Cholesterol crystal embolization demonstrated on GI biopsy

Nanoparticles as agents targeting cholesterol crystallization in atherosclerosis

This article introduces a hypothesis on nanoparticle-mediated modulation of cholesterol crystal behaviour in the atherosclerotic plaques. The role of cholesterol crystals in progression of atherosclerosis is emphasized. Proposed mechanism of spontaneous cholesterol crystal formation in the organism is discussed. Mechanisms and factors associated with the nanoparticle-mediated modulation of cholesterol crystal behaviour are proposed. Authors hypothesize that specially designed nanoparticles may therapeutically modulate cholesterol crystal behaviour in atherosclerosis. Nano-sized agents used in stent coatings and imaging techniques can possibly prevent cholesterol crystallization in the diseased vessels. On the other hand, new nanotechnologies should be implemented with caution as certain types of nanoparticles could become crystal seeds for cholesterol deposited in the atherosclerotically damaged vascular walls causing destabilization of the plaques. Studying nanoparticle-induced alterations of cholesterol crystal formation requires multidisciplinary approach involving biomedical researchers, computer scientists, and physical chemists specializing in crystal growth. The proposed hypothesis on nanoparticle-mediated modulation of cholesterol crystal behaviour may be relevant to other medical conditions including gallbladder stones, arthritis, and ophthalmological diseases such as synchysis scintillans.

Atheromatous embolization

Atheromatous embolization is a multisystem disease complicating advanced atherosclerosis. It occurs most often as a complication of angiography, an endovascular procedure or cardiovascular surgery. Atheromatous embolization can present in a subtle manner where it is often under-recognized, or with catastrophic results including myocardial infarction, strake or acute renal failure. It may mimic other disease processes and often goes underdiagnosed and undertreated. A high clinical suspicion is the key to diagnosis. Atheromatous embolization results in significant morbidity and mortality; therefore, early recognition followed by aggressive management may help to prevent end-organ damage and improve overall clinical outcomes. Management strategies should include risk factor modification, prevention of further insults by discontinuing or avoiding predisposing factors, supportive treatment and interventional or surgical approaches to remove the atheroembolic source. Atheromatous embolization is expected to increase as our population ages and the epidemics of diabetes mellitus and obesity increase.

Ileus caused by cholesterol crystal embolization: A case report

Cholesterol crystal embolization (CCE) is a rare systemic embolism caused by formation of cholesterol crystals from atherosclerotic plaques. CCE usually occurs during vascular manipulation, such as vascular surgery or endovascular catheter manipulation, or due to anticoagulation or thrombolytic therapy. We report a rare case of intestinal obstruction caused by spontaneous CCE. An 81-year-old man with a history of hypertension was admitted for complaints of abdominal pain, bloating, and anorexia persisting for 4 mo. An abdominal computed tomography revealed intestinal ileus. His symptoms were immediately relieved by an ileus tube insertion, and he was discharged 6 d later. However, these symptoms immediately reappeared and persisted, and partial resection of the small intestine was performed. A histopathological examination indicated that small intestine obstruction was caused by CCE. At the 12-mo follow-up, the patient showed no evidence of CCE recurrence. Thus, in cases of intestinal obstruction, CCE should also be considered.

Cholesterol crystal embolization presenting as either solid or cystic pancreatic lesion

Cholesterol crystal embolization (CCE) can result in end-organ ischemia. Retrospective review of clinicopathologic data. The first patient was anticoagulated with coumadin for chronic atrial fibrillation and presented subacutely with a solid mass. The second patient suffered from coronary artery disease post-angioplasty/stenting and presented with acute pancreatitis and pancreatic cystification. CCE should be considered in patients with significant vascular disease, arrhythmias or vascular manipulation who present with a pancreatic mass.

Atheroembolic renal disease

Atheroembolic renal disease develops when atheromatous aortic plaques rupture, releasing cholesterol crystals into the small renal arteries. Embolisation often affects other organs, such as the skin, gastrointestinal system, and brain. Although the disease can develop spontaneously, it usually develops after vascular surgery, catheterisation, or anticoagulation. The systemic nature of atheroembolism makes diagnosis difficult. The classic triad of a precipitating event, acute or subacute renal failure, and skin lesions, are strongly suggestive of the disorder. Eosinophilia further supports the diagnosis, usually confirmed by biopsy of an affected organ or by the fundoscopic finding of cholesterol crystals in the retinal circulation. Renal and patient prognosis are poor. Treatment is mostly preventive, based on avoidance of further precipitating factors, and symptomatic, aimed to the optimum treatment of hypertension and cardiac and renal failure. Statins, which stabilise atherosclerotic plaques, should be offered to all patients. Steroids might have a role in acute or subacute progressive forms with systemic inflammation.

Cholesterol atheroembolism of the colon can mimic the endoscopic features of pseudomembranous colitis

The endoscopic features of cholesterol atheroembolism affecting the colon have not been extensively described in the literature, owing to the rarity of this entity. We report a middle-aged man who presented with hematochezia after recent coronary artery bypass graft surgery. Colonoscopy revealed ulcerative skip lesions with overlying slough resembling pseudomembranes distal to the transverse colon, inconsistent with the initial clinical impression of ischemic colitis. As a consequence of continued bleeding with hemodynamic instability, the patient underwent an extended low anterior resection with end transverse colostomy. Histology revealed cholesterol atheroembolism resulting in patchy ischemic ulceration of the colon. Colonic cholesterol atheroembolism can mimic the endoscopic features of pseudomembranous colitis.

Novel properties of cholesterol–dioleoylphosphatidylcholine mixtures

We have studied the properties of mixtures of cholesterol with dioleoylphosphatidylcholine (DOPC), and with several other phospholipids, including 1-stearoyl-2-oleoylphosphatidylcholine (SOPC) and dioleoleoylphosphatidylserine (DOPS), as a function of cholesterol molar fraction and of temperature. Mixtures of DOPC with a cholesterol molar fraction of 0.4 or greater display polymorphic behavior. This polymorphism includes the formation of structures that give rise to isotropic peaks in 31P NMR at cholesterol molar fractions between 0.4 and 0.6, dependent on the thermal history of the sample. Cryo-electron microscopy studies demonstrate the formation of small globular aggregates that would contribute to a narrowing of the 31P NMR powder pattern. At molar fraction cholesterol 0.6 and higher and at temperatures above 70 degrees C, the mixtures with DOPC convert to the hexagonal phase. Lipid polymorphism is accompanied by the phase separation of cholesterol crystals in the anhydrous form and/or the monohydrate form. The crystals that are formed have substantially altered kinetics of hydration and dehydration, compared with both pure cholesterol monohydrate crystals and with crystals formed in the presence of the other phospholipids that do not form the hexagonal phase in the presence of cholesterol. This fact demonstrates that these cholesterol crystals are in intimate contact with the DOPC phospholipid and are not present as morphologically separate structures.

Cholesterol crystal embolization to the digestive system: characterization of a common, yet overlooked presentation of atheroembolism

In the 1359 published patients with multiorgan cholesterol crystal embolism (CCE), the digestive system seems to be the third most frequently affected system. Yet, this system received hitherto only little attention in the medical literature. Therefore, the aim of the present study was to clinically characterize the subset of patients with CCE involving the digestive system, based on our institutional experience and a review of the literature. Cases with CCE in a 7-yr period (1995-2001) were sought in the computerized records of our medical center. Of the CCE patients, those with digestive system involvement that could be related to CCE were included in this study. The clinical features of CCE were determined and compared with those found in published series. Fourteen cases with CCE were identified, giving an annual incidence of 0.8 per 10(5). Digestive system involvement was found in five (36%) of the 14 patients. All five patients had established atherosclerosis. Precipitating factors were vascular manipulations or anticoagulation treatment in four of these five patients. Two patterns of disease appeared: acute catastrophic multiorgan disorder with poor prognosis and chronic and more indolent GI disease. Abdominal pain, GI bleeding, fever, and diarrhea were the most common manifestations, resulting from bowel infarction, mucosal ulcerations, hepatocellular liver disorder, and/or pancreatitis. CCE is a systemic disorder with a frequent involvement of the digestive system and protean clinical manifestations. It should, therefore, be considered in any gastroenterological patient with atherosclerosis and recent vascular manipulations or systemic anticoagulation.