Effects of antioxidant drugs in rats with acute renal injury

Acute renal failure is mainly caused by ischemia/reperfusion (I/R) injury or nephrotoxic drugs, in which reactive oxygen species (ROS) may play an important role. Therefore, antioxidants are expected to decrease the vulnerability of renal injury associated with oxidative challenges. α-Lipoic acid (α-LA), potent antioxidant, could act as ROS scavengers, iron chelators and enzyme modulators. In rats with acute renal injury, dysregulation of aquaporin (AQP) water channels and sodium transporters has been noted. I/R injury or cisplatin induced marked down-regulation of AQP1, AQP2 and AQP3 water channels, and type-3 Na-H exchanger, Na,K-ATPase, and Na-K-2Cl cotransporters, in association with impairment of urinary concentration and tubular sodium reabsorption. Treatment with α-LA prevented the dysregulation of AQP channels and sodium transporters, along with improved urinary concentrating capability and renal sodium reabsorption.

Gentamicin decreases guanylyl cyclase activity in rat glomerulus

BACKGROUND

Effects of gentamicin (GM) on the local natriuretic peptide (NP) and nitric oxide (NO) systems in the kidney were investigated.

METHODS

Male Sprague-Dawley rats (180-200 g) were intramuscularly injected with GM (100 mg/kg/day) for 5 days. The expression of NO synthase (NOS) isoforms was determined by Western blot analysis, and that of NPs by real-time polymerase chain reaction. The activity of guanylyl cyclase was also determined by the amount of guanosine 3',5'-cyclic monophosphate (cGMP) generated in responses to atrial natriuretic peptide (ANP) or sodium nitroprusside (SNP).

RESULTS

GM treatment resulted in renal failure in association with increases in urinary flow and the fractional excretion of sodium. Accordingly, the expression of inducible NOS was increased in the cortex, while that of endothelial NOS remained unchanged. The urinary excretion of NO metabolites was increased. The expression of ANP, brain natriuretic peptide and C-type natriuretic peptide mRNA was increased in the kidney. The cGMP production provoked by either ANP or SNP was decreased in the glomerulus, but not in the papilla.

CONCLUSION

GM-induced nephropathy may be causally related with decreased guanylyl cyclase activities in the glomerulus.

Increased Renal Expression of Aquaporin-3 in Rats Inhibited Type 2 11β-Hydroxysteroid Dehydrogenase

AIMS

To investigate whether the regulation of aquaporin (AQP) channels is altered by inhibition of type 2 11beta-hydroxysteroid dehydrogenase (11betaHSD2).

METHODS

Male Sprague-Dawley rats were treated with glycyrrhizic acid (GA, 2 g/l drinking water) for 7 days. The expression of AQP2 and AQP3 was determined in the kidney by immunoblotting and immunohistochemistry. The expression of Gsalpha and type VI adenylyl cyclase, and the activity of adenylyl cyclase were also determined.

RESULTS

Following the GA treatment, the expression of 11betaHSD2 was significantly decreased in the kidney. The expression of AQP3 was increased, while that of AQP2 remained unchanged. Plasma renin activity and serum aldosterone levels were decreased. Plasma arginine vasopressin (AVP) levels were comparable between the groups. Neither the forskolin-stimulated cAMP generation nor the expression of Gsalpha and type VI adenylyl cyclase was altered significantly.

CONCLUSION

A decreased expression of 11betaHSD2 may result in an upregulation of AQP3, in which AVP/cAMP-dependent mechanisms are unlikely to be involved.

Altered Regulation of type 3 Na+/H+exchanger, type 1 Na+/HCO3-cotransporter, and Na+,K+-ATPase in the Kidney of Rats with Experimental Rhabdomyolysis

Metabolic acidosis was shown to correlate with deterioration of renal function in patients with rhabdomyolysis. The present study was aimed to investigate whether the changes of type 3 Na⁺/H⁺ exchanger (NHE3), type 1 Na⁺/HCO₃^- cotransporter (NBC1), and Na⁺,K⁺-ATPase α1 subunit may play a role in the pathogenesis of metabolic acidosis in glycerol-induced experimental rhabdomyolysis. Male Sprague-Dawley rats were deprived of fluid intake for 24 hours, and then were injected with 50% glycerol in normal saline (10 mL/kg, intramuscularly). At 24 hours after the glycerol injection, rats were sacrificed by decapitation. Control rats were injected with normal saline. The protein expression of NHE3, NBC1 and Na⁺,K⁺-ATPase α1 subunit was determined in the cortex of the kidney by immunoblotting and immunohistochemistry. Following the treatment of glycerol, creatinine clearance was significantly decreased, and high anion gap metabolic acidosis developed. In the experimental group, the expression of Na⁺,K⁺-ATPase α1 subunit was significantly decreased in the cortex of the kidney. On the contrary, the expression of NHE3 and NBC1 was significantly increased. Immunohistochemical analyses confirmed the immunoblotting data. In conclusion, the coordinate up-regulation of NHE3 and NBC1 may play an adaptive role against the metabolic acidosis in glycerol-induced rhabdomyolysis.

A case of malignant otitis externa caused by Candida glabrata in a patient receiving haemodialysis

A 74-y-old male receiving haemodialysis presented with right-sided otalgia, otorrhoea and diffuse swelling on the right external auditory canal. Following an initial successful treatment with prolonged intravenous antibiotics, the patient relapsed with a secondary infection in the same site due to Candida glabrata. We report an unusual case of malignant otitis externa caused by the fungus C. glabrata.

Long-term predictive factors of major adverse cardiac events in patients with acute myocardial infarction complicated by cardiogenic shock

BACKGROUND

Cardiogenic shock (CS) after acute myocardial infarction (AMI) develops in 5-10% of patients and it is associated with high mortality. The aim of this study is to assess the predictive factors of mortality for patients with AMI and CS.

METHODS

Two hundred fifty five AMI patients with CS (the mean age was 66.0 +/- 11.0 years, M:F=156:99) out of 1268 AMI patients who admitted at Chonnam National University Hospital between July 2000 and June 2002 were analyzed according to the clinical characteristics, coronary angiographic findings and MACE during admission and for the 1-year clinical follow-up.

RESULTS

Among the enrolled patients, 129 patients survived without MACE (Group I, mean age 64.2 +/- 10.6 years, M:F=76:53), and 126 patients had MACE (Group II, mean age 68.1 +/- 10.0 years, M:F = 80:46) during admission or during the 1-year follow-up period. There were significant differences in age between the Groups I and II (64.2 +/- 10.6 vs. 68.1 +/- 11.0 years, respectively, p = 0.004) and the previous MI history (0 vs. 17.4%, respectively, p<0.001). The left ventricular ejection fraction (EF) was lower in Group II (Group I vs. II: 49.1 +/- 13.0 vs. 39.1 +/- 12.9%, p < 0.001). The levels of troponin (Tn) I and C-reactive protein (CRP) were higher in Group II (Group I vs. II: 29.2 +/- 7.72 vs. 50.8 +/- 5.17 ng/dL, p = 0.017, 3.8 +/- 0.48 vs. 9.9 +/- 1.21 mg/dL, p < 0.001 respectively). Left main stem lesion (LMSL) was more common in Group II than in Group I (0.7% vs. 22.0%, respectively, p = 0.004). In-hospital death was associated with low Thrombolysis In Myocardial Infarction (TIMI) flow after coronary revascularization.

CONCLUSION

Old age, a previous MI history, high Tn and CRP, low EF and LMSL are associated with higher MACE for patients with AMI and CS. Coronary revascularization with TIMI 3 flow lowers the in-hospital mortality.

Predictive Factors of Major Adverse Cardiac Events in Acute Myocardial Infarction Patients Complicated by Cardiogenic Shock Undergoing Primary Percutaneous Coronary Intervention

BACKGROUND

The aim of this study was to assess in-hospital mortality and major adverse cardiac events (MACE) during long-term clinical follow-up of patients who developed cardiogenic shock (CS) after acute myocardial infarction (AMI) and who underwent primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

The data from 147 patients with CS after AMI (61.7 +/-10.4 years, M:F =156:99) who underwent primary PCI at Chonnam National University Hospital between January 1999 and December 2002 were analyzed: clinical characteristics, coronary angiographic findings and mortality during admission, and MACE during a 1-year clinical follow-up. Of the enrolled patients, 121 patients survived (group I, M:F =94:27) and 26 died (group II, M:F =14:12) during admission. By binary logistic regression analysis, in-hospital death was associated with low Thrombolysis In Myocardial Infarction (TIMI) flow after coronary revascularization (p=0.02, odds ratio (OR) =1.3). Eighty-nine patients (60.5%) survived without MACE during the 1-year clinical follow-up and MACE was associated with a C-reactive protein (CRP) of more than 1 mg/dl (p=0.002, OR =6.3) and low TIMI flow after coronary revascularization (p<0.001, OR =7.8).

CONCLUSIONS

Primary PCI achieving TIMI 3 flow reduces in-hospital death in AMI with CS. High concentration of CRP and low TIMI flow are associated with MACE during long-term clinical follow-up.

Effect of Combined Intracoronary Adenosine and Nicorandil on No-Reflow Phenomenon During Percutaneous Coronary Intervention

BACKGROUND

This study aimed to clarify the effect of intracoronary administration of combined adenosine and nicorandil on the no-reflow phenomenon.

METHODS AND RESULTS

Fifty patients (67+/-10 years, 30 male) with acute myocardial infarction (AMI) who developed no-reflow phenomenon during primary percutaneous coronary intervention (PCI) between June 2001 and May 2003 comprised the study group, which was divided into 2 groups: group I [25 patients, 67+/-10 years, 13 male; adenosine (24 microg/ml) alone in addition to nitrate] and group II [25 patients, 66+/-9 years, 17 male; combined intracoronary administration of adenosine and nicorandil (2 mg/ml) in addition to nitrate]. In-hospital and 6-month major adverse cardiac events (MACE) after PCI were compared between the 2 groups. Risk factors of coronary disease, left ventricular ejection fraction and wall motion score were not significantly different between the 2 groups (p=NS). Time interval from the onset of chest pain to PCI, number of involved vessels, lesion type according to ACC/AHA classification and TIMI flow grade (TFG) were not significantly different in both groups (p=NS). Incidence of thrombosis or dissection after balloon angioplasty, diameter and length of stent, and use of Reopro during PCI were not significantly different. TFG after PCI (2.0+/-0.9 vs 2.6+/-0.6, p=0.024), DeltaTFG (1.5+/-1.1 vs 2.2+/-1.0, p=0.033) and difference in TIMI frame count (TFC) before and after PCI (DeltaTFC) were greater in group II than group I (45.2+/-24.5 vs 63.6+/-23.2, p=0.014). Myocardial blush score 3 was obtained more frequently in group II than group I (44% vs 76%, p=0.014). In-hospital death did not occur in any of group II, but 4 patients of group I died (p=0.043). Two cases of MACE developed in each group and heart failure occurred in 3 (12%) of group I and 1 (4%) of group II patients during the 6-month follow-up (p=NS).

CONCLUSIONS

Intracoronary administration of adenosine combined with nicorandil may improve both the occurrence of no-reflow in patients during PCI for AMI and short-term clinical outcome, compared with adenosine alone.