Double deletion of orexigenic neuropeptide Y and dynorphin results in paradoxical obesity in mice

Objective

Orexigenic neuropeptide Y (NPY) and dynorphin (DYN) regulate energy homeostasis. Single NPY or dynorphin deletion reduces food intake or increases fat loss. Future developments of obesity therapeutics involve targeting multiple pathways. We hypothesised that NPY and dynorphin regulate energy homeostasis independently, thus double NPY and dynorphin ablation would result in greater weight and/or fat loss than the absence of NPY or dynorphin alone.

Design and methods

We generated single and double NPY and dynorphin knockout mice (NPYΔ, DYNΔ, NPYDYNΔ) and compared body weight, adiposity, feeding behaviour, glucose homeostasis and brown adipose tissue uncoupling protein-1 (UCP-1) expression to wildtype counterparts.

Results

Body weight and adiposity were significantly increased in NPYDYNΔ, but not in NPYΔ or DYNΔ. This was not due to increased food intake or altered UCP-1 expression, which were not significantly altered in double knockouts. NPYDYNΔ mice demonstrated increased body weight loss after a 24-h fast, with no effect on serum glucose levels after glucose injection.

Conclusions

Contrary to the predicted phenotype delineated from single knockouts, double NPY and dynorphin deletion resulted in heavier mice, with increased adiposity, despite no significant changes in food intake or UCP-1 activity. This indicates that combining long-term opioid antagonism with blockade of NPY-ergic systems may not produce anti-obesity effects.     

Categorical or Dimensional: How Do Attachment Measures Inform Clinicians in Couple Therapy?

Self-report measures of adult romantic attachment have been widely used in research but their application in clinical practice has not been adequately examined. One important issue is the selection of a practical and reliable attachment measure that therapists can rely on in couple therapy. In the present study, the three-category Attachment Style Prototype (Hazan & Shaver, 1987) representing the original classic conceptualization of attachment, and the Experiences in Close Relationships (Brennan, Clark, & Shaver, 1998), a more recent scale with two dimensions representing a new conceptualization, were compared. Experiences in Close Relationships data were also used to establish four clusters based on the scores of the two dimensions. The Experiences in Close Relationships and Attachment Style Prototype categories were related in meaningful ways; however, Attachment Style Prototype was less effective in detecting a group of insecurely attached individuals who tended to self-identify as securely attached. Experiences in Close Relationships clearly shows an advantage over Attachment Style Prototype in clinical application, and therefore was recommended. Examples of the clinical utilization of Experiences in Close Relationships in couple therapy were provided using Experiences in Close Relationships scores from couples seeking therapy.     

Effect of diabetes on glucoregulation. From glucose transporters to glucose metabolism in vivo.

Peripheral resistance to insulin is a prominent feature of both insulin-dependent and non-insulin-dependent diabetes. Skeletal muscle is the primary site responsible for decreased insulin-induced glucose utilization in diabetic subjects. Glucose transport is the rate-limiting step for glucose utilization in muscle, and that cellular process is defective in human and animal diabetes. The transport of glucose across the muscle cell plasma membrane is mediated by glucose transporter proteins, and two isoforms (GLUT1 and GLUT4) are expressed in muscle. Insulin acutely increases glucose transport in muscle by selectively stimulating the recruitment of the GLUT4 transporter (but not GLUT1) from an intracellular pool to the plasma membrane. In skeletal muscles of streptozocin-induced diabetic rats, there is a decreased GLUT4 protein content in intracellular and plasma membranes. In these rats, insulin induced the mobilization of GLUT4 from the internal pool, but the incorporation of the transporter protein into the plasma membrane is diminished. Conversely, the content of the GLUT1 transporter increases in the plasma membrane of these diabetic rats. Normalization of glycemia with phlorizin fully restores the amount of GLUT1 and GLUT4 proteins to normal levels in the plasma membrane without altering insulin levels. This suggests that glycemia regulates the number of glucose transporters at the cell surface, GLUT1 varying directly and GLUT4 inversely, to glycemia. The regulatory role of glycemia also can be seen in diabetic dogs in vivo, where correction of hyperglycemia with phlorizin restores, at least in part, the defective metabolic clearance rate of glucose seen in these animals. In addition to acutely stimulating glucose transport in muscle, insulin controls exercise- and possibly stress-mediated glucose uptake in vivo, by preventing hyperglycemia and by restraining the effects of catecholamines on lipolysis and/or muscle glycogenolysis. Finally, we postulated a neural pathway that requires the permissive effect of insulin to increase glucose uptake by the muscle. Thus, insulin, glucose, and neural pathways regulate muscle glucose utilization in vivo and are, therefore, important determinants of glucoregulation in diabetes.     

Role of IL‐17 and TGF‐β in peritoneal adhesion formation after surgical trauma

Peritoneal adhesions are fibrous tissues formed after surgery. Both cytokines and transforming growth factors (TGFs) are involved in this process. The objective of this study was to investigate the cross talk between these entities. Peritoneal drainage fluid after surgery from patients and rodent models was examined by enzyme‐linked immunosorbent assay and fluorescence‐activated cell sorter. Data showed that the concentrations of interferon (IFN)‐γ and interleukin (IL)‐17 reached their peaks 6–12 hours after surgery, whereas TGF‐β1 concentrations showed two postoperative peak time points at 2 and 72–96 hours. By neutralizing IFN‐γ, IL‐17 6–12 hours, and TGF‐β1 72–96 hours after surgery, the degree of adhesion reduced significantly. However, neutralizing TGF‐β1 2 hours after surgery did not affect adhesion formation. Furthermore, in vitro studies showed that compared with the fibroblasts that were directly stimulated with TGF‐β1, the prestimulation of IL‐17 promoted plasminogen activator inhibitor‐1 production while inhibiting tissue‐type plasminogen activator production. Moreover, additional stimulation with IFN‐γ enhanced this effect. Together, these data indicate that IL‐17 may promote adhesion formation by increasing the reaction of fibroblasts against TGF‐β1. Blocking IL‐17 might have a therapeutic potential in preventing adhesion formation after surgery.     

Prognostic Factors of Patients with Spinal Chondrosarcoma: A Retrospective Analysis of 98 Consecutive Patients in a Single Center

Purpose

Chondrosarcoma (CHS) in the spine is relatively rare and minimal information has been published in the literature regarding this subject. The objective of our study was to discuss the factors that may affect outcomes of patients with spinal CHS.

Methods

Univariate and multivariate analyses were performed to identify prognostic factors for recurrence, distant metastasis, and survival of spinal CHS. T test, χ ² test and rank sum test were used to analyze a single factor for recurrence and metastasis, while survival rate was estimated using the Kaplan–Meier method. Factors with p values of ≤0.1 were subjected to multivariate analyses by binary logistic regression analyses or Cox regression analyses. p Values of ≤0.05 were considered statistically significant.

Results

A total of 98 patients with spinal CHS were included in the study. The mean follow-up period was 49.7 months (range 6–178). Recurrence was detected in 42 patients after initial surgery in our center, while distant metastasis and death occurred in 24 and 32 cases, respectively. The statistical analyses suggested that pathology grade III was closely related with distant metastasis which was an independent prognostic factor for overall survival. Total en bloc spondylectomy could significantly decrease the risk of recurrence, distant metastasis, and death of patients with spinal CHS.

Conclusions

Total en bloc spondylectomy could significantly decrease the risk of recurrence and distant metastasis, and meanwhile improve overall survival of spinal CHS. Distant metastasis which was closely associated with pathology grade III was an adverse prognostic factor for overall survival of spinal CHS.     

Impact of Dietary Aromatic Amino Acids on Osteoclastic Activity

We had shown that aromatic amino acid (phenylalanine, tyrosine, and tryptophan) supplementation prevented bone loss in an aging C57BL/6 mice model. In vivo results from the markers of bone breakdown suggested an inhibition of osteoclastic activity or differentiation. To assess osteoclastic differentiation, we examined the effects of aromatic amino acids on early /structural markers as vitronectin receptor, calcitonin receptor, and carbonic anhydrase II as well as, late/functional differentiation markers; cathepsin K and matrix metalloproteinase 9 (MMP-9). Our data demonstrate that the aromatic amino acids down-regulated early and late osteoclastic differentiation markers as measured by real time PCR. Our data also suggest a link between the vitronectin receptor and the secreted cathepsin K that both showed consistent effects to the aromatic amino acid treatment. However, the non-attachment related proteins, calcitonin receptor, and carbonic anhydrase II, demonstrated less consistent effects in response to treatment. Our data are consistent with aromatic amino acids down-regulating osteoclastic differentiation by suppressing remodeling gene expression thus contributing initially to the net increase in bone mass seen in vivo.