Trophic factors and regulation of hippocampal neuroplasticity in the human brain

描述（由申请人提供）：神经发生，或新神经元的产生，发生在海马形成（HF）的齿状回（DG）中，并且在包括人类在内的成年哺乳动物中通过抗抑郁治疗（ADT）增加。神经发生减少是重度抑郁症（MDD）的假设。在啮齿类动物中，神经发生与新血管生成（血管生成）同时发生，两者都受到营养因子的刺激。血管新生是新生神经元分化和存活的必要条件，脑血容量已被提出作为神经新生的体内替代指标。在人脑中，营养因子的表达是否与神经发生和血管生成相关还没有研究。研究将分为三组进行：1。死亡时正在服用抗抑郁药（MDDT， 5例使用选择性血清素再摄取抑制剂，MDD*SSRI， 5例使用三环抗抑郁药，MDD*TCA）的心境障碍（MDD, n=10）患者；2. 3个月未服用抗抑郁药的重度抑郁症患者（n=10）。正常、非精神疾病对照（NC, n=10）。这三组将根据性别、年龄（整个样本在24至62岁之间）、死后间隔（PMI）和种族进行匹配。所有病例，包括对照组，将根据DSM轴I诊断、神经病理检查和毒理学筛查进行心理解剖。血管内皮生长因子（VEGF）及其受体VEGFR-2、脑源性神经营养因子（BDNF）及其受体TrkB的免疫细胞化学将用于鉴定它们在HF细胞中的表达。血管用巢蛋白染色，并用CD31（内皮细胞标记物）双标记。神经祖细胞（NPCs）鉴定采用巢蛋白染色法，分裂细胞鉴定采用Ki-67染色法，成熟神经元鉴定采用神经元特异性核蛋白（NeuN）染色法，树突标记采用神经丝染色法。研究将使用右心衰的俯仰范围，每隔2mm进行一系列切片，检测每种抗体。体视学将用于估计整个HF中标记细胞的数量，血管面积和体积，神经元大小和树突长度。我们将检验以下假设：DG中NPCs和有丝分裂细胞的数量与HF中表达VEGF、BDNF及其受体的细胞数量成正比，MDDT中表达VEGF、BDNF及其受体的细胞数量比MDD和NC中更多；神经元的数量、大小和树突长度与HF中表达VEGF、BDNF及其受体的细胞数量成正比，MDDT比MDD和NC更大；血管面积和体积与HF中表达VEGF、BDNF及其受体的细胞数量成正比，MDDT中表达VEGF、BDNF及其受体的细胞数量高于MDD和NC。这些结果对理解在MDD中使用营养因子作为ADT的可能性具有启示意义。

DESCRIPTION (provided by applicant): Neurogenesis, or the generation of new neurons, occurs in the dentate gyrus (DG) of the hippocampal formation (HF) and it is increased by antidepressant treatment (ADT) in adult mammals including humans. Decreased neurogenesis is hypothesized in major depressive disorder (MDD). Neurogenesis occurs together with the generation of new vasculature (angiogenesis) and both are stimulated by trophic factors in rodents. Angiogenesis is necessary for new neurons to differentiate and survive and cerebral blood volume has been proposed as a surrogate in vivo measure of neurogenesis. It has not been examined if trophic factors expression is correlated with neurogenesis and angiogenesis in the human brain. Studies will be carried out in three groups: 1. Patients with Mood Disorder (MDD, n=10) who were on antidepressants (MDDT, five treated with selective serotonin reuptake inhibitors, MDD*SSRI, five treated with tricyclic antidepressants, MDD*TCA) at the time of death; 2. MDD patients (n=10) who were not on antidepressants for 3 months and 3. normal, non-psychiatric controls (NC, n=10). The three groups will be matched for sex, age (between 24 and 62 in the whole sample), postmortem interval (PMI) and race. All cases, including controls, will have psychological autopsies according to DSM Axis I diagnosis, neuropathologic examination and toxicological screen. Immunocytochemistry for vascular endothelial growth factor (VEGF), its receptor VEGFR-2, brain derived neurotrophic factor (BDNF), its receptor TrkB will be used to identify their expression in HF cells. Vessels will be stained with nestin and double-labeled with CD31 (marker of endothelial cells). Neural progenitor cells (NPCs) will be identified by nestin stain, dividing cells by Ki-67 stain, mature neurons by neuronal-specific nuclear protein (NeuN) and their dendrites labeled by and neurofilament stain. The rostrocaudal extent of the right HF will be used for the study and series of sections at 2mm intervals will be assayed for each antibody. Stereology will be used to estimate the number of labeled cell in the whole HF, vessel area and volume, neuron size and dendrites length. We will test the hypotheses that: the number of NPCs and mitotic cells in the DG is proportional to the number of cells expressing VEGF, BDNF and their receptors in the HF, which will be greater in MDDT compared to MDD and NC; neuron number, size and dendrite length is proportional to the number of cells expressing VEGF, BDNF and their receptors in the HF and that they will be greater in MDDT vs MDD and NC; vessel area and volume are proportional to the number of cells expressing VEGF, BDNF and their receptors in the HF and that they will be greater in MDDT compared to MDD and NC. These results have implications for understanding the possibility to use trophic factors as ADT in MDD. PUBLIC HEALTH RELEVANCE: Major Depression (MDD) is a serious public health problem and antidepressant treatment (ADT) is not effective in all cases. There is evidence that neuronal replication (neurogenesis) occurs in adult mammals including humans and it occurs together with the generation of new vasculature (angiogenesis). Trophic factors might play a crucial role in support of these phenomena and angiogenesis appears necessary for ADT to work in rodents and therefore, we propose to examine the expression of trophic factors and its correlation with neurogenesis and angiogenesis in MDD patients, with and without ADT, compared to normal controls.