Protein kinase D1 is essential for contraction-induced glucose uptake but is not involved in fatty acid uptake into cardiomyocytes

Increased contraction enhances substrate uptake into cardiomyocytes via translocation of the glucose transporter GLUT4 and the long chain fatty acid (LCFA) transporter CD36 from intracellular stores to the sarcolemma. Additionally, contraction activates the signaling enzymes AMP-activated protein kinase (AMPK) and protein kinase D1 (PKD1). Although AMPK has been implicated in contraction-induced GLUT4 and CD36 translocation in cardiomyocytes, the precise role of PKD1 in these processes is not known. To study this, we triggered contractions in cardiomyocytes by electric field stimulation (EFS). First, the role of PKD1 in GLUT4 and CD36 translocation was defined. In PKD1 siRNA-treated cardiomyocytes as well as cardiomyocytes from PKD1 knock-out mice, EFS-induced translocation of GLUT4, but not CD36, was abolished. In AMPK siRNA-treated cardiomyocytes and cardiomyocytes from AMPKα2 knock-out mice, both GLUT4 and CD36 translocation were abrogated. Hence, unlike AMPK, PKD1 is selectively involved in glucose uptake. Second, we analyzed upstream factors in PKD1 activation. Cardiomyocyte contractions enhanced reactive oxygen species (ROS) production. Using ROS scavengers, we found that PKD1 signaling and glucose uptake are more sensitive to changes in intracellular ROS than AMPK signaling or LCFA uptake. Furthermore, silencing of death-activated protein kinase (DAPK) abrogated EFS-induced GLUT4 but not CD36 translocation. Finally, possible links between PKD1 and AMPK signaling were investigated. PKD1 silencing did not affect AMPK activation. Reciprocally, AMPK silencing did not alter PKD1 activation. In conclusion, we present a novel contraction-induced ROS-DAPK-PKD1 pathway in cardiomyocytes. This pathway is activated separately from AMPK and mediates GLUT4 translocation/glucose uptake, but not CD36 translocation/LCFA uptake.     

Overexpression of Vesicle-associated Membrane Protein (VAMP) 3, but Not VAMP2, Protects Glucose Transporter (GLUT) 4 Protein Translocation in an in Vitro Model of Cardiac Insulin Resistance

Cardiac glucose utilization is regulated by reversible translocation of the glucose transporter GLUT4 from intracellular stores to the plasma membrane. During the onset of diet-induced insulin resistance, elevated lipid levels in the circulation interfere with insulin-stimulated GLUT4 translocation, leading to impaired glucose utilization. Recently, we identified vesicle-associated membrane protein (VAMP) 2 and 3 to be required for insulin- and contraction-stimulated GLUT4 translocation, respectively, in cardiomyocytes. Here, we investigated whether overexpression of VAMP2 and/or VAMP3 could protect insulin-stimulated GLUT4 translocation under conditions of insulin resistance. HL-1 atrial cardiomyocytes transiently overexpressing either VAMP2 or VAMP3 were cultured for 16 h with elevated concentrations of palmitate and insulin. Upon subsequent acute stimulation with insulin, we measured GLUT4 translocation, plasmalemmal presence of the fatty acid transporter CD36, and myocellular lipid accumulation. Overexpression of VAMP3, but not VAMP2, completely prevented lipid-induced inhibition of insulin-stimulated GLUT4 translocation. Furthermore, the plasmalemmal presence of CD36 and intracellular lipid levels remained normal in cells overexpressing VAMP3. However, insulin signaling was not retained, indicating an effect of VAMP3 overexpression downstream of PKB/Akt. Furthermore, we revealed that endogenous VAMP3 is bound by the contraction-activated protein kinase D (PKD), and contraction and VAMP3 overexpression protect insulin-stimulated GLUT4 translocation via a common mechanism. These observations indicate that PKD activates GLUT4 translocation via a VAMP3-dependent trafficking step, which pathway might be valuable to rescue constrained glucose utilization in the insulin-resistant heart.     

Percutaneous coronary intervention versus medical therapy for chronic total coronary occlusions: a systematic review and meta-analysis of randomised trials

Background

The results of chronic total occlusion percutaneous coronary intervention (CTO-PCI) trials are inconclusive. Therefore, we studied whether CTO-PCI leads to improvement of clinical endpoints and patient symptoms when combining all available randomised data.

Methods and results

This meta-analysis was registered in PROSPERO prior to starting. We performed a literature search and identified all randomised trials comparing CTO-PCI to optimal medical therapy alone (OMT). A total of five trials were included, comprising 1790 CTO patients, of whom 964 were randomised to PCI and 826 to OMT. The all-cause mortality was comparable between groups at 1‑year [risk ratio (RR) 1.70, 95% confidence interval (CI) 0.50–5.80, p = 0.40] and at 4‑year follow-up (RR 1.14, 95% CI 0.38–3.40, p = 0.81). There was no difference in the incidence of major adverse cardiac events (MACE) between groups at 1 year (RR 0.69, 95% CI 0.36–1.33, p = 0.27) and at 4 years (RR 0.85, 95% CI 0.60–1.22, p = 0.38). Left ventricular function and volumes at follow-up were comparable between groups. However, the PCI group had fewer target lesion revascularisations (RR 0.28, 95% CI 0.15–0.52, p < 0.001) and was more frequently free of angina at 1‑year follow-up (RR 0.65, 95% CI 0.50–0.84, p = 0.001), although the scores on the subscales of the Seattle Angina Questionnaire were comparable.

Conclusion

In conclusion, in this meta-analysis of 1790 CTO patients, CTO-PCI did not lead to an improvement in survival or in MACE as reported at long-term follow-up of up to 4 years, or to improvement of left ventricular function. However, CTO-PCI resulted in less angina and fewer target lesion revascularisations compared to OMT.

     

No Evidence for Cardiac Dysfunction in Kif6 Mutant Mice

A KIF6 variant in man has been reported to be associated with adverse cardiovascular outcomes after myocardial infarction. No clear biological or physiological data exist for Kif6. We sought to investigate the impact of a deleterious KIF6 mutation on cardiac function in mice. Kif6 mutant mice were generated and verified. Cardiac function was assessed by serial echocardiography at baseline, after ageing and after exercise. Lipid levels were also measured. No discernable adverse lipid or cardiac phenotype was detected in Kif6 mutant mice. These data suggest that dysfunction of Kif6 is linked to other more complex biological/biochemical parameters or is unlikely to be of material consequence in cardiac function.     

Long-term ischaemic and bleeding outcomes after primary percutaneous coronary intervention for ST-elevation myocardial infarction in the elderly

Background

The population is ageing rapidly and the proportion of patients aged ≥ 80 years undergoing primary percutaneous coronary intervention (PCI) is rising, but clinical trials have primarily been performed in younger patients.

Methods

Patients undergoing primary PCI between 2003 and 2008 were subdivided into 3 groups: < 60, 60-79, and ≥ 80 years. Endpoints at 3-year follow-up included all-cause mortality, recurrent myocardial infarction (reMI), stent thrombosis, target lesion revascularisation (TLR), bleeding (BARC bleeding ≥ 3), stroke, and major adverse cardiovascular events (MACE, a composite of cardiac mortality, reMI, stroke and TLR).

Results

2002 patients with ST-segment elevation myocardial infarction (STEMI) were included, 885 (44.2 %) aged < 60, 921 (46.0 %) 60–79, and 196 (9.7 %) ≥ 80 years. Comorbidities such as diabetes mellitus, prior stroke, malignant disease, anaemia, and chronic kidney disease were more prevalent in patients ≥ 80 years. The incidence of both ischaemic and bleeding events strongly increased with age. Age ≥ 80 years was an independent predictor of mortality (HR 2.56, 95 % CI1.69–3.87, p < 0.001), a borderline non-significant predictor of overall bleeding (HR 1.38, 95 %CI 0.95–2.00, p = 0.088), and a significant predictor of non-access site bleeding (HR 2.26, 95 %CI 1.46–3.51, p < 0.001).

Conclusion

Patients ≥ 80 years experienced high rates of ischaemic and bleeding complications; especially in this high-risk patient group individualised therapy is needed to optimise clinical outcomes.

Electronic Supplementary Material

The online version of this article (doi:10.1007/s12471-015-0733-2 contains supplementary material, which is available to authorized users.     

Rationale and design of EXPLORE: a randomized, prospective, multicenter trial investigating the impact of recanalization of a chronic total occlusion on left ventricular function in patients after primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

Background

Hypothyroidism is a prevalent endocrine condition. Individuals with this disease are commonly managed through supplementation with synthetic thyroid hormone, with the aim of alleviating symptoms and restoring normal thyroid stimulating hormone levels. Generally this management strategy is effective and well tolerated. However, there is research to suggest that a significant proportion of hypothyroid sufferers are being inadequately managed. Furthermore, hypothyroid patients are more likely to have a decreased sense of well-being and more commonly experience constitutional and neuropsychiatric complaints, even with pharmacological intervention. The current management of hypothyroidism follows a biomedical model. Little consideration has been given to a biopsychosocial approach to this condition. Within the chiropractic profession there is growing support for the use of a biopsychosocial-based intervention called Neuro-Emotional Technique (NET) for this population.

Methods/Design

A placebo-controlled, single-blinded, randomised clinical pilot-trial has been designed to assess the influence of Neuro-Emotional Technique on a population with primary overt hypothyroidism. A sample of 102 adults (≥18 years) who meet the inclusion criteria will be randomised to either a treatment group or a placebo group. Each group will receive ten treatments (NET or placebo) over a six week period, and will be monitored for six months. The primary outcome will involve the measurement of depression using the Depression, Anxiety and Stress Scale (DASS). The secondary outcome measures to be used are; serum thyroid stimulating hormone, serum free-thyroxine, serum free-triiodothyronine, serum thyroid peroxidase auto-antibodies, serum thyroglobulin auto-antibodies as well as the measurement of functional health and well-being using the Short-Form-36 Version 2. The emotional states of anxiety and stress will be measured using the DASS. Self-measurement of basal heart rate and basal temperature will also be included among the secondary outcome measures. The primary and secondary measures will be obtained at commencement, six weeks and six months. Measures of basal heart rate and basal temperature will be obtained daily for the six month trial period, with recording to commence one week prior to the intervention.

Discussion

The study will provide information on the influence of NET when added to existing management regimens in individuals with primary overt hypothyroidism.

Trial Registration

ANZCTR Number: 12607000040460     

Sexual Behaviour and HPV Infections in 18 to 29 Year Old Women in the Pre-Vaccine Era in the Netherlands

Background

Infection with Human Papillomavirus (HPV) is a necessary event in the multi-step process of cervical carcinogenesis. Little is known about the natural history of HPV infection among unscreened young adults. As prophylactic vaccines are being developed to prevent specifically HPV 16 and 18 infections, shifts in prevalence in the post vaccine era may be expected. This study provides a unique opportunity to gather baseline data before changes by nationwide vaccination occur.

Methods and Principal Findings

This cross-sectional study is part of a large prospective epidemiologic study performed among 2065 unscreened women aged 18 to 29 years. Women returned a self-collected cervico-vaginal specimen and filled out a questionnaire. All HPV DNA-positive samples (by SPF₁₀ DEIA) were genotyped using the INNO-LiPA HPV genotyping assay. HPV point prevalence in this sample was 19%. Low and high risk HPV prevalence was 9.1% and 11.8%, respectively. A single HPV-type was detected in 14.9% of all women, while multiple types were found in 4.1%. HPV-types 16 (2.8%) and 18 (1.4%) were found concomitantly in only 3 women (0.1%). There was an increase in HPV prevalence till 22 years. Multivariate analysis showed that number of lifetime sexual partners was the most powerful predictor of HPV positivity, followed by type of relationship, frequency of sexual contact, age, and number of sexual partners over the past 6 months.

Conclusions and Significance

This study shows that factors independently associated with HPV prevalence are mainly related to sexual behaviour. Combination of these results with the relative low prevalence of HPV 16 and/or 18 may be promising for expanding the future target group for catch up vaccination. Furthermore, these results provide a basis for research on possible future shifts in HPV genotype prevalence, and enable a better estimate of the effect of HPV 16-18 vaccination on cervical cancer incidence.     

Incidence and outcomes of chronic total occlusion percutaneous coronary intervention in the Netherlands: data from a nationwide registry

Background

Patients with chronic total coronary occlusions (CTO) are at increased risk for poor clinical outcomes. We aimed to determine the incidence of CTO percutaneous coronary intervention (PCI) and to identify CTO patients at risk for cardiac events in the nationwide Netherlands Heart Registration (NHR).

Methods

We included all PCI procedures with ≥1 CTO registered in the NHR from January 2015 to December 2018, excluding acute interventions. We used multivariable logistic regression of baseline characteristics to calculate the risk for events as odds ratios (OR) with 95% confidence intervals (CI).

Results

Of the PCIs performed during the study period, 6.3% (8,343/133,042) were for CTOs, with the percentage increasing significantly over time from 5.9% in 2015 to 6.6% in 2018 (p < 0.001). Coronary artery bypass grafting <24 h was carried out in 0.3%, and the only significant predictor was diabetes mellitus (OR 2.97, 95% CI 1.04–8.49, p = 0.042). Myocardial infarction (MI) <30 days occurred in 0.5%, and renal insufficiency (i.e. estimated glomerular filtration rate <30 ml/min per 1.73 m²) was identified as an independent predictor (OR 4.70, 95% CI 1.07–20.61, p = 0.040). Among patients undergoing CTO-PCI, 1‑year mortality was 3.7%, and independent predictors included renal insufficiency (OR 5.59, 95% CI 3.25–9.59, p < 0.001), left ventricular ejection fraction <30% (OR 3.43, 95% CI 2.00–5.90, p < 0.001), previous MI (OR 1.62, 95% CI 1.14–2.31, p = 0.007) and age (OR 1.06 per year increment, 95% CI 1.04–1.07, p < 0.001). Target-vessel revascularisation <1 year occurred in 11.3%.

Conclusion

CTO-PCI is still infrequently performed in the Netherlands. The most important predictor of mortality after CTO-PCI was renal insufficiency. Identification of patients at risk may help improve the prognosis of CTO patients in the future.

     

Absence of fatty acid transporter CD36 protects against Western-type diet-related cardiac dysfunction following pressure overload in mice

Cardiac patients often are obese and have hypertension, but in most studies these conditions are investigated separately. Here, we aimed at 1) elucidating the interaction of metabolic and mechanophysical stress in the development of cardiac dysfunction in mice and 2) preventing this interaction by ablation of the fatty acid transporter CD36. Male wild-type (WT) C57Bl/6 mice and CD36(-/-) mice received chow or Western-type diet (WTD) for 10 wk and then underwent a sham surgery or transverse aortic constriction (TAC) under anesthesia. After a 6-wk continuation of the diet, cardiac function, morphology, lipid profiles, and molecular parameters were assessed. WTD administration affected body and organ weights of WT and CD36(-/-) mice, but it affected only plasma glucose and insulin concentrations in WT mice. Cardiac lipid concentrations increased in WT mice receiving WTD, decreased in CD36(-/-) on chow, and remained unchanged in CD36(-/-) receiving WTD. TAC induced cardiac hypertrophy in WT mice on chow but did not affect cardiac function and cardiac lipid concentrations. WTD or CD36 ablation worsened the outcome of TAC. Ablation of CD36 protected against the WTD-related aggravation of cardiac functional and structural changes induced by TAC. In conclusion, cardiac dysfunction and remodeling worsen when the heart is exposed to two stresses, metabolic and mechanophysical, at the same time. CD36 ablation prevents the metabolic stress resulting from a WTD. Thus, metabolic conditions are a critical factor for the compromised heart and provide new targets for metabolic manipulation in cardioprotection.