thiamine availability is suboptimal in donor kidneys prior to reperfusion in transplantation. These reasons include a high prevalence of untreated thiamine deficiency at admission of donors to intensive care units, quick exhaustion of body thiamine stores during periods of non-feeding or inappropriate feeding during hospital stays of donors, and loss of the water-soluble vitamin into water-based organ preservation solutions. We therefore hypothesize that a suboptimal tissue thiamine status is a cause of delayed graft function after renal transplantation, and that it can be prevented with thiamine supplementation.     

Superoxide dismutases of heavy metal resistant streptomycetes

Heavy metal tolerant and resistant strains of streptomycetes isolated from a former uranium mining site were screened for their superoxide dismutase expression. From the strains tolerating high concentrations of different heavy metals, one was selected for its tolerance of concentrations of heavy metals (Ni, Cu, Cd, Cr, Mn, Zn, Fe). This strain, Streptomyces acidiscabies E13, was chosen for the purpose of superoxide dismutase analysis. Gel electrophoresis and activity staining revealed only one each of a nickel (NiSOD) and an iron (FeZnSOD) containing superoxide dismutase as shown by differential enzymatic repression studies. The gene for nickel containing superoxide dismutase, sodN, was cloned and sequenced from this strain. The genomic sequence shows 92.7% nucleotide identity and 96.1% amino acid identity to sodN of S. coelicolor. Expression can be activated by nickel as well as other heavy metals and active enzyme is produced in media lacking nickel but containing copper, iron or zinc. Thus, the selected strain is well suited for further characterization of the enzyme encoded by sodN.     

Vaccinia virus double-stranded RNA-binding protein E3 does not interfere with siRNA-mediated gene silencing in mammalian cells

Vaccinia virus (VACV) evolved several strategies to evade antiviral cellular defence. The vaccinia virus E3 protein for example binds and sequesters double stranded RNA (dsRNA) and counteracts interferon action. We were interested to find out whether and to what extend E3 interferes with RNA silencing mediated by short interfering RNA (siRNA) in mammalian cells. We could show that the expression of a VACV-encoded marker gene can be efficiently inhibited by siRNA independently of the presence of the E3 protein. In addition, expression of E3 had no impact on RNA polymerase III promoter-derived shRNA-induced silencing of a cellular gene in human cells. Both VACV early and late gene expression could be inhibited by siRNA. Furthermore, downregulation of the expression of the E3L gene itself by siRNA in VACV infected cells produced the previously described phenotype of a knock-out virus, which illustrates the power of siRNA for vaccinia virus gene function analysis.     

Dolosigranulum pigrum causing nosocomial pneumonia and septicemia

We report a case of non-ventilator-associated nosocomial pneumonia and septicemia due to Dolosigranulum pigrum, a rare gram-positive opportunistic pathogen. The organism was isolated from bronchoalveolar lavage fluid and blood of a debilitated patient. D. pigrum was identified after 16S rRNA gene sequencing.     

Expression sites of the collectin SP-D suggest its importance in first line host defence: power of combining in situ hybridisation, RT-PCR and immunohistochemistry

Surfactant proteins A and D are pattern recognition molecules that play a role in pulmonary host defence. In this paper, we describe for the first time the expression and localisation of both collectins in various porcine tissues using a combination of in situ hybridisation (ISH), RT-PCR and immunohistochemistry (IHC). SP-D was expressed in several tissues including lung, tongue, intestinal tract, thymus, skin, gall bladder and lacrimal gland. Focal SP-D expression was detected in oesophagus, stomach, kidney, liver, prostate and spleen with both histological techniques. These tissues tested negative with RT-PCR. In contrast, SP-A expression was limited to the lung as measured by ISH and IHC. Interestingly, analysis by RT-PCR showed that thymus, trachea, jejunum and duodenum are positive for the presence of SP-A mRNA. We conclude that the combination of different methods can be advantageous if tissue-specific expression is studied. The importance of SP-D in innate immune defence of the pig is underlined by its expression at the potential ports of entry of pathogens.