Description: Elevated blood branched-chain amino acids (BCAA) are often associated with insulin resistance and type 2 diabetes, which might result from a reduced cellular utilization and/or incomplete BCAA oxidation. White adipose tissue (WAT) has become appreciated as a potential player in whole body BCAA metabolism. We tested if expression of the mitochondrial BCAA oxidation checkpoint, branched-chain α-ketoacid dehydrogenase (BCKD) complex, is reduced in obese WAT and regulated by metabolic signals. WAT BCKD protein (E1α subunit) was significantly reduced by 35–50% in various obesity models ( fa/fa rats, db/db mice, diet-induced obese mice), and BCKD component transcripts significantly lower in subcutaneous (SC) adipocytes from obese vs. lean Pima Indians. Treatment of 3T3-L1 adipocytes or mice with peroxisome proliferator-activated receptor- agonists increased WAT BCAA catabolism enzyme mRNAs, whereas the nonmetabolizable glucose analog 2-deoxy- d -glucose had the opposite effect. The results support the hypothesis that suboptimal insulin action and/or perturbed metabolic signals in WAT, as would be seen with insulin resistance/type 2 diabetes, could impair WAT BCAA utilization. However, cross-tissue flux studies comparing lean vs. insulin-sensitive or insulin-resistant obese subjects revealed an unexpected negligible uptake of BCAA from human abdominal SC WAT. This suggests that SC WAT may not be an important contributor to blood BCAA phenotypes associated with insulin resistance in the overnight-fasted state. mRNA abundances for BCAA catabolic enzymes were markedly reduced in omental (but not SC) WAT of obese persons with metabolic syndrome compared with weight-matched healthy obese subjects, raising the possibility that visceral WAT contributes to the BCAA metabolic phenotype of metabolically compromised individuals.

Description: Treatment of vaso-occlusive crises (VOC) or events in sickle cell disease (SCD) remains limited to symptom relief with opioids. Animal models support the effectiveness of the pan-selectin inhibitor GMI-1070 in reducing selectin-mediated cell adhesion and abrogating VOC. We studied GMI-1070 in a prospective multicenter, randomized, placebo-controlled, double-blind, phase 2 study of 76 SCD patients with VOC. Study drug (GMI-1070 or placebo) was given every 12 hours for up to 15 doses. Other treatment was per institutional standard of care. All subjects reached the composite primary end point of resolution of VOC. Although time to reach the composite primary end point was not statistically different between the groups, clinically meaningful reductions in mean and median times to VOC resolution of 41 and 63 hours (28% and 48%, P = .19 for both) were observed in the active treatment group vs the placebo group. As a secondary end point, GMI-1070 appeared safe in acute vaso-occlusion, and adverse events were not different in the two arms. Also in secondary analyses, mean cumulative IV opioid analgesic use was reduced by 83% with GMI-1070 vs placebo ( P = .010). These results support a phase 3 study of GMI-1070 (now rivipansel) for SCD VOC. This trial was registered at www.clinicaltrials.gov as #NCT01119833.

Description: The extracellular matrix (ECM) plays an important role in the maintenance of white adipose tissue (WAT) architecture and function, and proper ECM remodeling is critical to support WAT malleability to accomodate changes in energy storage needs. Obesity and adipocyte hypertrophy place a strain on the ECM remodeling machinery, which may promote disordered ECM and altered tissue integrity and could promote proinflammatory and cell stress signals. To explore these questions, new methods were developed to quantify omental and subcutaneous WAT tensile strength and WAT collagen content by three-dimensional confocal imaging, using collagen VI knockout mice as a methods validation tool. These methods, combined with comprehensive measurement of WAT ECM proteolytic enzymes, transcript, and blood analyte analyses, were used to identify unique pathophenotypes of metabolic syndrome and type 2 diabetes mellitus in obese women, using multivariate statistical modeling and univariate comparisons with weight-matched healthy obese individuals. In addition to the expected differences in inflammation and glycemic control, approximately 20 ECM-related factors, including omental tensile strength, collagen, and enzyme transcripts, helped discriminate metabolically compromised obesity. This is consistent with the hypothesis that WAT ECM physiology is intimately linked to metabolic health in obese humans, and the studies provide new tools to explore this relationship.

Description: The period around bariatric surgery offers a unique opportunity to characterize metabolism responses to dynamic shifts in energy, gut function, and anesthesia. We analyzed plasma acylcarnitines in obese women ( n = 17) sampled in the overnight fasted/postabsorptive state approximately 1–2 wk before surgery ( condition A ), the morning of surgery (prior restriction to a 48-h clear liquid diet coupled in some cases a standard polyethylene glycol gut evacuation: condition B ), and following induction of anesthesia ( condition C ). Comparisons tested if 1 ) plasma acylcarnitine derivatives reflective of fatty acid oxidation (FAO) and xenometabolism would be significantly increased and decreased, respectively, by preoperative gut preparation/negative energy balance ( condition A vs. B ), and 2 ) anesthesia would acutely depress markers of FAO. Acylcarnitines associated with fat mobilization and FAO were significantly increased in condition B : long-chain acylcarnitines (i.e., C18:1, ~70%), metabolites from active but incomplete FAO [i.e., C14:1 (161%) and C14:2 (102%)] and medium- to short-chain acylcarnitines [i.e., C2 (91%), R -3-hydroxybutyryl-(245%), C6 (45%), and cis -3,4-methylene-heptanoyl-(17%), etc.]. Branched-chain amino acid markers displayed disparate patterns [i.e., isobutyryl-(40% decreased) vs. isovaleryl carnitine (51% increased)]. Anesthesia reduced virtually every acylcarnitine. These results are consistent with a fasting-type metabolic phenotype coincident with the presurgical "gut preparation" phase of bariatric surgery, and a major and rapid alteration of both fat and amino acid metabolism with onset of anesthesia. Whether presurgical or anesthesia-associated metabolic shifts in carnitine and fuel metabolism impact patient outcomes or surgical risks remains to be evaluated experimentally.

Description: Introduction: Acute painful episodes, frequently called sickle cell-related pain crises (SCPC), are a substantial cause of morbidity in sickle cell disease (SCD). Although hydroxyurea (HU) is known to decrease the frequency of SCPC in sickle cell anemia, many patients continue to experience acute painful episodes despite such therapy. P-selectin is an adhesion molecule expressed on activated vascular endothelial cells and platelets. It is a key molecule in the initiation of leukocyte rolling on the vessel wall that leads to firm attachment and extravasation to underlying tissues during inflammation. Upregulation of P-selectin on endothelial cells and platelets also contributes to the cell-cell interactions involved in the pathogenesis of SCPC. The SUSTAIN study evaluated the safety of SelG1, a first-in-class humanized anti-P-selectin antibody, and its effect on the frequency of SCPC in SCD patients. Methods: We conducted a randomized, double-blind, placebo-controlled, multinational study. Patients were randomized to receive placebo, 2.5 mg/kg or 5.0 mg/kg SelG1; patients received their initial dose, a dose 14 days later, and then every 4 weeks through week 50 for a total of 14 doses. The primary efficacy endpoint was the annual rate of SCPC in the 5.0 mg/kg SelG1 group vs. placebo. A hierarchical testing procedure was employed (α = 0.05 for high dose vs. placebo, and if significant, low dose vs. placebo). An SCPC was defined as acute sickle cell-related pain that resulted in a visit to a medical facility and required a parenteral or oral narcotic or parenteral NSAID. Acute chest syndrome (ACS), priapism, hepatic and splenic sequestration were also included in this definition. A blinded, independent committee adjudicated all SCPC events. Key inclusion criteria included patients 16 to 65 years of age; diagnosis of SCD (HbSS, HbSC, HbSβ 0 thalassemia or HbSβ + thalassemia); and history of 2 to 10 SCPC in the previous 12 months. Patients receiving HU or erythropoietin were included if prescribed for the preceding 6 months and dose was stable for at least 3 months. The randomization was stratified by historical SCPC in the prior year (2-4 or 5-10) and concomitant HU use (yes or no). Secondary endpoints included annual rate of days hospitalized, times to first and second SCPC and annual rate of uncomplicated SCPC (defined as typical SCPC other than ACS, priapism and hepatic or splenic sequestration) and ACS. Results: 198 SCD patients were randomized for the 1-year study. The Intent-To-Treat (ITT) population included all randomized patients; 67, 66 and 65 patients in the 5.0 mg/kg, 2.5 mg/kg and placebo groups, respectively. Demographic parameters were evenly distributed in the treatment groups. The primary endpoint, the annual rate of SCPC in the ITT population at 5.0 mg/kg vs. placebo, was reduced 47% (medians of 1.6 vs. 3.0, p = 0.010, Table 1). The SelG1 drug effect was dose-dependent as the annual rate of SCPC at 2.5 mg/kg vs. placebo was reduced 33% (medians of 2.0 vs. 3.0, p = 0.180). Time to first SCPC at 5.0 mg/kg vs. placebo was increased 2.9-fold (medians of 4.1 vs. 1.4 months, p = 0.001, Fig. 1) and time to second SCPC was increased 2.0-fold (medians of 10.3 vs. 5.1 months, p = 0.022, Fig. 2). The annual rate of uncomplicated SCPC at 5.0 mg/kg vs. placebo was reduced by 62% (medians of 1.1 vs. 2.9, p = 0.015). ACS events were rare in this study. The annual rate of days hospitalized at 5.0 mg/kg vs. placebo showed a non-significant, 42% reduction (medians of 4.0 vs. 6.9, p = 0.450). Adverse events that occurred in 5% or more of patients in an active dose group and were elevated over placebo by at least 2-fold were arthralgia, pruritus, vomiting, chest pain, diarrhea, road traffic accident, fatigue, myalgia, musculoskeletal chest pain, abdominal pain, influenza and oropharyngeal pain. There were no apparent increases in infections with SelG1 treatment. Five deaths occurred during the study, 2 at 5.0 mg/kg, 1 at 2.5 mg/kg and 2 in placebo; no deaths were deemed related to study drug. Conclusions: The P-selectin inhibitor SelG1 significantly reduced SCPC and appeared to be safe and well tolerated. Significant improvements were also achieved for several secondary endpoints including increases in times to first and second SCPC. Chronic inhibition of P-selectin with once a month IV dosing of SelG1 represents a novel and potentially new disease-modifying, prophylactic treatment option for patients with SCD. clinicaltrials.gov: NCT01895361 Disclosures Kutlar: Novartis Pharmaceuticals: Research Funding. Kanter: Novartis: Consultancy. Rollins: Selexys Pharmaceuticals: Equity Ownership, Other: Previous Employment. Stocker: Selexys Pharmaceuticals: Equity Ownership, Other: Previous Employment. Rother: Selexys Pharmaceuticals: Equity Ownership, Other: Previous Employment.

Description: Skeletal muscle mass can increase during hypertrophy or decline dramatically in response to normal or pathological signals that trigger atrophy. Many reports have documented that the number of nuclei within these cells is also plastic. It has been proposed that a yet-to-be-defined regulatory mechanism functions to maintain a relatively stable relationship between the cytoplasmic volume and nuclear number within the cell, a phenomenon known as the "myonuclear domain" hypothesis. While it is accepted that hypertrophy is typically associated with the addition of new nuclei to the muscle fiber from stem cells such as satellite cells, the loss of myonuclei during atrophy has been controversial. The intersegmental muscles from the tobacco hawkmoth Manduca sexta are composed of giant syncytial cells that undergo sequential developmental programs of atrophy and programmed cell death at the end of metamorphosis. Since the intersegmental muscles lack satellite cells or regenerative capacity, the tissue is not "contaminated" by these nonmuscle nuclei. Consequently, we monitored muscle mass, cross-sectional area, nuclear number, and cellular DNA content during atrophy and the early phases of cell death. Despite a ~75–80% decline in muscle mass and cross-sectional area during the period under investigation, there were no reductions in nuclear number or DNA content, and the myonuclear domain was reduced by ~85%. These data suggest that the myonuclear domain is not an intrinsic property of skeletal muscle and that nuclei persist through atrophy and programmed cell death.