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

 描述(由申请人提供)：神经囊虫病(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病。这种寄生虫的幼虫包囊建立在脑实质中，并最终通过自然退化或经过抗寄生虫治疗而退化。这一过程经常会导致残差 大脑钙化，成为癫痫发作的焦点。一系列证据表明，钙化病变在癫痫活动的病理生理学中发挥作用，例如与钙化病变的定位相适应的局灶性癫痫症状，癫痫发作时钙化周围的水肿等。在单个退行性囊肿的患者，癫痫发作显著 与感染未导致钙化的患者相比，在一年内形成残留钙化的患者更常见。在这些假设下，减少或避免囊性钙化可能会潜在地减少癫痫的活动。在人类研究和动物模型中，双膦酸盐显示了对异位钙化的抑制作用。其抑制钙化的作用可能是通过抑制磷酸钙的沉淀、阻止无定形磷酸钙向羟基磷灰石的转化和减少羟基磷灰石的晶体聚集三个过程实现的。通过这些过程，双膦酸盐抑制了磷酸钙晶体的生长。我们的目的是在动物模型中评价双膦酸盐是否能降低肌肉和脑囊肿退变引起的残留钙化的可能性和程度。我们的方法包括四个连续的阶段：(1)我们将首先标准化啮齿动物(大鼠、豚鼠和兔子)的实验性肌肉内感染，以便建立一个具有足够重复性的实用模型。 在进一步的研究中，(2)我们将在前一阶段获得的最佳模型中，以及在先前标准化的大鼠脑模型感染中，表征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(依替膦酸盐、阿伦磷酸酯和伊班膦酸盐)减少啮齿动物大脑和肌肉中钙化的能力，以及(4)在最终研究中，我们将试图在自然感染的猪身上复制这些发现，作为更自然的模型。该项目可以提供必要的证据来支持NCC患者抗钙化治疗的发展，目的是减少癫痫的发生。由于我们的干预药物是FDA批准的，阳性结果可能会迅速转化为临床试验。此外，我们开发的新动物模型可以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.