Analgesia via blockade of NGF/TrkA signaling does not influence fracture healing in mice

Abatement of fracture‐related pain is important in patient welfare. However, the frequently used non‐steroidal anti‐inflammatory drugs are considered to impair fracture healing through blockade of cyclooxygenase‐2. An alternative for fracture‐related pain treatment may be blockade of nerve growth factor (NGF)/neurotrophic tyrosine kinase receptor type 1 (TrkA) signaling. Because the effect of blocking this signal‐pathway on bone healing has not been extensively investigated, we addressed this issue by applying neutralizing antibodies that target NGF and TrkA, respectively, in a mouse fracture model. Mice with a knock‐in for human TrkA underwent femur osteotomy and were randomly allocated to phosphate‐buffered‐saline, anti‐NGF‐antibody, or anti‐TrkA‐antibody treatment. The analgesic effect of the antibodies was determined from the activity and the ground reaction force of the operated limb. The effect of antibody administration on fracture healing was assessed by histomorphometry, micro‐computed tomography, and biomechanics. NGF/TrkA‐signaling blockade had no negative effect on fracture healing as callus formation and maturation were not altered. Mice treated with anti‐TrkA antibody displayed significantly greater activity on post‐operative day 2 compared to PBS treatment indicating effective analgesia. Our data indicate, that blockade of NGF/TrkA signaling via specific neutralizing antibodies for pain reduction during fracture healing does not influence fracture healing. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1235–1241, 2015.     

Beneficial actions of neurotrophin treatment on diabetes-induced hypoalgesia in mice

Studies were carried out in streptozotocin-treated diabetic mice to evaluate their behavioral responses to different noxious stimuli. In opposition to rats, streptozotocin-injected diabetic mice display a persistent hypoalgesia to non-noxious mechanical stimulation (von Frey monofilament). Similarly, nocifensive responses of diabetic mice to formalin injection were significantly reduced in both acute and inflammatory phases. However, no overt differences were detected between nondiabetic and diabetic mice in their sensitivity to noxious heat (radiant heat), cold (acetone), or noxious mechanical (pinprick) stimuli applied to the hind paw. To evaluate whether neurotrophin treatment could normalize the sensory deficits, nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was administered intrathecally to diabetic mice for 3 weeks. Neurotrophin-treated mice were also compared to mice that received insulin for 3 weeks. Both NGF and insulin treatment significantly restored mechanical and chemogenic behavioral responses of diabetic mice. In contrast, GDNF treatment only reversed behavioral responses to chemogenic stimuli during the acute phase of the formalin test. These results demonstrate that diabetic mice develop reduced sensitivity to mechanical and chemical stimuli. Furthermore, these studies show that dorsal root ganglion neurons in diabetic mice are responsive to treatment with either NGF or GDNF; however, these 2 neurotrophins differ in their ability to affect distinct somatosensations.     

Past, present and future of A(2A) adenosine receptor antagonists in the therapy of Parkinson's disease

Several selective antagonists for adenosine A_2A receptors (A_2AR) are currently under evaluation in clinical trials (phases I to III) to treat Parkinson's disease, and they will probably soon reach the market. The usefulness of these antagonists has been deduced from studies demonstrating functional interactions between dopamine D₂ and adenosine A_2A receptors in the basal ganglia. At present it is believed that A_2AR antagonists can be used in combination with the dopamine precursor L-DOPA to minimize the motor symptoms of Parkinson's patients. However, a considerable body of data indicates that in addition to ameliorating motor symptoms, adenosine A_2AR antagonists may also prevent neurodegeneration. Despite these promising indications, one further issue must be considered in order to develop fully optimized antiparkinsonian drug therapy, namely the existence of (hetero)dimers/oligomers of G protein-coupled receptors, a topic that is currently the focus of intense debate within the scientific community. Dopamine D₂ receptors (D₂Rs) expressed in the striatum are known to form heteromers with A_2A adenosine receptors. Thus, the development of heteromer-specific A_2A receptor antagonists represents a promising strategy for the identification of more selective and safer drugs.     

神经生长因子对脑出血血肿灶周神经元和神经胶质细胞的影响

目的 探讨神经生长因子（NGF）对脑出血血肿灶周神经元和神经胶质细胞的影响。方法 健康家犬28只．随机分为两组：NGF组（n=20）：注血后0．5h，将NGF 2000 AU立体定向导入血肿灶周区；脑出血（ICH）组（n=8）：只注血，不注药。在ICH后1、3、10、28d四个时间点进行以下检测：①采用Purdy评分观察临床神经功能恢复情况。②采用免疫组化SP法，检测外源性NGF在血肿灶周脑组织中的有效表达。③激光共聚焦显微镜检测血肿灶周神经元烯醇化酶（NSE）、神经纤维酸性蛋白（GFAP）荧光单标阳性细胞的数目。结果 ①1～3d Purdy评分两组比较无显著性差异（P〉0．05），但10～28d评分NGF组显著好于ICH组（P〈0．05）。②NGF组血肿灶周免疫阳性细胞3d时大量出现，染色较深。持续10d，而ICH组表达量少且持续时间短（P〈0．05）。③NGF组激光共聚焦显微镜下NSE、GFAP单标阳性细胞数均明显多于ICH组（P〈0，05）。结论 外源性NGF立体定向导入血肿灶周区，早期能够通过保护神经元提高存活率；晚期能够通过促进胶质细胞适度增生、神经纤维生长来促进血肿灶周神经功能的修复。     

ShcC proteins: Brain aging and beyond

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.     

鼠神经生长因子对新生儿缺氧缺血性脑病患儿血清神经肽Y和神经元特异性烯醇化酶水平的影响及疗效观察

摘 要 目的： 探讨鼠神经生长因子对新生儿缺氧缺血性脑病(HIE)患儿血清神经肽Y(NPY)和神经元特异性烯醇化酶(NSE)水平的影响及疗效观察。方法: 采用随机数字表法将70例新生儿HIE患儿分成观察组和对照组。两组患儿均予以吸氧、控制颅内压、血压和血糖,抗惊厥、保持水电解质平衡等常规治疗。观察组患儿加用鼠神经生长因子20 μg, im,qd。对照组患儿加用胞磷胆碱注射液100 mg,ivd,qd,均连用10～14 d。观察两组患儿治疗前后血清NPY 和NSE水平变化,比较两组疗效及药品不良反应,随访1年内神经系统后遗症的发生率。结果: 治疗2周后,两组血清NPY和NSE水平较前均明显下降(P<0.05和P<0.01),且观察组下降幅度明显大于对照组(P<0.05);观察组临床总有效率为94.28%,明显高于对照组的68.57%(P<0.01),两组患儿治疗中未出现明显药品不良反应。随访观察1年,观察组后遗症的发生率明显低于对照组(P<0.05)。结论: 鼠神经生长因子治疗新生儿HIE的疗效肯定,安全性好,可促进受损神经元细胞的修复,减少神经系统后遗症的发生率,其作用与降低血清NPY和NSE水平密切相关。     

蛴螬对激光损伤兔血-视网膜屏障后视网膜TekC、NGF表达的影响＊

目的 探讨蛴螬促进激光损伤兔血-视网膜屏障后的修复作用及机理。方法 30只实验性兔随机分为正常组、模型组、蛴螬组。采用激光损伤血-视网膜屏障动物模型，在屏障损伤后1周及2周两个时相，观察蛴螬对兔血-视网膜屏障损伤修复情况、血-视网膜屏障组织形态结构及神经营养因子受体TrkC、NGF表达及影响。结果 蛴螬能促进损伤的血-视网膜屏障修复，减轻激光导致的视网膜组织及细胞形态学损伤，促进TrkC、NGF的表达，抑制视网膜细胞增殖与变性，从而改善视网膜功能。结论 蛴螬可能通过改善视网膜组织能量代谢，清除氧自由基，促进神经营养因子受体的表达，抑制视细胞增殖，起到保护血-视网膜屏障组织结构的作用。     

Not all neurogenic bladders are the same: a proposal for a new neurogenic bladder classification system

Neurogenic bladder (NGB) has long been defined as a clinical entity that describes a heterogeneous collection of syndromes. The common theme is a bladder disorder concomitant with a neurologic disorder. This definition does not give the clinician much information about the bladder disorder, nor how to treat it, or even what the natural history of the disorder is likely to be. It may be time for a new classification scheme to better define the bladder defect and prognosis, as well as inform treatment. We propose a classification system based on seven categories, each having a neurologic defect in a distinct anatomic location. This is termed SALE (Stratify by Anatomic Location and Etiology). In addition, the presence or absence of bowel dysfunction and autonomic dysreflexia will be reported. In the future, as more definite prognostic information can be gleaned from biomarkers, we anticipate adding urinary nerve growth factor (NGF) and urinary brain-derived neurotrophic factor (BDNF) levels to the definition. We expect the SALE system to efficiently describe a patient suffering from NGB and simultaneously inform the most appropriate treatment, follow-up regimen, and long-term prognosis.