Cellular and functional actions of tofacitinib related to the pathophysiology of hibernoma development

Takotsubo Syndrome in a Rheumatoid Arthritis Patient Under Tofacitinib: A Case Report

We describe a case of a 57-year-old white woman treated for rheumatoid arthritis (RA) with tofacitinib 10mg daily (started one year ago) and prednisolone 5mg daily. She presented to the emergency department with a tight squeezing chest pain and shortness of breath for 7h and the clinical evaluation revealed regional systolic dysfunction of the left ventricle, mimicking a myocardial infarction, in the absence of angiographic evidence of obstructive coronary artery disease or acute plaque rupture. All changes were transient and resolved completely within 4 days. The diagnosis of Takotsubo cardiomyopathy (TKM) was established. This is, as far as we know, the first report of a case of TKM in a RA patient taking tofacitinib. Although the association has not been previously described and the precise cause cannot be identified in this patient, the association with tofacitinib should be considered given the etiopathogenic rationale and the absence of any other identifiable cause.

Takotsubo Syndrome in a Rheumatoid Arthritis Patient Under Tofacitinib: A Case Report

We describe a case of a 57-year-old white woman treated for rheumatoid arthritis (RA) with tofacitinib 10mg daily (started one year ago) and prednisolone 5mg daily. She presented to the emergency department with a tight squeezing chest pain and shortness of breath for 7h and the clinical evaluation revealed regional systolic dysfunction of the left ventricle, mimicking a myocardial infarction, in the absence of angiographic evidence of obstructive coronary artery disease or acute plaque rupture. All changes were transient and resolved completely within 4 days. The diagnosis of Takotsubo cardiomyopathy (TKM) was established. This is, as far as we know, the first report of a case of TKM in a RA patient taking tofacitinib. Although the association has not been previously described and the precise cause cannot be identified in this patient, the association with tofacitinib should be considered given the etiopathogenic rationale and the absence of any other identifiable cause.

Nipple Hibernoma in a Dog: A Case Report With Literature Review

This report provides a clinical, histological, and immunohistochemical description of an unusual hibernoma (pale cell variant) in the subepidermal area of the nipple of a six-year-old bitch. Furthermore, an extensive literature review of hibernomas in animals was made. Physical examination revealed a nodular lesion in the subepidermal area of the third nipple of the left mammary chain. The histopathological findings included lobules of round to oval cells with abundant pale to eosinophilic cytoplasm, containing one or multiple optically empty vacuoles, consistent with nipple hibernoma. Immunohistochemically, the neoplastic cells were negative for cytokeratin AE1/AE3 and p53 but showed strong immunoreaction for vimentin and uncoupling protein-1, thus confirming the brown adipose tissue origin. Local recurrence was not detected after 18 months of follow-up. Hibernomas are rare and benign neoplastic lesions, originating from brown adipose tissue. Due to their histological and molecular resemblance with liposarcoma, a correct diagnosis of these neoplasms is required. In addition, the literature review suggests that hibernomas may present different features, according to species.

Immunologic effects of chronic administration of tofacitinib, a Janus kinase inhibitor, in cynomolgus monkeys and rats - Comparison of juvenile and adult responses

Tofacitinib, an oral Janus kinase (JAK) inhibitor for treatment of rheumatoid arthritis, targets JAK1, JAK3, and to a lesser extent JAK2 and TYK2. JAK1/3 inhibition impairs gamma common chain cytokine receptor signaling, important in lymphocyte development, homeostasis and function. Adult and juvenile cynomolgus monkey and rat studies were conducted and the impact of tofacitinib on immune parameters (lymphoid tissues and lymphocyte subsets) and function (T-dependent antibody response (TDAR), mitogen-induced T cell proliferation) assessed. Tofacitinib administration decreased circulating T cells and NK cells in juvenile and adult animals of both species. B cell decreases were observed only in rats. These changes and decreased lymphoid tissue cellularity are consistent with the expected pharmacology of tofacitinib. No differences were observed between juvenile and adult animals, either in terms of doses at which effects were observed or differential effects on immune endpoints. Lymphomas were observed in three adult monkeys. Tofacitinib impaired the primary TDAR in juvenile monkeys, although a recall response was generated. Complete or partial reversal of the effects on the immune system was observed.