Use of bisphosphonates to reduce the calcification process in animal models of cysticercosis

 描述（由申请人提供）：脑囊虫病（NCC）是世界各地流行国家继发性癫痫的最重要原因，因此是一个重大的全球健康问题。在秘鲁，约30%的癫痫可归因于这种人畜共患疾病。这种寄生虫的幼虫包囊在脑实质中建立，并最终通过自然退化或抗寄生虫治疗后退化。这个过程经常会产生残留物， 大脑钙化成为癫痫发作的病灶。一系列证据表明，钙化病变在癫痫发作活动的病理生理学中起作用，例如与钙化病变定位一致的局灶性癫痫发作症状学、癫痫发作时钙化周围水肿等。 与感染未导致钙化的患者相比，1年后出现残余钙化的患者更常见。在这些假设下，减少或避免囊肿钙化可能会减少癫痫活动。在人体研究和动物模型中，双膦酸盐对异位钙化具有抑制作用。其抑制钙化的作用可能是通过抑制磷酸钙沉淀、阻止无定形磷酸钙向羟基磷灰石转化和减少羟基磷灰石晶体聚集三个过程实现的。通过这些过程，二膦酸盐抑制磷酸钙晶体生长。我们的目的是评估双膦酸盐是否能降低动物模型中肌肉和大脑囊肿变性引起的残余钙化的可能性和程度。我们的方法包括四个连续的阶段：（1）我们将开始通过标准化啮齿动物（大鼠，豚鼠和兔子）的实验肌内感染，以允许具有足够重复性的实用模型， 进一步的研究，（2）我们将在前一阶段获得的最佳模型以及先前标准化的大鼠脑模型感染中描述抗寄生虫治疗后囊肿的钙化过程，（3）一旦我们定义了钙化的通常过程，我们将评估三种不同的双膦酸盐的能力。（依替膦酸盐、阿仑膦酸盐和伊班膦酸盐）减少啮齿动物大脑和肌肉中的钙化，以及（4）在最终研究中，我们将尝试在自然感染的猪中复制这些发现，作为更自然的模型。该项目可以提供必要的证据，以支持NCC患者抗钙化治疗的发展，目的是减少癫痫发作的发生。由于我们的干预药物是FDA批准的，积极的发现可以迅速转化为临床试验。此外，我们开发的新动物模型可用于测试新的抗寄生虫和抗炎药物以及新的候选疫苗。

 DESCRIPTION (provided by applicant): Neurocysticercosis (NCC) is the most important cause of secondary epilepsy in endemic countries around the world, and is thus a significant global health problem. In Peru, around 30% of epilepsy is attributable to this zoonotic disease. Larval cysts of this parasite establish in the brain parenchyma and eventually degenerate by natural involution or after anti-parasitic treatment. Frequently this process results in a residual brain calcification which becomes a foci for seizures. A chain of evidence suggests that calcified lesions play a role in the pathophysiology of seizure activity, such as focal seizure semiology compatible with the localization of the calcified lesion, edema surrounding the calcifications at the time of a seizure, etc. In patients with a single degenerating cyst, seizures are significantly more frequent in those who develop a residual calcification by one year compared with those whose infection does not result in calcification. Under these assumptions, reduction or avoidance of cyst calcification could potentially decrease epilepsy activity. Bisphosphonates have shown an inhibitory effect on ectopic calcification in human studies and in animal models. The inhibitory effect on calcification is probably due to three processes; including, inhibiting precipitation of calcium phosphate, blocking transformation of amorphous calcium phosphate into hydroxyapatite and reducing hydroxyapatite crystal aggregation. Through these processes bisphosphonates inhibit calcium phosphate crystal growth. Our objective is to evaluate whether bisphosphonates decrease the likelihood and degree of residual calcification resulting from degeneration of muscular and cerebral cysts in animal models. Our approach includes four consecutive phases: (1) we will begin by standardizing the experimental intramuscular infection in rodents (rats, guinea pigs and rabbits) to allow a practical model with enough repeatability for further studies, (2) we will then characterize the calcification process of the cyst after antiparasitic treatment in the best models obtained in the preceding phase, as well as in an previously standardized brain model infection in rats, (3) once we have defined the usual process of calcifications, we will then evaluate the ability of three different bisphosphonates (etidronate, alendronate, and ibandronate) to reduce calcification in rodent brain and muscles, and (4) in a final study we will attempt to replicate these findings in naturally-infected pigs as more natural model. This project could provide essential evidence needed to support development of an anti- calcification treatment in NCC patients, with the goal of reducing seizure occurrence. Since our intervention drugs are FDA-approved, positive findings could be rapidly translated into clinical trials. In addition, the new animal models we develop could be used to test new anti-parasitic and anti-inflammatory drugs and also new candidate vaccines.