Nourin-Dependent miR-137 and miR-106b: Novel Biomarkers for Early Diagnosis of Myocardial Ischemia in Coronary Artery Disease Patients

Background: Although cardiovascular imaging techniques are widely used to diagnose myocardial ischemia in patients with suspected stable coronary artery disease (CAD), they have limitations related to lack of specificity, sensitivity and “late” diagnosis. Additionally, the absence of a simple laboratory test that can detect myocardial ischemia in CAD patients, has led to many patients being first diagnosed at the time of the development of myocardial infarction. Nourin is an early blood-based biomarker rapidly released within five minutes by “reversible” ischemic myocardium before progressing to necrosis. Recently, we demonstrated that the Nourin-dependent miR-137 (marker of cell damage) and miR-106b-5p (marker of inflammation) can diagnose myocardial ischemia in patients with unstable angina (UA) and also stratify severity of ischemia, with higher expression in acute ST-segment elevation myocardial infarction (STEMI) patients compared to UA patients. Minimal baseline-gene expression levels of Nourin miRNAs were detected in healthy subjects. Objectives: To determine: (1) whether Nourin miRNAs are elevated in chest pain patients with myocardial ischemia suspected of CAD, who also underwent dobutamine stress echocardiography (DSE) or ECG/Treadmill stress test, and (2) whether the elevated levels of serum Nourin miRNAs correlate with results of ECHO/ECG stress test in diagnosing CAD patients. Methods: Serum gene expression levels of miR-137, miR-106b-5p and their corresponding molecular pathway network were measured blindly in 70 enrolled subjects using quantitative real time PCR (qPCR). Blood samples were collected from: (1) patients with chest pain suspected of myocardial ischemia (n = 38) both immediately “pre-stress test” and “post-stress test” 30 min. after test termination; (2) patients with acute STEMI (n = 16) functioned as our positive control; and (3) healthy volunteers (n = 16) who, also, exercised on ECG/Treadmill stress test for Nourin baseline-gene expression levels. Results: (1) strong correlation was observed between Nourin miRNAs serum expression levels and results obtained from ECHO/ECG stress test in diagnosing myocardial ischemia in CAD patients; (2) positive “post-stress test” patients with CAD diagnosis showed upregulation of miR-137 by 572-fold and miR-106b-5p by 122-fold, when compared to negative “post-stress test” patients (p < 0.001); (3) similarly, positive “pre-stress test” CAD patients showed upregulation of miR-137 by 1198-fold and miR-106b-5p by 114-fold, when compared to negative “pre-stress test” patients (p < 0.001); and (4) healthy subjects had minimal baseline-gene expressions of Nourin miRNAs. Conclusions: Nourin-dependent miR-137 and miR-106b-5p are promising novel blood-based biomarkers for early diagnosis of myocardial ischemia in chest pain patients suspected of CAD in outpatient clinics. Early identification of CAD patients, while patients are in the stable state before progressing to infarction, is key to providing crucial diagnostic steps and therapy to limit adverse cardiac events, improve patients’ health outcome and save lives.

Nourin-Dependent miR-137 and miR-106b: Novel Early Inflammatory Diagnostic Biomarkers for Unstable Angina Patients

BACKGROUND

Currently, no blood biomarkers exist that can diagnose unstable angina (UA) patients. Nourin is an early inflammatory mediator rapidly released within 5 min by reversible ischemic myocardium, and if ischemia persists, it is also released by necrosis. Nourin is elevated in acute coronary syndrome (ACS) patients but not in symptomatic noncardiac and healthy subjects. Recently, circulating microRNAs (miRNAs) have been established as markers of disease, including cardiac injury and inflammation.

OBJECTIVES

To profile and validate the potential diagnostic value of Nourin-dependent miR-137 (marker of cell damage) and miR-106b-5p (marker of inflammation) as early biomarkers in suspected UA patients and to investigate the association of their target and regulating genes.

METHODS

Using Nourin amino acid sequence, an integrated bioinformatics analysis was conducted. Analysis indicated that Nourin is a direct target for miR-137 and miR-106b-5p in myocardial ischemic injury. Two linked molecular networks of lncRNA/miRNAs/mRNAs were also retrieved, including CTB89H12.4/miR-137/FTHL-17 and CTB89H12.4/miR-106b-5p/ANAPC11. Gene expression profiling was assessed in serum samples collected at presentation to an emergency department (ED) from: (1) UA patients (n = 30) (confirmed by invasive coronary angiography with stenosis greater than 50% and troponin level below the clinical decision limit); (2) patients with acute ST elevation myocardial infarction (STEMI) (n = 16) (confirmed by persistent ST-segment changes and elevated troponin level); and 3) healthy subjects (n = 16).

RESULTS

Gene expression profiles showed that miR-137 and miR-106b-5p were significantly upregulated by 1382-fold and 192-fold in UA compared to healthy, and by 2.5-fold and 4.6-fold in STEMI compared to UA, respectively. Healthy subjects showed minimal expression profile. Receiver operator characteristics (ROC) analysis revealed that the two miRNAs were sensitive and specific biomarkers for assessment of UA and STEMI patients. Additionally, Spearman's correlation analysis revealed a significant association of miRNAs with the associated mRNA targets and the regulating lncRNA.

CONCLUSIONS

Nourin-dependent gene expression of miR-137 and miR-106b-5p are novel blood-based biomarkers that can diagnose UA and STEMI patients at presentation and stratify severity of myocardial ischemia, with higher expression in STEMI compared to UA. Early diagnosis of suspected UA patients using the novel Nourin biomarkers is key for initiating guideline-based therapy that improves patients' health outcomes.

External beam radiotherapy versus brachytherapy in the management of malignant oesophageal dysphagia: a retrospective study

PURPOSE

Dysphagia is a prominent symptom of oesophageal cancer which may be palliated by stent, external beam radiation (EBRT) or intraluminal brachytherapy (ILBT). Brachytherapy is not widely practised in the UK. The aim of this study was to compare the efficacy of ILBT and EBRT in relieving malignant dysphagia.

METHODS

The radiotherapy database at Northampton Cancer Centre (NCC) was used to identify patients who underwent ILBT or EBRT for malignant dysphagia between 1.1.2008 and 31.3 2010. Data was collected on patient demographics, tumour characteristics, treatment received and dysphagia score pre- and post- treatment. Serial assessment of dysphagia was used to determine the duration of symptomatic improvement. EBRT involved 20-30 Gy in 5-10 fractions. Brachytherapy applicator placement was done by an experienced endoscopist at the high dose rate (HDR) suite and a single treatment dose of 12 Gy was prescribed at 1 cm depth. Oesophageal dilation was performed prior to brachytherapy treatment if needed.

RESULTS

44 patients were included in this study (EBRT: 21; ILBT: 23). Patient characteristics were well balanced between the two groups. The average dysphagia scores in the EBRT group prior to treatment were 3, and at 4, 8 and 16 weeks following treatment they were 3.4, 2.4, 2.1 and 2.1, respectively. The corresponding dysphagia scores in the ILBT group were 3.5 before treatment and 2.2, 2.1 and 2.3 following treatment, respectively. There was significant improvement in dysphagia in both groups at 4 weeks (p<0.0001), and the benefit was sustained after 8 and 16 weeks. No major complications were reported from either EBRT or oesophageal brachytherapy.

CONCLUSION

ILBT is an effective alternative to multifractionated EBRT for palliation of malignant dysphagia providing a convenient one-stop treatment for patients who live a long distance from their cancer centre. Our model of performing the endoscopically guided procedure in the brachytherapy unit is comparable in cost to fractionated EBRT and can be adopted by other centres.

Design of thoracolumbosacral orthosis (TLSO) braces using CT/MR

The field of orthotics has gained scientific attention over the last few years. Its objective is to correct, adjust, or modify the operation of human limbs, joints, or muscles. Thoracolumbosacral orthosis (TLSO) braces are used by scoliosis and postoperative patients who need back correction and/or support. The anatomic dimensions for TLSO braces have been acquired mainly by casting the patient. Casting is a time-proven method for obtaining surface geometry, but it can be inconvenient in certain situations. For example, casting might not be suitable for postoperative and trauma patients owing to the risk of further injury. Such prohibitive cases can still be handled safely by X-ray CT or MR scanning. This article presents an alternative method for data acquisition of TLSO patients' anatomic dimensions using CT/MRI. The experimental results show the method to be statistically accurate, efficient, and feasible compared with the conventional casting method.

CT/MR imaging: a design tool for custom orthosis

PURPOSE

Orthotics attempts to correct imperfections of the human body. These deficiencies can be either congenital or due to injury. Orthotic devices have continuously evolved over the years and range in sophistication from simple joint braces to spinal body jackets. Generic orthoses, such as knee braces, come in various sizes and can be purchased over-the-counter. Sophisticated orthoses, such as those used to correct scoliosis, have to be custom made. Each of such orthoses has to be fabricated for one particular patient and requires the patient's exact geometry. The conventional technique to acquire patient geometric information has generally been casting. This latter is a time proven method of capturing the geometry of body sections of interest. However, in certain situations, casting might not always be the best alternative to obtain patient geometric data.

METHOD/RESULTS

This paper presents a new approach to acquire patient geometric information using CT/MR imaging. The proposed approach can help in cases where casting is not the best option.

CONCLUSION

Using CT/MR imaging to acquire patient geometry is shown to be feasible both clinically and economically.