Characterization of Toxicity with Spinal Opiates

项目摘要 持续鞘内（IT）吗啡输注用于慢性疼痛患者。一个局限是吗啡 导致脑膜产生炎性细胞团（肉芽肿）。我们概括了这些 犬模型中的观察结果，其中导致肉芽肿的腰椎CSF浓度相当 在人类身上观察到的。在该基金的最后两个资助周期中，我们发现肉芽肿是 由吗啡和其他阿片类药物以浓度依赖性方式诱导，而完全不由芬太尼诱导， 阿芬太尼我们假设肉芽肿是由脑膜肥大细胞（MMC）脱颗粒引起的。 因此：i）在皮下（SQ）递送后，使离体MMC脱髓鞘和皮肤潮红的阿片类药物产生 肉芽肿; ii）脑膜/皮下脱颗粒/耀斑和肉芽肿被MC阻断 稳定剂克罗利汀，但不是通过阿片拮抗作用。这种阿片受体非依赖性MC的起源 假设脱粒反应了非肽类和肽类阿片配体的阳离子性质 通过G蛋白偶联受体家族，如Mas相关基因， 受体（MrgX）。这些观察共同导致了一个假设的阐述，以表征和避免 肉芽肿假设1：阿片类药物对肥大细胞的脱颗粒作用不依赖于阿片受体 激活，但可能依赖于由阳离子电荷激活的受体（MrgX; HFPR）。假设2.的 阿片样物质肉芽肿不依赖于阿片样物质受体的激活，但与非肽类物质的能力有协变， 肽类阿片配体去肥大细胞。在假设1中，我们将检验浓度依赖性 阿片肽（DAMGO、TAPP、DALGA和DMT-DALGA）和非阿片肽（齐考诺肽）和非阿片肽的作用 肽类（如巴氯芬、可乐定、新斯的明）：犬的潮红、人原发性肥大细胞脱粒 肥大细胞培养物和鼠原代细胞培养物。使用人肥大细胞培养物，我们将检查 MgrX-r使用shRNA减少蛋白质表达的作用，并确定阳离子受体在 肥大细胞脱颗粒在假设2中，我们将i）在狗中进行剂量反应曲线， 上述μ阿片肽定义最大有效镇痛剂量：JMEAD和 最大耐受（例如急性副作用有限）剂量（MTD），ii）定义所选药剂的鞘内PK，以及 iii）确定这些肽的最大等效（镇痛）剂量的输注是否导致 肉芽肿

Project Summary Continuous intrathecal (IT) morphine infusion is used in chronic pain patients. A limitation is that morphine results in an inflammatory cell mass (granuloma) arising from the meninges. We recapitulated these observations in a canine model wherein lumbar CSF concentrations leading to granulomas were comparable to those observed in humans. In the last two funding cycles of this grant, we showed that granulomas are induced in a concentration dependent fashion by morphine and other opiates and not at all by fentanyl or alfentanil. We hypothesized that the granuloma arises from the degranulation of meningeal mast cells (MMC). Thus: i) opiates that degranulate MMCs ex vivo and cutaneous flare after subcutaneous (SQ) delivery produce a granuloma; ii) the meningeal/subcutaneous degranulation/flare and the granuloma are blocked by the MC stabilizer cromolyn, but not by opiate antagonism. The origin of this opiate receptor-independent MC degranulation is hypothesized to reflect the cationic properties of the nonpeptide and peptide opioid ligands acting to degranulate mast cells through G protein coupled receptor families, such as the Mas-related gene like receptors (MrgX). These observations jointly lead to an elaboration of hypotheses to characterize and avoid the granuloma. Hypothesis 1: Degranulation of mast cells by opioid agents is independent of opiate receptor activation but potentially depend upon receptors activated by cationic charge (MrgX; HFPR). Hypothesis 2. The opiate granuloma is independent of opiate receptor activation but will covary with ability of the nonpeptide and peptide opioid ligands to degranulate mast cells. In hypothesis 1, we will examine concentration dependent effects of opioid (DAMGO, TAPP, DALGA, and DMT- DALGA) and nonopioid peptides (ziconotide) and non- peptides (e.g. baclofen, clonidine, neostigmine) on: flare in the dog, mast cell degranulation in human primary mast cell cultures and on murine primary cell cultures. Using the human mast cell cultures, we will examine the role of MgrX-r using shRNA to reduce that protein expression and define the role of that cationic receptor on mast cell degranulation. In hypothesis 2, we will i) undertake dose response curves in dogs with IT infusion of the above mentioned mu opioid peptides to define the just maximally effective analgesic dose: JMEAD and the maximum tolerable (e.g. acute side effect limited) dose (MTD), ii) define intrathecal PK of selected agent and iii) determine if infusion of the maximum equi-effective (analgesic) doses of these peptides lead to a granuloma.