Anomalous origin of left main coronary artery from the right sinus of Valsalva.

BACKGROUND: Anomalous coronary arteries are rare congenital variations with cases ranging from asymptomatic to life-threatening. Given the wide variability of coronary anomalies, it is challenging to predict their clinical consequences. Here, we present the 'malignant' variant - interarterial course of the left coronary artery between the aorta and pulmonary trunk - given the highest risk of sudden cardiac death among the various coronary anomalies. CASE PRESENTATION: Our case presents a 22-year-old male presenting to the emergency department after a syncopal episode that occurred while the patient was driving a motor vehicle. Initial Computed Tomography (CT) of the chest performed as part of the trauma work-up revealed a rare case of an anomalous origin of the left main coronary artery (LMCA) originating from a common ostium with the right coronary artery (RCA). The LMCA was found to have a malignant course, as it was positioned between the aorta and pulmonary artery. Given the high risk of sudden cardiac arrest with this congenital variant, the patient underwent coronary artery bypass grafting. CONCLUSION: Anomalous coronary arteries remain the second leading cause of sudden cardiac death in young adult patients. The risk of sudden cardiac death depends on the congenital variant of the anomalous coronary artery as well as the course these vessels take. This case highlights a rare congenital variant featuring both the LMCA and RCA originating from a common ostium, with the LMCA having a malignant course, a variant with the highest risk of sudden cardiac death.

Pregnancy-related spontaneous coronary artery dissection: a rare cause of acute coronary syndrome in the third trimester.

BACKGROUND: Spontaneous Coronary Artery Dissection (SCAD) is a rare cause of myocardial infarction and sudden cardiac death that is mostly seen in younger patients without significant cardiac risk factors. The mechanism by which SCAD causes an acute coronary event is related to the compromise of the coronary artery lumen as a result of hematoma within the vessel wall. In comparison to their non-pregnant counterparts, when SCAD is associated with pregnancy, it has been associated with an increased risk of life-threatening arrhythmias, cardiogenic shock, and death. The underlying mechanism behind SCAD is not yet fully understood, and despite the condition's high mortality rate, it remains underdiagnosed. CASE PRESENTATION: Our case features a 38-year-old woman at 29 weeks of gestation presenting with chest pain that persisted despite initial management. Coronary angiography revealed a Type 2a spontaneous dissection of the left anterior descending artery. Given the risks of percutaneous coronary intervention in SCAD management and overall clinical stability, the patient was treated with conservative management. CONCLUSION: SCADs are a rare cause of acute coronary syndrome that can be found in patients without any prior cardiac risk factors. It is important to have a high index of suspicion when diagnosing SCADs given, they can cause life-threatening arrhythmias, cardiogenic shock, and death. This case highlights considerations that must be taken into account when treating P-SCAD, as opposed to SCAD in the postpartum period.

Left atrial myxoma: an unusual cause of pre-syncope and symptomatic bradycardia.

BACKGROUND: Atrial myxomas account for approximately 50% of all primary cardiac tumors. The size, location, risk of embolic event, and involvement of other cardiac structures, are all factors that contribute to the wide range of presentation for cardiac myxomas. Patients with myxomas may remain asymptomatic, while others may report symptoms such as fatigue and fever, dyspnea, and syncope. It is important to recognize arrhythmias as an uncommon symptom of myxomas. CASE PRESENTATION: We report a rare case of a 67-year-old man who presented with pre-syncopal episodes, symptomatic bradycardia, and night sweats found to have a 5.5 × 5.1 × 3 cm myxoma in the left atrium. During diastole the mass caused dynamic flow obstruction across the mitral valve. The patient underwent surgical resection of the mass given his symptomatology and risk of embolic events. Removal of the myxoma resulted in resolution of both pre-syncopal episodes and the patient's sinus bradycardia. CONCLUSION: Atrial myxomas are a rare cause of pre-syncope and symptomatic bradycardia. It is important to have a clinical suspicion for atrial myxomas given early diagnosis and surgical intervention are key in improving the prognosis of these patients. This case also highlights the importance of taking into account the source of the myxoma's blood supply in relationship to other cardiac structures, and further correlating these findings with clinical symptoms.

A pro-inflammatory and fibrous cap thinning transcriptome profile accompanies carotid plaque rupture leading to stroke.

Atherosclerotic plaque rupture is the etiology of ischemic stroke and myocardial infarction. The molecular mechanisms responsible for rupture remain unclear, in part, due to the lack of data from plaques at the time of rupture. Ribosome-depleted total RNA was sequenced from carotid plaques obtained from patients undergoing carotid endarterectomy with high-grade stenosis and either (1) a carotid-related ischemic cerebrovascular event within the previous 5 days ('recently ruptured,' n = 6) or (2) an absence of a cerebrovascular event ('asymptomatic,' n = 5). Principal component analysis confirmed plaque rupture was responsible for the greatest percentage of the variability between samples (23.2%), and recently ruptured plaques were enriched for transcripts associated with inflammation and extracellular matrix degradation. Hierarchical clustering achieved differentiation of the asymptomatic from the recently ruptured plaques. This analysis also found co-expression of transcripts for immunoglobulins and B lymphocyte function, matrix metalloproteinases, and interferon response genes. Examination of the differentially expressed genes supported the importance of inflammation and inhibition of proliferation and migration coupled with an increase in apoptosis. Thus, the transcriptome of recently ruptured plaques is enriched with transcripts associated with inflammation and fibrous cap thinning and support further examination of the role of B lymphocytes and interferons in atherosclerotic plaque rupture.

Publisher Correction: IAPP toxicity activates HIF1α/PFKFB3 signaling delaying ß-cell loss at the expense of ß-cell function.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

IAPP toxicity activates HIF1α/PFKFB3 signaling delaying ß-cell loss at the expense of ß-cell function.

The islet in type 2 diabetes (T2D) is characterized by amyloid deposits derived from islet amyloid polypeptide (IAPP), a protein co-expressed with insulin by ß-cells. In common with amyloidogenic proteins implicated in neurodegeneration, human IAPP (hIAPP) forms membrane permeant toxic oligomers implicated in misfolded protein stress. Here, we establish that hIAPP misfolded protein stress activates HIF1α/PFKFB3 signaling, this increases glycolysis disengaged from oxidative phosphorylation with mitochondrial fragmentation and perinuclear clustering, considered a protective posture against increased cytosolic Ca2+ characteristic of toxic oligomer stress. In contrast to tissues with the capacity to regenerate, ß-cells in adult humans are minimally replicative, and therefore fail to execute the second pro-regenerative phase of the HIF1α/PFKFB3 injury pathway. Instead, ß-cells in T2D remain trapped in the pro-survival first phase of the HIF1α injury repair response with metabolism and the mitochondrial network adapted to slow the rate of cell attrition at the expense of ß-cell function.

Cell cycle-related metabolism and mitochondrial dynamics in a replication-competent pancreatic beta-cell line.

Cell replication is a fundamental attribute of growth and repair in multicellular organisms. Pancreatic beta-cells in adults rarely enter cell cycle, hindering the capacity for regeneration in diabetes. Efforts to drive beta-cells into cell cycle have so far largely focused on regulatory molecules such as cyclins and cyclin-dependent kinases (CDKs). Investigations in cancer biology have uncovered that adaptive changes in metabolism, the mitochondrial network, and cellular Ca2+ are critical for permitting cells to progress through the cell cycle. Here, we investigated these parameters in the replication-competent beta-cell line INS 832/13. Cell cycle synchronization of this line permitted evaluation of cell metabolism, mitochondrial network, and cellular Ca2+ compartmentalization at key cell cycle stages. The mitochondrial network is interconnected and filamentous at G1/S but fragments during the S and G2/M phases, presumably to permit sorting to daughter cells. Pyruvate anaplerosis peaks at G1/S, consistent with generation of biomass for daughter cells, whereas mitochondrial Ca2+ and respiration increase during S and G2/M, consistent with increased energy requirements for DNA and lipid synthesis. This synchronization approach may be of value to investigators performing live cell imaging of Ca2+ or mitochondrial dynamics commonly undertaken in INS cell lines because without synchrony widely disparate data from cell to cell would be expected depending on position within cell cycle. Our findings also offer insight into why replicating beta-cells are relatively nonfunctional secreting insulin in response to glucose. They also provide guidance on metabolic requirements of beta-cells for the transition through the cell cycle that may complement the efforts currently restricted to manipulating cell cycle to drive beta-cells through cell cycle.

Administration of Melatonin and Metformin Prevents Deleterious Effects of Circadian Disruption and Obesity in Male Rats.

Circadian disruption and obesity synergize to predispose to development of type 2 diabetes mellitus (T2DM), signifying that therapeutic targeting of both circadian and metabolic dysfunctions should be considered as a potential treatment approach. To address this hypothesis, we studied rats concomitantly exposed to circadian disruption and diet-induced obesity (CDO), a rat model recently shown to recapitulate phenotypical aspects of obese T2DM (eg, circadian disruption, obesity, insulin resistance, and islet failure). CDO rats were subsequently treated daily (for 12 wk) by timed oral gavage with vehicle, melatonin (a known chronobiotic), metformin, or combination treatment of both therapeutics. Melatonin treatment alone improved circadian activity rhythms, attenuated induction of ß-cell failure, and enhanced glucose tolerance. Metformin alone did not modify circadian activity but enhanced insulin sensitivity and glucose tolerance. Importantly, the combination of melatonin and metformin had synergistic actions to modify progression of metabolic dysfunction in CDO rats through improved adiposity, circadian activity, insulin sensitivity, and islet cell failure. This study suggests that management of both circadian and metabolic dysfunctions should be considered as a potential preventative and therapeutic option for treatment of obesity and T2DM.