Effects of meal composition on postprandial incretin, glucose and insulin responses after surgical and medical weight loss

Background

Meal tolerance tests are frequently used to study dynamic incretin and insulin responses in the postprandial state; however, the optimal meal that is best tolerated and suited for hormonal response following surgical and medical weight loss has yet to be determined.

Objective

To evaluate the tolerability and effectiveness of different test meals in inducing detectable changes in markers of glucose metabolism in individuals who have undergone a weight loss intervention.

Methods

Six individuals who underwent surgical or medical weight loss (two Roux‐en‐Y gastric bypass, two sleeve gastrectomy and two medical weight loss) each completed three meal tolerance tests using liquid‐mixed, solid‐mixed and high‐fat test meals. The tolerability of each test meal, as determined by the total amount consumed and palatability, as well as fasting and meal‐stimulated glucagon‐like peptide, glucose‐dependent insulinotropic polypeptide, insulin and glucose were measured.

Results

Among the six individuals, the liquid‐mixed meal was better and more uniformly tolerated with a median meal completion rate of 99%. Among the four bariatric surgical patients, liquid‐mixed meal stimulated on average a higher glucagon‐like peptide (percent difference: 83.7, 89), insulin secretion (percent difference: 155.1, 158.7) and glucose‐dependent insulinotropic polypeptide (percent difference: 113.5, 34.3) compared with solid‐mixed and high‐fat meals.

Conclusions

The liquid‐mixed meal was better tolerated with higher incretin and insulin response compared with the high‐fat and solid‐mixed meals and is best suited for the evaluation of stimulated glucose homeostasis.

Effect of certolizumab pegol over 96 weeks in patients with psoriatic arthritis with and without prior antitumour necrosis factor exposure

Objective

Previous reports of RAPID-PsA (NCT01087788) demonstrated efficacy and safety of certolizumab pegol (CZP) over 24 weeks in patients with psoriatic arthritis (PsA), including patients with prior antitumour necrosis factor (TNF) therapy. We report efficacy and safety data from a 96-week data cut of RAPID-PsA.

Methods

RAPID-PsA was placebo-controlled to week 24, dose-blind to week 48 and open-label to week 216. We present efficacy data including American College of Rheumatology (ACR)/Psoriasis Area and Severity Index (PASI) responses, HAQ-DI, pain, minimal disease activity (MDA), modified total Sharp score (mTSS) and ACR responses in patients with/without prior anti-TNF exposure, in addition to safety data.

Results

Of 409 patients randomised, 273 received CZP from week 0. 54 (19.8%) CZP patients had prior anti-TNF exposure. Of patients randomised to CZP, 91% completed week 24, 87% week 48 and 80% week 96. ACR responses were maintained to week 96: 60% of patients achieved ACR20 at week 24, and 64% at week 96. Improvements were observed with both CZP dose regimens. ACR20 responses were similar in patients with (week 24: 59%; week 96: 63%) and without (week 24: 60%; week 96: 64%) prior anti-TNF exposure. Placebo patients switching to CZP displayed rapid clinical improvements, maintained to week 96. In patients with ≥3% baseline skin involvement (60.8% week 0 CZP patients), PASI responses were maintained to week 96. No progression of structural damage was observed over the 96-week period. In the Safety Set (n=393), adverse events occurred in 345 patients (87.8%) and serious adverse events in 67 (17.0%), including 6 fatal events.

Conclusions

CZP efficacy was maintained to week 96 with both dose regimens and in patients with/without prior anti-TNF exposure. The safety profile was in line with that previously reported from RAPID-PsA, with no new safety signals observed with increased exposure.

Trial registration number

NCT01087788.

First measurements of hydrodynamic instability growth in indirectly driven implosions at ignition-relevant conditions on the National Ignition Facility

Ignition experiments have shown an anomalous susceptibility to hydrodynamic instability growth. To help understand these results, the first hydrodynamic instability growth measurements in indirectly driven implosions on the National Ignition Facility were performed at ignition conditions with peak radiation temperatures up to ∼300  eV. Plastic capsules with two-dimensional preimposed, sinusoidal outer surface modulations of initial wavelengths of 240 (corresponding to a Legendre mode number of 30), 120 (mode 60), and 80  μm (mode 90) were imploded by using actual low-adiabat ignition laser pulses. The measured growth was in excellent agreement, validating 2D hydra simulations for the most dangerous modes in the acceleration phase. These results reinforce confidence in the predictive capability of calculations that are paramount to illuminating the path toward ignition.

An evaluation of the pharmacokinetics of treprostinil diolamine in subjects with hepatic impairment

WHAT IS KNOWN AND OBJECTIVE

Treprostinil diolamine (oral treprostinil) is a prostacyclin analogue under evaluation for the treatment for pulmonary arterial hypertension (PAH). This study assessed the pharmacokinetics (PK) and safety of treprostinil following oral administration of a single sustained-release 1 mg dose in subjects with hepatic impairment.

METHODS

Four cohorts, including healthy volunteers, and subjects with mild, moderate and severe hepatic impairment were enrolled. Thirty subjects completed the study. Mean treprostinil clearance values (CL/F) decreased with the severity of hepatic impairment. The decrease in CL/F resulted in a marked increase in exposure levels of treprostinil. Relative to healthy subjects, mean area under the curve from time zero to 24 h after dosing interval (AUC0-24) values in subjects with mild, moderate and severe hepatic impairment increased by approximately 2·2-, 4·9- and 7·6-fold, respectively. The most frequent adverse events (AEs) exhibited in this study were similar to those seen with prostacyclin and its analogues and with AEs seen in other clinical studies with oral treprostinil (e.g. headache, diarrhoea and nausea). The overall incidence of all AEs and the specific events of headache and nausea increased with severity of hepatic impairment.

WHAT IS NEW AND CONCLUSION

Based on these results, dosage adjustments should be performed in subjects with hepatic impairment.

Impact of switching from epoprostenol to IV treprostinil on treatment satisfaction and quality of life in patients with pulmonary hypertension

BACKGROUND

Transition from intravenous (IV) epoprostenol to IV treprostinil in patients with pulmonary hypertension (PH) has traditionally been performed by gradually decreasing the epoprostenol dose while increasing the treprostinil dose. Preliminary data suggest that this transition can be performed more rapidly without the need for epoprostenol weaning. We conducted a single center, prospective clinical trial to assess the safety, efficacy, and treatment satisfaction of rapidly switching from epoprostenol to IV treprostinil.

METHODS

This study included patients with PH who had rapidly transitioned from epoprostenol to IV treprostinil. Data collected included clinical status, adverse events, PH symptoms, and previously validated measures of quality of life and treatment satisfaction.

RESULTS

Ten patients were enrolled in this study. Exercise capacity measured by mean 6-min walk distance was maintained from baseline throughout follow-up. Severity of disease as assessed by WHO functional class was maintained or improved for the majority of patients. Adverse events were minimal during the transition, and all patients remained on IV treprostinil throughout the follow-up period. A favorable impact on quality of life and treatment satisfaction measures was observed by eight weeks following the transition from epoprostenol to IV treprostinil. Specifically, time spent on drug preparation activities decreased by 39.5% with treprostinil compared to epoprostenol.

CONCLUSIONS

Rapidly switching from epoprostenol to IV treprostinil can be achieved without safety concerns, with minimal patient monitoring and without the need for extended hospitalization, while favorably impacting on patients' quality of life.

Role of outer membrane c-type cytochromes MtrC and OmcA in Shewanella oneidensis MR-1 cell production, accumulation, and detachment during respiration on hematite

The iron-reducing bacterium Shewanella oneidensis MR-1 has the capacity to contribute to iron cycling over the long term by respiring on crystalline iron oxides such as hematite when poorly crystalline phases are depleted. The ability of outer membrane cytochromes OmcA and MtrC of MR-1 to bind to and transfer electrons to hematite has led to the suggestion that they function as terminal reductases when this mineral is used as a respiratory substrate. Differences in their redox behavior and hematite-binding properties, however, indicate that they play different roles in the electron transfer reaction. Here, we investigated how these differences in cytochrome behavior with respect to hematite affected biofilm development when the mineral served as terminal electron acceptor (TEA). Upon attachment to hematite, cells of the wild-type (WT) strain as well as those of a ΔomcA mutant but not those of a ΔmtrC mutant replicated and accumulated on the mineral surface. The results indicate that MtrC but not OmcA is required for growth when this mineral serves as TEA. While an OmcA deficiency did not impede cell replication and accumulation on hematite prior to achievement of a maximum surface cell density comparable to that established by WT cells, OmcA was required for efficient electron transfer and cell attachment to hematite once maximum surface cell density was achieved. OmcA may therefore play a role in overcoming barriers to electron transfer and cell attachment to hematite imposed by reductive dissolution of the mineral surface from cell respiration associated with achievement of high surface cell densities.

Comparison of exposures among Arab American and non-Hispanic White female thyroid cancer cases in metropolitan Detroit

Arab American (ArA) women may be at greater risk for thyroid cancer (TC) than White women. This case-case comparison explored differences in known and proposed risk factors of TC among ArA and non-Hispanic White (NHW) female TC cases in metropolitan Detroit. Cases of invasive TC identified from a population-based registry responded to a telephone survey regarding potential TC risk factors. Thirty ArA women (response rate 52%) and 70 NHW women (67%) participated. NHW women reported significantly more prior thyroid disease (TD), family history of TD, hormone use, cumulative years of hormone use, cigarette and alcohol consumption. In adjusted logistic regression analysis, ArA women had significantly higher odds of exposure to dental x-rays (OR = 3.48, CI 1.01-12.00) and medical radiation (OR = 13.58, CI 1.49-124.04) than NHW women. Risk factors for TC may differ among ArA women and their NHW counterparts.

Gfi-1 inhibits proliferation and colony formation of p210BCR/ABL-expressing cells via transcriptional repression of STAT 5 and Mcl-1

Expression of the transcription repressor Gfi-1 is required for the maintenance of murine hematopoietic stem cells. In human cells, ectopic expression of Gfi-1 inhibits and RNA interference-mediated Gfi-1 downregulation enhances proliferation and colony formation of p210BCR/ABL expressing cells. To investigate the molecular mechanisms that may explain the effects of perturbing Gfi-1 expression in human cells, Gfi-1-regulated genes were identified by microarray analysis in K562 cells expressing the tamoxifen-regulated Gfi-1-ER protein. STAT 5B and Mcl-1, two genes important for the proliferation and survival of hematopoietic stem cells, were identified as direct and functionally relevant Gfi-1 targets in p210BCR/ABL-transformed cells because: (i) their expression and promoter activity was repressed by Gfi-1 and (ii) when constitutively expressed blocked the proliferation and colony formation inhibitory effects of Gfi-1. Consistent with these findings, genetic or pharmacological inhibition of STAT 5 and/or Mcl-1 markedly suppressed proliferation and colony formation of K562 and CD34+ chronic myelogenous leukemia (CML) cells. Together, these studies suggest that the Gfi-1STAT 5B/Mcl-1 regulatory pathway identified here can be modulated to suppress the proliferation and survival of p210BCR/ABL-transformed cells including CD34+ CML cells.

Chromosome 14q imbalances and pathways associated with resistance to antiangiogenic therapy in clear cell renal cell carcinoma

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Background: Antiangiogenic agents are used to treat metastatic clear cell renal cell carcinoma (ccRCC). Currently there are no biomarkers of therapeutic efficacy for these agents. Hypoxia inducible factor (HIF) alpha ratios have been linked to phenotypically distinct ccRCC subpopulations. The HIF1 alpha gene is located on chromosome 14q. In this study, the goal was to determine whether chromosomal imbalances identified with SNP arrays are linked to HIF ratios, and to clinical outcome.

Methods: We obtained archival FFPE tumor specimens from 56 patients with mRCC treated with sorafenib or bevacizumab. DNA from the FFPE blocks was analyzed with Affymetrix 250K Nsp SNP microarrays. We identified the presence of genomic imbalances and loss of heterozygosity (LOH) to obtain virtual karyotypes. We then evaluated candidate genes in gain/lost chromosomal regions by qPCR and immunohistochemistry (IHC) in the bevacizumab treated specimens.

Results: In the bevacizumab cohort, HIF1-alpha containing14q loss showed a significant association with worse response to treatment (CR/ PR vs. SD/PD, Fisher exact test, p = 0.0473). In addition, HIF1A mRNA expression was significantly reduced in all samples with 14q loss and was associated with PFS (HR = 2.29, 95% CI = 1.01-5.16, p = 0.045). HIF-1alpha protein expression was also reduced in samples with 14q loss.

Conclusions: Chromosomal imbalances are associated with outcomes in ccRCC patients treated with antiangiogenic agents, and can lead to changes in gene expression. Low HIF1A expression was strongly correlated with shorter PFS. We hypothesize that loss of 14q could lead to an imbalance in HIF-1alpha/HIF-2alpha activity, leading to increased HIF-2alpha and enhanced c-Myc expression, which improves tumor cell viability and engenders resistance to cellular stress induced by antiangiogenic therapy.

No significant financial relationships to disclose.