Development of bioartificial myocardium using stem cells and nanobiotechnology templates

Non-occupational physical activity and risk of cardiovascular disease, cancer and mortality outcomes: a dose-response meta-analysis of large prospective studies

OBJECTIVE

To estimate the dose-response associations between non-occupational physical activity and several chronic disease and mortality outcomes in the general adult population.

DESIGN

Systematic review and cohort-level dose-response meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science and reference lists of published studies.

ELIGIBILITY CRITERIA

Prospective cohort studies with (1) general population samples >10 000 adults, (2) ≥3 physical activity categories, and (3) risk measures and CIs for all-cause mortality or incident total cardiovascular disease, coronary heart disease, stroke, heart failure, total cancer and site-specific cancers (head and neck, myeloid leukaemia, myeloma, gastric cardia, lung, liver, endometrium, colon, breast, bladder, rectum, oesophagus, prostate, kidney).

RESULTS

196 articles were included, covering 94 cohorts with >30 million participants. The evidence base was largest for all-cause mortality (50 separate results; 163 415 543 person-years, 811 616 events), and incidence of cardiovascular disease (37 results; 28 884 209 person-years, 74 757 events) and cancer (31 results; 35 500 867 person-years, 185 870 events). In general, higher activity levels were associated with lower risk of all outcomes. Differences in risk were greater between 0 and 8.75 marginal metabolic equivalent of task-hours per week (mMET-hours/week) (equivalent to the recommended 150 min/week of moderate-to-vigorous aerobic physical activity), with smaller marginal differences in risk above this level to 17.5 mMET-hours/week, beyond which additional differences were small and uncertain. Associations were stronger for all-cause (relative risk (RR) at 8.75 mMET-hours/week: 0.69, 95% CI 0.65 to 0.73) and cardiovascular disease (RR at 8.75 mMET-hours/week: 0.71, 95% CI 0.66 to 0.77) mortality than for cancer mortality (RR at 8.75 mMET-hours/week: 0.85, 95% CI 0.81 to 0.89). If all insufficiently active individuals had achieved 8.75 mMET-hours/week, 15.7% (95% CI 13.1 to 18.2) of all premature deaths would have been averted.

CONCLUSIONS

Inverse non-linear dose-response associations suggest substantial protection against a range of chronic disease outcomes from small increases in non-occupational physical activity in inactive adults. PROSPERO registration number CRD42018095481.

Alterations in plantar vessel blood flow in patients with mild diabetic peripheral neuropathy

INTRODUCTION

Early identification and treatment of diabetic peripheral neuropathy (DPN) are crucial. Presently, the mechanism of DPN is not very clear, and there are inconclusive conclusions about the influencing factors of vascular dynamic characteristics in DPN. This study aims to detect and compare the hemodynamic characteristics of plantar blood vessels in patients with mild DPN and healthy participants to explore a simple and reliable new idea and a potential method for early assessment of DPN and to investigate the influence of gender and age on hemodynamic characteristics.

RESEARCH DESIGN AND METHODS

Sixty age-matched and gender-matched patients with mild DPN (30 men and 30 women) and 60 healthy participants were randomly recruited. Color Doppler ultrasound was used to measure and analyze the hemodynamic characteristics of plantar-related vessels.

RESULTS

Ultrasonic measurements had good test-retest reliability. There may be no statistically significant differences in the blood flow velocity and blood flow in the plantar-related blood vessels of participants, irrespective of their gender and age. For patients with mild DPN, color Doppler ultrasound may indicate early hemodynamic abnormalities when there are no obvious abnormalities in the large arteries of the lower limbs, which are specifically manifested as increased blood flow velocity and blood flow in the distal small vessels.

CONCLUSIONS

Our study provides in vivo data support for the dynamic characteristics of the plantar blood vessel biomechanical model and provides a new idea of in vivo and non-invasive early diagnosis of DPN.

Effect of cigarette smoking on smoking biomarkers, blood pressure and blood lipid levels among Sri Lankan male smokers

Study purpose

The aim of this study was to determine the fractional exhaled nitric oxide (FeNO) levels, exhaled breath carbon monoxide (eCO) levels, blood pressure, blood lipid levels between smokers and non-smokers and to determine the association of smoking intensity with the above parameters.

Methods

This descriptive study was conducted in selected periurban areas of the Colombo District, Sri Lanka. Adult male current tobacco smokers (n=360), aged between 21 and 60 years were studied and compared with anthropometrically matched male non-smokers (n=180). Data were collected by interviewer-administered questionnaire, clinical assessment and measurement of FeNO by FENO monitor and eCO bySmokerlyser.

Results

Smokers had significantly lower mean FeNO levels and higher mean eCO values compared with non-smokers. Presentation of palpitations was higher among the smokers and a significantly positive correlation was identified between palpitations and eCO levels. There was a significantly positive correlation between the systolic blood pressure of smokers with the duration of smoking (DS), Brinkman Index (BI), Body Mass Index (BMI) and there was a significantly negative correlation with FeNO levels. The mean arterial pressure was positively correlated with the DS, BI and BMI. There was a significantly negative correlation between FeNO and the number of cigarettes smoked per day, DS and BI of smokers. Significantly higher total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), very LDL-C, TC: HDL ratio and low high density lipoprotein cholesterol (HDL-C) level was observed among smokers compared with the non-smokers.

Conclusions

Tobacco smoking was found to impact blood pressure and serum lipid levels thus enhancing the cardiovascular risk among smokers. The levels of eCO and FeNO are useful biomarkers for determining the intensity of smoking. The results indicate the necessity for urgent measures to stop cigarette smoking in Sri Lanka.

Cardiac tamponade from anticoagulant-related spontaneous haemopericardium in a patient with ischaemic cardiomyopathy and heart failure

We describe the case of an 86-year-old man with a background of severe left ventricular dysfunction and ischaemic cardiomyopathy who, having been optimised for heart failure therapy in hospital, unexpectedly deteriorated again with hypotension and progressive renal failure over the course of 2 days. Common causes of decompensation were ruled out and a bedside echocardiogram unexpectedly diagnosed new pericardial effusion with tamponade physiology. The patient underwent urgent pericardiocentesis and 890 mL of haemorrhagic fluid was drained. Common causes for haemopericardium were ruled out, and the spontaneous haemopericardium was thought to be related to introduction of rivaroxaban anticoagulation. The patient made a full recovery and was well 2 months following discharge. This case highlights the challenges of diagnosing cardiac tamponade in the presence of more common disorders that share similar non-specific clinical features. In addition, this case adds to growing evidence that therapy with direct oral anticoagulants can be complicated by spontaneous haemopericardium, especially when coadministered with other agents that affect clotting, renal dysfunction and cytochrome P3A5 inhibitors.

Advanced atrioventricular block and left bundle branch block in a patient with coronary artery fistula

Coronary artery fistulas are abnormal vascular conduits, rarely related to atrioventricular conduction abnormalities. We report the case of a 52-year-old woman who presented with dyspnoea on exertion. Her ECG revealed advanced atrioventricular block and left bundle branch block. CT scans confirmed two fistulas, from the conus branch of right coronary artery and from the left anterior descending coronary artery, into the pulmonary artery. The patient underwent pacemaker implantation. To date, only nine patients with different degrees of heart blocks associated with coronary artery fistulas have been reported. Herein, we review and summarise previously reported cases of different degrees of heart blocks associated with coronary artery fistulas.

Association between chronic kidney disease and incident diagnosis of dementia in England: a cohort study in Clinical Practice Research Datalink

OBJECTIVES

To investigate the association between chronic kidney disease (CKD) and dementia diagnosis in a real-world primary care setting in England.

DESIGN

Matched cohort study.

SETTINGS

English primary care in the Clinical Practice Research Datalink.

PARTICIPANTS

People aged ≥18 years with predialysis CKD (stages 3-5, defined as two measurements of estimated glomerular filtration rate <60 mL/min/1.73 m² for 3 months) from 2004 to 2014, and people without known CKD who were matched on age, sex, general practice and calendar time in a 1:1 ratio.

PRIMARY AND SECONDARY OUTCOME MEASURES

First-ever diagnosis of dementia recorded by GPs. We also examined all-cause death as a secondary outcome to discuss potential competing risk of mortality in the association between CKD and dementia diagnosis.

RESULTS

In a matched cohort of 242 349 pairs with and without CKD (mean age 75.4±9.7 years, 39.3% male), the crude incidence rate of dementia diagnosis was 11.4/1000 and 9.4/1000 person-years, respectively. There was an association between CKD status and incident dementia diagnosis in the first 6 months of the follow-up (adjusted rate ratio (aRR) 1.58, 95% CI 1.44 to 1.74), which attenuated after 6 months (aRR 1.12, 95% CI 1.08 to 1.16). Among patients with CKD, there was no evidence of association between CKD stage and incident dementia diagnosis; compared with stage 3a, aRR (95% CI) was 1.04 (0.91 to 1.18) for stage 3b and 0.94 (0.74 to 1.20) for stages 4 or 5 in the first 6 months, and 0.97 (0.92 to 1.01) and 0.89 (0.80 to 0.98) thereafter. We found a strong association between worsening CKD stage and all-cause mortality.

CONCLUSION

We identified a co-occurrence of detection of CKD and dementia in real-world clinical practice and a strong competing risk of mortality in the association between CKD stage and dementia, while a weak association between CKD status and dementia was suggested in the long term.

Identifying circulating microRNAs as biomarkers of cardiovascular disease: a systematic review

The aim of the present study is to identify microRNAs (miRs) with high potential to be used as biomarkers in plasma and/or serum to clinically diagnose, or provide accurate prognosis for survival in, patients with atherosclerosis, coronary artery disease, and acute coronary syndrome (ACS). A systematic search of published original research yielded a total of 72 studies. After review of the risk of bias of the published studies, according to Cochrane Collaboration and the QUADUAS Group standards, 19 studies were selected. Overall 52 different miRs were reported. In particular, miR-133a/b (5 studies), miR-208a/b (6 studies), and miR-499 (7 studies) were well studied and found to be significant diagnostic and/or prognostic markers across different cardiovascular disease progression stages. miR-1 and miR-145b are potential biomarkers of ACS; miR-1 with higher sensitivity for all acute myocardial infarction (AMI), and miR-145 for STEMI and worse outcome of AMI. But when miRs were studied across different ACS study populations, patients had varying degrees of coronary stenosis, which was identified as an important confounder that limited the ability to quantitatively pool the study results. The identified miRs were found to regulate endothelial function and angiogenesis (miR-1, miR-133), vascular smooth muscle cell differentiation (miR-133, miR-145), communication between vascular smooth muscle and endothelial cell to stabilize plaques (miR-145), apoptosis (miR-1, miR-133, miR-499), cardiac myocyte differentiation (miR-1, miR-133, miR-145, miR-208, miR-499), and to repress cardiac hypertrophy (miR-133). Their role in these processes may be explained by regulation of shared RNA targets such as cyclin-dependent kinase inhibitor 1A (or p21), ETS proto-oncogene 1, fascin actin-bundling protein 1, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, insulin-like growth factor 1 receptor LIM and SH3 protein 1, purine nucleoside phosphorylase, and transgelin 2. These mechanistic data further support the clinical relevance of the identified miRs. miR-1, miR-133a/b, miR-145, miR-208a/b, and miR-499(a) in plasma and/or serum show some potential for diagnosis of cardiovascular disease. However, biased selection of miRs in most studies and unexplained contrasting results are major limitations of current miR research. Inconsistencies need to be addressed in order to definitively identify clinically useful miRs. Therefore, this paper presents important aspects to improve future miR research, including unbiased selection of miRs, standardization/normalization of reference miRs, adjustment for patient comorbidities and medication, and robust protocols of data-sharing plans that could prevent selective publication and selective reporting of miR research outcomes.

The acellular myocardial flap: a novel extracellular matrix scaffold enriched with patent microvascular networks and biocompatible cell niches

There is a great need for acellular, fully vascularized, and biocompatible myocardial scaffolds that provide agreeable biological, nutritional, and biomechanical niches for reseeded cells for in vitro and in vivo applications. We generated myocardial flap scaffolds comprising porcine left-anterior ventricular myocardium and its associated coronary arteries and veins and investigated the combinatorial effects of sodium dodecyl sulfate (SDS) and sodium hydroxide (NaOH) perfusion on both the myocardial extracellular matrix (ECM) and the vascular ECM. Results showed that all scaffolds displayed a fully intact and patent vasculature, with arterial burst pressures indistinguishable from native coronary arteries and perfusion to the level of capillaries. Scaffolds were free of cellular proteins and retained collagen and elastin ECM components, exhibited excellent mechanical properties, and were cytocompatible toward relevant seeded cells. SDS perfusion preserved collagen IV, laminin, and fibronectin well, but only reduced DNA content by 33%; however, this was further improved by post-SDS nuclease treatments. By comparison, NaOH was very effective in removing cells and eliminated more than 95% of tissue DNA, but also significantly reduced levels of laminin and fibronectin. Such constructs can be readily trimmed to match the size of the infarct and might be able to functionally integrate within host myocardium and be nourished by direct anastomotic connection with the host's own vasculature; they might also be useful as physiologically accurate models for in vitro studies of cardiac physiology and pathology.

Development of bioartificial myocardium by electrostimulation of 3D collagen scaffolds seeded with stem cells

Electrostimulation (ES) can be defined as a safe physical method to induce stem cell differentiation. The aim of this study is to evaluate the effectiveness of ES on bone marrow mesenchymal stem cells (BMSCs) seeded in collagen scaffolds in terms of proliferation and differentiation into cardiomyocytes. BMSCs were isolated from Wistar rats and seeded into 3D collagen type 1 templates measuring 25 × 25 × 6 mm. Bipolar in vitro ES was performed during 21 days. Electrical impedance and cell proliferation were measured. Expression of cardiac markers was assessed by immunocytochemistry. Viscoelasticity of collagen matrix was evaluated. Electrical impedance assessments showed a low resistance of 234±41 Ohms which indicates good electrical conductivity of collagen matrix. Cell proliferation at 570 nm as significantly increased in ES groups after seven day (ES 0.129±0.03 vs non-stimulated control matrix 0.06±0.01, P=0.002) and after 21 days, (ES 0.22±0.04 vs control 0.13±0.01, P=0.01). Immunocytoche mistry of BMSCs after 21 days ES showed positive staining of cardiac markers, troponin I, connexin 43, sarcomeric alpha-actinin, slow myosin, fast myosin and desmin. Staining for BMSCs marker CD29 after 21 days was negative. Electrostimulation of cell-seeded collagen matrix changed stem cell morphology and biochemical characteristics, increasing the expression of cardiac markers. Thus, MSC-derived differentiated cells by electrostimulation grafted in biological scaffolds might result in a convenient tissue engineering source for myocardial diseases.

Nano-regenerative medicine towards clinical outcome of stem cell and tissue engineering in humans

Nanotechnology is a fast growing area of research that aims to create nanomaterials or nanostructures development in stem cell and tissue-based therapies. Concepts and discoveries from the fields of bio nano research provide exciting opportunities of using stem cells for regeneration of tissues and organs. The application of nanotechnology to stem-cell biology would be able to address the challenges of disease therapeutics. This review covers the potential of nanotechnology approaches towards regenerative medicine. Furthermore, it focuses on current aspects of stem- and tissue-cell engineering. The magnetic nanoparticles-based applications in stem-cell research open new frontiers in cell and tissue engineering.

Biomaterial strategies for alleviation of myocardial infarction

World Health Organization estimated that heart failure initiated by coronary artery disease and myocardial infarction (MI) leads to 29 per cent of deaths worldwide. Heart failure is one of the leading causes of death in industrialized countries and is expected to become a global epidemic within the twenty-first century. MI, the main cause of heart failure, leads to a loss of cardiac tissue impairment of left ventricular function. The damaged left ventricle undergoes progressive ‘remodelling’ and chamber dilation, with myocyte slippage and fibroblast proliferation. Repair of diseased myocardium with in vitro-engineered cardiac muscle patch/injectable biopolymers with cells may become a viable option for heart failure patients. These events reflect an apparent lack of effective intrinsic mechanism for myocardial repair and regeneration. Motivated by the desire to develop minimally invasive procedures, the last 10 years observed growing efforts to develop injectable biomaterials with and without cells to treat cardiac failure. Biomaterials evaluated include alginate, fibrin, collagen, chitosan, self-assembling peptides, biopolymers and a range of synthetic hydrogels. The ultimate goal in therapeutic cardiac tissue engineering is to generate biocompatible, non-immunogenic heart muscle with morphological and functional properties similar to natural myocardium to repair MI. This review summarizes the properties of biomaterial substrates having sufficient mechanical stability, which stimulates the native collagen fibril structure for differentiating pluripotent stem cells and mesenchymal stem cells into cardiomyocytes for cardiac tissue engineering.