Effects of CETP inhibition with anacetrapib on metabolism of VLDL-TG and plasma apolipoproteins C-II, C-III, and E.

Cholesteryl ester transfer protein (CETP) mediates the transfer of HDL cholesteryl esters for triglyceride (TG) in VLDL/LDL. CETP inhibition, with anacetrapib, increases HDL-cholesterol, reduces LDL-cholesterol, and lowers TG levels. This study describes the mechanisms responsible for TG lowering by examining the kinetics of VLDL-TG, apoC-II, apoC-III, and apoE. Mildly hypercholesterolemic subjects were randomized to either placebo (N = 10) or atorvastatin 20 mg/qd (N = 29) for 4 weeks (period 1) followed by 8 weeks of anacetrapib, 100 mg/qd (period 2). Following each period, subjects underwent stable isotope metabolic studies to determine the fractional catabolic rates (FCRs) and production rates (PRs) of VLDL-TG and plasma apoC-II, apoC-III, and apoE. Anacetrapib reduced the VLDL-TG pool on a statin background due to an increased VLDL-TG FCR (29%; P = 0.002). Despite an increased VLDL-TG FCR following anacetrapib monotherapy (41%; P = 0.11), the VLDL-TG pool was unchanged due to an increase in the VLDL-TG PR (39%; P = 0.014). apoC-II, apoC-III, and apoE pool sizes increased following anacetrapib; however, the mechanisms responsible for these changes differed by treatment group. Anacetrapib increased the VLDL-TG FCR by enhancing the lipolytic potential of VLDL, which lowered the VLDL-TG pool on atorvastatin background. There was no change in the VLDL-TG pool in subjects treated with anacetrapib monotherapy due to an accompanying increase in the VLDL-TG PR.

Cholesteryl Ester Transfer Protein Inhibition With Anacetrapib Decreases Fractional Clearance Rates of High-Density Lipoprotein Apolipoprotein A-I and Plasma Cholesteryl Ester Transfer Protein.

OBJECTIVE: Anacetrapib (ANA), an inhibitor of cholesteryl ester transfer protein (CETP) activity, increases plasma concentrations of high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (apoA)-I, apoA-II, and CETP. The mechanisms responsible for these treatment-related increases in apolipoproteins and plasma CETP are unknown. We performed a randomized, placebo (PBO)-controlled, double-blind, fixed-sequence study to examine the effects of ANA on the metabolism of HDL apoA-I and apoA-II and plasma CETP. APPROACH AND RESULTS: Twenty-nine participants received atorvastatin (ATV) 20 mg/d plus PBO for 4 weeks, followed by ATV plus ANA 100 mg/d for 8 weeks (ATV-ANA). Ten participants received double PBO for 4 weeks followed by PBO plus ANA for 8 weeks (PBO-ANA). At the end of each treatment, we examined the kinetics of HDL apoA-I, HDL apoA-II, and plasma CETP after D3-leucine administration as well as 2D gel analysis of HDL subspecies. In the combined ATV-ANA and PBO-ANA groups, ANA treatment increased plasma HDL-C (63.0%; P<0.001) and apoA-I levels (29.5%; P<0.001). These increases were associated with reductions in HDL apoA-I fractional clearance rate (18.2%; P=0.002) without changes in production rate. Although the apoA-II levels increased by 12.6% (P<0.001), we could not discern significant changes in either apoA-II fractional clearance rate or production rate. CETP levels increased 102% (P<0.001) on ANA because of a significant reduction in the fractional clearance rate of CETP (57.6%, P<0.001) with no change in CETP production rate. CONCLUSIONS: ANA treatment increases HDL apoA-I and CETP levels by decreasing the fractional clearance rate of each protein.

Is Pes Cavus Alignment Associated With Lisfranc Injuries of the Foot?

BACKGROUND: Lisfranc (tarsometatarsal joint) injuries are relatively rare, accounting for less than 1% of all fractures, and as many as 20% of subtle Lisfranc injuries are missed at the initial patient presentation. An undiagnosed Lisfranc injury can have devastating consequences to the patient. Therefore, any factor that can raise a clinician's index of suspicion to make this diagnosis is potentially important. The cavus foot has been associated with various maladies of the lower extremity, but to our knowledge, it has not been reported to be associated with Lisfranc injury. QUESTIONS/PURPOSES: Do patients who experience a low-energy Lisfranc injury have greater talar head coverage and a greater talo-first metatarsal angle than control subjects? METHODS: A retrospective, case-control study was conducted from September 2011 to December 2014 to identify patients diagnosed and treated for a low-energy Lisfranc injury. Twenty-three adult patients with an average age of 42.6 years (SD, 16.3 years) were identified and compared with 61 adult control subjects with an average age of 49.4 years (SD, 14.1 years). Control subjects came from the practice of a fellowship-trained foot and ankle orthopaedic surgeon. Control subjects underwent a history and physical, clinical examination, and diagnostic imaging to confirm that they had no prior foot disorder, no prior foot surgeries, were within 3 years of age of a patient with a Lisfranc injury, and were independent ambulators. Two authors (DSD and JDP) measured the talonavicular and talo-first metatarsal angles on weightbearing AP and lateral radiographs of the foot. The intrarater reliability and interrater reliability for the talo-first metatarsal angle and the talonavicular angle showed high agreement. The intrarater intraclass correlation coefficients (ICC) of the talo-first metatarsal angle were 0.94 (95% CI, 0.91-0.96) and 0.93 (95% CI, 0.9-0.96). For the talonavicular angle the ICCs were 0.83 (95% CI, 0.75-0.89) and 0.88 (95% CI, 0.81-0.92) for Raters 1 and 2 respectively. The interrater ICCs were 0.91 (95% CI, 0.69-0.96) for the talo-first metatarsal angle and 0.9 (95% CI, 0.85-0.94) for the talonavicular angle. The patients and controls were compared to determine if the patients who sustained a Lisfranc injury were more likely to have a pes cavus foot alignment. We performed a mixed modeling analysis to control for potential cofounding variables and determine if there was an association of Lisfranc injury with the talo-first metatarsal angle and the talonavicular angle. RESULTS: After controlling for confounding variables such as the effect of the measurement round effect and the effect of the rater, our repeated measures analysis via mixed model showed patients were associated with a higher talo-first metatarsal angle than control subjects (adjusted least square mean for patients = 3.05; for controls = -2.65; mean difference, 5.7; p = 0.001). Repeated measures analysis via mixed model showed that patients also were associated with a more positive talonavicular angle than control subjects (adjusted least square mean for patients = -4.83, for controls = -11; mean difference, 6.17; p = 0.002). Patients with Lisfranc injuries had a higher mean talo-first metatarsal angle than did control subjects (1.9° ± 7.9° versus -2.2° ± 7.3°; mean difference, 4.1°; 95% CI, -7.7° to -0.5°; p = 0.028), and less talar uncovering (-4.2° ± 9.7° versus -11° ± 8°; mean difference, 6.7°; 95% CI, -6.7° to -10.8°; p = 0.001). CONCLUSIONS: We found that cavus midfoot alignment was more prevalent among patients with Lisfranc injuries than among individuals with no foot injury or disorder. Although this does not suggest that cavus alignment causes or predisposes patients to this injury, we believe the finding is important because this provides a radiographic parameter that clinicians can use to raise their index of suspicion for a Lisfranc injury and aggressively pursue this diagnosis. Future studies would benefit from obtaining contralateral foot imaging at the time of injury in all patients with Lisfranc injury or prospectively following patients with foot imaging and recording the incidence of future foot injury. LEVEL OF EVIDENCE: Level III, prognostic study.

Effect of Recombinant Human Growth Hormone and Rosiglitazone for HIV-Associated Abdominal Fat Accumulation on Adiponectin and other Markers of Inflammation.

BACKGROUND/OBJECTIVE: In a previous report of HIV-infected patients with fat redistribution, we found that recombinant human growth hormone (rhGH) therapy reduced visceral adipose tissue (VAT) but increased insulin resistance, and that the addition of rosiglitazone reversed the negative effects of rhGH on insulin sensitivity. In this study, we sought to determine the effects of rhGH and rosiglitazone therapy on an array of inflammatory and fibrinolytic markers. METHODS: 72 patients with HIV-associated abdominal obesity and insulin resistance were randomized to treatment with rhGH, rosiglitazone, the combination of rhGH and rosiglitazone, or placebo for 12 weeks. Subjects with plasma and serum samples available at weeks 0 (n=63) and 12 (n=46-48) were assessed for adiponectin, C-reactive protein, homocysteine, interleukin-1, interleukin-6, tumor necrosis factor alpha, interferon gamma, fibrinogen, plasminogen activator inhibitor-1 antigen, and tissue plasminogen activator antigen. RESULTS: Treatment with both rosiglitazone alone and the combination of rosiglitazone and rhGH for 12 weeks resulted in significant increases in adiponectin levels from baseline. Adiponectin levels did not change significantly in the rhGH arm alone . There were no significant changes in the other biomarkers among the different treatment groups. DISCUSSION: In this study of HIV-infected patients with altered fat distribution, treatment with rosiglitazone had beneficial effects on adiponectin concentrations, an effect that was also seen with a combination of rosiglitazone and rhGH. RhGH administration alone, however, did not demonstrate any significant impact on adiponectin levels despite reductions in VAT.

Accuracy and Reliability of Radiographic Estimation of Volar Lip Fragment Size in PIP Dorsal Fracture-Dislocations.

Background: A cadaveric study was performed to evaluate the accuracy and reliability of radiographic estimation of the volar lip fragment size in proximal interphalangeal joint fracture-dislocations. Methods: Middle phalangeal base volar lip fractures of varying size and morphology were simulated in 18 digits. Radiographs and digital photographs of the middle phalangeal joint surface were obtained pre- and postinjury. Ten orthopedic surgeons of varying levels of training estimated the fracture size based on radiographs. The estimated joint involvement on radiograph was compared with the digitally measured joint involvement. Results: Radiographic estimation underestimated the volar lip fragment size by 9.02%. Estimations possessed high intraobserver (0.76-0.98) and interobserver (0.88-0.97) reliabilities. No differences were detected between levels of surgeon training. Conclusions: The significant underestimation of the volar lip fragment size demonstrates the lack of radiographic estimation accuracy and suggests that surgeons should be mindful of these results when making treatment plans.

Incidence of Delayed Diagnosis of Orthopaedic Injury in Pediatric Trauma Patients.

OBJECTIVE: Determine the incidence of the delayed diagnosis of orthopaedic injuries in pediatric trauma patients. DESIGN: Cross-sectional retrospective analysis. SETTING: Level I pediatric trauma center. PATIENTS/PARTICIPANTS: All patients with an orthopaedic consultation after a trauma activation with a diagnosis of fracture, dislocation, traumatic arthrotomy, neurovascular injury, amputation, and tendon or ligament injury requiring intervention. A total of 1009 trauma codes and alerts occurred during the study period, of which 196 patients were diagnosed with an orthopaedic injury. INTERVENTION: Charts were reviewed to obtain demographic information, time of presentation, Glasgow Coma Score (GCS) on presentation, injury severity score (ISS), mechanism of injury, intubation status, length of intensive care unit and hospital stay, primary and secondary survey diagnoses, discharge diagnoses, time of additional diagnoses, and reason for delayed diagnosis. MAIN OUTCOME MEASURES: Incidence of delayed diagnosis of injury (DDI). RESULTS: There were 196 patients with a confirmed orthopaedic injury, of which, 18 were classified as a delayed diagnosis (9.18%). The mean time to detection of injury was 77.46 hours and the mean patient age was 132.22 months. One of the 18 patients required surgical intervention while the rest were treated conservatively. The mean GCS score of patients with a DDI were significantly lower than patients without a missed injury, 12 versus 14.19 (P = 0.0009). The median ISS, 21 versus 9 (P = 0.0021), and median hospital length of stay, 4 days versus 3 days (P = 0.0369) were significantly higher for patients with a missed injury compared with those without a missed injury. The intensive care unit length of stay approached significance with a median of 2 days for patients with a missed injury versus 1 day for patients without a missed injury (P = 0.057). CONCLUSIONS: In our study, factors that were associated with a DDI included lower GCS, higher ISS, and greater hospital length of stay. There was only 1 missed injury that required surgical intervention, and the remainder were treated conservatively. The initial evaluation of the trauma patient is able to detect life-threatening injuries, but the tertiary survey remains an important part of patient care to detect missed injuries. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A puzzle assembly strategy for fabrication of large engineered cartilage tissue constructs.

Engineering of large articular cartilage tissue constructs remains a challenge as tissue growth is limited by nutrient diffusion. Here, a novel strategy is investigated, generating large constructs through the assembly of individually cultured, interlocking, smaller puzzle-shaped subunits. These constructs can be engineered consistently with more desirable mechanical and biochemical properties than larger constructs (~4-fold greater Young׳s modulus). A failure testing technique was developed to evaluate the physiologic functionality of constructs, which were cultured as individual subunits for 28 days, then assembled and cultured for an additional 21-35 days. Assembled puzzle constructs withstood large deformations (40-50% compressive strain) prior to failure. Their ability to withstand physiologic loads may be enhanced by increases in subunit strength and assembled culture time. A nude mouse model was utilized to show biocompatibility and fusion of assembled puzzle pieces in vivo. Overall, the technique offers a novel, effective approach to scaling up engineered tissues and may be combined with other techniques and/or applied to the engineering of other tissues. Future studies will aim to optimize this system in an effort to engineer and integrate robust subunits to fill large defects.

Complex effects of inhibiting hepatic apolipoprotein B100 synthesis in humans.

Mipomersen is a 20mer antisense oligonucleotide (ASO) that inhibits apolipoprotein B (apoB) synthesis; its low-density lipoprotein (LDL)-lowering effects should therefore result from reduced secretion of very-low-density lipoprotein (VLDL). We enrolled 17 healthy volunteers who received placebo injections weekly for 3 weeks followed by mipomersen weekly for 7 to 9 weeks. Stable isotopes were used after each treatment to determine fractional catabolic rates and production rates of apoB in VLDL, IDL (intermediate-density lipoprotein), and LDL, and of triglycerides in VLDL. Mipomersen significantly reduced apoB in VLDL, IDL, and LDL, which was associated with increases in fractional catabolic rates of VLDL and LDL apoB and reductions in production rates of IDL and LDL apoB. Unexpectedly, the production rates of VLDL apoB and VLDL triglycerides were unaffected. Small interfering RNA-mediated knockdown of apoB expression in human liver cells demonstrated preservation of apoB secretion across a range of apoB synthesis. Titrated ASO knockdown of apoB mRNA in chow-fed mice preserved both apoB and triglyceride secretion. In contrast, titrated ASO knockdown of apoB mRNA in high-fat-fed mice resulted in stepwise reductions in both apoB and triglyceride secretion. Mipomersen lowered all apoB lipoproteins without reducing the production rate of either VLDL apoB or triglyceride. Our human data are consistent with long-standing models of posttranscriptional and posttranslational regulation of apoB secretion and are supported by in vitro and in vivo experiments. Targeting apoB synthesis may lower levels of apoB lipoproteins without necessarily reducing VLDL secretion, thereby lowering the risk of steatosis associated with this therapeutic strategy.

Anacetrapib lowers LDL by increasing ApoB clearance in mildly hypercholesterolemic subjects.

BACKGROUND: Individuals treated with the cholesteryl ester transfer protein (CETP) inhibitor anacetrapib exhibit a reduction in both LDL cholesterol and apolipoprotein B (ApoB) in response to monotherapy or combination therapy with a statin. It is not clear how anacetrapib exerts these effects; therefore, the goal of this study was to determine the kinetic mechanism responsible for the reduction in LDL and ApoB in response to anacetrapib. METHODS: We performed a trial of the effects of anacetrapib on ApoB kinetics. Mildly hypercholesterolemic subjects were randomized to background treatment of either placebo (n = 10) or 20 mg atorvastatin (ATV) (n = 29) for 4 weeks. All subjects then added 100 mg anacetrapib to background treatment for 8 weeks. Following each study period, subjects underwent a metabolic study to determine the LDL-ApoB-100 and proprotein convertase subtilisin/kexin type 9 (PCSK9) production rate (PR) and fractional catabolic rate (FCR). RESULTS: Anacetrapib markedly reduced the LDL-ApoB-100 pool size (PS) in both the placebo and ATV groups. These changes in PS resulted from substantial increases in LDL-ApoB-100 FCRs in both groups. Anacetrapib had no effect on LDL-ApoB-100 PRs in either treatment group. Moreover, there were no changes in the PCSK9 PS, FCR, or PR in either group. Anacetrapib treatment was associated with considerable increases in the LDL triglyceride/cholesterol ratio and LDL size by NMR. CONCLUSION: These data indicate that anacetrapib, given alone or in combination with a statin, reduces LDL-ApoB-100 levels by increasing the rate of ApoB-100 fractional clearance. TRIAL REGISTRATION: ClinicalTrials.gov NCT00990808. FUNDING: Merck & Co. Inc., Kenilworth, New Jersey, USA. Additional support for instrumentation was obtained from the National Center for Advancing Translational Sciences (UL1TR000003 and UL1TR000040).

Efficacy of glyburide/metformin tablets compared with initial monotherapy in type 2 diabetes.

Many patients with type 2 diabetes fail to achieve or maintain the American Diabetes Association's recommended treatment goal of glycosylated hemoglobin levels. This multicenter, double-blind trial enrolled patients with type 2 diabetes who had inadequate glycemic control [glycosylated hemoglobin A(1C) (A1C), >7% and <12%) with diet and exercise alone to compare the benefits of initial therapy with glyburide/metformin tablets vs. metformin or glyburide monotherapy. Patients (n = 486) were randomized to receive glyburide/metformin tablets (1.25/250 mg), metformin (500 mg), or glyburide (2.5 mg). Changes in A1C, fasting plasma glucose, fructosamine, serum lipids, body weight, and 2-h postprandial glucose after a standardized meal were assessed after 16 wk of treatment. Glyburide/metformin tablets caused a superior mean reduction in A1C from baseline (-2.27%) vs. metformin (-1.53%) and glyburide (-1.90%) monotherapy (P = 0.0003). Glyburide/metformin also significantly reduced fasting plasma glucose and 2-h postprandial glucose values compared with either monotherapy. The final mean doses of glyburide/metformin (3.7/735 mg) were lower than those of metformin (1796 mg) and glyburide (7.6 mg). First-line treatment with glyburide/metformin tablets provided superior glycemic control over component monotherapy, allowing more patients to achieve American Diabetes Association treatment goals with lower component doses in drug-naive patients with type 2 diabetes.