Nitric oxide donors offer protection to RBC from storage lesion

BackgroundRed blood cell (RBC), which is the most commonly transfused blood component, due to its ability to save a life in absence of any other blood components, can be stored up to maximum 6 weeks by following standard preservation procedure. During storage, RBC undergoes various biophysical and biochemical changes (commonly known as storage lesion) for which blood transfusion with “old RBC” shows a lot of clinical problems especially relevant to critically ill patients. Recent research on S-nitrosylation of haemoglobin to improve oxygen delivery of banked blood revealed the important role of nitric oxide (NO) in protecting storage lesion.Materials and methodsIn the present study, we used various “NO donating” chemicals with different NO release dynamics and chemistries in RBC storage cocktails to test the effects of NO on storage lesion. Changes in different storage markers were evaluated after 7 days storage of pre-treated RBC.ResultsAll the NO donors have shown protection against hemolysis. However, S-nitroso glutathione (GSNO) ranks first in shielding RBCs from storage lesion and additionally, it helps in elevating the value of 2, 3-di phosphoglycerate (2, 3-DPG), improving the RBC membrane fluidity and decreasing the adhesion towards endothelial monolayer.DiscussionPresent study reveals that NO released from NO donors confers protection against storage lesions of the RBC. Further, the study confirms that pre-treatment with GSNO, a NO donor and a nitrosylating agent, ensures the best protection to RBC during low temperature storage, when compared to other NO donor treatments.     

Targeting sirtuin activity with nicotinamide riboside reduces neuroinflammation in a GWI mouse model

Gulf War Illness (GWI) affects 30% of veterans from the 1991 Gulf War (GW), who suffer from symptoms that reflect ongoing mitochondria dysfunction. Brain mitochondria bioenergetics dysfunction in GWI animal models corresponds with astroglia activation and neuroinflammation. In a pilot study of GW veterans (n = 43), we observed that blood nicotinamide adenine dinucleotide (NAD) and sirtuin 1 (Sirt1) protein levels were decreased in the blood of veterans with GWI compared to healthy GW veterans. Since nicotinamide riboside (NR)-mediated targeting of Sirt1 is shown to improve mitochondria function, we tested whether NR can restore brain bioenergetics and reduce neuroinflammation in a GWI mouse model. We administered a mouse diet supplemented with NR at 100μg/kg daily for 2-months to GWI and control mice (n = 27). During treatment, mice were assessed for fatigue-type behavior using the Forced Swim Test (FST), followed by euthanasia for biochemistry and immunohistochemistry analyses. Fatigue-type behavior was elevated in GWI mice compared to control mice and lower in GWI mice treated with NR compared to untreated GWI mice. Levels of plasma NAD and brain Sirt1 were low in untreated GWI mice, while GWI mice treated with NR had higher levels, similar to those of control mice. Deacetylation of the nuclear-factor κB (NFκB) p65 subunit and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) was an increase in the brains of NR-treated GWI mice. This corresponded with a decrease in pro-inflammatory cytokines and lipid peroxidation and an increase in markers of mitochondrial bioenergetics in the brains of GWI mice. These findings suggest that targeting NR mediated Sirt1 activation restores brain bioenergetics and reduces inflammation in GWI mice. Further evaluation of NR in GWI is warranted to determine its potential efficacy in treating GWI.     

人类免疫缺陷病毒暴露前预防的应用与挑战

抗病毒治疗不仅将HIV感染从一个致死性疾病转变为一种可以治疗的慢性疾病，同时减少了HIV在人群间的传播，近年来“治疗即是预防”的观念已被人们所认可。随着研究的深入，人们发现HIV暴露前预防（PrEP）能有效减少HIV在高危人群间的传播。临床试验显示PrEP是安全的，可以有效预防HIV感染。目前，欧美国家及WHO指南均推荐对男男性行为者、感染HIV高风险的异性性行为者、HIV单阳伴侣中的HIV阴性者以及静脉吸毒者等高危人群进行PrEP。推荐使用的药物和方法是每日口服替诺福韦和恩曲他滨合剂，部分人群也可使用替诺福韦。PrEP应结合其他预防措施如安全套使用、静脉吸毒的处理以及抗病毒治疗来进一步降低HIV感染的风险。目前，PrEP面临的主要挑战是伦理学、药物可及性、服药依从性以及使用率等问题，应该针对高危人群大力推行PrEP，让更多的人群受益减少HIV感染。     

HPLC法检查腺苷注射液的有关物质

目的:建立腺苷注射液中有关物质的检查方法。方法:采用高效液相色谱法。色谱柱为Agilent TC C18,流动相为乙腈-0.01 mol/L磷酸二氢钾溶液(pH 5.8)(12∶88),流速为1.0 ml/min,检测波长为260 nm。已知杂质按外标法以峰面积计算含量;总杂质及其他单个杂质以自身对照法计算。结果:在该色谱条件下,腺苷与各杂质分离良好,腺苷检测质量浓度线性范围为0.3³0μg/ml,特定杂质尿苷、鸟苷、肌苷及腺嘌呤检测质量浓度线性范围均为0.0330μg/ml,特定杂质尿苷、鸟苷、肌苷及腺嘌呤检测质量浓度线性范围均为0.03³.0μg/ml(r=0.999 83.0μg/ml(r=0.999 8¹.000),检测限为0.03、0.21、1.20、0.21、0.03 ng。结论:该方法操作简单、灵敏度高,为更好地控制产品的质量提供了有效的检查方法。     

Effect of creatine phosphate administration on the rat heart adenylate pool

Creatine phosphate (CP) has been shown to possess some pharmacological properties. When added to cardioplegic solutions it improves their myocardial protection. Furthermore exogenous creatine phosphate shows an anti-arrhythmic effect in the experimental animal and appears to decrease lactate formation following haemorrhagic shock. These properties have been ascribed to the conservation of the tissue stores of ATP. Recently Down et al. have observed higher rat heart levels of ATP and creatine phosphate after the intravenous administration of creatine phosphate. Since it is difficult to find the conditions for an increase of the adenylate pool, it seems of interest to establish whether the ATP increase is due to a rise of the total adenylate pool or of the energy charge or of both. Similarly the higher creatine phosphate concentration may be ascribed to a variation of the CP/creatine ratio or to an increase in the creatine plus CP pool. In the present paper we report that the administration of creatine phosphate raises both the adenylate pool and the energy charge. An increase of creatine and the creatine phosphate pool was also observed.     

Proteomic changes in rat kidney injured by adenine and the regulation of anemoside B4

Adenine is commonly used to establish the animal models for chronic kidney injury and its renal interstitial fibrosis. As an endogenous substance, adenine-induced kidney damage has not yet been fully studied and elucidated, except for inflammatory reaction. Here we analyzed the proteomics of kidney of rats after adenine overloading using LS-MS/MS assay, and observed the role of anemoside B4 (B4). The results showed that adenine could down-regulate 285 proteins and up-regulate 164 proteins in rat kidney tissue compared with the normal group. Down-regulated proteins mainly affected related pathways, such as energy metabolism, while up-regulated proteins affected inflammatory response pathways and metabolic pathways. B4 could significantly reverse the down-regulation of about 40 proteins, which were involved in mitochondria, redox processes, extracellular exosomes, acetylation and other signaling pathways. Simultaneously, B4 could inhibit the up-regulation of five proteins caused by adenine, which were involved in cell cycle, oocyte meiosis, PI3K-Akt and other signaling pathways. Further experimental results of mRNA expression using real-time PCR assay supported the proteomic analysis. Therefore, we proposed that the damage of rat kidney caused by adenine was more complicated, not only with an inflammatory reaction, but also with extensive effects to various metabolic processes in the body. This work provided a valuable clue for comprehensive understanding of adenine-induced renal damage.     

KATP channel interaction with adenine nucleotides

ATP-sensitive potassium (K(ATP)) channels are regulated by adenine nucleotides to convert changes in cellular metabolic levels into membrane excitability. Hence, elucidation of interaction of SUR and Kir6.x with adenine nucleotides is an important issue to understand the molecular mechanisms underlying the metabolic regulation of the K(ATP) channels. We analyzed direct interactions with adenine nucleotides of each subunit of K(ATP) channels. Kir6.2 binds adenine nucleotides in a Mg(2+)-independent manner. SUR has two NBFs which are not equivalent: NBF1 is a Mg(2+)-independent high affinity nucleotide binding site, whereas NBF2 is a Mg-dependent low affinity site. Although SUR has ATPase activity at NBF2, it is not used to transport substrates against the concentration gradient unlike other ABC proteins. The ATPase cycle at NBF2 serves as a sensor of cellular metabolism. This may explain the low ATP hydrolysis rate compared to other ABC proteins. Based on studies of photoaffinity labeling, a model of K(ATP) channel regulation is proposed, in which K(ATP) channel activity is regulated by SUR via monitoring the intracellular MgADP concentration. K(ATP) channel activation is expected to be induced by the cooperative interaction of ATP binding at NBF1 and MgADP binding at NBF2.     

Effects of calcium ions on adenine nucleotide translocase from cardiac muscle

The properties of a specific adenosine nucleotide translocase from rat and pigeon heart mitochondria are similar to those of the system from liver. In particular, the K_m for external ADP is very low, i.e. about 7 μm. The maximum activity of the translocase system, which was measured by following the exchange of adenine nucleotides across the mitochondrial membrane, or the K_m of the system for ADP or ATP were not affected by Ca²⁺ concentration in the range 0.001 to 10 μm. Consequently the concentration change in sarcoplasmic Ca²⁺ that modifies the activities of several key metabolic enzymes plus the myofibrillar ATPase is unlikely to affect the activity of the translocase. However, in confirmation of previous work, higher concentrations of Ca²⁺ (up to 400 μm) increased considerably the exchange of the adenine nucleotides. There is some recent evidence that heart muscle mitochondria possess high affinity binding sites for Ca²⁺ in the mitochondrial membrane, which bind up to 300 nmol Ca²⁺ per g of heart muscle. It is emphasized that, if the adenine nucleotide translocase and the high affinity binding sites for Ca²⁺ are adjacent (or identical), the effects of the higher concentrations of Ca²⁺ on the translocase could be of considerable importance in control of the rate of translocation in heart muscle.     

The mitochondrial permeability transition pore regulates Parkinson's disease development in mutant α-synuclein transgenic mice

Parkinson's disease (PD) is a movement disorder caused by neurodegeneration in neocortex, substantia nigra and brainstem, and synucleinopathy. Some inherited PD is caused by mutations in α-synuclein (αSyn), and inherited and idiopathic PD is associated with mitochondrial perturbations. However, the mechanisms of pathogenesis are unresolved. We characterized a human αSyn transgenic mouse model and tested the hypothesis that the mitochondrial permeability transition pore (mPTP) is involved in the disease mechanisms. C57BL/6 mice expressing human A53T-mutant αSyn driven by a thymic antigen-1 promoter develop a severe, age-related, fatal movement disorder involving ataxia, rigidity, and postural instability. These mice develop synucleinopathy and neocortical, substantia nigra, and cerebello-rubro-thalamic degeneration involving mitochondriopathy and apoptotic and non-apoptotic neurodegeneration. Interneurons undergo apoptotic degeneration in young mice. Mutant αSyn associated with dysmorphic neuronal mitochondria and bound voltage-dependent anion channels. Genetic ablation of cyclophilin D, an mPTP modulator, delayed disease onset, and extended lifespans of mutant αSyn mice. Thus, mutant αSyn transgenic mice on a C57BL/6 background develop PD-like phenotypes, and the mPTP is involved in their disease mechanisms.