Histopathological and biochemical changes following fat embolism with administration of corn oil micelles A NEW ANIMAL MODEL FOR FAT EMBOLISM SYNDROME
ABSTRACT Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight. Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A(2), nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid. This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome.
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ABSTRACT: Fat Embolism is a complication of long bone fractures, intramedullary fixation and joint arthroplasty. It may progress to fat embolism syndrome, which is rare but involves significant morbidity and can occasionally be fatal. Fat Embolism can be detected at the time of embolization by transoesophageal echocardiography or atrial blood sampling. Later, a combination of clinical signs and symptoms will point towards fat embolism but there is no specific test to confirm the diagnosis. We investigated serum Interleukin-6 (IL-6) as a possible early marker for fat embolism. An animal study was conducted to simulate a hip replacement in 31 adult male Sprague Dawley rats. The procedure was performed under general anesthesia and the animals divided into 3 groups: control, uncemented and cemented. Following surgery and recovery from anaesthesia, the rats allowed to freely mobilize in their cages. Blood was taken before surgery and at 6 hours, 12 hours and 24 hours to measure serum IL-6 levels. The rats were euthanized at 24 hours and lungs removed and stained for fat. The amount of fat seen was then correlated with serum IL-6 levels. No rats in the control group had fat emboli. Numerous fat emboli were seen in both the uncemented and cemented implant groups. The interleukin levels were raised in all groups reaching a peak at 12 hours after surgery reaching 100 pg/ml in the control group and around 250 pg/ml in the uncemented and cemented implant groups. The IL-6 levels in the control group were significantly lower than any of the implant groups at 12 and 24 hours. At these time points, the serum IL-6 correlated with the amount of fat seen on lung histology. Serum IL-6 is a possible early marker of fat embolism.Journal of Orthopaedic Surgery and Research 07/2009; 4:18. DOI:10.1186/1749-799X-4-18 · 1.58 Impact Factor
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ABSTRACT: Fat embolism syndrome (FES) associated with acute lung injury (ALI) is a clinical condition following long bone fracture. We have reported 14 victims due to ALI with FES. Our laboratory has developed an animal model that produced fat emboli (FE). The major purpose of this study was to test whether neutrophil activation with phorbol myristate acetate (PMA) and inhibition with sivelestat (SVT) exert protection on the lung. The lungs of Sprague-Dawley rats were isolated and perfused. FE was produced by addition of corn oil micelles into the lung perfusate. PMA and SVT were given simultaneously with FE. Parameters such as lung weight/body weight ratio, LW gain, exhaled nitric oxide (NO), protein concentration in bronchoalveolar lavage relating to ALI were measured. The neutrophil elastase (NE), myeloperoxidase, malondialdehyde and phopholipase A₂ activity were determined. We also measured the nitrate/nitrite, methyl guanidine (MG), and cytokines. Pulmonary arterial pressure and microvascular permeability were assessed. Lung pathology was examined and scored. The inducible and endothelial NO synthase (iNOS and eNOS) were detected. FE caused ALI and increased biochemical factors. The challenge also resulted in pulmonary hypertension and increased microvascular permeability. The NE appeared to be the first to reach its peak at 1 hr, followed by other factors. Coadministration with PMA exacerbated the FE-induced changes, while SVT attenuated the effects of FE. The FE-induced lung changes were enhanced by PMA, while SVT had the opposite effect. Sivelestat, a neutrophil inhibitor may be a therapeutic choice for patients with acute respiratory distress syndrome (ARDS) following fat embolism.Journal of Biomedical Science 01/2012; 19(1):3. DOI:10.1186/1423-0127-19-3 · 2.74 Impact Factor
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ABSTRACT: Interleukin 6 (IL-6), a marker of inflammation, is one of the major cytokines released during joint replacement. In the orthopedic patient population, high levels have been linked to many adverse effects including acute respiratory distress syndrome, postoperative mental status changes, and fever. We looked to assess the efficacy of low-dose steroids on the postinflammatory response as measured by IL-6 in patients undergoing bilateral total knee replacement (BTKR). The role of steroids has never been evaluated before in that setting. Double-blind, randomized, placebo-controlled study of 30 patients undergoing BTKR. The study was powered in order to detect at least a 25% decrease in IL-6 from control. Hydrocortisone (100 mg) or placebo was given at 2 doses 8 hrs apart to the study and control group respectively. Clinical outcome was assessed as well. Levels of IL-6 were 40% lower in the study group by 10 hrs (P = 0.0037) but were similar to the control group at 24 hrs. Greater hemodynamic stability was noted in the study group with fewer episodes of hypotension postoperatively (P = 0.031). Range of motion gained on discharge was also greatest in the study group (P = 0.049). Absence of infection and normal wound healing were noted in all patients. The use of hydrocortisone significantly decreased the inflammatory response in patients undergoing BTKR as measured by IL-6 production. Further studies looking at clinical implications of such findings in a larger patient population and with a longer course of steroids are warranted.Regional anesthesia and pain medicine 01/2011; 36(1):36-40. DOI:10.1097/AAP.0b013e31820306c5 · 2.12 Impact Factor