Efficacy and Safety of Teprotumumab in Patients With Thyroid Eye Disease of Long Duration and Low Disease Activity

CONTEXT

Early inflammatory thyroid eye disease (TED) can lead to symptomatic chronic disease, including disabling proptosis. Teprotumumab, an insulin-like growth factor-1 receptor (IGF-1R) inhibitor, previously demonstrated efficacy in acute, high-inflammation TED trials.

OBJECTIVE

We present data from the first placebo-controlled trial with teprotumumab in chronic/low disease activity TED.

METHODS

This randomized double-masked, placebo-controlled trial, conducted at 11 US centers, enrolled adult participants with TED duration of 2 to 10 years, Clinical Activity Score (CAS) ≤ 1 or no additional inflammation or progression in proptosis/diplopia for ≥1 year, proptosis ≥3 mm from before TED and/or from normal, euthyroid/mildly hypo/hyperthyroid, no prior teprotumumab, and no steroids within 3 weeks of baseline. Patients received (2:1) intravenous teprotumumab or placebo once every 3 weeks (total 8 infusions). The primary endpoint was proptosis (mm) improvement at Week 24. Adverse events (AEs) were assessed.

RESULTS

A total of 62 (42 teprotumumab and 20 placebo) patients were randomized. At Week 24, least squares mean (SE) proptosis improvement was greater with teprotumumab (-2.41 [0.228]) than with placebo (-0.92 [0.323]), difference -1.48 (95% CI -2.28, -0.69; P = .0004). Proportions of patients with AEs were similar between groups. Hyperglycemia was reported in 6 (15%) vs 2 (10%) and hearing impairment in 9 (22%) vs 2 (10%) with teprotumumab and placebo, respectively. AEs led to discontinuation in 1 teprotumumab (left ear conductive hearing loss with congenital anomaly) and 1 placebo patient (infusion-related). There were no deaths.

CONCLUSION

Teprotumumab significantly improved proptosis vs placebo in longstanding/low inflammation TED, demonstrating efficacy regardless of disease duration/activity. The safety profile was comparable to that previously reported.

LY3041658/ interleukin-8 complex structure as targets for IL-8 small molecule inhibitors discovery using a combination of in silico methods

Since interleukin-8 (IL-8/CXCL8) and its receptor, CXCR1 and CXCR2, were known in the early 1990s, biological pathways related to these proteins were proven to have high clinical value in cancer and inflammatory/autoimmune conditions treatment. Recently, IL-8 has been identified as biomarker for severe COVID-19 patients and COVID-19 prognosis. Boyles et al. (mAbs 12 (2020), pp. 1831880) have published a high-resolution X-ray crystal structure of the LY3041658 Fab in a complex human CXCL8. They described the ability to bind to IL-8 and the blocking of IL-8/its receptors interaction by the LY3041658 monoclonal antibody. Therefore, the study has been designed to identify potential small molecules inhibiting interleukin-8 by targeting LY3041658/IL-8 complex structure using an in silico approach. A structure‑based pharmacophore and molecular docking models of the protein active site cavity were generated to identify possible candidates, followed by virtual screening with the ZINC database. ADME analysis of hit compounds was also conducted. Molecular dynamics simulations were then performed to survey the behaviour and stability of the ligand-protein complexes. Furthermore, the MM/PBSA technique has been utilized to evaluate the free binding energy. The final data confirmed that one newly obtained compound, ZINC21882765, may serve as the best potential inhibitor for IL-8.

The Effect of Discontinuing Continuous Glucose Monitoring in Adults With Type 2 Diabetes Treated With Basal Insulin

OBJECTIVE

To explore the effect of discontinuing continuous glucose monitoring (CGM) after 8 months of CGM use in adults with type 2 diabetes treated with basal without bolus insulin.

RESEARCH DESIGN AND METHODS

This multicenter trial had an initial randomization to either real-time CGM or blood glucose monitoring (BGM) for 8 months followed by 6 months in which the BGM group continued to use BGM (n = 57) and the CGM group was randomly reassigned either to continue CGM (n = 53) or discontinue CGM with resumption of BGM for glucose monitoring (n = 53).

RESULTS

In the group that discontinued CGM, mean time in range (TIR) 70-180 mg/dL, which improved from 38% before initiating CGM to 62% after 8 months of CGM, decreased after discontinuing CGM to 50% at 14 months (mean change from 8 to 14 months -12% [95% CI -21% to -3%], P = 0.01). In the group that continued CGM use, little change was found in TIR from 8 to 14 months (baseline 44%, 8 months 56%, 14 months 57%, mean change from 8 to 14 months 1% [95% CI -11% to 12%], P = 0.89). Comparing the two groups at 14 months, the adjusted treatment group difference in mean TIR was -6% (95% CI -16% to 4%, P = 0.20).

CONCLUSIONS

In adults with type 2 diabetes treated with basal insulin who had been using real-time CGM for 8 months, discontinuing CGM resulted in a loss of about one-half of the initial gain in TIR that had been achieved during CGM use.

Delay in the diagnosis and treatment of breast cancer in Vietnam

BACKGROUND

Delays in diagnosis and treatment from first noticeable breast cancer symptoms are associated with poor outcomes. Understanding the reasons and barriers for patients' delay in seeking medical care is critical to mitigating the problem.

METHODS

In-person surveys were conducted among 462 women, aged 18-79, with incident breast cancer cases, recruited from two cancer hospitals in North Vietnam. Delay, defined as the time interval between symptom recognition to the diagnosis and initiation of treatment equal to or exceeding 3 months, was categorized as follows: no delay (<3 months), moderate delay (3-8 months), and serious delay (≥9 months). Multivariable multinomial logistic regression was applied in data analyses.

RESULTS

Over one-quarter patients (31.5%) experienced moderate delays, and close to one-fifth (17.5%) experienced serious delays. Adjusted odds ratios and 95% confidence intervals for moderate and serious delays were 5.60 (3.00-10.47) and 4.25 (2.05-8.85) for financial and physical barriers, respectively. Moderate delay was positively associated with psychological barriers (5.55 [1.75-17.57]) and lack of proper knowledge (3.15 [1.47-6.74]). The associations of barriers with delays in diagnosis and treatment appeared stronger among women living in rural areas. A lack of proper knowledge was significantly associated with delay among young women (<45 years old) and those with high incomes, while psychological barriers were significantly associated with delay among older women (≥45 years old).

CONCLUSION

Delays in diagnosis and treatment are common among Vietnamese breast cancer patients and are affected by several noted barriers. Proper policy needs to be developed to address this public health issue.

SPECT imaging of pulmonary vascular disease in bleomycin-induced lung fibrosis using a vascular endothelium tracer

Background

Pulmonary hypertension (PH) complicating idiopathic pulmonary fibrosis (IPF) is associated to worse outcome. There is a great need for a non-invasive diagnostic modality to detect and evaluate the severity of pulmonary vascular disease (PVD). ^99mTc-PulmoBind is a novel imaging agent that binds to the adrenomedullin (AM) receptor on the pulmonary microvascular endothelium. SPECT imaging employing the endothelial cell tracer ^99mTc-PulmoBind was used to assess PVD associated with lung fibrosis.

Methods

Rats with selective right lung bleomycin-induced fibrosis were compared to control rats. SPECT imaging was performed after three weeks with ^99mTc-PulmoBind and ^99mTc-macroaggregates of albumin (MAA). PH and right ventricular (RV) function were assessed by echocardiography. Lung perfusion was evaluated by fluorescent microangiography. Lung AM receptor expression was measured by qPCR and by immunohistology. Relevance to human IPF was explored by measuring AM receptor expression in lung biopsies from IPF patients and healthy controls.

Results

The bleomycin group developed preferential right lung fibrosis with remodeling and reduced perfusion as assessed with fluorescent microangiography. These rats developed PH with RV hypertrophy and dysfunction. ^99mTc-PulmoBind uptake was selectively reduced by 50% in the right lung and associated with reduced AM receptor expression, PH and RV hypertrophy. AM receptor was co-expressed with the endothelial cell protein CD31 in alveolar capillaries, and markedly reduced after bleomycin. Quantitative dynamic analysis of ^99mTc-PulmoBind uptake in comparison to ^99mTc-MAA revealed that the latter distributed only according to flow, with about 60% increased left lung uptake while left lung uptake of ^99mTc-PulmoBind was not affected. Lung from human IPF patients showed important reduction in AM receptor expression closely associated with CD31.

Conclusions

SPECT imaging with ^99mTc-PulmoBind detects PVD and its severity in bleomycin-induced lung fibrosis. Reduced AM receptor expression in human IPF supports further clinical development of this imaging approach.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01836-3.

Effect of Continuous Glucose Monitoring on Glycemic Control in Patients With Type 2 Diabetes Treated With Basal Insulin: A Randomized Clinical Trial

IMPORTANCE

Continuous glucose monitoring (CGM) has been shown to be beneficial for adults with type 2 diabetes using intensive insulin therapy, but its use in type 2 diabetes treated with basal insulin without prandial insulin has not been well studied.

OBJECTIVE

To determine the effectiveness of CGM in adults with type 2 diabetes treated with basal insulin without prandial insulin in primary care practices.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted at 15 centers in the US (enrollment from July 30, 2018, to October 30, 2019; follow-up completed July 7, 2020) and included adults with type 2 diabetes receiving their diabetes care from a primary care clinician and treated with 1 or 2 daily injections of long- or intermediate-acting basal insulin without prandial insulin, with or without noninsulin glucose-lowering medications.

INTERVENTIONS

Random assignment 2:1 to CGM (n = 116) or traditional blood glucose meter (BGM) monitoring (n = 59).

MAIN OUTCOMES AND MEASURES

The primary outcome was hemoglobin A1c (HbA1c) level at 8 months. Key secondary outcomes were CGM-measured time in target glucose range of 70 to 180 mg/dL, time with glucose level at greater than 250 mg/dL, and mean glucose level at 8 months.

RESULTS

Among 175 randomized participants (mean [SD] age, 57 [9] years; 88 women [50%]; 92 racial/ethnic minority individuals [53%]; mean [SD] baseline HbA1c level, 9.1% [0.9%]), 165 (94%) completed the trial. Mean HbA1c level decreased from 9.1% at baseline to 8.0% at 8 months in the CGM group and from 9.0% to 8.4% in the BGM group (adjusted difference, -0.4% [95% CI, -0.8% to -0.1%]; P = .02). In the CGM group, compared with the BGM group, the mean percentage of CGM-measured time in the target glucose range of 70 to 180 mg/dL was 59% vs 43% (adjusted difference, 15% [95% CI, 8% to 23%]; P < .001), the mean percentage of time at greater than 250 mg/dL was 11% vs 27% (adjusted difference, -16% [95% CI, -21% to -11%]; P < .001), and the means of the mean glucose values were 179 mg/dL vs 206 mg/dL (adjusted difference, -26 mg/dL [95% CI, -41 to -12]; P < .001). Severe hypoglycemic events occurred in 1 participant (1%) in the CGM group and in 1 (2%) in the BGM group.

CONCLUSIONS AND RELEVANCE

Among adults with poorly controlled type 2 diabetes treated with basal insulin without prandial insulin, continuous glucose monitoring, as compared with blood glucose meter monitoring, resulted in significantly lower HbA1c levels at 8 months.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03566693.

Colchicine reduces lung injury in experimental acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is characterized by intense dysregulated inflammation leading to acute lung injury (ALI) and respiratory failure. There are no effective pharmacologic therapies for ARDS. Colchicine is a low-cost, widely available drug, effective in the treatment of inflammatory conditions. We studied the effects of colchicine pre-treatment on oleic acid-induced ARDS in rats. Rats were treated with colchicine (1 mg/kg) or placebo for three days prior to intravenous oleic acid-induced ALI (150 mg/kg). Four hours later they were studied and compared to a sham group. Colchicine reduced the area of histological lung injury by 61%, reduced lung edema, and markedly improved oxygenation by increasing PaO2/FiO2 from 66 ± 13 mmHg (mean ± SEM) to 246 ± 45 mmHg compared to 380 ± 18 mmHg in sham animals. Colchicine also reduced PaCO2 and respiratory acidosis. Lung neutrophil recruitment, assessed by myeloperoxidase immunostaining, was greatly increased after injury from 1.16 ± 0.19% to 8.86 ± 0.66% and significantly reduced by colchicine to 5.95 ± 1.13%. Increased lung NETosis was also reduced by therapy. Circulating leukocytosis after ALI was not reduced by colchicine therapy, but neutrophils reactivity and CD4 and CD8 cell surface expression on lymphocyte populations were restored. Colchicine reduces ALI and respiratory failure in experimental ARDS in relation with reduced lung neutrophil recruitment and reduced circulating leukocyte activation. This study supports the clinical development of colchicine for the prevention of ARDS in conditions causing ALI.

PBI-4050 reduces pulmonary hypertension, lung fibrosis, and right ventricular dysfunction in heart failure

AIMS

Heart failure with reduced ejection fraction (HFrEF) causes lung remodelling with myofibroblasts proliferation and fibrosis leading to a restrictive lung syndrome with pulmonary hypertension (PH) and right ventricular (RV) dysfunction. PBI-4050 is a first-in-class anti-fibrotic, anti-inflammatory, and anti-proliferative compound. The present study evaluated the therapeutic impact of PBI-4050 on PH in an HFrEF model.

METHODS AND RESULTS

HFrEF was induced after myocardial infarction (MI) in rats. Two weeks later, sham-operated and MI groups received PBI-4050 (200 mg/kg/day by gavage) or saline for 3 weeks. Animals were analysed according to infarct size as large (≥30% left ventricle) or medium MI (<30%). Large MI caused PH and RV hypertrophy (RVH) with a restrictive lung syndrome. PBI-4050 did not adversely affect left ventricular (LV) function but markedly reduced PH and RVH and improved RV dysfunction. PBI-4050 reduced lung remodelling and improved respiratory compliance with decreased lung fibrosis, alveolar wall cellular proliferation and α-smooth muscle actin expression. The increased expression of endothelin-1 (ET-1), transforming growth factor beta (TGF-β), interleukin-6 (IL-6) and of tissue inhibitor of metalloprotease-1 in the lungs from HFrEF were reduced with PBI-4050 therapy. Activation of isolated human lung fibroblasts (HLFs) to a myofibroblastic pro-fibrogenic phenotype was markedly reduced by PBI-4050. The fatty acid receptor GPR84 was increased in HFrEF lungs and in activated HLFs, and reduced by PBI-4050. GPR84 agonists activated fibrogenesis in HLFs and finally, PBI-4050 reduced ERK1/2 phosphorylation.

CONCLUSIONS

PBI-4050 reduces PH and RVH in HFrEF by decreasing lung fibrosis and remodelling. This novel agent decreases the associated restrictive lung syndrome and recovers RV function. A contributing mechanism involves reducing the activation of lung fibroblasts by IL-6, TGF-β, and ET-1 by antagonism of GPR84 and reduced ERK1/2 phosphorylation. PBI-4050 is a novel promising therapy for targeting lung remodelling in group II PH.

Lumbar Spinal Stenosis Severity by CT or MRI Does Not Predict Response to Epidural Corticosteroid versus Lidocaine Injections

BACKGROUND AND PURPOSE

Epidural steroid injections may offer little-to-no short-term benefit in the overall population of patients with symptomatic spinal stenosis compared with lidocaine alone. We investigated whether imaging could identify subgroups of patients who might benefit most.

MATERIALS AND METHODS

A secondary analysis of the Lumbar Epidural Steroid Injections for Spinal Stenosis prospective, double-blind trial was performed, and patients were randomized to receive an epidural injection of lidocaine with or without corticosteroids. Patients (n = 350) were evaluated for qualitative and quantitative MR imaging or CT measures of lumbar spinal stenosis. The primary clinical end points were the Roland-Morris Disability Questionnaire and the leg pain numeric rating scale at 3 weeks following injection. ANCOVA was used to assess the significance of interaction terms between imaging measures of spinal stenosis and injectate type on clinical improvement.

RESULTS

There was no difference in the improvement of disability or leg pain scores at 3 weeks between patients injected with epidural lidocaine alone compared with corticosteroid and lidocaine when accounting for the primary imaging measures of qualitative spinal stenosis assessment (interaction coefficients for disability score, -0.1; 95% CI, -1.3 to 1.2; P = .90; and for the leg pain score, 0.1; 95% CI, -0.6 to 0.8; P = .81) or the quantitative minimum thecal sac cross-sectional area (interaction coefficients for disability score, 0.01; 95% CI, -0.01 to 0.03; P = .40; and for the leg pain score, 0.01; 95% CI, -0.01 to 0.03; P = .33).

CONCLUSIONS

Imaging measures of spinal stenosis are not associated with differential clinical responses following epidural corticosteroid injection.

A successful compartmental approach for the treatment of breast cancer brain metastases

BACKGROUND

Brain metastases are challenging daily practice in oncology and remain a compartmental problem since most anti-cancer drugs do not cross the blood-brain barrier at relevant pharmacological concentrations.

METHODS

In a young woman with HER2-overexpressing breast cancer resistant to standard treatments, at the time of brain metastases progression, a ventricular reservoir was implanted for intrathecal drug injections and detailed pharmacokinetic studies.

RESULTS

A first association of intrathecal trastuzumab with intravenous cisplatin was offered to the patient. For trastuzumab, the mean cerebrospinal fluid trough concentration of 53.4 mg/L reached relevant levels, enabling the stabilization of the metastases. Adding intravenous cisplatin was not beneficial, since the cerebrospinal fluid exposure was almost undetectable under 0.08 mg/L. We then offered the patient an intrathecal combination of trastuzumab and methotrexate, because of their in vitro synergic cytotoxicity. The cerebrospinal fluid peak of methotrexate was 1037 µmol/L at 2 h, and the concentrations remained above the theoretical therapeutic concentration. After 2 months of this drug combination, we obtained an excellent response on the brain metastases.

CONCLUSION

Our preliminary study supports the interest of a compartmental approach through a direct administration of drugs into the cerebrospinal fluid for the treatment of breast cancer brain metastases.

Al[18F]F-complexation of DFH17, a NOTA-conjugated adrenomedullin analog, for PET imaging of pulmonary circulation

INTRODUCTION

Adrenomedullin receptors are highly expressed in human alveolar capillaries and provide a molecular target for imaging the integrity of pulmonary microcirculation. In this work, we aimed to develop a NOTA-derivatized adrenomedullin analog (DFH17), radiolabeled with [¹⁸F]AlF, for PET imaging of pulmonary microcirculation.

METHODS

Highly concentrated [¹⁸F](AlF)²⁺ (15 μL) was produced from purified fluorine-18 in NaCl 0.9%. Various complexation experiments were carried out at Al-to-NOTA molar ratios ranging from 1:1 to 1:40 to assess optimal radiolabeling conditions before using the peptide. DFH17 peptide (2 mM, pH 4) was radiolabeled with [¹⁸F](AlF)²⁺ for 15 min at 100 °C in a total volume of 60 μL. As part of the radiolabeling process, parameters such as fluorine-18 activity (~37 and 1480 MBq), concentration of AlCl₃ (0.75, 2, 3, 6 or 10 mM) and the effects of hydrophilic organic solvent (aqueous vs ethanol 50%) were studied. The final formulation was tested for purity, identity and stability in saline. Initial in vivo evaluation of [¹⁸F]AlF-DFH17 was performed in normal rats by PET/CT.

RESULTS

The scaled-up production of [¹⁸F]AlF-DFH17 was performed in high radiochemical and chemical purities in an overall radiochemical yield of 22-38% (at end-of-synthesis) within 60 min. The final formulation was stable in saline at different radioactive concentrations for 8 h. PET evaluation in rats revealed high lung-to-background ratios and no defluorination in vivo up to 1 h post-injection.

CONCLUSION

The novel radioconjugate [¹⁸F]AlF-DFH17 appears to be a promising PET ligand for pulmonary microcirculation imaging.

Overview of Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Patients with Type 2 Diabetes

BACKGROUND

It is estimated that 29.1 million people or 9.3% of the US population have diabetes, which contributes to considerable medical and financial burden. Type 2 diabetes mellitus is characterized by insulin resistance and insulin secretion impairment leading to hyperglycemia. The presence of insulin resistance is strongly correlated with obesity.

OBJECTIVE

This article reviews the available glucagon-like peptide-1 (GLP-1) receptor agonists and their role in the management of patients with diabetes, to help guide the selection of the most suitable agent for the individualized treatment of patients with type 2 diabetes.

DISCUSSION

This article reviews the evidence from phase 3 clinical trials for each of the 5 GLP-1 receptor agonists by comparing them against one another and with other existing therapies, including metformin, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sulfonylureas. Incretin-based therapies have emerged as attractive agents for the treatment of type 2 diabetes. They target the GLP-1 hormone, which is partly responsible for insulin release and for attenuating hyperglycemia during meals (ie, the incretin effect). The 2 classes of incretin-based therapy currently available are GLP-1 receptor agonists and DPP-4 inhibitors, which prevent the breakdown of GLP-1. Both classes are attractive options, given their glucose-lowering effects without the adverse effects of hypoglycemia and weight gain. The different mechanisms of action of these therapies result in generally greater efficacy with GLP-1 receptor agonists, albeit at the expense of slightly increased gastrointestinal symptoms. These agents exert their effects by improving glucose-dependent insulin release, suppressing glucagon release, suppressing hepatic glucose output, and decreasing the rate of gastric emptying, thereby reducing appetite. Currently, 5 GLP-1 receptor agonists are available, including exenatide, liraglutide, albiglutide, dulaglutide, and lixisenatide; semaglutide may soon become available as the newest agent. With the exception of the investigational oral semaglutide, which has shown promising results, the other 5 agents are administered as subcutaneous injections, at different dosing intervals.

CONCLUSION

Currently, 5 GLP-1 receptor agonists are available for use in the United States. Although they are all in the same drug class, some significant differences exist among the various GLP-1 receptor agonists. The choice of a specific GLP-1 receptor agonist will depend on the patient preferences, potential adverse effects, and cost.

Molecular imaging of the human pulmonary vascular endothelium in pulmonary hypertension: a phase II safety and proof of principle trial

PURPOSE

The adrenomedullin receptor is densely expressed in the pulmonary vascular endothelium. PulmoBind, an adrenomedullin receptor ligand, was developed for molecular diagnosis of pulmonary vascular disease. We evaluated the safety of PulmoBind SPECT imaging and its capacity to detect pulmonary vascular disease associated with pulmonary hypertension (PH) in a human phase II study.

METHODS

Thirty patients with pulmonary arterial hypertension (PAH, n = 23) or chronic thromboembolic PH (CTEPH, n = 7) in WHO functional class II (n = 26) or III (n = 4) were compared to 15 healthy controls. Lung SPECT was performed after injection of 15 mCi ^99mTc-PulmoBind in supine position. Qualitative and semi-quantitative analyses of lung uptake were performed. Reproducibility of repeated testing was evaluated in controls after 1 month.

RESULTS

PulmoBind injection was well tolerated without any serious adverse event. Imaging was markedly abnormal in PH with ∼50% of subjects showing moderate to severe heterogeneity of moderate to severe extent. The abnormalities were unevenly distributed between the right and left lungs as well as within each lung. Segmental defects compatible with pulmonary embolism were present in 7/7 subjects with CTEPH and in 2/23 subjects with PAH. There were no segmental defects in controls. The PulmoBind activity distribution index, a parameter indicative of heterogeneity, was elevated in PH (65% ± 28%) vs. controls (41% ± 13%, p = 0.0003). In the only subject with vasodilator-responsive idiopathic PAH, PulmoBind lung SPECT was completely normal. Repeated testing 1 month later in healthy controls was well tolerated and showed no significant variability of PulmoBind distribution.

CONCLUSIONS

In this phase II study, molecular SPECT imaging of the pulmonary vascular endothelium using ^99mTc-PulmoBind was safe. PulmoBind showed potential to detect both pulmonary embolism and abnormalities indicative of pulmonary vascular disease in PAH. Phase III studies with this novel tracer and direct comparisons to lung perfusion agents such as labeled macro-aggregates of albumin are needed.

CLINICAL TRIAL

ClinicalTrials.gov, NCT02216279.

Effects of Inflammation on Multiscale Biomechanical Properties of Cartilaginous Cells and Tissues

Cells within cartilaginous tissues are mechanosensitive and thus require mechanical loading for regulation of tissue homeostasis and metabolism. Mechanical loading plays critical roles in cell differentiation, proliferation, biosynthesis, and homeostasis. Inflammation is an important event occurring during multiple processes, such as aging, injury, and disease. Inflammation has significant effects on biological processes as well as mechanical function of cells and tissues. These effects are highly dependent on cell/tissue type, timing, and magnitude. In this review, we summarize key findings pertaining to effects of inflammation on multiscale mechanical properties at subcellular, cellular, and tissue level in cartilaginous tissues, including alterations in mechanotransduction and mechanosensitivity. The emphasis is on articular cartilage and the intervertebral disc, which are impacted by inflammatory insults during degenerative conditions such as osteoarthritis, joint pain, and back pain. To recapitulate the pro-inflammatory cascades that occur in vivo, different inflammatory stimuli have been used for in vitro and in situ studies, including tumor necrosis factor (TNF), various interleukins (IL), and lipopolysaccharide (LPS). Therefore, this review will focus on the effects of these stimuli because they are the best studied pro-inflammatory cytokines in cartilaginous tissues. Understanding the current state of the field of inflammation and cell/tissue biomechanics may potentially identify future directions for novel and translational therapeutics with multiscale biomechanical considerations.

An updated view of plasmid conjugation and mobilization in Staphylococcus

The horizontal gene transfer facilitated by mobile genetic elements impacts almost all areas of bacterial evolution, including the accretion and dissemination of antimicrobial-resistance genes in the human and animal pathogen Staphylococcus aureus. Genome surveys of staphylococcal plasmids have revealed an unexpected paucity of conjugation and mobilization loci, perhaps suggesting that conjugation plays only a minor role in the evolution of this genus. In this letter we present the DNA sequences of historically documented staphylococcal conjugative plasmids and highlight that at least 3 distinct and widely distributed families of conjugative plasmids currently contribute to the dissemination of antimicrobial resistance in Staphylococcus. We also review the recently documented “relaxase-in trans” mechanism of conjugative mobilization facilitated by conjugative plasmids pWBG749 and pSK41, and discuss how this may facilitate the horizontal transmission of around 90% of plasmids that were previously considered non-mobilizable. Finally, we enumerate unique sequenced S. aureus plasmids with a potential mechanism of mobilization and predict that at least 80% of all non-conjugative S. aureus plasmids are mobilizable by at least one mechanism. We suggest that a greater research focus on the molecular biology of conjugation is essential if we are to recognize gene-transfer mechanisms from our increasingly in silico analyses.

Evaluation of pulmonary perfusion by SPECT imaging using an endothelial cell tracer in supine humans and dogs

Background

Pulmonary perfusion is not spatially homogeneously distributed, and its variations could be of diagnostic value in lung vascular disease. PulmoBind is a ligand of the adrenomedullin receptor densely expressed in endothelial cells of lung capillaries. The aim of this study was to evaluate spatial distribution of human lung perfusion by using this novel molecular tracer of the pulmonary vascular endothelium.

Methods

Normal humans (n = 19) enrolled into the PulmoBind phase I trial were studied (Clinicaltrials.gov.NCT01539889). They were injected with ^99mTc-PulmoBind for SPECT imaging. Results were compared with ^99mTc-PulmoBind in quadruped mammals (dogs, n = 5). Imaging was performed in the supine position and distribution of activity was determined as a function of cumulative voxels along the different anatomical planes.

Results

PulmoBind uptake in humans was 58 ± 1 % (mean ± SEM) of the injected dose. Dorsal activity was 18.1 ± 2.1 % greater than ventral, and caudal activity was 25.7 ± 1.6 % greater than cranial. Lateral activity was only mildly higher than medial by 7.0 ± 1.0 %. In supine dogs, similar but higher PulmoBind gradients were present: dorsal 28.6 ± 2.5 %, caudal 34.1 ± 5.0 % and lateral 18.1 ± 2.0 %.

Conclusions

The perfused pulmonary circulation of supine humans, assessed by an adrenomedullin receptor ligand, is not homogeneously distributed with more prominent distribution in dorsal and caudal regions. It is qualitatively similar to a supine quadruped mammal confirming the presence of a microcirculatory gravitational perfusion gradient detectable with this tracer. Future studies are needed to determine if this novel endothelial cell tracer could be used to detect physiologic and pathologic variations of lung perfusion such as in pulmonary hypertension.

Clinical trial

ClinicalTrial.gov, NCT01539889

Systematic Evaluation of Genes and Genetic Variants Associated with Type 1 Diabetes Susceptibility

Genome-wide association studies have found >60 loci that confer genetic susceptibility to type 1 diabetes (T1D). Many of these are defined only by anonymous single nucleotide polymorphisms: the underlying causative genes, as well as the molecular bases by which they mediate susceptibility, are not known. Identification of how these variants affect the complex mechanisms contributing to the loss of tolerance is a challenge. In this study, we performed systematic analyses to characterize these variants. First, all known genes in strong linkage disequilibrium (r(2) > 0.8) with the reported single nucleotide polymorphisms for each locus were tested for commonly occurring nonsynonymous variations. We found only a total of 22 candidate genes at 16 T1D loci with common nonsynonymous alleles. Next, we performed functional studies to examine the effect of non-HLA T1D risk alleles on regulating expression levels of genes in four different cell types: EBV-transformed B cell lines (resting and 6 h PMA stimulated) and purified CD4(+) and CD8(+) T cells. We mapped cis-acting expression quantitative trait loci and found 24 non-HLA loci that affected the expression of 31 transcripts significantly in at least one cell type. Additionally, we observed 25 loci that affected 38 transcripts in trans. In summary, our systems genetics analyses defined the effect of T1D risk alleles on levels of gene expression and provide novel insights into the complex genetics of T1D, suggesting that most of the T1D risk alleles mediate their effect by influencing expression of multiple nearby genes.

Obesity Management: Clinical Review and Update of the Pharmacologic Treatment Options

The toolbox of medications available for medical weight management is more robust than ever and includes a wide variety of mechanisms of actions and options for patients.

SGLT2 Inhibitors for Type 2 Diabetes Mellitus Treatment

SGLT2 inhibitors are plausible second-line drugs that provide powerful additional A_1c-lowering effects while inducing weight loss without hypoglycemia.

Molecular imaging of the human pulmonary vascular endothelium using an adrenomedullin receptor ligand

This phase I study (NCT01539889) evaluated the safety, efficacy, and dosing of PulmoBind for molecular imaging of pulmonary circulation. PulmoBind is a ligand of the adrenomedullin receptor abundantly distributed in lung capillaries. Labeled with 99mTc, it allows single-photon emission computed tomographic (SPECT) imaging of lung perfusion. In preclinical studies, PulmoBind scans enabled detection of lung perfusion defects and quantification of microcirculatory occlusion caused by pulmonary hypertension. Healthy humans (N  =  20) were included into escalating groups of 5 mCi (n  =  5), 10 mCi (n  =  5), or 15 mCi (n  =  10) 99mTc-PulmoBind. SPECT imaging was serially performed, and 99mTc-PulmoBind dosimetric analysis was accomplished. The radiochemical purity of 99mTc-PulmoBind was greater than 95%. There were no safety concerns at the three dosages studied. Imaging revealed predominant and prolonged lung uptake with a mean peak extraction of 58% ± 7%. PulmoBind was well tolerated, with no clinically significant adverse event related to the study drug. The highest dose of 15 mCi provided a favorable dosimetric profile and excellent imaging. The postural lung perfusion gradient was detectable. 99mTc-PulmoBind is safe and provides good quality lung perfusion imaging. The safety/efficacy of this agent can be tested in disorders of pulmonary circulation such as pulmonary arterial hypertension.

Diagnosis and treatment of patients with thyroid cancer

BACKGROUND

Thyroid cancer is the most common malignancy of the endocrine system, representing 3.8% of all new cancer cases in the United States and is the ninth most common cancer overall. The American Cancer Society estimates that 62,450 people in the United States will be diagnosed with thyroid cancer in 2015, and 1950 deaths will result from the disease.

OBJECTIVE

To review the current approach to the diagnosis and treatment of patients with thyroid cancer.

DISCUSSION

Over the past 3 decades, there has been a dramatic increase in the number of people diagnosed with thyroid cancer, which may be attributable to the wide use of imaging studies, including ultrasounds, computed tomography, magnetic resonance imaging, and positron emission tomography scans that incidentally detect thyroid nodules. Thyroid cancer is divided into several main types, with papillary thyroid cancer being the most common. The treatment options for patients with thyroid cancer include the surgical removal of the entire thyroid gland (total thyroidectomy), radioactive iodine therapy, and molecular-targeted therapies with tyrosine kinase inhibitors. This article summarizes the diagnosis and treatment of thyroid cancer, with recommendations from the American Thyroid Association regarding thyroid nodules and differentiated thyroid cancer. Recently approved drugs and treatment trends are also explored.

CONCLUSION

The prognosis and treatment of thyroid cancer depend on the tumor type and its stage at the time of diagnosis. Many thyroid cancers remain stable, microscopic, and indolent. The increasing treatment options for patients with thyroid cancer, including therapies that were recently approved by the US Food and Drug Administration, have kept the mortality rate from this malignancy low, despite the increase in its incidence. Early diagnosis and appropriate treatment can improve prognosis and reduce mortality.

Molecular imaging of the pulmonary circulation in health and disease

The pulmonary circulation, at the unique crossroads between the left and the right heart, is submitted to large physiologic hemodynamic variations and possesses numerous important metabolic functions mediated through its vast endothelial surface. There are many pathologic conditions that can directly or indirectly affect the pulmonary vasculature and modify its physiology and functions. Pulmonary hypertension, the end result of many of these affections, is unfortunately diagnosed too late in the disease process, meaning that there is a crying need for earlier diagnosis and surrogate markers of disease progression and regression. By targeting endothelial, medial and adventitial targets of the pulmonary vasculature, novel molecular imaging agents could provide early detection of physiologic and biologic perturbation in the pulmonary circulation. This review provides the rationale for the development of molecular imaging agents for the diagnosis and follow-up of disorders of the pulmonary circulation and discusses promising targets for SPECT and positron emission tomographic imaging.

New and emerging drugs and targets for type 2 diabetes: reviewing the evidence

BACKGROUND

Diabetes is a deadly and costly disease. The number of adults in the United States with newly diagnosed diabetes has nearly tripled from 1980 to 2011. At the current pace, 1 in 3 US adults will have diabetes in their lifetime. Currently, 14 classes of drugs are available to treat type 2 diabetes mellitus, but only 36% of patients with type 2 diabetes achieve glycemic control with the currently available therapies. Therefore, new treatment options are desperately needed.

DISCUSSION

Despite the availability of many pharmacotherapies, in 2011 an estimated 3.1 million (14.9%) patients with type 2 diabetes still reported not taking medications to treat their diabetes. Patient compliance is a major obstacle facing practicing clinicians on a daily basis. New treatment options are desperately needed, but efficacy and tolerability are no longer the only criteria contributing to the success of a drug. Ease of administration, convenient dosing frequency, being weight control friendly, and having a low risk for hypoglycemia are important factors for the survival of a new drug in the US healthcare system. The present review is focused on important new drugs and drug classes in the pipeline, as well as on recently approved drugs, including sodium glucose cotransporter-2 inhibitors, glucagon-like peptide-1 agents, and new insulin therapies, as well as on the technologic improvements in the delivery and dosing frequency of some of the currently available drugs.

CONCLUSIONS

In the United States, diabetes can be expected to continue to wreak significant human and financial tolls. The associated complications will continue to climb if they are not controlled and stopped. New therapies for diabetes are clearly needed that will better address these unmet needs. The common threads among the emerging therapies are their convenience of administration and dosing frequency, which are important to the improvement of patient adherence.

Adipose-derived cell construct stabilizes heart function and increases microvascular perfusion in an established infarct

We have previously shown that myocardial infarction (MI) immediately treated with an epicardial construct containing stromal vascular fraction (SVF) from adipose tissue preserved microvascular function and left ventricle contractile mechanisms. In order to evaluate a more clinically relevant condition, we investigated the cardiac recovery potential of an SVF construct implanted onto an established infarct. SVF cells were isolated from rat adipose tissue, plated on Vicryl, and cultured for 14 days. Fischer-344 rats were separated into MI groups: (a) 6-week MI (MI), (b) 6-week MI treated with an SVF construct at 2 weeks (MI SVF), (c) 6-week MI with Vicryl construct at 2 weeks (MI Vicryl), and (d) MI 2wk (time point of intervention). Emax, an indicator of systolic performance and contractile function, was lower in the MI and MI Vicryl versus MI SVF. Positron emission tomography imaging ((18)F-fluorodeoxyglucose) revealed a decreased percentage of relative infarct volume in the MI SVF versus MI and MI Vicryl. Total vessel count and percentage of perfusion assessed via immunohistochemistry were both increased in the infarct region of MI SVF versus MI and MI Vicryl. Overall cardiac function, percentage of relative infarct, and percentage of perfusion were similar between MI SVF and MI 2wk; however, total vessel count increased after SVF treatment. These data suggest that SVF treatment of an established infarct stabilizes the heart at the time point of intervention by preventing a worsening of cardiac performance and infarcted volume, and is associated with increased microvessel perfusion in the area of established infarct.

Discovery of new antagonists aimed at discriminating UII and URP-mediated biological activities: insight into UII and URP receptor activation

BACKGROUND AND PURPOSE

Recent evidence suggested that urotensin II (UII) and its paralog peptide UII-related peptide (URP) might exert common but also divergent physiological actions. Unfortunately, none of the existing antagonists were designed to discriminate specific UII- or URP-associated actions, and our understanding, on how these two endogenous peptides can trigger different, but also common responses, is limited.

EXPERIMENTAL APPROACH

Ex vivo rat and monkey aortic ring contraction as well as dissociation kinetics studies using transfected CHO cells expressing the human urotensin (UT) receptors were used in this study.

KEY RESULTS

Ex vivo rat and monkey aortic ring contraction studies revealed the propensity of [Pep(4)]URP to decrease the maximal response of human UII (hUII) without any significant change in potency, whereas no effect was noticeable on the URP-induced vasoconstriction. Dissociation experiments demonstrated the ability of [Pep(4)]URP to increase the dissociation rate of hUII, but not URP. Surprisingly, URP, an equipotent UII paralog, was also able to accelerate the dissociation rate of membrane-bound (125)I-hUII, whereas hUII had no noticeable effect on URP dissociation kinetics. Further experiments suggested that an interaction between the glutamic residue at position 1 of hUII and the UT receptor seems to be critical to induce conformational changes associated with agonistic activation. Finally, we demonstrated that the N-terminal domain of the rat UII isoform was able to act as a specific antagonist of the URP-associated actions.

CONCLUSION

Such compounds, that is [Pep(4)]URP and rUII(1-7), should prove to be useful as new pharmacological tools to decipher the specific role of UII and URP in vitro but also in vivo.

Genetic amplification of the NOTCH modulator LNX2 upregulates the WNT/β-catenin pathway in colorectal cancer

Chromosomal copy number alterations (aneuploidy) define the genomic landscape of most cancer cells, but identification of the oncogenic drivers behind these imbalances remains an unfinished task. In this study, we conducted a systematic analysis of colorectal carcinomas that integrated genomic copy number changes and gene expression profiles. This analysis revealed 44 highly overexpressed genes mapping to localized amplicons on chromosome 13, gains of which occur often in colorectal cancers (CRC). RNA interference (RNAi)-mediated silencing identified eight candidates whose loss-of-function reduced cell viability 20% or more in CRC cell lines. The functional space of the genes NUPL1, LNX2, POLR1D, POMP, SLC7A1, DIS3, KLF5, and GPR180 was established by global expression profiling after RNAi exposure. One candidate, LNX2, not previously known as an oncogene, was involved in regulating NOTCH signaling. Silencing LNX2 reduced NOTCH levels but also downregulated the transcription factor TCF7L2 and markedly reduced WNT signaling. LNX2 overexpression and chromosome 13 amplification therefore constitutively activates the WNT pathway, offering evidence of an aberrant NOTCH-WNT axis in CRC.

Diabetes medications and cancer risk: review of the literature

BACKGROUND

Cancer and diabetes are major public health problems for the United States and the world. Diabetes remains the leading cause of blindness, kidney failure, and nontraumatic lower limb amputation, whereas cancer continues to be a major cause of death, accounting for approximately 1 of 4 deaths in the United States. Recently, a potential link between diabetes and cancer has been suggested in the medical literature.

OBJECTIVE

To review the current literature on any potential link between diabetes medications and the risk for cancer.

DISCUSSION

Increasing evidence suggests that diabetic patients are at increased risk of developing cancer. The exact mechanism for the increased cancer risk in patients with diabetes is unknown. Because of a potential correlation between diabetes and cancer, studies are emerging that evaluate the cancer risk of medications used to treat diabetes. This article reviews the current data in the literature regarding the association between the various drug classes indicated for the treatment of diabetes and cancer development or prevention.

CONCLUSION

Despite many studies showing a correlation between some medications for diabetes and the development of cancer, there is no clear evidence of a direct causation between these drugs and cancer. Therefore, providers and patients should continue to use medications to control diabetes as before, because the correlation between uncontrolled diabetes and cancer is stronger than the correlation between medications for diabetes and cancer.

Managing hypertension in the elderly: a common chronic disease with increasing age

BACKGROUND

Hypertension increases with age, affecting approximately 66% of the elderly population (aged ≥65 years). By the year 2030, 1 of 5 Americans will be aged ≥65 years. A number of placebo-controlled clinical trials have demonstrated that blood pressure (BP) control reduces cardiovascular events in elderly patients, even in those aged >80 years. Despite advances in medical care, hypertension control rates remain low, especially in the elderly population.

OBJECTIVE

The goal of this article is to review the information that addresses hypertension in the elderly and current strategies that can facilitate improvement in the management of this common, chronic, and life-threatening condition, which is often undertreated or inappropriately managed.

DISCUSSION

The goals and strategies of treating hypertension in the elderly population are different from, and more challenging than, those in younger patients. Lifestyle modification is effective in this population, but it is difficult to maintain. Many antihypertensive medications are available, with thiazide diuretics being the preferred first-line treatment. Beta-blockers and alpha-blockers are generally not recommended in this population. A majority of older patients will require 2 or 3 antihypertensive medications to reach BP goal. This article reviews current data on hypertensive treatment in the elderly and summarizes the strategies and challenges healthcare providers face when dealing with this population.

CONCLUSION

Understanding the strategies and challenges that apply to the management of hypertension in the US elderly population can help providers and payers better address the growing need for improving the management of this condition in the elderly, because their numbers are expected to increase dramatically in the coming decades.

Current therapies and emerging drugs in the pipeline for type 2 diabetes

BACKGROUND

Diabetes is a global epidemic that affects 347 million people worldwide and 25.8 million adults in the United States. In 2007, the total estimated cost associated with diabetes in the United States in 2007 was $174 billion. In 2009, $16.9 billion was spent on drugs for diabetes. The global sales of diabetes pharmaceuticals totaled $35 billion in 2010, and these are expected to rise to $48 billion by 2015. Despite such considerable expenditures, in 2000 only 36% of patients with type 2 diabetes in the United States achieved glycemic control, defined as hemoglobin A1c <7%.

OBJECTIVE

To review some of the most important drug classes currently in development for the treatment of type 2 diabetes.

DISCUSSION

Despite the 13 classes of antidiabetes medications currently approved by the US Food and Drug Administration (FDA) for the treatment of type 2 diabetes, the majority of patients with this chronic disease do not achieve appropriate glycemic control with these medications. Many new drug classes currently in development for type 2 diabetes appear promising in early stages of development, and some of them represent novel approaches to treatment, with new mechanisms of action and a low potential for hypoglycemia. Among these promising pharmacotherapies are agents that target the kidney, liver, and pancreas as a significant focus of treatment in type 2 diabetes. These investigational agents may potentially offer new approaches to controlling glucose levels and improve outcomes in patients with diabetes. This article focuses on several new classes, including the sodium-glucose cotransporter-2 inhibitors (which are furthest along in development); 11beta-hydroxysteroid dehydrogenase (some of which are now in phase 2 trials); glycogen phosphorylase inhibitors; glucokinase activators; G protein-coupled receptor 119 agonists; protein tyrosine phosphatase 1B inhibitors; and glucagon-receptor antagonists.

CONCLUSION

Despite the abundance of FDA-approved therapeutic options for type 2 diabetes, the majority of American patients with diabetes are not achieving appropriate glycemic control. The development of new options with new mechanisms of action may potentially help improve outcomes and reduce the clinical and cost burden of this condition.

Spiers Memorial Lecture. Breeding and building molecular spies

To circumvent the limited spatial resolution of fluorescent protein imaging, we are developing genetically encoded tags for electron microscopy (EM).

Abstract 247: A functional genomics and a systems biology approach identify POMP as a potential therapeutic target for colorectal cancer

Colorectal cancer (CRC) is one of the most frequent malignancies in many parts of the world and a leading cause of cancer deaths in both men and women. The identification of rationale therapeutic targets is one possibility to provide personalized medicine to cancer patients. Our approach consisted of identifying overexpressed genes located at sites of recurrent chromosomal amplifications, as these regions are likely to harbor genes required for cancer cell survival. Thirty-one colon cancers and 15 CRC cell lines were analyzed by high-resolution array CGH and microarray gene expression profiling. RNA interference (RNAi)-based analysis identified a subset of genes whose loss-of-function (LOF) reduced the cellular viability of CRC cell lines. Consistent with previous reports, the vast majority of CRC assayed exhibited amplification of the chromosome band 13q12.13-q12.3. Among the genes residing within the 13q12.13-q12.3 amplified region showing an overexpression level of at least two-fold higher in the tumor compared to normal mucosa and whose gene silencing impaired cellular survival, we identified NUPL1, LNX2, POLR1D, CDX2, POMP, and SLC7A1. As little is know of the function of these proteins, we decided to use an unbiased systems biology approach to identify genes, pathways and networks altered following RNAi-mediated LOF of each of these candidate genes. To do this we perturbed the expression of each candidate gene through application of two or more siRNAs corresponding to each gene, followed by whole genome expression profiling to monitor cellular transcriptional responses to gene specific LOF. Concordant gene expression signatures generated using three different RNAi effectors targeting POMP, over a time-course (10, 24, 48, and 72 hours), showed that a decrease in POMP expression of more than 80% at 24 hours initially resulted in only minor downstream changes in gene expression. However, by 48 hours approximately 100 genes exhibited altered expression and by 72 hours nearly 2000 genes. At this last time point a statistically significant enrichment (p&lt;0.05) for the altered expression of genes linked to the gene ontologies of cancer, cell death, and cellular growth was observed. POMP, a proteasome maturation protein, is an essential factor for mammalian proteasome biogenesis. This dynamic loss-of-function approach revealed a regulatory network that controls the transcriptional response of colorectal cancer cells after impairing the function of the proteasome. We are also investigating whether the gene expression profiles observed following silencing of POMP resemble the transcriptomic changes that undergo cells treated with proteasome inhibitors as this may shed further light on the mechanism of action of this new class of anti-cancer drugs particularly in CRC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 247.

An analysis of the healthcare informatics and systems in Southeast Asia: a current perspective from seven countries

This paper presents an overview of the healthcare systems in Southeast Asia, with a focus on the healthcare informatics development and deployment in seven countries, namely, Singapore, Cambodia, Malaysia, Thailand, Laos, the Philippines and Vietnam. Brief geographic and demographic information is provided for each country, followed by a historical review of the national strategies for healthcare informatics development. An analysis of the state-of-the-art healthcare infrastructure is also given, along with a critical appraisal of national healthcare provisions.

Three stage axillary lymphatic massage optimizes sentinel lymph node localisation using blue dye

Aims

This paper describes a simple technique of axillary and breast massage which improves the successful identification of blue sentinel nodes using patent blue dye alone.

Methods

Patent blue dye was injected in the subdermal part of the retroaroelar area in 167 patients having surgical treatment for invasive breast cancer. Three stage axillary lymphatic massage was performed prior to making the axillary incision for sentinel lymph node biopsy. All patients had completion axillary sampling or clearance.

Results

A blue lymphatic duct leading to lymph nodes of the first drainage was identified in 163 (97%) of the patients. Results are compared with 168 patients who had sentinel lymph node biopsy using blue dye without axillary massage. Allergic reactions were observed in four patients (1.2%).

Conclusion

Three stage axillary lymphatic massage improves the successful identification of a blue sentinel lymph node in breast cancer patients.

Effects of the vasopeptidase inhibitor omapatrilat on peri- and postmyocardial infarction in Zucker lean rats

BACKGROUND

The vasopeptidase inhibitor omapatrilat improves insulin sensitivity and survival following myocardial infarction (MI). It also improves left ventricular (LV) remodelling following MI and reduces MI size.

OBJECTIVES

To determine whether improvement in LV remodelling and function is accompanied by a reduction in fetal gene expression of the contractile apparatus, and whether reduction in MI size is accompanied by an increase in the expression of the glucose transporter GLUT-4.

METHODS

Eighty-nine rats were pretreated for seven days with omapatrilat 20 mg/kg/day and 91 rats were left untreated. MI was induced in 180 Zucker lean male rats by ligating the left anterior descending coronary artery, and omapatrilat was given for another 38 days in the survivors. After 30 days, echocardiography was performed. At 38 days, hemodynamic measurements were performed, the rats were sacrificed and morphological measurements were done. Using quantitative reverse transcriptase-polymerase chain reaction, gene expression was measured in the LV using transcript levels.

RESULTS

Treatment with omapatrilat resulted in improved early (24 h) and late (38 days) survival following MI (50% to 67%, P=0.023, and 44% to 59%, P=0.045, respectively). Omapatrilat treatment reduced MI size and resulted in beneficial ventricular remodelling as reflected by a reduction in cardiac dimensions by echocardiography, and LV and right ventricular hypertrophy, which resulted in borderline hemodynamic improvement. A large MI resulted in an increased expression of beta-myosin heavy chain, alpha-skeletal actin and atrial natriuretic peptide, and a decreased expression of GLUT-4. Omapatrilat treatment did not modify the expression of these genes.

CONCLUSIONS

The results suggest that the vasopeptidase inhibitor omapatrilat does not modify fetal gene expression of the contractile apparatus or the expression of GLUT-4 despite reducing cardiac hypertrophy and MI size.

Meta-analysis of the effects of endothelin receptor blockade on survival in experimental heart failure

BACKGROUND

Although an initial study of endothelin receptor blockade reported positive findings, subsequent experiments and clinical trials in humans found little or no benefit.

METHODS

We applied meta-analytic methods to assess the methodologic rigor of preclinical studies of endothelin blockade and to quantitatively evaluate the totality of evidence regarding the effect of endothelin receptor blockers in experimental heart failure. A total of 396 animals were assigned to control and 594 were assigned to experimental therapy in the pooled analysis. Of the 9 studies identified, no study reported a priori sample size justification. Although there was a tendency to increased mortality with early administration (relative risk 1.39, P=.15) and decreased mortality with late administration (relative risk 0.85, P=.6), in the overall analysis, there was no significant evidence of benefit or harm (relative risk 1.03, P=.9). Studies with a small sample size had estimated effects that tended to deviate further from the pooled estimate of all studies.

CONCLUSIONS

Consideration of mortality effects in the totality of studies revealed no significant effect of endothelin antagonists in animal models of experimental heart failure. Given the potential for between-study variability, reliance on studies with small sample size may lead to unrealistic expectations when extrapolating preclinical experimental results to future research.

Role of endothelins in congestive heart failure

Despite major advances in conventional medical therapy, patients with heart failure continue to experience significant morbidity and mortality. Endothelin-1 (ET-1) is a potent vasocontrictor and mitogenic peptide that is activated in heart failure. There is increasing experimental and clinical evidence in support of an important role of ET-1 in the pathophysiology of heart failure. Manipulation of the activity of ET-1, especially using endothelin receptor blockers, has allowed for the further elucidation of the role of this neurohormonal system and development of novel therapeutic strategies in heart failure. Published clinical studies of these agents to date have involved relatively small numbers of patients with severe heart failure, followed for a relatively short period of time, and have mainly examined surrogate endpoints. Large-scale trials that address to hard clinical outcomes are ongoing and their results forthcoming. A key question that remains concerns whether selective ETA or dual ETA-ETB receptor blockade will be more effective.

AT1 receptor antagonist therapy preferentially ameliorated right ventricular function and phenotype during the early phase of remodeling post-MI

1. The influence of AII on contractile dysfunction, regulation of the tyrosine kinase-dependent signaling molecule extracellular signal-regulated kinase (ERK), and natriuretic peptide gene expression were examined in the noninfarcted left ventricle (NILV) and right ventricle (RV) during the early phase of remodeling post-myocardial infarct (MI) in the rat. The selective AT(1) receptor antagonist irbesartan was administered <10 h following coronary artery ligation, and rats were killed either at 4-day or 2-week post-MI. 2. At 4 days post-MI, left ventricular systolic pressure (LVSP: sham=125+/-12, MI=91+/-4 mmHg) was decreased, whereas left ventricular end-diastolic pressure (LVEDP: sham=9+/-2, MI=17+/-2 mm Hg), right ventricular systolic (RVSP: sham=26+/-1, MI=34+/-2 mm Hg), and end-diastolic pressures (RVEDP: sham=3+/-0.5, MI=7+/-1 mm Hg) were increased. ERK phosphorylation was significantly elevated in the NILV and RV. 3. Irbesartan (40 mg x kg(-1)/day(-1)) administration did not improve left ventricular function, or suppress increased ERK phosphorylation in the 4-day post-MI rat. By contrast, irbesartan therapy normalized RVSP (MI+irbesartan=25+/-1 mm Hg), RVEDP (MI+irbesartan=3+/-0.3 mm Hg), and reduced ERK1 (MI=3.0+/-0.6, MI+irbesartan=2.0+/-0.3-fold increase), and ERK2 (MI=3.8+/-0.8, MI+irbesartan=2.2+/-0.5-fold increase) phosphorylation. 4. In 2-week post-MI rats, biventricular dysfunction was associated with increased prepro-ANP, and prepro-BNP mRNA expression. Irbesartan therapy normalized RVSP, attenuated RVEDP, and abrogated natriuretic peptide mRNA expression (prepro-ANP; MI=9+/-2, MI+irbesartan=2+/-1-fold increase, prepro-BNP; MI=6+/-2, MI+irbesartan=1+/-1-fold increase), whereas both transcripts remained elevated in the NILV despite the partial attenuation of LVEDP. 5. These data suggest that the therapeutic benefit of irbesartan treatment during the early phase of remodeling post-MI was associated with the preferential amelioration of RV contractile function and phenotype.

Response of the adult prostate to prepubertal and postpubertal obstruction of the vas deferens in the rat

OBJECTIVES

To determine whether obstruction of the vas deferens alters several general measures of prostate development during puberty and during prostate maintenance in the adult rat. Previous reports have suggested the possibility that vasectomy results in alterations of prostate function in experimental animals and humans.

METHODS

Adult rats and 10-day-old rats were subjected to bilateral sham operations or bilateral vasectomy, and the prostates were extirpated either 14 or 60 days later. The total prostate weight and dorsolateral and ventral lobe total protein per milligram tissue, DNA per milligram tissue, and DNA per milligram protein were determined. Dorsolateral and ventral prostate lobe sections from each group were also stained with hematoxylin-eosin and subjected to histologic examination.

RESULTS

The histologic features of the adult rat prostate were not qualitatively altered by vasectomy whether it occurred before puberty or in adult animals with mature prostates. Furthermore, vasectomy did not significantly alter the prostate weight or the protein or DNA content of either the dorsolateral or ventral lobes of the prostate compared with the sham-operated animals of either age.

CONCLUSIONS

Vas deferens obstruction does not significantly alter the parameters associated with the development or maintenance of the adult rat prostate measured in this study.