The db/db mouse is a well-established model of diabetes. Previous reports have documented contractile dysfunction (i.e., cardiomyopathy) in these animals, although the extant literature provides limited insights into cardiac structure and function as they change over time. To better elucidate the natural history of cardiomyopathy in db/db mice, we performed cardiac magnetic resonance (CMR) scans on these animals. CMR imaging was conducted with a 4.7-T magnet on female db/db mice and control db/ϩ littermates at 5, 9, 13, 17, and 22 wk of age. Gated gradient echo sequences were used to obtain cineographic short-axis slices from apex to base. From these images left ventricular (LV) mass (LVM), wall thickness, end-diastolic volume (LVEDV), and ejection fraction (LVEF) were determined. 18 F]FDG metabolic imaging showed a 40% decrease in glucose uptake in db/db mice. Furthermore, contractile dysfunction was observed in 15-wk db/db mice undergoing pressure-volume loops. Finally, real-time quantitative PCR revealed an age-dependent recapitulation of the fetal gene program, consistent with a myopathic process. In summary, as assessed by CMR, db/db mice develop characteristic structural and functional changes consistent with cardiomyopathy. diabetes mellitus; insulin resistance; heart failure; metabolism CONGESTIVE HEART FAILURE (CHF) is a significant yet often underappreciated complication of diabetes mellitus (25). While atherosclerotic coronary artery disease is highly prevalent and likely responsible for CHF in many diabetic patients, findings from several large-scale heart failure clinical trials reveal a 16 -20% prevalence of diabetes in patients with nonischemic cardiomyopathy (9). Moreover, an analysis of hospital discharge data showed a 27% prevalence of diabetes in patients discharged with idiopathic cardiomyopathy, compared with 18% for control subjects (13). Collectively these data suggest an alternative mechanism for CHF in diabetics-one independent of the effects of epicardial coronary disease. However, studies investigating this unique form of "diabetic cardiomyopathy" (51) have failed to establish a unifying mechanistic basis for this phenomenon.The C57BL/KLS-lepr db /lepr db (db/db) mouse, which has a mutation in the leptin receptor, is a well-established animal model of Type 2 diabetes mellitus (19). Leptin resistance results in hyperphagia and weight gain from birth. Homozygous db/db mice become noticeably obese by 3-4 wk of age and develop hyperglycemia at 4 -8 wk. Serum insulin levels increase as early as 10 -14 days, peak at 6 -8 wk, then decrease precipitously afterward (although db/db mice continue to be hyperinsulinemic throughout life). This drop, which is believed to be secondary to pancreatic islet cell dysfunction, further exacerbates the hyperglycemia.In addition to these characteristic phenotypic changes, db/db mice also develop cardiomyopathy. Metabolic experiments using cultured db/db cardiomyocytes have shown impaired glucose oxidation as early as 6 wk of age (1). Echocardiographic studie...

Background Complex regional pain syndrome (CRPS) is a painful, disabling and often chronic condition, where many patients transition from an acute phase with prominent peripheral neurogenic inflammation to a chronic phase with evident central nervous system (CNS) changes. Ketamine is a centrally-acting agent believed to work through blockade of N-methyl-D-aspartate (NMDA) receptors and is being increasingly used for the treatment of refractory CRPS, although the basis for the drug’s effects and efficacy at different stages of the syndrome remain unclear. Methods We used a mouse model of CRPS (n=8–12/group) involving tibia fracture/cast immobilization to test the efficacy of ketamine (2 mg/kg/day; 7 days) or vehicle infusion during acute (3weeks [3w] post-fracture) and chronic (7w post-fracture) stages. Results Acute phase fracture mice displayed elevated limb temperature, edema and nociceptive sensitization that were not reduced by ketamine. Fracture mice treated with ketamine during the chronic phase showed reduced nociceptive sensitization that persisted beyond completion of the infusion. During this chronic phase, ketamine also reduced latent nociceptive sensitization and improved motor function at 18 weeks post-fracture. No side effects of the infusions were identified. These behavioral changes were associated with altered spinal astrocyte activation and expression of pain-related proteins including NMDA receptor 2b (NR2b), Ca2+/calmodulin-dependent protein kinase ii (CaMK2), and brain-derived neurotrophic factor (BNDF). Conclusions Collectively, these results demonstrate that ketamine is efficacious in the chronic, but not acute stages of CRPS, suggesting that the centrally-acting drug is relatively ineffective in early CRPS when peripheral mechanisms are more critical for supporting nociceptive sensitization.

Brain metastasis is a major cause of morbidity and mortality in patients with breast cancer. Our previous studies indicated that Stat3 plays an important role in brain metastasis. Here, we present evidence that Stat3 functions at the level of the microenvironment of brain metastases. Stat3 controlled constitutive and inducible VEGFR2 expression in tumor-associated brain endothelial cells. Furthermore, inhibition of Stat3 by WP1066 decreased the incidence of brain metastases and increased survival in a preclinical model of breast cancer brain metastasis. WP1066 inhibited Stat3 activation in tumor-associated endothelial cells, reducing their infiltration and angiogenesis. WP1066 also inhibited breast cancer cell invasion. Our results indicate that WP1066 can inhibit tumor angiogenesis and brain metastasis mediated by Stat3 in endothelial and tumor cells.

Objectives Transthoracic echocardiography (TTE) is the mainstay of clinical practice for evaluating right ventricular (RV) size and function, but its accuracy in patients with pulmonary hypertension (PH) has not been well validated. Methods Magnetic resonance imaging (MRI) and TTE images were retrospectively reviewed in 40 consecutive patients with PH. Right and left ventricular (LV) volumes and ejection fractions (EFs) were calculated by MRI. TTE areas and indices of RVEF were compared. Results The average age was 42 ± 12 years with a majority of women (85%). There was a wide range of mean pulmonary arterial pressure (27 to 81 mmHg), and RV end diastolic volumes (111 to 576 mL), RVEFs (8 to 67 %), and LVEFs (26 to 72%) by MRI. There was a strong association between TTE and MRI derived parameters: RV end-diastolic area (RVEDA, TTE) and RV end-diastolic volume (RVEDV, MRI), R2 = 0.78, p<0.001; fractional area change (RVFAC) by TTE and RVEF by MRI, R2 = 0.76, p<0.001; and tricuspid annular plane systolic excursion (TAPSE), by TTE, and MRI RVEF, R2 = 0.64, p<0.001. By ROC curve analysis, an RVFAC<25%, provides excellent discrimination of moderate systolic dysfunction (RVEF<35%), AUC of 0.97, p<0.001. An RVEDA index of 18 cm2/m2 provides excellent discrimination for moderate RV enlargement (AUC of 0.89, p<0.001). Conclusions Echocardiographic estimates of RV volume, by RVEDA, and function, by RVFAC and TAPSE, offer good approximation of RV size and function in patients with PH and allow for accurate discrimination of normal from abnormal.