Dilbahar Mohar

Serum level of pigment epithelium-derived factor is a marker of atherosclerosis in humans

OBJECTIVE Pigment epithelium-derived factor (PEDF) could play a protective role against atherosclerosis. However, there is no clinical study to examine the relationship between serum level of PEDF and atherosclerosis in humans. METHODS/RESULTS The study involved 317 consecutive outpatients in Kurume University Hospital (220 male and 97 female) with a mean age of 62.1±9.1. We examined whether serum level of PEDF were independently associated with vascular inflammation evaluated by [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and intima-media thickness (IMT) in carotid artery in humans. Carotid [(18)F]-FDG uptake, an index of vascular inflammation within the atherosclerotic plaques, was measured as standardized uptake value (SUV). Mean serum PEDF level, carotid SUV and IMT values were 13.5±1.1 μg/mL, 1.34±0.19, and 0.71±0.15 mm, respectively. In multiple stepwise regression analysis, estimated glomerular filtration rate (p<0.001), males (p<0.001), homeostasis model assessment of insulin resistance index (p<0.05), heart rate (p<0.05), triglycerides (p<0.05), carotid IMT (p<0.05), waist circumference (p<0.05) and carotid SUV (p<0.05) were independently correlated to PEDF level (R(2)=0.332). CONCLUSION The present study reveals that serum level of PEDF is independently associated with vascular inflammation and IMT, thus suggesting that PEDF level is a novel biomarker that could reflect atherosclerosis in humans.

Integrated IVUS-OCT Imaging for Atherosclerotic Plaque Characterization

For the diagnosis of atherosclerosis, biomedical imaging techniques such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been developed. The combined use of IVUS and OCT is hypothesized to remarkably increase diagnostic accuracy of vulnerable plaques. We have developed an integrated IVUS-OCT imaging apparatus, which includes the integrated catheter, motor drive unit, and imaging system. The dual-function imaging catheter has the same diameter of current clinical standard. The imaging system is capable for simultaneous IVUS and OCT imaging in real time. Ex vivo and in vivo experiments on rabbits with atherosclerosis were conducted to demonstrate the feasibility and superiority of the integrated intravascular imaging modality.

Integrated IVUS-OCT for real-time imaging of coronary atherosclerosis.

Objective Combined use of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) is a potential method for accurate assessment of plaques characteristics and vulnerability. The aim of this study is to develop and evaluate the feasibility of a fully integrated intracoronary OCT-IVUS imaging technique to visualize plaques in living animals.

Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

Atherosclerotic coronary artery disease (CAD) is the number one cause of death worldwide. The majority of CAD-induced deaths are due to the rupture of vulnerable plaques. Accurate assessment of plaques is crucial to optimize treatment and prevent death in patients with CAD. Current diagnostic techniques are often limited by either spatial resolution or penetration depth. Several studies have proved that the combined use of optical and ultrasonic imaging techniques increase diagnostic accuracy of vulnerable plaques. Here, we introduce an ultrafast optical-ultrasonic dual-modality imaging system and flexible miniaturized catheter, which enables the translation of this technology into clinical practice. This system can perform simultaneous optical coherence tomography (OCT)-intravascular ultrasound (IVUS) imaging at 72 frames per second safely in vivo, i.e., visualizing a 72 mm-long artery in 4 seconds. Results obtained in atherosclerotic rabbits in vivo and human coronary artery segments show that this ultrafast technique can rapidly provide volumetric mapping of plaques and clearly identify vulnerable plaques. By providing ultrafast imaging of arteries with high resolution and deep penetration depth simultaneously, this hybrid IVUS-OCT technology opens new and safe opportunities to evaluate in real-time the risk posed by plaques, detect vulnerable plaques, and optimize treatment decisions.

Role of Echocardiography in the Treatment of Cardiac Tamponade

Accumulation of fluid within the pericardial sac results in elevation of intrapericardial pressure with consequent cardiac compression or tamponade. Cardiac tamponade is a life‐threatening condition which requires urgent evacuation of pericardial effusion (PE). Current pericardial evacuation techniques and approaches are varied. Echocardiography provides valuable insights into identifying patients who are suitable candidates and further facilitates pericardiocentesis by improving guidance techniques. Several previous publications have provided excellent reviews of the pathophysiology of cardiac tamponade. We review the clinical presentation and role of echocardiography for diagnosis of tamponade. We focus on medical and surgical approaches for the removal of PE. Moreover, as the clinical and hemodynamic consequences of PE depend on the volume and the rate of accumulation of PE, we review the various scenarios of “small” PE resulting in cardiac tamponade.

The Sirtuin System: The Holy Grail of Resveratrol?

The oxidative stress theory has been associated with atherosclerosis and has prompted a multitude of studies to evaluate the effects of antioxidants on cardiovascular disease prevention. Resveratrol, a relatively new antioxidant has gained considerable curiosity. This polyphenol stilbene identified in grape skin, is believed to be the main component contributing to the anti-atherosclerotic benefits linked to red wine consumption. It has demonstrated the ability to protect endothelial cells from lipid damage, promote vasodilation via modulation of nitric oxide synthesis, and inhibit platelet aggregation and smooth muscle proliferation. Although the complete mechanism of Resveratrol has yet to be fully elucidated, the Sirtuin system, consisting of 7 highly conserved families of regulator genes, are thought to be instrumental in establishing the various health benefits. In this article we assess the current applications, mechanism, pharmacokinetics, bioavailability, and safety profile of the novel antioxidant Resveratrol and provide an in-depth review of the influence of the Sirtuin system on the Resveratrol mechanism of action. We resolve that while early data on Resveratrol are promising, the anti-oxidative and ultimately, anti-atherosclerotic potential depends on further clarification of the intricate and complex relationship between Resveratrol and the Sirtruin system.

Atherosclerosis in Chronic Kidney Disease: Lessons Learned from Glycation in Diabetes

In diabetes, glycation is a nonenzymatic posttranslational modification resulting from the bonding of a sugar molecule with a protein or lipid followed by oxidation, resulting in the development of advanced glycation end products (AGE). Like glycation, carbamylation is a posttranslational protein modification that is associated with AGE formation. Glycation of extracellular matrix proteins and low-density lipoprotein with subsequent deposition in the vessel wall could contribute to inflammatory response and atheroma formation. It is logical to extrapolate that carbamylation may result in modification of vessel wall proteins similar to glycation, and predispose to atherosclerosis.

Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) catheter for characterization of atherosclerotic plaques in vivo

A miniature integrated intravascular optical coherence tomography (OCT) - ultrasound (US) catheter for real-time imaging of atherosclerotic plaques has been developed, providing high resolution and deep tissue penetration at the same time. This catheter, with an outer diameter of 1.18mm, is suitable for imaging in human coronary arteries. The first in vivo 3D imaging of atherosclerotic microstructure in a rabbit abdominal aorta obtained by an integrated OCT-US catheter is presented. In addition, in vitro imaging of cadaver coronary arteries were conducted to demonstrate the imaging capabilities of this integrated catheter to classify different atherosclerotic plaque types.

Use of contrast echocardiography to detect displacement of the needle during pericardiocentesis.

Bedside pericardiocentesis is a safe and routinely practiced procedure. We report a case in which echocardiography‐guided pericardiocentesis was performed urgently for cardiac tamponade. In this case, there was displacement of the periocardiocentesis needle that was only detected by change in the color of aspirated fluid and confirmed by the use of contrast echocardiography. We proscribe the use of routine echocardiographic monitoring during pericardiocentesis to avoid this type of complication. (Echocardiography 2012;29:E60‐E61)

Optimal flushing agents for integrated optical and acoustic imaging systems

Abstract. An increasing number of integrated optical and acoustic intravascular imaging systems have been developed and hold great promise for accurately diagnosing vulnerable plaques and guiding atherosclerosis treatment. However, in any intravascular environment, the vascular lumen is filled with blood, a high-scattering source for optical and high-frequency ultrasound signals. Blood must be flushed away to provide clearer images. To our knowledge, no research has been performed to find the ideal flushing agent for combined optical and acoustic imaging techniques. We selected three solutions as potential flushing agents for their image-enhancing effects: mannitol, dextran, and iohexol. Testing of these flushing agents was performed in a closed-loop circulation model and in vivo on rabbits. We found that a high concentration of dextran was the most useful for simultaneous intravascular ultrasound and optical coherence tomography imaging.