Assessment of myeloperoxidase and oxidative alpha1-antitrypsin in patients on hemodialysis.

BACKGROUND AND OBJECTIVES: The present study assesses the effects of the oxidative stress marker, myeloperoxidase (MPO), and the possible MPO-related oxidative stress marker, oxidative alpha(1)-antitrypsin (oxAT), on carotid intima-media thickness (CIMT) and protein-energy wasting (PEW) in patients on hemodialysis (HD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Blood samples were obtained from 383 patients before HD to measure WBC count, serum albumin, lipids, high-sensitivity C-reactive protein (CRP), alpha(1)-antitrypsin (AT), interleukin-6, oxidative LDL-C, MPO, and oxAT. We assessed both CIMT and the geriatric nutritional risk index (GNRI) in this cross-sectional competitive study. RESULTS: Levels of MPO and oxAT correlated. Myeloperoxidase was associated with max-CIMT, and oxAT correlated with max-CIMT and GNRI. Multivariate linear regression models showed that MPO and oxAT were independent predictors of increasing max-CIMT, whereas oxAT, but not MPO, independently correlated with GNRI. In four combined MPO and oxAT groups classified according to median values, a multinomial logistic regression model showed that high MPO together with high oxAT was independently associated with increased max-CIMT. Moreover, the OR for max-CIMT with positive PEW and high MPO was significantly increased in the four groups with combined MPO and PEW. CONCLUSIONS: High MPO with high oxAT and high MPO with PEW seem to contribute to plaque formation in patients on HD, whereas elevated MPO or oxAT alone might not predict increasing CIMT. In contrast, a high oxAT value seems to be an independent predictor of PEW in patients on HD.

Cardioprotective effects of erythropoietin in rats subjected to ischemia-reperfusion injury: assessment of infarct size with 99mTc-annexin V.

UNLABELLED: Administration of erythropoietin (EPO) during or immediately after myocardial ischemia can reduce subsequent myocardial apoptosis, a key phenomenon in myocardial ischemia-reperfusion injury. In this study, we assessed the effect of EPO on (99m)Tc-annexin V myocardial uptake and whether the accumulation of (99m)Tc-annexin V can predict cardiac remodeling and functional deterioration. METHODS: Eighteen rats with left coronary artery (LCA) occlusion were randomized to receive either an intravenous injection of EPO (EPO group) or saline (nontherapy [nT] group) immediately after release of the occlusion. After 20 min of LCA occlusion and 30 min of reperfusion, the rats were injected with (99m)Tc-annexin V. One hour after (99m)Tc-annexin V injection, the LCA was reoccluded and (201)Tl was injected intravenously, and the rats were sacrificed 1 min later. The heart was removed and sectioned, and dual-tracer autoradiography was performed to evaluate the distribution of the area at risk (defined on the thallium autoradiograph) and the area of apoptosis (defined on the annexin autoradiograph). Adjacent histologic specimens had deoxyuridine triphosphate nick-end labeling (TUNEL) staining to confirm the presence of apoptosis and were compared with autoradiography. Another 16 rats were randomized to EPO and nT groups and underwent echocardiography immediately after release of the LCA occlusion and at 2 and 4 wk after surgery. RESULTS: The areas of (99m)Tc-annexin V accumulation in the EPO group were smaller than those in the nT group, though the (201)Tl defect areas of these 2 groups were comparable (area ratio, 0.318 +/- 0.038 vs. 0.843 +/- 0.051, P < 0.001, for annexin and 24.8 +/- 2.1 vs. 25.9 +/- 2.6 mm(2), P = NS, for thallium). (99m)Tc-annexin V accumulation correlated with the density of TUNEL-positive cells (r = 0.886, P < 0.001). In the nT group, left ventricular end-diastolic dimension (Dd) increased from baseline at 2 wk by 34.7% +/- 3.8% and remained stable at 34.9% +/- 5.0% at 4 wk after coronary occlusion. In the EPO group, Dd increased by 8.5% +/- 2.1% (P < 0.01 vs. nT at 2 wk) and 13.2% +/- 2.8% (P < 0.01 vs. nT at 4 wk). In the nT group, the left ventricular percentage of fractional shortening decreased by 42.2% +/- 3.4% and 52.9% +/- 3.4% at 2 and 4 wk, respectively, whereas in the EPO group it decreased 9.0% +/- 1.9% at 2 wk (P < 0.01 vs. nT at 2 wk) and 11.1% +/- 6.7% at 4 wk (P < 0.01 vs. nT at 4 wk). CONCLUSION: This study demonstrated that a single treatment with EPO immediately after release of coronary ligation suppressed cardiac remodeling and functional deterioration. (99m)Tc-annexin V autoradiographs and TUNEL staining confirm that this change is due to a decrease in the extent of myocardial apoptosis in the ischemic/reperfused region.

5-[123I]Iodo-A-85380: assessment of pharmacological safety, radiation dosimetry and SPECT imaging of brain nicotinic receptors in healthy human subjects.

Recently, 5-[123I]iodo-3-(2(S)-azetidinylmethoxy)pyridine ([123I]5IA) was developed as a ligand for imaging the nicotinic acetylcholine receptor (nAChR) in human brain using single photon emission computed tomography (SPECT). In the present study, the toxicity and radiation absorbed dose of [123I]5IA were investigated. Behavior and physiological parameters were examined in mice and rats after administration of 5IA. There were no changes in these parameters in animals administered 1 microg/kg of 5IA or less, indicating that the no observed effect level (NOEL) of 5IA was 1 microg/kg. [123I]5IA was then administered to healthy human subjects and serial whole-body images were acquired over 24 hr. Initially, high levels of radioactivity were observed in the liver and urinary bladder and moderate levels in the lungs, kidneys, and brain. Whole brain activity at 1 hr was 4.6 +/- 0.4% of the injected dose and this value gradually decreased with time. The majority (-75%) of the radioactivity was excreted in urine within 24 hr, and less than 1% remained in all organs tested. The biological half-life of [1231]51A averaged 7.2 +/- 4.0 hr. Based on the biodistribution data, radiation absorbed doses were estimated using MIRDOSE 3.1 software with the dynamic bladder model and the ICRP gastrointestinal (GI) tract model. Consequently, the effective dose equivalent was estimated to be 30 +/- 1.4 microSv/MBq, which is an acceptable radiation burden. Having determined the safety of this compound, we performed SPECT imaging in a healthy human subject using 171 MBq of [123I]5IA. SPECT images clearly revealed a cerebral distribution of radioactivity that was consistent with the known distribution of central nAChRs in humans. These results suggest that [123I]5IA is a promising ligand for imaging nAChRs in humans, with an acceptable dosimetry and pharmacological safety at the dose required for adequate SPECT imaging.