Ascorbic acid reduces redox potential in human spermatozoa subjected to heat‐induced oxidative stress

Oxidation–reduction potential (ORP) is a new measure of oxidative stress. It is a balance between the total available oxidants and reductants. This study measures the efficiency of ascorbic acid (AA) against oxidative stress induced by either heat alone or heat and hydrogen peroxide in sperm suspensions using the MiOXSYS System. Two concentrations of ascorbic acid (400 and 600 μmol/L) were tested against heat‐ and heat plus hydrogen peroxide‐induced oxidative stress in sperm suspensions after 2 and 4 hr of incubation. Sperm motility and static oxidation reduction potential (sORP) were measured at 2 and 4 hr of incubation at three different temperatures. A significant decrease in sORP was observed as a function of AA concentration. The 600 μmol/L AA had more pronounced reduction in sORP compared to 400 μmol/L AA (p = .001). Significant decreases in sperm motility ranging from 4.89% to 14.02% were observed both as a function of incubation time and addition of H₂O₂ (p < .001). Ascorbic acid is efficacious to reduce heat‐induced oxidative stress in sperm preparations in vitro. The supplementation of ascorbic acid may be advantageous for semen preparations in IUI, IVF and ICSI.     

Double‐blind,randomised, placebo‐controlled trial on the effect of L‐carnitine and L‐acetylcarnitine on sperm parameters in men with idiopathic oligoasthenozoospermia

Carnitine is essential for energy metabolism and spermatozoa maturation. Combining L‐carnitine and L‐acetylcarnitine with micronutrients has been investigated as a treatment for infertility in men. We evaluated the effects of a therapeutic formulation, Proxeed Plus, on sperm parameters in oligoasthenozoospermic men. This prospective, randomised, double‐blind, placebo‐controlled clinical trial involved 175 males (19–44 years) with idiopathic oligoasthenozoospermia who failed to impregnate their partners (12 months). Males received Proxeed Plus or placebo for 3 and 6 months. Sperm volume, progressive motility and vitality significantly (p < 0.001) improved after 6 months compared to baseline. Sperm DNA fragmentation index significantly decreased compared to baseline (p < 0.001) and the 3‐month therapy (p = 0.014) in treated men. Increased seminal carnitine and α‐glucosidase concentration also positively correlated with improved progressive motility. Decreased DNA fragmentation index was the good predictor of progressive sperm motility >10%, and simultaneous measurement of changes in sperm vitality and DNA fragmentation index gave the highest probability of sperm motility 10% (AUC = 0.924; 95% CI = 0.852–0.996; p < 0.001). Logistic regression analyses revealed DNA fragmentation index decrease as the only independent predictor of sperm motility 10% (OR = 1.106; p = 0.034). We have demonstrated the beneficial effects of carnitine derivatives on progressive motility, vitality and sperm DNA fragmentation. Combining metabolic and micronutritive factors is beneficial for male infertility.     

Decreased serum carnitine is independently correlated with increased tissue accumulation levels of advanced glycation end products in haemodialysis patients

Aim: There is accumulating evidence that advanced glycation end products (AGE) play a role in cardiovascular disease (CVD) in patients with haemodialysis (HD). Carnitine deficiency is frequently observed in HD patients, which may also contribute to CVD. In this study, we examined whether carnitine deficiency was independently associated with increased tissue accumulation levels of AGE in HD patients. Methods: One hundred and twenty‐nine HD patients underwent determinations of blood chemistries including serum level of carnitine. Tissue AGE levels were evaluated by measuring skin autofluorescence with an AGE‐reader. Results: Serum carnitine levels were significantly lower, while skin AGE levels were significantly higher in HD patients compared with healthy controls (P < 0.001). In univariate analysis, β₂‐microglobulin (β₂‐MG) and carnitine (inversely) were correlated with skin AGE levels. Multiple stepwise regression analysis revealed that carnitine levels were one of the independent determinants of skin AGE levels (P = 0.024). When β₂‐MG‐adjusted skin AGE levels were stratified by serum carnitine levels, a statistical significance and dose‐response relationship were observed (P = 0.043). Furthermore, skin AGE levels were one of the independent determinants of serum carnitine levels as well (P = 0.012). Conclusion: The present study demonstrated that decreased carnitine levels were independently associated with increased skin AGE levels in HD patients. Since carnitine is reported to inhibit the formation of AGE in vitro, our study suggests that supplementation of carnitine may be a therapeutic target for preventing the accumulation of tissue AGE and subsequently reducing the risk of CVD in HD patients.     

Expression of NOX5 in human teratozoospermia compared to normozoospermia

Spermatozoa are capable of producing small amounts of reactive oxygen species (ROS), and sperm in teratozoospermia generate more ROS than sperm in normozoospermia. The source of ROS production in ejaculated human sperm has not been fully clarified. Recently, NADPH oxidase 5 (NOX5) was detected in human sperm, and ROS generation by this enzyme was reported. We investigated the magnitude of NOX5 expression in normozoospermic (n = 12) and teratozoospermic (n = 13) semen samples with different percentages of abnormal sperm. The existence of NOX5 enzymes in sperm was analysed by immunocytochemistry and flow cytometry and correlated with morphological abnormalities. Immunofluorescent studies identified NOX5 in acrosomal, equatorial, post‐acrosomal regions, the body and the tail of both normal and abnormal sperm. Teratozoospermic semen samples had higher percentages of NOX5‐positive sperm and expressed more NOX5 (based on higher mean fluorescent intensity) than normal semen samples. Positive correlations were observed between abnormal sperm morphology and both the percentage of NOX5‐positive sperm and the magnitude of NOX5 expression. Based on these findings, we can assume that there is a positive correlation between ROS generation in teratozoospermia and that in NOX5 expression.     

Platelet isoprostane overproduction in diabetic patients treated with aspirin

Aspirin modestly influences cardiovascular events in patients with type 2 diabetes mellitus (T2DM), but the reason is unclear. The aim of the study was to determine whether in T2DM patients aspirin enhances platelet isoprostanes, which are eicosanoids with proaggregating properties derived from arachidonic acid oxidation by platelet NOX2, the catalytic subunit of reduced NAD phosphate oxidase. A cross-sectional study was performed comparing T2DM patients, treated (n = 50) or not treated (n = 50) with 100 mg/day aspirin, with 100 nondiabetic patients, matched for age, sex, atherosclerosis risk factors, and aspirin treatment. A short-term (7 days) treatment with 100 mg/day aspirin also was performed in 36 aspirin-free diabetic and nondiabetic patients. Higher platelet recruitment, platelet isoprostane, and NOX2 activation was found in diabetic versus nondiabetic patients and in aspirin-treated diabetic patients versus nontreated patients (P < 0.001). Platelet thromboxane (Tx) A(2) (P < 0.001) was inhibited in all aspirin-treated patients. In the interventional study, aspirin similarly inhibited platelet TxA(2) in diabetic and nondiabetic patients (P < 0.001). Platelet recruitment, isoprostane levels, and NOX2 activation showed a parallel increase in diabetic patients (P < 0.001) and no changes in nondiabetic patients. These findings suggest that in aspirin-treated diabetic patients, oxidative stress-mediated platelet isoprostane overproduction is associated with enhanced platelet recruitment, an effect that mitigates aspirin-mediated TxA(2) inhibition.     

Elevated circulating levels of soluble CD-40 ligand in haemodialysis patients with symptomatic coronary heart disease

Aim: The CD40–CD40L system has been implicated in the pathogenesis of atherothrombotic complications in cardiovascular disease. The aim of this study was to determine the relationship between plasma soluble CD40 ligand (sCD40L) and symptomatic coronary heart disease (CHD) in end-stage renal disease (ESRD) patients on maintenance haemodialysis (HD). Methods: This cross-sectional study included 57 HD patients, 31 of whom had symptomatic CHD. Lipid profile, markers of endothelial activation such as sCD40L, and both inflammatory and oxidative stress markers were measured and analyzed. Results: The sCD40L concentration was significantly higher in HD patients than in controls (1.34 ± 0.53 vs 0.86 ± 0.12 ng/mL, P < 0.01). Plasma concentration of sCD40L (P < 0.01), soluble vascular adhesion molecule-1 (sVCAM-1; P < 0.01) and high-sensitivity CRP (hsCRP; P < 0.01) were higher in HD patients with symptomatic CHD than in those without CHD. In addition, we also found that oxidative stress biomarkers such as nitrotyrosine (NT), malonaldehyde (MDA) and protein carbonyl (PC) were significantly elevated in patients with symptomatic CHD compared to those without. There was a strong overall positive relationship between sCD40L concentration and sVCAM-1 (r = 0.54, P < 0.001), MDA (r = 0.365, P < 0.01), NT (r = 0.293, r < 0.05) and log-transformed triglycerides (r = 0.275, P < 0.05). Conclusion: Circulating concentrations of sCD40L were elevated in HD patients with symptomatic CHD. This study suggests that CD40–CD40L may play a potentially important role in the atherosclerotic complications of HD patients.     

sCD40L及sP选择素在糖尿病下肢动脉病变介入治疗前后的变化及其意义

目的探讨可溶性CD40配体(sCD40L)和可溶性P选择素(sP选择素)在糖尿病下肢动脉病变发生、发展中的作用及其在下肢动脉介入治疗前后的变化及意义。方法选取2型糖尿病合并下肢动脉病变并成功行介入治疗的患者28例作为A组;选取同期确诊为单纯2型糖尿病患者28例为B组;另选健康体检者28名作为C组。3组患者均在相同条件下抽取肘静脉血测定空腹血糖(FBG)、糖化血红蛋白(HbA1c)、血脂、sCD40L及sP选择素水平。A组介入治疗过程中,导管鞘置入后鞘内取血4ml(术前动脉血),导丝、导管跨越狭窄或闭塞动脉后于其远段取血4ml(缺血部位术前动脉血),球囊扩张或支架植入后(缺血改善后)再于该部位取血4ml(缺血部位术后动脉血),于术后24h、7天分别取肘静脉血4ml,均测定sCD40L及sP选择素的水平。对A组于介入治疗前和治疗后1天分别测量踝肱指数(ABI)及TcPO_2以对比疗效。结果术前静脉血sCD40L、sP选择素水平,A组明显高于B、C组(P均0.01),B组明显高于C组(P均0.01),A组术后24h、7天静脉血sCD40L、sP选择素水平高于术前静脉血(P均0.01),而术后7天sCD40L、sP选择素水平明显低于术后24h(P均0.01)。A组术前静脉血与术前动脉血sCD40L、sP水平的差异无统计学意义(P均0.05);缺血部位术后、术前及介入治疗前动脉血sCD40L水平依次降低(P均0.05);缺血部位术前动脉血sP选择素水平明显高于介入治疗前动脉血(P0.01)。3组术前静脉血sP选择素与sCD40L呈正相关(r=0.750,P0.01)。A组术后24h的ABI、TcPO_2水平明显高于术前水平(P均0.01)。结论糖尿病下肢动脉病变患者sCD40L、sP选择素水平明显升高,表明血小板活化可能是下肢动脉硬化形成的原因之一;下肢动脉介入治疗进一步促进血小板活化并加重炎症反应,可能是介入治疗后再狭窄的原因之一。     

Cytoprotective and Antioxidant Effects of Steen Solution on Human Lung Spheroids and Human Endothelial Cells

Respiratory diseases represent a major healthcare burden worldwide. Lung transplantation (LTx) is the “gold standard” for end‐stage patients, strongly limited by shortage of available/suitable donor lungs. Normothermic ex vivo lung perfusion (EVLP) has significantly increased the number of lungs suitable for transplantation. Steen solution is used for EVLP, but the mechanisms involved in its beneficial properties remain to be clarified. We investigated the effects of Steen solution in an in vitro protocol of cold starvation and normothermic recovery on human lung spheroids, named pneumospheres (PSs), containing epithelial/basal cells, and on endothelial human umbilical vein endothelial cells (HUVEC). Steen solution significantly preserved the viability of PSs, reduced reactive oxygen species (ROS) release by PSs and HUVECs, decreased NADPH‐oxidase (NOX) activity in PSs, and reduced inflammatory cytokines expression levels in HUVECs. Steen solution was able to specifically reduce NADPH oxidase 2 (NOX2) isoform activation, particularly in PSs, as detected by soluble‐NOX2 peptide and p47‐phosphorylation. Interestingly, a specific NOX2 inhibitor could partly mimic the pro‐survival effect of Steen on PSs. We provide the first evidence that Steen solution can preserve lung epithelial/progenitor cells viability partially through NOX2 downregulation, and exert antioxidant effects on parenchymal cells, with consequent ROS reduction. These results suggest that NOX2 inhibition might be an additional strategy to reduce cellular damage during LTx procedures.     

Leucocytes and intrinsic ROS production may be factors compromising sperm chromatin condensation status

Considering that the final protection of the DNA against major assaults in terms of chromatin condensation is finalised in the epididymis, it is not known how sperm production of reactive oxygen species (ROS) and inflammatory processes can contribute to protamine deficiency that is predetermined in the testes. Therefore, this study aimed at investigating relationships between poor chromatin condensation, morphology, ROS production, DNA damage and the impact of the presence of leucocytes. In 70 patients, sperm DNA status was determined using TUNEL and chromomycin A₃ (CMA₃) assays, and ROS‐production by means of dihydroethidine. Morphology was evaluated according to strict criteria. The percentage of CMA₃‐positive spermatozoa and leucocyte concentration (r = 0.178, P = 0.0377) as well as percentage of ROS‐positive spermatozoa (r = 0.3010; P = 0.012) correlated significantly. Particularly, patients with leucocyte counts >0.5 × 10⁶ ml^?1 exhibited higher CMA₃ positivity. No association was found between CMA₃ positivity, TUNEL positivity and sperm morphology. While P‐ (poor prognosis: 0–4% normal morphology) and G‐pattern (good prognosis: 5–14% normal morphology) morphology did not differ regarding chromatin condensation, P‐pattern patients had a significantly higher percentage of DNA fragmentation (P = 0.0323). As oxidative stress is associated with disturbed chromatin condensation, results suggest that the idea that under‐protamination of sperm DNA will automatically lead to DNA fragmentation might have to be revisited.     

The Possible Protective effect of L‐carnitine on Tilmicosin‐induced Cardiotoxicity in Mice

The protective effect of l ‐carnitine was investigated against tilmicosin‐induced cardiotoxic effects including blood creatine kinase (CK), CK‐MB, total sialic acid as well as the alterations in glutathione and malondialdehyde concentrations in mice. Thirty‐two Balb/C mice were divided into four groups including group 1 (control), group 2 (l ‐carnitine, s.c., 500 mg/kg for 5 days), group 3 (tilmicosin, s.c., single dose of 75 mg/kg) and group 4 (l ‐carnitine plus tilmicosin). Serum CK, CK‐MB and malondialdehyde (MDA) levels were significantly (P < 0.05) higher in group 3 compared with those of other groups. Total sialic acid level in group 3 was found to be significantly (P < 0.05) higher than that in groups 1 and 2, as well. Contrary to these results, glutathione level in group 3 was found to be significantly (P < 0.05) lower than that in groups 1 and 2. In group 4, serum CK, CK‐MB, MDA and total sialic acid levels were found to be significantly (P < 0.05) lower than those in group 3. These results suggest that tilmicosin is cardiotoxic in mice as evidenced by higher total sialic acid, CK and CK‐MB. In addition, tilmicosin caused the decrease in glutathione and increase in MDA levels. However, administration of l ‐carnitine could ameliorate these adverse toxic effects of tilmicosin in mice.     

Mitochondrial‐derived reactive oxygen species (ROS) play a causal role in aging‐related intervertebral disc degeneration

Oxidative damage is a well‐established driver of aging. Evidence of oxidative stress exists in aged and degenerated discs, but it is unclear how it affects disc metabolism. In this study, we first determined whether oxidative stress negatively impacts disc matrix metabolism using disc organotypic and cell cultures. Mouse disc organotypic culture grown at atmospheric oxygen (20% O₂) exhibited perturbed disc matrix homeostasis, including reduced proteoglycan synthesis and enhanced expression of matrix metalloproteinases, compared to discs grown at low oxygen levels (5% O₂). Human disc cells grown at 20% O₂ showed increased levels of mitochondrial‐derived superoxide anions and perturbed matrix homeostasis. Treatment of disc cells with the mitochondria‐targeted reactive oxygen species (ROS) scavenger XJB‐5‐131 blunted the adverse effects caused by 20% O₂. Importantly, we demonstrated that treatment of accelerated aging Ercc1^?/Δ mice, previously established to be a useful in vivo model to study age‐related intervertebral disc degeneration (IDD), also resulted in improved disc total glycosaminoglycan content and proteoglycan synthesis. This demonstrates that mitochondrial‐derived ROS contributes to age‐associated IDD in Ercc1^?/Δ mice. Collectively, these data provide strong experimental evidence that mitochondrial‐derived ROS play a causal role in driving changes linked to aging‐related IDD and a potentially important role for radical scavengers in preventing IDD. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1150–1157, 2013

     

Platelet proinflammatory activity in clinically stable patients with CF starts in early childhood

BackgroundEarly onset chronic inflammation is present in CF. Platelets may contribute to inflammation by cytokine release and interaction with leukocytes.MethodsParameters of platelet proinflammatory function (soluble CD62P, soluble CD40L, the percentage of platelet–leukocyte aggregates, platelet CD62P) and platelet procoagulatory function (PAC-1-binding to activated integrin α_IIbβ₃ and expression of integrin α_IIbβ₃ = CD41a) were measured in patients and controls.ResultsLevels of sCD62P, sCD40L were increased in CF irrespective of age and activity of inflammation. The number of platelet–leukocyte aggregates was elevated in older CF patients. PAC-1-binding to platelets decreased with growing activity of inflammation. Exocytosis of CD41a upon platelet activation was reduced.ConclusionIn CF, platelet proinflammatory activity is increased at very young age already and might promote inflammation and tissue damage. On the other hand, platelets seem to downregulate the activation of their most important integrin (α_IIbβ₃) for clot formation.     

Circulating immune markers in advanced renal cell carcinoma during immunotherapy with interferon gamma

Circulating immune markers sICAM-1, sELAM-1, sMHC-I, ₂-MG, sCD4 and sCD8 were evaluated prior to and during immunotherapy with biologically active doses of interferon gamma (IFN-) in 16 patients with advanced renal cell carcinoma (RCC) over a period of 12 months. Compared to 20 healthy controls, significantly (P < 0.01) elevated baseline levels of circulating adhesion molecules sICAM-1 (mean 1166 vs 230 ng/ml) and sELAM-1 (70 vs 17 ng/ml) were found in all patients. Compared to responders (n = 2) or patients with stable disease (n = 2), progressive disease during therapy (n = 12) was associa ed with significantly (P < 0.05) higher mean concentrations of sICAM-1 (1574 vs 962 ng/ml) and sELAM-1 (86 vs 46 ng/ml). Pretherapeutic and intratherapeutic levels of sMHC-I among the RCC patients were significantly (P < 0.05) lower than among the controls (0.41 vs 0.8 ng/ml). sCD4 levels clearly showed the same tendency (24 vs 33 U/l). sCD8 baseline levels, by contrast, were significantly (P < 0.05) elevated (564 vs 336 U/l), reflecting either activation of the NK-cell subset or increased synthesis of CD8 + T-suppressor cells. Again, significantly (P < 0.05) higher intratherapeutic sCD8 concentrations were observable with progressive disease than with response to therapy or stable disease (721 vs 355 U/l). Interestingly, although the biologically active dose of IFN- was defined by an increase in ₂-MG release of at least 30% within 48 h after injection, none of the other markers showed any significant alteration following IFN- administration, suggesting that IFN- in vivo does not produce changes in circulating markers of activation that might be expected on the basis of its effects in vitro. The finding of significantly elevated concentrations of sICAM-1, sELAM-1 and sCD8 in the presence of low sCD4 and sMHC-I levels might be of clinical significance for indicating ongoing tumor progression.     

Different surgical techniques and L‐carnitine supplementation in an experimental varicocele model

We aimed to investigate the impact of various varicocelectomy techniques and/or L‐carnitine as an adjunct treatment, following the emergence of oxidative stress, on the expression levels of SCF/c‐kit signalling pathways in spermatogenesis. Forty‐two rats were divided into seven groups: group 1 (G1) control; group 2 (G2) sham; group 3 (G3) varicocele; group 4 (G4) varicocele + varicocelectomy with testicular nonartery sparing; group 5 (G5) same as G4 but with artery sparing; group 6 (G6) same as G4 but with L‐carnitine and group 7 (G7) same as G5 with L‐carnitine. mRNA expression levels of SCF and c‐kit were measured quantitatively using real‐time polymerase chain reaction. CASP‐3 activity at protein level was determined, and histological evaluation was performed. mRNA expression level of SCF increased in G6 as compared to control group (3.52‐folds change; P = 0.035), whereas mRNA expression level of c‐kit gene remained the same. We found that in the left testis of G6 group, mRNA expression level of SCF increased 2.2‐folds in comparison with the right testis (P < 0.05). There were no statistically significant differences in the CASP‐3 protein expression levels between the control and other groups. When Cosentino Score analyses of immunostaining were conducted, we observed no significant differences among groups. Spermatogenic failure could be primarily due to a sertoli cell dysfunction. Although surgical treatment has been the best option for management of varicocele, auxiliary agents like L‐carnitine may be considered as supportive treatment regimes in addition to conventional surgical treatments.     

Low‐Grade Metabolic Acidosis May Be the Cause of Sodium Chloride–Induced Exaggerated Bone Resorption

Stepwise increase in NaCl intake in healthy male test subjects led to a low‐grade metabolic acidosis. This was most likely the cause for increased bone resorption during high sodium chloride intake, as determined by analyzing bone resorption markers. Introduction : We examined the effect of increased dietary sodium chloride (NaCl) on bone metabolism and acid‐base balance. Materials and Methods : Subjects were nine healthy men (mean age, 25.7 ± 3.1 yr; mean body weight [BW], 71.5 ± 4.0 kg). During the first period (6 days), subjects received 0.7 mEq NaCl/kg BW per day (phase 1), during the second period (6 days) 2.8 mEq NaCl/kg BW per day (phase 2), during the third period (10 days) 7.7 mEq NaCl/kg BW per day (phase 3), and during the fourth period (6 days) 0.7 mEq NaCl/kg BW per day (phase 4). Results : Twenty‐four‐hour urinary excretion of calcium and sodium rose significantly with increasing NaCl intake (p < 0.001 for both). Urinary excretion of bone resorption markers C‐ and N‐terminal telopeptide of type I collagen (CTX, NTX) increased from phase 2 to phase 3 (CTX, p = 0.013; NTX, p < 0.001) and decreased from phase 3 to phase 4 (CTX, p < 0.001; NTX, p = 0.002). Bone formation markers N‐terminal propeptide of type I procollagen, bone‐specific alkaline phosphatase, and osteocalcin remained unchanged from low to high NaCl intake. Blood pH levels decreased (p = 0.04) between phases 1 and 3. Blood bicarbonate (HCO₃^?) and base excess (BE) decreased from phases 1 to 3 (p < 0.001 for both) and from phases 2–3 (HCO₃^?, p = 0.003; BE, p = 0.015). Nearly all bone resorption markers and acid‐base variables reached their baseline levels in phase 4. Conclusions : We conclude that low‐grade metabolic acidosis may be the cause of NaCl‐induced exaggerated bone resorption.     

Contemporary Oxygenator Design: Shear Stress‐Related Oxygen and Carbon Dioxide Transfer

Design of contemporary oxygenators requires better understanding of the influence of hydrodynamic patterns on gas exchange. A decrease in blood path width or an increase in intraoxygenator turbulence for instance, might increase gas transfer efficiency but it will increase shear stress as well. The aim of this clinical study was to examine the association between shear stress and oxygen and carbon dioxide transfer in different contemporary oxygenators during cardiopulmonary bypass (CPB). The effect of additional parameters related to gas transfer efficiency, that is, blood flow, gas flow, sweep gas oxygen fraction (FiO₂), hemoglobin concentration, the amount of hemoglobin pumped through the oxygenator per minute—Qhb, and shunt fraction were contemplated as well. Data from 50 adult patients who underwent elective CPB for coronary artery bypass grafting or aortic valve replacement were retrospectively analyzed. Data included five different oxygenator types with an integrated arterial filter. Relationships were determined using Pearson bivariate correlation analysis and scatterplots with LOESS curves. In the Capiox FX25, Fusion, Inspire 8F, Paragon, and Quadrox‐i groups, mean blood flows were 4.8 ± 0.9, 5.3 ± 0.7, 4.9 ± 0.7, 5.0 ± 0.6, and 5.7 ± 0.6 L/min, respectively. The mean O₂ transfer/m² membrane surface area was 44 ± 14, 51 ± 9, 60 ± 10, 63 ± 14, and 77 ± 18, respectively, whereas the mean CO₂ transfer/m² was 26 ± 14, 60 ± 22, 73 ± 29, 74 ± 19, and 96 ± 20, respectively. Associations between oxygen transfer/m² and shear stress differed per oxygenator, depending on oxygenator design and the level of shear stress (r = 0.249, r = 0.562, r = 0.402, r = 0.465, and r = 0.275 for Capiox FX25, Fusion, Inspire 8F, Paragon, and Quadrox‐i, respectively, P < 0.001 for all). Similar associations were noted between CO₂ transfer/m² and shear stress (r = 0.303, r = 0.439, r = 0.540, r = 0.392, and r = 0.538 for Capiox FX25, Fusion, Inspire 8F, Paragon, and Quadrox‐i, respectively, P < 0.001 for all). In addition, O₂ transfer/m² was strongly correlated with FiO₂ (r = 0.633, P < 0.001), blood flow (r = 0.529, P < 0.001), and Qhb (r = 0.589, P < 0.001). CO₂ transfer/m² in contrast was predominately correlated to sweep gas flow (r = 0.567, P < 0.001). The design‐dependent relationship between shear stress and gas transfer revealed that every oxygenator has an optimal range of blood flow and thus shear stress at which gas transfer is most efficient. Gas transfer is further affected by factors influencing the O₂ or CO₂ concentration gradient between the blood and the gas compartment.     

Soluble CD30 and ELISA‐detected human leukocyte antigen antibodies for the prediction of acute rejection in pediatric renal transplant recipients

Biomarker‐based post‐transplant immune monitoring for the prediction of impending graft rejection requires validation in specific patient populations. Serum of 28 pediatric renal transplant recipients within the framework of a well‐controlled prospective randomized trial was analyzed pre‐ and post‐transplant for soluble CD30 (sCD30), a biomarker reflecting mainly T‐cell reactivity, and anti‐human leukocyte antigen (anti‐HLA) antibody reactivity, a biomarker for B‐cell activation. A sCD30 concentration ≥40.3 U/ml on day 14 was able to discriminate between patients with or without biopsy‐proven acute rejection (BPAR) with a sensitivity of 100% and a specificity of 76%. Six of seven patients (86%) with BPAR showed a sCD30 above this cut‐off, whereas only 3/21 patients (14%) without BPAR had a sCD30 above this cut‐off (P = 0.004). For pre‐ and post‐transplant anti‐HLA class II reactivities by enzyme‐linked immunosorbent assay, a cut‐off value of 140 optical density was able to discriminate rejecters from nonrejecters with a sensitivity of 86% or 71% and a specificity of 81% or 90%, respectively. Withdrawal of steroids was associated with a approximately twofold higher serum sCD30 compared to controls, but did not affect anti‐HLA reactivities. An increased post‐transplant sCD30 serum concentration and positive pre‐ and post‐transplant anti‐HLA class II reactivities are informative biomarkers for impending BPAR in pediatric renal transplant recipients. (TWIST, Clinical Trial No: FG‐506‐02‐43)     

Reduction of renal ischemia reperfusion injury by hydrogen sulfide preconditioning through inhibiting oxidative stress

Objective To investigate the possible role of oxidative stress in the protection of hydrogen sulfide during renal ischemia reperfusion. Methods Male Wistar rats were randomly divided into 3 groups: sham operation (Sham) group, renal ischemia reperfusion (IR) group subject to occlusion of left renal pedicle for 45 min then reperfusion for 24 h, and sodium hydrosulfide (NaHS) preconditioning group with continuous infusion of NaHS (450 nmol/min) by left renal artery for 10 min before ischemia reperfusion. Renal injuries were evaluated by PAS staining. The protein levels of NADPH oxidase (NOX) 4, NOX2 were analyzed by Western blotting. The reactive oxygen species (ROS) level of renal tissue was determined by dihydroethidium (DHE) staining assay. Renal superoxide dismutase (SOD), malonic dialdehyde (MDA) and Scr, BUN were evaluated by chromatometry assay. Cell apoptosis were evaluated by TdT-mediated dUTP nick end labeling (TUNEL) staining. Results Compared with Sham group, in IR group the renal NOX4 and NOX2 protein expressions, the existence of acute tubular necrosis and ROS expression were up-regulated (all P＜0.01); MDA, Scr, and BUN were increased and SOD was decreased significantly in IR-treated kidney (all P＜0.01); Moreover, more apoptotic cells presented in the risk zone of IR-treated kindey (P＜0.01). The effects induced by IR were inhibited by NaHS. Compared to that in IR group, NaHS precondition reversed IR-induced damages of renal function and renal tissue, increased SOD activity and decreased MDA expression (all P＜0.05), as well as reduced the expression of NOX4, NOX2 and ROS (all P＜0.05). Moreover, NaHS precondition reduced apoptosis after IR (P＜0.05). Conclusions NaHS alleviates renal ischemia reperfusion injury through inhibiting oxidative stress. Hydrogen sulfide can decrease ROS by inhibiting the activation of NOX, further inhibit the activation of NOD-like receptor, and alleviate kidney damage.     

Inflammatory activation and recovering BKV‐specific immunity correlate with self‐limited BKV replication after renal transplantation

As BKV‐associated nephropathy has emerged as an important cause of allograft failure, it has been of major importance to find immune mechanisms suitable to identify kidney transplant recipients (KTRs) at increased risk of BKV replication. We monitored 29 KTRs with seven measurements during the first year post‐transplantation. BKV‐specific T cells directed to 5 BKV proteins were analyzed in an interferon‐γ ELISPOT assay. BKV‐specific antibodies were measured using an ELISA. The extent of immunosuppression and inflammatory activation were quantified by measures of immune function including lymphocyte subpopulations, IP‐10, and adhesion molecule serum levels. All 5 BKV‐specific T cells increased significantly from diagnosis to resolution of BKV replication (P < 0.001). While antistructural T cells were significantly higher in KTRs with BKV replication (P < 0.05), no differences were observed for antismall t‐ and large T‐antigen‐directed T cells (P > 0.05). Interestingly, 65% of KTRs without BKV replication showed transient appearance of antismall t‐ and large T‐antigen‐directed T cells. Although no significant differences were observed for T‐cell subpopulations and adhesion molecules, IP‐10 levels increased significantly during BKV replication (P < 0.05). Assessment of BKV‐specific T cells identifies recovering BKV‐specific immunity in KTRs with BKV replication and suggests their protective ability in KTRs without BKV replication. Increases in IP‐10 levels stress the importance of infiltrating inflammatory leukocytes in the regulation of BKV replication and point to inflammatory activation in the pathogenesis of BKV replication.     

Excitatory effect of propiverine hydrochloride on urethral activity in rats

Objectives: To investigate the effects of the antimuscarinic agent, propiverine, on the bladder and urethra in rats. Methods: A total of 54 female rats were given propiverine, imidafenacin (an antimuscarinic agent), or distilled water by gavage once or twice daily. After 2 weeks, bladder and urethral activity were recorded under urethane anesthesia. In the propiverine group, the changes of bladder and urethral activity before and after intravenous injection of α₁‐adrenergic antagonists (prazosin, silodosin and naftopidil) were also recorded. Furthermore, the leak point pressure after electrical stimulation of abdominal wall muscles was measured in rats with vaginal distension from the control and propiverine groups. Results: Intravesical baseline pressure was significantly lower in the propiverine and imidafenacin groups compared with the control group, whereas the urethral baseline pressure was significantly higher in the propiverine group compared with the control or imidafenacin groups. Intravenous injection of prazosin (an α₁‐receptor antagonist) significantly decreased the urethral baseline pressure in both of the propiverine and control groups. Intravenous injection of silodosin and naftopidil (α_1A‐ and α_1D‐receptor antagonists, respectively) significantly decreased the maximum contraction pressure and the urethral baseline pressure in the propiverine group. The leak point pressure of the propiverine group was significantly higher than that of the control group. Conclusions: An increase of catecholamines after propiverine administration might activate smooth muscle of the proximal urethra via α_1A‐ and α_1D‐adrenergic receptors, as well as activating urethral and pelvic floor striated muscle via the spinal motoneurons.