Acute Liver Injury Associated with Khat Use in a 24-Year-Old Male.

Chewing khat leaves (Catha edulis) is common cultural practice in Eastern African countries. Khat has been implicated in cases of acute liver injury, sometimes leading to liver failure and requiring transplantation. We report the case of a 24-year-old gentleman presenting with symptoms of acute liver failure. Bloodwork demonstrated hepatocyte-predominant liver injury. Microbiological and serological hepatitis panels were negative, and his liver biopsy demonstrated acute cholestatic hepatitis. He admitted to regular khat use for several years prior to his presentation. His liver function tests improved with cessation of khat use. This is the first reported case of acute khat-associated hepatitis in Canada. Considering cultural practices such as khat chewing in presentations of acute liver injury are important when caring for diverse patient populations.

Variations in Use of Optimal Medical Therapy in Patients With Nonobstructive Coronary Artery Disease: A Population-Based Study.

BACKGROUND: There is a paucity of data on the need for optimal medical therapy (OMT) in nonobstructive coronary artery disease . We sought to understand if there was variation in the use of OMT between hospitals for patients with nonobstructive coronary artery disease, the factors associated with such variation, and its clinical consequences. METHODS AND RESULTS: Using a population-level clinical registry in Ontario, Canada, we identified all patients >66 years undergoing coronary angiography for the indication of stable angina, who had nonobstructive coronary artery disease between November 1, 2010, and October 31, 2013. Hierarchical multivariable logistic models were developed to identify the factors associated with OMT use, with median odds ratio used to quantify the degree of variation between hospitals not explained by the modeled risk factors. Clinical outcomes of interest were all-cause mortality and rehospitalization, with follow-up until March 31, 2015. Our cohort consisted of 5413 patients, of whom 2554 (47.2%) were receiving OMT within 1 year. There was a 2-fold variation in OMT across hospitals (30.4%-61.8%). The variation between hospitals was fully explained by preangiography medication use (median odds ratio of 1.21 in the null model and 1.03 in the full model). There was no difference in risk-adjusted mortality (hazard ratio, 0.94; 95% confidence interval, 0.76-1.16); however, patients receiving OMT had a lower risk of all-cause hospital readmission (hazard ratio, 0.89; 95% confidence interval, 0.84-0.95). CONCLUSIONS: There is wide variation in the use of OMT in patients with nonobstructive coronary artery disease, the major driver of which is differences in baseline medication use.

Fibroblast progenitor cells are recruited into the myocardium prior to the development of myocardial fibrosis.

Using an established model of myocardial hypertrophy and fibrosis after angiotensin II (AngII) infusion, our aim was to characterize the early cellular element involved in the development of myocardial fibrosis in detail. Male Lewis rats were infused with saline or AngII (0.7 mg/kg per day) for up to seven days. Collagen deposition and cellular infiltration were identified by histology stains. Infiltrating cells were grown in vitro and examined by flow cytometry and immunostaining. Chemokine expression was measured using qRT-PCR. AngII infusion resulted in multifocal myocardial cellular infiltration (peak at three days) that preceded collagen deposition. Monocyte chemotactic protein (MCP)-1 transcripts peaked after one day of AngII exposure. Using a triple-labelling technique, the infiltrating cells were found to express markers of leucocyte (ED1(+)), mesenchymal [α-smooth muscle actin (SMA)(+)] and haematopeotic progenitor cells (CD133(+)) suggesting a fibroblast progenitor phenotype. In vitro, ED1(+)/SMA(+)/CD133(+) cells were isolated and grown from AngII-exposed animals. Comparatively few cells were cultured from untreated control hearts, and they were found to be ED1(-)/SMA(+)/CD133(-). We provide evidence that myocardial ECM deposition is preceded by infiltration into the myocardium by cells that express a combination of haematopoietic (ED1, CD133) and mesenchymal (SMA) cell markers, which is a characteristic of the phenotype of fibroblast precursor cells, termed fibrocytes. This suggests that fibrocytes rather than (as is often presumed) leucocytes may have effector functions in the initiation of myocardial fibrosis.

Highly purified human peripheral blood monocytes produce IL-6 but not TNFalpha in response to angiotensin II.

HYPOTHESIS: Monocytes produce pro-inflammatory cytokines in response to Angiotensin II (AngII). INTRODUCTION: AngII has been suggested by many to be pro-inflammatory and likely to contribute to the migration of leukocytes in patients with cardiovascular conditions. MATERIALS AND METHODS: Monocytes were purified from peripheral blood mononuclear cells (PBMCs) by negative selection using antibodies conjugated to magnetic beads. Detection of CD14(+) and AT(1)R expression was achieved by double-labeling flow cytometry. Highly purified monocytes were then stimulated with AngII (6 and 24 h) to assess IL-6 and TNF-α transcript levels by qRT-PCR and protein secretion by ELISA. RESULTS: Monocytes comprised 9.7 ± 2.0% of the PBMCs. Monocyte isolation by negative selection yielded a purity of up to 99.8%. We demonstrated AT(1)R expression on 9.5 ± 0.3% of highly purifed CD14(+)/CD16(-) monocytes. Stimulation of highly purified monocytes with AngII resulted in increased transcript levels of IL-6 at 6 h but not at 24 h, and increased secretion of IL-6 in a dose-dependent manner compared with controls (p <0.01). Conversely, there was no increase in TNF-α mRNA transcripts or protein secretion. CONCLUSIONS: We provide evidence that a CD14(+)/CD16(-) subset of highly purified human monocytes express AT(1)R and respond to AngII exposure in vitro by producing IL-6 but not TNF-α.

Integrins and monocyte migration to the ischemic myocardium.

AIMS: Characterize mononuclear cell migration after acute-myocardial infarction (MI). MATERIAL AND METHODS: Male Lewis rats underwent a left thoracotomy and ligation of the left anterior descending coronary artery (MI group). Control animals underwent thoracotomy without ligation (Sham group). Animals were sacrificed at 0, 2, 4, or 24 hr after the onset of ischemia. Leukocyte migration was assessed using isolated and In(111) labeled mononuclear cells (injected at the onset of ischemia) and gamma-count determined at 24 hours. Inhibition of migration was evaluated with monoclonal anti alpha4 and/or beta2 antibodies. RESULTS: Serum troponin was significantly elevated in animals with MI as compared with Sham (p = .017). Labeled mononuclear cell migration was five-fold higher in MI-treated animals than in Sham (p = .006). ED-1 positive mononuclear cells were confirmed in the left myocardium after 24 hr of ischemia. MCP-1 mRNA was significantly elevated in the left myocardium at 2 hr and 4 hr and peaked at 24 hr (p <.05). In addition, alpha4 integrin blockade inhibited labeled mononuclear cell migration by 22%. Blockade of beta2 integrin inhibited mononuclear cell migration by 48%, while the combined alpha4+beta2 blockade resulted in 59% inhibition of labeled mononuclear cell migration compared with treatment with isotype control antibody (p = .001). CONCLUSIONS: Significant ED1+ mononuclear cell migration within 24 hr of MI correlated with peak MCP-1 mRNA. Monoclonal antibody blockade suggested that early mononuclear cell migration is dependent only in part on alpha4 and beta2 integrins.

Heat shock treatment prior to myocardial infarction results in reduced ventricular remodeling.

BACKGROUND: Heat shock (HS) treatment has been suggested to confer myocardial protection following ischemia. However, the effects of HS on left ventricular (LV) remodeling weeks after infarction have yet to be described. METHODS: Myocardial infarction (MI) was created by coronary ligation in Lewis rats. Two experimental groups of animals were created: HS+MI group (n = 13) and MI group (n = 13). HS treatment consisted of an elevation in core temperature to 42 degrees C for 15 min, 24 hr prior to MI. LV remodeling was assessed by transthoracic echocardiography (day 0, 1, 7, and 28) and by morphometric histology (day 28). RESULTS: There was no significant difference in infarct size (TTC stain 24 hr) between HS+MI and MI groups. Using transthoracic echo there was a significant preservation of LV ejection fraction and fractional shortening in the HS+MI group as compared to MI group (7 and 28 days). Similar trends were seen by histology at 28 days but failed to reach significance. HSP27 expression by myocardial cells was shown to remain up-regulated (at 28 days) in both groups at the edges of the infarct area as compared to control myocardium. CONCLUSIONS: Our findings suggest that HS treatment prior to MI can result in a significant decrease in LV remodeling independent of a reduction in infarct size.

Heat shock treatment results in increased recruitment of labeled PMN following myocardial infarction.

One of the proposed mechanisms for the myocardial protective effects of heat shock (HS) treatment has been a reduction in the inflammatory response. The objective of the present study was to evaluate the impact of HS treatment in an established model of polymorphonuclear cell (PMN) migration following myocardial infarction (MI). Isolated purified PMNs (10 x 10(6) cells) labeled with (51)Cr were injected into Lewis rats following a left thoracotomy and ligation of the left anterior descending coronary artery causing MI. Two experimental groups of animals were created: MI group (n = 11) and HS+MI group (n = 7). HS treatment consisted of an elevation in core temperature to 42 degrees C for 15 min 24 h prior to MI. An additional group of control animals underwent sham thoracotomy (n = 5). All animals were euthanized at 24 h after MI, and gamma counts were obtained to estimate PMN migration. Myocardial injury was confirmed in all experimental animals (histology and echocardiography). The serum troponin I and infarct size (triphenyltetrazolium chloride) were similar in both groups. Labeled PMN migration was significantly higher in HS+MI animals (14.3 x 10(4) +/- 3.7 x 10(4) PMN) compared with MI group (9.5 x 10(4) +/- 3.6 x 10(4); P = 0.01), suggesting increased PMN migration as a result of HS treatment. HS treatment did not affect PMN migration to positive skin control sites (LPS). ICAM-1 myocardial expression was not significantly increased in HS+MI compared with MI group. In summary, HS treatment results in increased PMN migration into myocardium following MI independent of ICAM-1. These findings suggest that the proposed cardioprotective effect of HS may not be entirely due to a downregulation of myocardial inflammation as previously proposed.

Infiltration of polymorphonuclear cells into the post-ischaemic myocardium is dependent on beta2 and alpha4 integrins.

Polymorphonuclear cells (PMN) are believed to be important effector cells responsible the myocardial damage seen following ischaemia. However, the exact kinetics of their migration remains controversial. Isolated PMN (10 x 10(6) cells) labelled with (51)Cr were injected into four groups of Lewis rats: 0 h (T0h; n = 13), 2 h (T2h; n = 7), 4 h (T4h; n = 7) or 6 h following ischaemia (T6h; n = 4). In all recipients, a left thoracotomy and ligation of the left anterior descending coronary was performed. Control animals underwent sham thoracotomy (n = 10). All animals were killed at 24 h and the radioactivity in the tissue measured to estimate labelled PMN migration. Monoclonal antibody blockade was also performed in experimental animals to assess the contribution of beta2 and alpha4 integrins to the PMN migration (n = 32). Labelled PMN migration to the myocardium was similar in all experimental groups, T0-T6h (7.2-11 x 10(5) labelled PMN) and significantly higher than sham controls (2.2 x 10(5) labelled PMN; P = 0.03). In contrast PMN migration to dermal inflammatory sites was highest in T0h group, and reached background level in the T4h and T6h groups. beta2 integrin blockade inhibited labelled PMN migration by 32%. Blockade of alpha4 integrin inhibited PMN migration by 30% while the combined beta2 + alpha4 blockade resulted in 63% inhibition of labelled PMN migration compared to treatment with isotype control antibody (P = 0.035). PMN migration following myocardial ischaemia persists over several hours after myocardial infarction and does not follow similar migration kinetics to dermal inflammation. Our findings also suggest that PMN migration is dependent equally on beta2 and alpha4 integrins.