Adipose Tissue Remodeling as Homeostatic Inflammation

Evidence has accumulated indicating that obesity is associated with a state of chronic, low-grade inflammation. Obese adipose tissue is characterized by dynamic changes in cellular composition and function, which may be referred to as “adipose tissue remodeling”. Among stromal cells in the adipose tissue, infiltrated macrophages play an important role in adipose tissue inflammation and systemic insulin resistance. We have demonstrated that a paracrine loop involving saturated fatty acids and tumor necrosis factor-α derived from adipocytes and macrophages, respectively, aggravates obesity-induced adipose tissue inflammation. Notably, saturated fatty acids, which are released from hypertrophied adipocytes via the macrophage-induced lipolysis, serve as a naturally occurring ligand for Toll-like receptor 4 complex, thereby activating macrophages. Such a sustained interaction between endogenous ligands derived from parenchymal cells and pathogen sensors expressed in stromal immune cells should lead to chronic inflammatory responses ranging from the basal homeostatic state to diseased tissue remodeling, which may be referred to as “homeostatic inflammation”. We, therefore, postulate that adipose tissue remodeling may represent a prototypic example of homeostatic inflammation. Understanding the molecular mechanism underlying homeostatic inflammation may lead to the identification of novel therapeutic strategies to prevent or treat obesity-related complications

Large Right Pulmonary Vein Is a Predictor of Atrial Fibrillation Recurrence after Pulmonary Vein Isolation in Patients with Persistent Atrial Fibrillation

Pulmonary vein isolation（PVI）is an effective treatment for atrial fibrillation（AF）. However, outcomes differ between paroxysmal AF and persistent AF. We analyzed the predictors of recurrence by examining the recurrence group after ablation. Of 372 consecutive patients with AF who underwent PVI between June 2016 and December 2018, we evaluated 250 patients（age, 67±12y, 65％ men）whose left atrium（LA）was constructed using the PENTARAY catheter（BioSense Webster, Los Angeles, CA）, a multipolar electrode catheter with a novel shape and excellent mapping capability. We measured the LA total volume（LATV）, right pulmonary vein＋antrum volume（RPAV）, left PV＋antrum volume（LPAV）, LA central volume（LACV）, and LA bipolar voltage. Of the 250 patients, 78 had persistent AF（recurrence, 20）and 172 had paroxysmal AF（recurrence, 16）. In all patients, LATV, LACV, RPAV, and LPAV were significantly larger in patients with persistent AF than those with paroxysmal AF. The mean LA bipolar voltage in patients with persistent AF was significantly lower than those with paroxysmal AF. In cases of persistent AF, RPAV was significantly larger in the recurrence group than that in the non-recurrence group（15.9±4.8 vs 13.4±5.4ml; P＜0.05）. In cases of paroxysmal AF, there were no differences in any volume between the recurrence and non-recurrence groups. In conclusion, larger right PV is a predictor of AF recurrence after PVI in patients with persistent AF. The right PV is close to the atrial septum and the septopulmonary bundle, and the expansion of RPAV reflects the disruption of these structures, which may be involved in this result

Identification of clinical factors related to antibody-mediated immune response to the subfornical organ

Objective : We recently reported cases of adipsic hypernatremia caused by autoantibodies against the subfornical organ in patients with hypothalamic-pituitary lesions. This study aimed to clarify the clinical features of newly identified patients with adipsic hypernatremia whose sera displayed immunoreactivity to the mouse subfornical organ. Design : Observational cohort study of patients diagnosed with adipsic hypernatremia in Japan, United States, and Europe. Methods : The study included 22 patients with adipsic hypernatremia but without overt structural changes in the hypothalamic-pituitary region and congenital disease. Antibody response to the mouse subfornical organ was determined using immunohistochemistry. The clinical characteristics were compared between the patients with positive and negative antibody responses. Results : Antibody response to the mouse subfornical organ was detected in the sera of 16 patients (72.7%, female/male ratio, 1:1, 12 pediatric and 4 adult patients). The prolactin levels at the time of diagnosis were significantly higher in patients with positive subfornical organ (SFO) immunoreactivity than in those with negative SFO immunoreactivity (58.9 ± 33.5 vs. 22.9 ± 13.9 ng/ml, p <.05). Hypothalamic disorders were found in 37.5% of the patients with positive SFO immunoreactivity. Moreover, six patients were diagnosed with rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation/neural tumor syndrome after the diagnosis of adipsic hypernatremia. Plasma renin activity levels were significantly higher in patients with serum immunoreactivity to the Nax channel. Conclusions : The patients with serum immunoreactivity to the SFO had higher prolactin levels and hypothalamic disorders compared to those without the immunoreactivity. The clinical characteristics of patients with serum immunoreactivity to the subfornical organ included higher prolactin levels and hypothalamic disorders, which were frequently associated with central hypothyroidism and the presence of retroperitoneal tumors