Pharmacological effects of denervated muscle atrophy due to metabolic imbalance in different periods

Denervation-induced skeletal muscle atrophy can potentially cause the decline in the quality of life of patients and an increased risk of mortality.Complex pathophysiological mechanisms with dynamic alterations have been documented in skeletal muscle atrophy resulting from innervation loss.Hence,an in-depth comprehension of the key mechanisms and molecules governing skeletal muscle atrophy at varying stages,along with targeted treatment and protection,becomes essential for effective atrophy management.Our preliminary research categorizes the skeletal muscle atrophy process into four stages using microarray analysis.This review extensively discusses the pathways and molecules potentially implicated in regulating the four stages of denervation and muscle atrophy.Notably,drugs targeting the reactivare oxygen species stage and the inflammation stage assume critical roles.Timely intervention during the initial atrophy stages can expedite protection against skeletal muscle atrophy.Additionally,pharmaceutical intervention in the ubiquitin-proteasome pathway associated with atrophy and autophagy lysosomes can effectively slow down skeletal muscle atrophy.Key molecules within this stage encompass MuRF1,MAFbx,LC3II,p62/SQSTM1,etc.This review also compiles a profile of drugs with protective effects against skeletal muscle atrophy at distinct postdenervation stages,thereby augmenting the evidence base for denervation-induced skeletal muscle atrophy treatment.

miRNA targeted signaling pathway in the early stage of denervated fast and slow muscle atrophy

Denervation often results in skeletal muscle atrophy.Different mechanisms seem to be involved in the determination between denervated slow and fast skeletal muscle atrophy.At the epigenetic level,mi RNAs are thought to be highly involved in the pathophysiological progress of denervated muscles.We used mi RNA microarrays to determine mi RNA expression profiles from a typical slow muscle（soleus muscle） and a typical fast muscle（tibialis anterior muscle） at an early denervation stage in a rat model.Results showed that mi R-206,mi R-195,mi R-23 a,and mi R-30 e might be key factors in the transformation process from slow to fast muscle in denervated slow muscles.Additionally,certain mi RNA molecules（mi R-214,mi R-221,mi R-222,mi R-152,mi R-320,and Let-7e） could be key regulatory factors in the denervated atrophy process involved in fast muscle.Analysis of signaling pathway networks revealed the mi RNA molecules that were responsible for regulating certain signaling pathways,which were the final targets（e.g.,p38 MAPK pathway; Pax3/Pax7 regulates Utrophin and follistatin by HDAC4; IGF1/PI3K/Akt/m TOR pathway regulates atrogin-1 and Mu RF1 expression via Fox O phosphorylation）.Our results provide a better understanding of the mechanisms of denervated skeletal muscle pathophysiology.

Perlecan and synaptophysin changes in denervated skeletal muscle

The present study observed sciatic nerve and gastrocnemius muscle changes in denervated rats using morphology methods, and assessed expression of perlecan, an extracellular matrix component, which is located at the skeletal muscle cell surface as acetylcholine esterase, as well as synaptophysin, a synaptic marker. Results showed degeneration and inflammation following transection of the sciatic nerve. In addition, the sciatic nerve-dominated skeletal muscle degenerated with mild inflammation, indicating that skeletal muscle atrophy primarily contributed to denervation-induced nutritional disturbances. With prolonged injury time （1-4 weeks post-injury）, perlecan expression gradually decreased and reached the lowest level at 4 weeks, but synaptophysin expression remained unchanged after denervation. Results suggested that perlecan expression was more sensitive to denervation and reflected regional extracellular matrix changes following denervation.

Role of the Notch Signaling Pathway in Fibrosis of Denervated Skeletal Muscle

In order to investigate the role of the Notch signaling pathway in skeletal muscle fibrosis after nerve injury, 60 Sprague-Dawley rats were selected and divided randomly into a control and two experimental groups. Group A served as controls without any treatment. Rats in groups B were injected intraperitoneally with 0.2 mL PBS and those in group C were injected intraperitoneally with 0.2 mL PBS+100 ymol/L, 0.2 mL N-[N-(3,5-difluorophenacetyl)-l-alanyl]- S-phenylglycine t-butyl ester (DAPT, a gamma-secretase inhibitor that suppresses Notch signaling) respectively, on postoperative days 1, 3, 7, 10, and 14 in a model of denervation-induced skeletal muscle fibrosis by right sciatic nerve transection. Five rats from each group were euthanized on postoperative days 1, 7, 14, and 28 to collect the right gastrocnemii, and hematoxylin and eosin (HE) staining, immunohistochemistry test, real-time PCR, and Western blotting were performed to assess connective tissue hyperplasia and fibroblast density as well as expression of Notch 1, Jagged 1, and Notch downstream molecules Hes 1 and collagen I (COL I) on day 28. There was no significant difference in HE-stained fibroblast density between group B and C on postoperative day 1. However, fibroblast density was significantly higher in group B than in group C on postoperative days 7, 14, and 28. Notch 1, Jagged 1, Hes 1, and COL I proteins in the gastrocnemius were expressed at very low levels in group A but at high levels in group B. Expression levels of these proteins were significantly lower in group C than in group B (P<0.05), but they were higher in group C than in group A (P<0.05) on postoperative day 28. We are led to conclude that locking the Notch signaling pathway inhibits fibrosis progression of denervated skeletal muscle. Thus, it may be a new approach for treatment of fibrosis of denervated skeletal muscle.

Electrical stimulation and denervated muscles after spinal cord injury

Spinal cord injury(SCI)population with injury below T10 or injury to the cauda equina region is characterized by denervated muscles,extensive muscle atrophy,infiltration of intramuscular fat and formation of fibrous tissue.These morphological changes may put individuals with SCI at higher risk for developing other diseases such as various cardiovascular diseases,diabetes,obesity and osteoporosis.Currently,there is no available rehabilitation intervention to rescue the muscles or restore muscle size in SCI individuals with lower motor neuron denervation.We,hereby,performed a review of the available evidence that supports the use of electrical stimulation in restoration of denervated muscle following SCI.Long pulse width stimulation(LPWS)technique is an upcoming method of stimulating denervated muscles.Our primary objective is to explore the best stimulation paradigms(stimulation parameters,stimulation technique and stimulation wave)to achieve restoration of the denervated muscle.Stimulation parameters,such as the pulse duration,need to be 100–1000 times longer than in innervated muscles to achieve desirable excitability and contraction.The use of electrical stimulation in animal and human models induces muscle hypertrophy.Findings in animal models indicate that electrical stimulation,with a combination of exercise and pharmacological interventions,have proven to be effective in improving various aspects like relative muscle weight,muscle cross sectional area,number of myelinated regenerated fibers,and restoring some level of muscle function.Human studies have shown similar outcomes,identifying the use of LPWS as an effective strategy in increasing muscle cross sectional area,the size of muscle fibers,and improving muscle function.Therefore,displaying promise is an effective future stimulation intervention.In summary,LPWS is a novel stimulation technique for denervated muscles in humans with SCI.Successful studies on LPWS of denervated muscles will help in translating this stimulation technique to the clinical level as a rehabilitation intervention after SCI.

Denervated muscle extract promotes recovery of muscle atrophy through activation of satellite cells. An experimental study

Purpose: The objective of the present study was to determine whether a denervated muscle extract(DmEx) could stimulate satellite cell response in denervated muscle.Methods: Wistar rats were divided into 4 groups: normal rats, normal rats treated with DmEx, denervated rats, and denervated rats treated with DmEx. The soleus muscles were examined using immunohistochemical techniques for proliferating cell nuclear antigen, desmin, and myogenic differentiation antigen(MyoD), and electron microscopy was used for analysis of the satellite cells.Results: The results indicate that while denervation causes activation of satellite cells, DmEx also induces myogenic differentiation of cells localized in the interstitial space and the formation of new muscle fibers. Although DmEx had a similar effect in nature on innervated and denervated muscles, this response was of greater magnitude in denervated vs. intact muscles.Conclusion: Our study shows that treatment of denervated rats with DmEx potentiates the myogenic response in atrophic denervated muscles.

Role of Transforming Growth Factor-β1 in the Process of Fibrosis of Denervated Skeletal Muscle

In order to investigate the biological function of transforming growth factor-β1（TGF-β1） during fibrosis in denervated skeletal muscle,we recruited sciatic nerve injury model of SD rats in which denervated gastrocnemius was isolated for analysis.At different time points after operation,denervated muscle was examined by several methods.Masson trichrome staining showed morphological changes of denervated skeletal muscle.Quantitative RT-PCR detected the rapid increase of TGF-β1 expression at mRNA level after nerve injury.It was found that a peak of TGF-β1 mRNA expression appeared one week post-operation.The expression of collagen Ⅰ（COL Ⅰ） mRNA was up-regulated in the nerve injury model as well,and reached highest level two weeks post-injury.Immunoblot revealed similar expression pattern of TGF-β1 and COL Ⅰ in denervated muscles at protein level.In addition,we found that the area of the gastrocnemius muscle fiber was decreased gradually along with increased interstitital fibrosis.Interestingly,this pathological change could be prevented,at least partly,by local injection of TGF-β1 antibodies,which could be contributed to the reduced production of COL Ⅰ by inhibiting function of TGF-β1.Taken together,in this study,we demonstrated that the expression of TGF-β1 was increased significantly in denervated skeletal muscle,which might play a crucial role during muscle fibrosis after nerve transection.

Key changes in denervated muscles and their impact on regeneration and reinnervation

The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle＇s residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair.

Overexpression of MyoD Attenuates Denervated Rat Skeletal Muscle Atrophy and Dysfunction

Nerve injury commonly contributes to irreversible functional impairment, reconstruction of the function of muscle is big challenge. In denervated skeletal muscle, therapid expression of MyoD mRNA and protein also occurs during early postdenervation, which suggested that the function of denervation-induced MyoD may be to prevent denervation-induced skeletal muscle atrophy. However, the detail mechanism is not clear. Therefore, in this study, we established a stable-transfected MyoD L6 cell line. After the operation for cutting the rats’ tibial nerve, the MyoD-L6 cells were injected in the gastrocnemius, the function of the gastronemius was monitored. It was found that injected the MyoD-L6 cells could attenuate the muscle atrophy and dysfunction. Therefore, overexpression of MyoD could serve as a new therapy strategy to cure denervation-induced dysfunction of skeletal muscle.

The Protective Effect of EGB761 on Vessels of Denervated Gastrocnemius in Rats and Its Mechanism

This study investigated the protective effect of EGB761 on blood vessels of denervated gastrocnemius of rat and its possible mechanism. Fifteen male adult SD rats were randomly divided into three groups： normal control group （n=3）, control group （n=6） and EGB761-treated group （n=6）. The rats in the control and EGB761-treated group underwent a neurotomy to bilateral sciatic nerves. Then, they were administered EGB761 [100 mg/（kg.d）] and isovolumic normal saline, respectively by gavage everyday. No treatment was given to the rats in the normal control group. Gastrocnemius was harvested at 1 and 3 week（s） postoperatively in each group. Immunohistochemical method was used to detect the ratio of capillary/fiber （CFR） of denervated gastrocnemius and the expression of VEGF, fetal liver kinase -l（Flk-1） receptor and HSP70 in the vascular wall. The results showed that in the normal control group, VEGF, Flk-1 and HSP70 were expressed in the vessel wall of gastrocnemius, with Flk-1 expressed only in the endothelial cell of vessels. CFR in the EGB761-treated group was significantly higher than that in the control group at 1 week and 3 week（s） after neurotomy. The expression of VEGF and Flk-1 in the vessel wall of both control and EGB761-treated group was much lower than that in the normal control group, and the expression of these proteins in the EGB761-treated group was decreased as compared with that in the control group. The expression of HSP70 in the vessel wall of both control and EGB761-treated groups was enhanced when compared with that in the normal control group, and it was substantially augmented in the EGB761-treated group in comparison to the control group. It was concluded that EGB761 has a protective effect on blood vessels of denervated gastrocnemius, which is related to the increased HSP70 expression but not the expression of VEGF and its receptor Flk-1.

Experimental study on aortic remodeling in sinoaortic denervated rats

Objective:To studytheaorticremodelingproducedby chronicsinoaorticdenervation(SAD)anditstime course,andto studytheroleof humoralfactorintheSAD-inducedaorticremodeling.Methods:In ratswithchronicSAD or shamoperation,theaorticstructurewasmeasuredby computer-assistedimageanalysis,theaorticfunctionby isolated arterypreparation,andangiotensinⅡconcentrationby radioimmunoassay.Results and Conclusion:Theaorticstructural remodelingdevelopedprogressivelyat4,8,16and32weeksafterSAD.AorticstructuralremodelingafterSADexpressed mainlyas aortichypertrophydue to SMC growthand collagenaccumulation.The aorticcontractionelicitedby nore-pinephrine(NE)wasprogressivelyincreased8,16and32weeksafterSAD.Theaorticrelaxationelicitedby acetylcholine(ACh)wasdepressed8,16and32weeksafterSAD.Inaddition,in32-weekSADratstheNE-inducedcontractionwasnot increasedby endothelialdenudation.TheseindicatedthattheincreasedcontractionanddepressedrelaxationafterSAD wererelatedto thechangeof endotheliumand/orthechangeof interactionbetweenendotheliumandSMC.In10-week SADrats,plasmaangiotensinⅡconcentrationremainedunchanged,whereasaorticangiotensinⅡconcentrationwas sig-nificantlyincreased,suggestingthatactivationof tissuerenin-angiotensinsystemmaybe involvedin SAD-inducedaortic remodeling.

Inflammation and apoptosis accelerate progression to irreversible atrophy in denervated intrinsic muscles of the hand compared with biceps: proteomic analysis of a rat model of obstetric brachial plexus palsy

In treating patients with obstetric brachial plexus palsy,we noticed that denervated intrinsic muscles of the hand become irreversibly atrophic at a faster than denervated biceps.In a rat model of obstetric brachial plexus palsy,denervated intrinsic musculature of the forepaw entered the irreversible atrophy far earlier than denervated biceps.In this study,isobaric tags for relative and absolute quantitation were examined in the intrinsic musculature of forepaw and biceps on denervated and normal sides at 3 and 5 weeks to identify dysregulated proteins.Enrichment of pathways mapped by those proteins was analyzed by Kyoto Encyclopedia of Genes and Genomes analysis.At 3 weeks,119 dysregulated proteins in denervated intrinsic musculature of the forepaw were mapped to nine pathways for muscle regulation,while 67 dysregulated proteins were mapped to three such pathways at 5 weeks.At 3 weeks,27 upregulated proteins were mapped to five pathways involving inflammation and apoptosis,while two upregulated proteins were mapped to one such pathway at 5 weeks.At 3 and 5 weeks,53 proteins from pathways involving regrowth and differentiation were downregulated.At 3 weeks,64 dysregulated proteins in denervated biceps were mapped to five pathways involving muscle regulation,while,five dysregulated proteins were mapped to three such pathways at 5 weeks.One protein mapped to inflammation and apoptotic pathways was upregulated from one pathway at 3 weeks,while three proteins were downregulated from two other pathways at 5 weeks.Four proteins mapped to regrowth and differentiation pathways were upregulated from three pathways at 3 weeks,while two proteins were downregulated in another pathway at 5 weeks.These results implicated inflammation and apoptosis as critical factors aggravating atrophy of denervated intrinsic muscles of the hand during obstetric brachial plexus palsy.All experimental procedures and protocols were approved by the Experimental Animal Ethics Committee of Fudan University,China(approval No.DF-325)in January 2015.

Neurosurgical and pharmacological management of dystonia

Dystonia characterizes a group of neurological movement disorders characterized by abnormal muscle movements,often with repetitive or sustained contraction resulting in abnormal posturing.Different types of dystonia present based on the affected body regions and play a prominent role in determining the potential efficacy of a given intervention.For most patients afflicted with these disorders,an exact cause is rarely identified,so treatment mainly focuses on symptomatic alleviation.Pharmacological agents,such as oral anticholinergic administration and botulinum toxin injection,play a major role in the initial treatment of patients.In more severe and/or refractory cases,focal areas for neurosurgical intervention are identified and targeted to improve quality of life.Deep brain stimulation(DBS)targets these anatomical locations to minimize dystonia symptoms.Surgical ablation procedures and peripheral denervation surgeries also offer potential treatment to patients who do not respond to DBS.These management options grant providers and patients the ability to weigh the benefits and risks for each individual patient profile.This review article explores these pharmacological and neurosurgical management modalities for dystonia,providing a comprehensive assessment of each of their benefits and shortcomings.

The observation of transplanted embryonic motoneurons in the denervated muscles of adult rats

OBJECTIVE: To observe the survival of embryonic motoneurons after they were transplanted into the denervated skeletal muscles and to find a new method to retard the atrophy of denervated muscles. METHODS: Dissociated embryonic motoneurons prelabled with 5-bromo-2'-deoxyuridine (Brdur) on the embryonic days 12 were injected into the denervated gastrocnemius muscles of adult rats. Then gastrocnemius muscles were processed with Nissl staining, acetylcholinesterase staining and Brdur immunocytochemical staining to show the implanted motoneurons at 9 and 22 weeks post-transplantation. Myofibrillar ATPase staining was used to show the morphology of muscle fibers. The rats in experimental group were implanted with embryonic motoneurons in the predenervation muscles, while the rats in control group were injected with just culture medium without motoneurons. RESULTS: Embryonic motoneurons survived, developed and extended long axons to form neuromuscular junctions with the denervated muscles. The differentiation of muscle fibers and fiber type grouping occurred among bigger fibers in experimental group. The transverse area was smaller and there was no apparent fiber type grouping in control group. CONCLUSIONS: Embryonic motoneurons can survive, develop and reinnervate denervated muscles after being transplanted into denervated muscles. It is worth further investigating on ameliorating the atrophy of denervated muscle.

GSK3β inhibitor promotes myelination and mitigates muscle atrophy after peripheral nerve injury

Delay of axon regeneration after peripheral nerve injury usually leads to progressive muscle atrophy and poor functional recovery. The Wnt/β-catenin signaling pathway is considered to be one of the main molecular mechanisms that lead to skeletal muscle atrophy in the elderly. We hold the hypothesis that the innervation of target muscle can be promoted by accelerating axon regeneration and decelerating muscle cell degeneration so as to improve functional recovery of skeletal muscle following peripheral nerve injury. This process may be associated with the Wnt/β-catenin signaling pathway. Our study designed in vitro cell models to simulate myelin regeneration and muscle atrophy. We investigated the effects of SB216763, a glycogen synthase kinase 3 beta inhibitor, on the two major murine cell lines RSC96 and C2C12 derived from Schwann cells and muscle satellite cells. The results showed that SB216763 stimulated the Schwann cell migra- tion and myotube contraction. Quantitative polymerase chain reaction results demonstrated that myelin related genes, myelin associated glycoprotein and cyclin-D1, muscle related gene myogenin and endplate-associated gene nicotinic acetylcholine receptors levels were stimulated by SB216763. Immunocytochemical staining revealed that the expressions of ^-catenin in the RSC96 and C2C12 cytosolic and nuclear compartments were increased in the SB216763-treated cells. These findings confirm that the glycogen synthase kinase 3 beta in- hibitor, SB216763, promoted the myelination and myotube differentiation through the Wnt/β-catenin signaling pathway and contributed to nerve remyelination and reduced denervated muscle atrophy after peripheral nerve injury.

Stimulating effect of thyroid hormones in peripheral nerve regeneration:research history and future direction toward clinical therapy

Injury to peripheral nerves is often observed in the clinic and severe injuries may cause loss of motor and sensory functions.Despite extensive investigation,testing various surgical repair techniques and neurotrophic molecules,at present,a satisfactory method to ensuring successful recovery does not exist.For successful molecular therapy in nerve regeneration,it is essential to improve the intrinsic ability of neurons to survive and to increase the speed of axonal outgrowth.Also to induce Schwann cell phenotypical changes to prepare the local environment favorable for axonal regeneration and myelination.Therefore,any molecule that regulates gene expression of both neurons and Schwann cells could play a crucial role in peripheral nerve regeneration.Clinical and experimental studies have reported that thyroid hormones are essential for the normal development and function of the nervous system,so they could be candidates for nervous system regeneration.This review provides an overview of studies devoted to testing the effect of thyroid hormones on peripheral nerve regeneration.Also it emphasizes the importance of combining biodegradable tubes with local administration of triiodothyronine for future clinical therapy of human severe injured nerves.We highlight that the local and single administration of triiodothyronine within biodegradable nerve guide improves significantly the regeneration of severed peripheral nerves,and accelerates functional recovering.This technique provides a serious step towards future clinical application of triiodothyronine in human severe injured nerves.The possible regulatory mechanism by which triiodothyronine stimulates peripheral nerve regeneration is a rapid action on both axotomized neurons and Schwann cells.

神经递质释放中的有关蛋白

神经递质释放中的有关蛋白ＮＩＰＳ１９９５年２月号综述了神经递质释放过程中的许多重要蛋白质的作用。这些蛋白质分属于突触囊泡膜、胞液及神经末梢质膜。在突触囊泡膜上的蛋白有：Ｓｙｎａｐｔｏｂｒｅｖｉｎ，Ｓｙｎａｐｔｏｔａｇｍｉｎ，Ｓｙｎａｐｔｏｐｈｙ－ｓｉ...

Renal sympathetic nervous system and the effects of denervation on renal arteries

Resistant hypertension is associated with chronic activation of the sympathetic nervous system resulting in various comorbidities. The prevalence of resistant hypertension is often under estimated due to various reasons. Activation of sympathetic nervous system at the renal-as well as systemic-level contributes to the increased level of catecholamines and resulting increase in the blood pressure. This increased activity was demonstrated by increased muscle sympathetic nerve activity and renal and total body noradrenaline spillover. Apart from the hypertension, it is hypothesized to be associated with insulin resistance, congestive heart failure and obstructive sleep apnea. Renal denervation is a novel procedure where the sympathetic afferent and efferent activity is reduced by various techniques and has been used successfully to treat drug-resistant hypertension improvement of various metabolic derangements.Renal denervation has the unique advantage of offering the denervation at the renal level, thus mitigating the systemic side effects. Renal denervation can be done by various techniques including radiofrequency ablation, ultrasound guided ablation and chemical ablation. Various trials evaluated the role of renal denervation in the management of resistant hypertension and have found promising results. More studies are underway to evaluate the role of renal denervation in patients presenting with resistant hypertension in different scenarios. Appropriate patient selection might be the key in determining the effectiveness of the procedure.

Early changes of graft function,cytokines and superoxide dismutase serum levels after donor liver denervation and Kupffer cell depletion in a rat-to-rat liver transplantation model

BACKGROUND: Hepatic reperfusion injury may cause acute inflammatory damage, producing significant organ dysfunction, and is an important problem in liver transplantation. This experiment aimed to study early changes of hepatic function after donor liver denervation and Kupffer cell depletion in rat-to-rat liver transplantation and to evaluate the effect of pre-treatment on liver reperfusion injury. METHODS: Donor rats were divided into four groups: control group; group G was pre-treated with gadolinium chloride (G), an inhibitor of Kupffer cells; group H with hexamethonium (H), a sympathetic ganglionic blocking agent; and group HG, with combined H and G pre-treatment. Under the same conditions, serum alanine aminotransferase (ALT), arterial ketone body ratio (AKBR), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and superoxide dismutase (SOD) of recipient rats were assessed at 4, 8, 16 and 24 hours after liver transplantation. Histological studies of the grafts were compared. RESULTS: HG pre-treatment significantly decreased ALT, TNF-alpha, and IL-6 levels, increased AKBR and SOD levels, and demonstrated less pathological damage at 8, 16 and 24 hours compared with the control group. Similar trends were also found in the other groups (G and H). However, the differences among them were not significant at 4 postoperative hours. CONCLUSIONS: Donor denervation and Kupffer cell depletion had preventive effect on liver reperfusion injury. HG pre-treatment is a feasible and reproducible method to protect grafts from reperfusion injury.

Renal sympathetic denervation in resistant hypertension

Resistant hypertension remains a major clinical problem despite the available multidrug therapy.Over the next decades,its incidence will likely increase given that it is strongly associated with older age and obesity.Resistant hypertension patients have an increased cardiovascular risk,thus effective antihypertensive treatment will provide substantial health benefits.The crosstalk between sympathetic nervous system and kidneys plays a crucial role in hypertension.It influences several pathophysiological mechanisms such as the central sympathetic tone,the sodium balance and the systemic neurohumoral activation.In fact,studies using several animal models demonstrated that the renal denervation prevented and attenuated hypertension in multiple species.Large reductions in blood pressure were also observed in malignant hypertension patients submitted to sympathectomy surgeries.However,these approaches had an unacceptably high rates of periprocedural complications and disabling adverse events.Recently,an innovative non-pharmacological therapy that modulates sympathetic activation has been successfully developed.Renal sympathetic percutaneous denervation is an endovascular procedure that uses radiofrequency energy to destroy the autonomic renal nerves running inside the adventitia of renal arteries.This method represents a promising new approach to the strategy of inhibiting the sympathetic nervous system.The aim of this review is to examine the background knowledge that resulted in the development of this hypertension treatment and to critically appraise the available clinical evidence.