Relapsing Polychondritis with a Cobble-stone Appearance of the Tracheal Mucosa, Preceded by Posterior Reversible Encephalopathy Syndrome.

A 25-year-old woman had convulsions and disturbance of consciousness. Head magnetic resonance imaging (MRI) showed punctate areas in the occipital lobes with increased signals on T2-weighted imaging. The MRI abnormalities responded well to steroid pulse therapy, so we made a diagnosis of posterior reversible encephalopathy syndrome (PRES). Three months later, she developed a fever and dyspnea. Chest computed tomography revealed marked thickness of the tracheal and bronchial wall, and bronchoscopy showed a cobble-stone appearance of the tracheal mucosa, indicative of relapsing polychondritis (RPC). We consider that PRES had developed due to autoimmune vasculitis in the brain with RPC.

Role of small proliferative adipocytes: possible beige cell progenitors.

Despite extensive investigation, the mechanisms underlying adipogenesis are not fully understood. We previously identified proliferative cells in adipose tissue expressing adipocyte-specific genes, which were named small proliferative adipocytes (SPA). In this study, we investigated the characteristics and roles of SPA in adipose tissue. Epididymal and inguinal fat was digested by collagenase, and then SPA were separated by centrifugation from stromal vascular cells (SVC) and mature white adipocytes. To clarify the feature of gene expression in SPA, microarray and real-time PCR were performed. The expression of adipocyte-specific genes and several neuronal genes was increased in the order of SVC < SPA < mature white adipocytes. In addition, proliferin was detected only in SPA. SPA differentiated more effectively into lipid-laden cells than SVC. Moreover, differentiated SPA expressed uncoupling protein 1 and mitochondria-related genes more than differentiated SVC. Treatment of SPA with pioglitazone and CL316243, a specific ß3-adrenergic receptor agonist, differentiated SPA into beige-like cells. Therefore, SPA are able to differentiate into beige cells. SPA isolated from epididymal fat (epididymal SPA), but not SPA from inguinal fat (inguinal SPA), expressed a marker of visceral adipocyte precursor, WT1. However, no significant differences were detected in the expression levels of adipocyte-specific genes or neuronal genes between epididymal and inguinal SPA. The ability to differentiate into lipid-laden cells in epididymal SPA was a little superior to that in inguinal SPA, whereas the ability to differentiate into beige-like cells was greater in inguinal SPA than epididymal SPA. In conclusion, SPA may be progenitors of beige cells.

Development and validation of a scoring system for prediction of insulin requirement for optimal control of blood glucose during glucocorticoid treatments.

AIMS: We have developed and validated a novel scoring system to predict insulin requirement for optimal control of blood glucose during glucocorticoid (GC) treatments, by retrospective analyses of clinical parameters before GC treatment. METHODS: Three hundred-three adults (the Developing set) undergoing their first treatment of prednisolone (PSL) were divided into two groups, depending on treatment with or without insulin. Independent risk factors for insulin requirement were identified by a stepwise logistic regression analysis after univariate analyses between the two groups. We constructed a point-addition scoring system consisting of several categories and their coefficients in each risk factor derived from another logistic regression analysis. We validated it to two validation sets, A and B. RESULTS: Male, higher levels of fasting plasma glucose (FPG), HbA1c, and serum creatinine (CRE) and a higher initial dose of PSL were identified as the risk factors. The sensitivity, specificity, and accuracy were 90.0%, 88.1%, and 88.4%; 87.5%, 66.7%, and 70.5%; 83.3%, 76.1%, and 76.6% in the Developing set, Validation set A, and Validation set B, respectively, when the scoring system was applied. CONCLUSIONS: The scoring system is a valid and reliable tool to predict insulin requirements in advance during GC treatment.

Blockade of Sphingosine 1-Phosphate Receptor 2 Signaling Attenuates High-Fat Diet-Induced Adipocyte Hypertrophy and Systemic Glucose Intolerance in Mice.

Sphingosine 1-phosphate (S1P) is known to regulate insulin resistance in hepatocytes, skeletal muscle cells, and pancreatic ß-cells. Among its 5 cognate receptors (S1pr1-S1pr5), S1P seems to counteract insulin signaling and confer insulin resistance via S1pr2 in these cells. S1P may also regulate insulin resistance in adipocytes, but the S1pr subtype(s) involved remains unknown. Here, we investigated systemic glucose/insulin tolerance and phenotypes of epididymal adipocytes in high-fat diet (HFD)-fed wild-type and S1pr2-deficient (S1pr2(-/-)) mice. Adult S1pr2(-/-) mice displayed smaller body/epididymal fat tissue weights, but the differences became negligible after 4 weeks with HFD. However, HFD-fed S1pr2(-/-) mice displayed better scores in glucose/insulin tolerance tests and had smaller epididymal adipocytes that expressed higher levels of proliferating cell nuclear antigen than wild-type mice. Next, proliferation/differentiation of 3T3-L1 and 3T3-F442A preadipocytes were examined in the presence of various S1pr antagonists: JTE-013 (S1pr2 antagonist), VPC-23019 (S1pr1/S1pr3 antagonist), and CYM-50358 (S1pr4 antagonist). S1P or JTE-013 treatment of 3T3-L1 preadipocytes potently activated their proliferation and Erk phosphorylation, whereas VPC-23019 inhibited both of these processes, and CYM-50358 had no effects. In contrast, S1P or JTE-013 treatment inhibited adipogenic differentiation of 3T3-F442A preadipocytes, whereas VPC-23019 activated it. The small interfering RNA knockdown of S1pr2 promoted proliferation and inhibited differentiation of 3T3-F442A preadipocytes, whereas that of S1pr1 acted oppositely. Moreover, oral JTE-013 administration improved glucose tolerance/insulin sensitivity in ob/ob mice. Taken together, S1pr2 blockade induced proliferation but suppressed differentiation of (pre)adipocytes both in vivo and in vitro, highlighting a novel therapeutic approach for obesity/type 2 diabetes.

Elevated mitochondrial biogenesis in skeletal muscle is associated with testosterone-induced body weight loss in male mice.

Androgen reduces fat mass, although the underlying mechanisms are unknown. Here, we examined the effect of testosterone on heat production and mitochondrial biogenesis. Testosterone-treated mice exhibited elevated heat production. Treatment with testosterone increased the expression level of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), ATP5B and Cox4 in skeletal muscle, but not that in brown adipose tissue and liver. mRNA levels of genes involved in mitochondrial biogenesis were elevated in skeletal muscle isolated from testosterone-treated male mice, but were down-regulated in androgen receptor deficient mice. These results demonstrated that the testosterone-induced increase in energy expenditure is derived from elevated mitochondrial biogenesis in skeletal muscle.

Effect of nematode Trichinella infection on glucose tolerance and status of macrophage in obese mice.

We investigated the effect of Trichinella infection on glucose tolerance and (pro- or anti-inflammatory) macrophage status in adipose tissue. Ob/ob mice and high fat-fed mice (obesity model) and C57/BL mice (control mice) were orally infected with (infected group) or without (uninfected group) 400 Trichinella per mouse. Four weeks later, the mice were subjected to investigation, which showed that fasting plasma glucose levels decreased in the infected group of C57/BL and ob/ob mice. Glucose tolerance, evaluated with intraperitoneal GTT, improved in the infected group of ob/ob mice and high fat-fed mice compared with the uninfected groups. Additional assay included anti-inflammatory macrophage (M2) markers and pro-inflammatory macrophage (M1) markers, with the aim to explore the effect of Trichinella infection on adipose tissue inflammation, since our previous study identified anti-inflammatory substances in secreted proteins by Trichinella. The result showed that mRNA levels of M2 markers, such as CD206, arginase and IL-10, increased, whereas M1 markers, such as CD11c, iNOS and IL-6, decreased in the stromal vascular fraction (SVF) isolated from epididymal fat in ob/ob mice. Residential macrophages obtained from the peritoneal lavage exhibited lower M1 markers and higher M2 markers levels in the infected group than in the uninfected group. Trichinella infection increases the ratio of M2/M1 systemically, which results in an improvement in pro-inflammatory state in adipose tissue and amelioration of glucose tolerance in obese mice.

The role of small proliferative adipocytes in the development of obesity: comparison between Otsuka Long-Evans Tokushima Fatty (OLETF) rats and non-obese Long-Evans Tokushima Otsuka (LETO) rats.

Obesity consists of hypertrophy and hyperplasia of adipocytes. Although the number of adipocytes is influenced by anatomical location, nutritional environment, hormone and genetic variation, it has been thought to be determined by the proliferation of precursor cells and subsequent differentiation. However, our recent research has identified the population of small adipocytes less than 20 µm in diameter, exhibiting tiny or no lipid droplets and expressing adipocyte marker proteins (small proliferative adipocytes: SPA) in isolated adipocytes. Notably, 5-bromo-2'-deoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) expression were detected in these cells. In this study, we investigated the role of SPA in development of adipose tissue using genetically obese diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats and their non-obese and non-diabetic littermates, Long-Evans Tokushima Otsuka (LETO) rats. Proliferation of SPA was determined by measurement of PCNA at the protein level in isolated fractions of adipocytes with collagenase digestion. In general, expression levels of PCNA rose, reached a maximum, and declined in adipose tissues during aging. The expression levels of PCNA were maximum in epididymal fat at 32 w and 12 w of age in LETO and OLETF, respectively. They reached the maximum at 20 w of age both in LETO and OLETF in mesenteric fat. Although the PCNA expression level was higher in OLETF in the early period, it reversed later. Enlargement of adipocytes developed during aging, which was enhanced when the expression levels of PCNA declined. These results suggest that proliferation of SPA may prevent adipocyte hypertrophy and the resultant development of metabolic disorders.

Small proliferative adipocytes: identification of proliferative cells expressing adipocyte markers.

It has been thought that adipocytes lack proliferative ability and do not revert to precursor cells. However, numerous findings that challenge this notion have also been reported. The idea that adipocytes dedifferentiate to fibroblast-like cells with increasing cell number was reported in 1975. This possibility has been ignored despite knowledge gained in the 1990s regarding adipocyte differentiation. Several studies on proliferation and dedifferentiation of adipocytes have been published, most of which were conducted from the perspective of regenerative medicine. However, the concept of proliferation of adipocytes remains unclear. In this study, we postulate a new population of adipocytes, which consist of small sized cells (less than 20 µm in diameter) expressing adipocyte markers, such as adiponectin and peroxisome proliferator-activated receptor γ (PPARγ), but not possessing large lipid droplets. These cells show marked ability to incorporate 5-bromo-2'-deoxyuridine (BrdU), for which reason we termed them "small proliferative adipocytes (SPA)". In addition, SPA are observed in the stromal vascular fraction. Since SPA are morphologically different from mature adipocytes, we regarded them as committed progenitor cells. When proliferation of adipocytes in vivo is assessed by measuring BrdU incorporation and expression levels of proliferating cell nuclear antigen (PCNA) in isolated fractions of adipocytes from adipose tissues, subcutaneous SPA proliferate less actively than visceral SPA. Treatment with pioglitazone increases the number of proliferating SPA in subcutaneous, but not visceral, fat, suggesting that SPA may be important in regulating systemic insulin sensitivity and glucose metabolism.

Pioglitazone enhances small-sized adipocyte proliferation in subcutaneous adipose tissue.

The possibility that mature adipocytes proliferate has not been fully investigated. In this study, we demonstrate that adipocytes can proliferate. 5-bromo-2'-deoxyuridine (BrdU)-labeled adipocyte like cells, most of which were less than 30 µm in diameter, were observed in adipose tissue. Proliferating cell nuclear antigen (PCNA) was simultaneously detected in BrdU-labeled nuclei. Observation of individual mature adipocytes of smeared specimens on glass slides revealed that small sized adipocytes more frequently incorporated BrdU. Cultured mature adipocytes using the ceiling-cultured method showed clustering of proliferating cells in small-sized adipocytes. These small cultured adipocytes, but not large ones, extensively incorporated BrdU. Quantified analysis of BrdU incorporation demonstrated that mature visceral adipocytes, including epididymal, mesenteric and perirenal adipocytes, proliferated more actively than subcutaneous ones. On the other hand, treatment with pioglitazone (Pio), a ligand of peroxisome proliferator-activated receptor γ, containing food for 2w, elevated BrdU incorporation and expression of PCNA in mature adipocytes isolated from subcutaneous, but not visceral adipose tissue. Moreover, Pio induced increased BrdU-labeled small-sized subcutaneous adipocytes, which was associated with an increased number of total small adipocytes in subcutaneous adipose tissue. In conclusion, mature adipocytes have a subgroup representing the potential to replicate, and this proliferation is more active in visceral adipocytes. Treatment with Pio increases proliferation in subcutaneous adipocytes. These results may explain the mechanism of Pio-induced hyperplasia especially in subcutaneous adipocytes.