Irisin exerts dual effects on browning and adipogenesis of human white adipocytes.

To better understand the role of irisin in humans, we examined the effects of irisin in human primary adipocytes and fresh human subcutaneous white adipose tissue (scWAT). Human primary adipocytes derived from 28 female donors' fresh scWAT were used to examine the effects of irisin on browning and mitochondrial respiration, and preadipocytes were used to examine the effects of irisin on adipogenesis and osteogenesis. Cultured fragments of scWAT and perirenal brown fat were used for investigating signal transduction pathways that mediate irisin's browning effect by Western blotting to detect phosphorylated forms of p38, ERK, and STAT3 as well as uncoupling protein 1 (UCP1). Individual responses to irisin in scWAT were correlated with basal expression levels of brown/beige genes. Irisin upregulated the expression of browning-associated genes and UCP1 protein in both cultured primary mature adipocytes and fresh adipose tissues. It also significantly increased thermogenesis at 5 nmol/l by elevating cellular energy metabolism (OCR and ECAR). Treating human scWAT with irisin increased UCP1 expression by activating the ERK and p38 MAPK signaling. Blocking either pathway with specific inhibitors abolished irisin-induced UCP1 upregulation. However, our results showed that UCP1 in human perirenal adipose tissue was insensitive to irisin. Basal levels of brown/beige and FNDC5 genes correlated positively with the browning response of scWAT to irisin. In addition, irisin significantly inhibited adipogenic differentiation but promoted osteogenic differentiation. We conclude that irisin promotes "browning" of mature white adipocytes by increasing cellular thermogenesis, whereas it inhibits adipogenesis and promotes osteogenesis during lineage-specific differentiation. Our findings provide a rationale for further exploring the therapeutic use of irisin in obesity and exercise-associated bone formation.

Nodular fasciitis: differential considerations and current management strategies.

Nodular fasciitis (NF) typically presents as an enlarging soft tissue mass with imaging characteristics that may be suggestive of soft tissue sarcoma or desmoid tumor. This presentation can make a correct diagnosis and management of patients with NF a challenge. We report our recent experience with two cases of NF that were both referred with a diagnoses of "soft tissue sarcoma." Patient 1 was a 46-year-old woman who had undergone breast augmentation and was referred with a rapidly growing firm mass on the left chest wall beneath the breast implant. Computed tomography of the chest noted the mass to be 8 cm x 11 cm in size displacing the implant laterally with no radiological involvement of the bony structures of the chest. Core biopsy was suggestive of inflammation only. Given the clinical suspicion of malignancy, the patient underwent resection of the mass with implant removal. Final pathology showed NF. Patient 2 was a 65-year-old woman referred with an enlarging tender 3-cm infraclavicular mass and a clinical diagnosis of "soft tissue sarcoma." Preoperative biopsy suggested NF. The patient underwent complete excision, which confirmed the diagnosis. These cases highlight the clinical issues associated with management of patients with NF. Current approaches to evaluation, diagnosis, and treatment of NF are discussed.

Idiopathic granulomatous mastitis: in search of a therapeutic paradigm.

Idiopathic granulomatous mastitis, also known as idiopathic granulomatous lobular mastitis, is a benign breast lesion that represents both a diagnostic and therapeutic dilemma. We report two cases of granulomatous mastitis recently evaluated and managed at our institution. To better understand this rare disease, we analyzed treatment outcomes in reported cases of granulomatous mastitis. One hundred sixteen cases were subsequently analyzed. Primary management strategies included observation (n = 9), steroids (n = 29), partial mastectomy (n = 75), and mastectomy (n = 3). Success rates with each treatment were observation, 56 per cent; steroids, 42 per cent; partial mastectomy, 79 per cent; and mastectomy, 100 per cent. Based on this analysis, we propose a clinically useful algorithm for both workup and management of these challenging cases.

CNS intraoperative consultation: a survival guide for non-neuropathologists.

Intraoperative consultations for central nervous system disease may be challenging due to limitations of sample size, lack of familiarity with neurosurgical procedures, or poor access to neuroimaging studies. Despite these challenges, the surgical pathologist is charged with determining if the tissue sample is representative of the pathologic process while ensuring that enough diagnostic tissue has been retained for routine histology, immunohistochemistry, fluorescence in situ hybridization, molecular testing, and in some cases, tissue banking. Here, we present basic methods and a practical approach for CNS intraoperative consultation including critical pre-analytic considerations that promote optimal tissue management.

Collection protocol for human pancreas.

This dissection and sampling procedure was developed for the Network for Pancreatic Organ Donors with Diabetes (nPOD) program to standardize preparation of pancreas recovered from cadaveric organ donors. The pancreas is divided into 3 main regions (head, body, tail) followed by serial transverse sections throughout the medial to lateral axis. Alternating sections are used for fixed paraffin and fresh frozen blocks and remnant samples are minced for snap frozen sample preparations, either with or without RNAse inhibitors, for DNA, RNA, or protein isolation. The overall goal of the pancreas dissection procedure is to sample the entire pancreas while maintaining anatomical orientation. Endocrine cell heterogeneity in terms of islet composition, size, and numbers is reported for human islets compared to rodent islets. The majority of human islets from the pancreas head, body and tail regions are composed of insulin-containing ß-cells followed by lower proportions of glucagon-containing α-cells and somatostatin-containing δ-cells. Pancreatic polypeptide-containing PP cells and ghrelin-containing epsilon cells are also present but in small numbers. In contrast, the uncinate region contains islets that are primarily composed of pancreatic polypeptide-containing PP cells. These regional islet variations arise from developmental differences. The pancreas develops from the ventral and dorsal pancreatic buds in the foregut and after rotation of the stomach and duodenum, the ventral lobe moves and fuses with the dorsal. The ventral lobe forms the posterior portion of the head including the uncinate process while the dorsal lobe gives rise to the rest of the organ. Regional pancreatic variation is also reported with the tail region having higher islet density compared to other regions and the dorsal lobe-derived components undergoing selective atrophy in type 1 diabetes. Additional organs and tissues are often recovered from the organ donors and include pancreatic lymph nodes, spleen and non-pancreatic lymph nodes. These samples are recovered with similar formats as for the pancreas with the addition of isolation of cryopreserved cells. When the proximal duodenum is included with the pancreas, duodenal mucosa may be collected for paraffin and frozen blocks and minced snap frozen preparations.