Intercellular Mechanisms of Therapeutic Resistance at the Tumor-Stromal Interface Using Ultra High-Plex Single-Cell Spatial Transcriptomics and Genetically-Engineered Tumoroids

PURPOSE/OBJECTIVE(S)

There is a major gap in knowledge regarding how intercellular interactions in the tumor microenvironment (TME) mediate therapeutic resistance. Achievement of this goal has been limited by a lack of (1) spatial context in dissociated single-cell methods; (2) single-cell resolution in spatial profiling approaches; (3) high quality data and yield with FFPE patient specimens; and (4) computational methods for ligand-receptor analyses that consider both gene expression and spatial coordinates.

MATERIALS/METHODS

We developed an innovative spatial biology paradigm that combines cutting-edge experimental and computational methods to enable high-resolution, spatially-guided discovery of critical mediators of therapeutic resistance. We applied this approach to dissect the single-cell spatial transcriptomic landscape of untreated vs. chemoradiotherapy-treated primary human pancreatic ductal adenocarcinoma (PDAC; n = 21) using ultra-high plex spatial molecular imaging (SMI) optimized for high-sensitivity, subcellular detection of up to 6000 gene transcripts in FFPE sections-an order of magnitude greater than contemporary methods.

RESULTS

We recovered over 1,000,000 high-quality single cells in situ representing more than 20 distinct cell types, including epithelial, immune, endothelial, endocrine, and diverse stromal cells. We developed an optimal transport-based computational method to infer cell-cell communication at the cancer-stromal interface. Treatment with chemoradiotherapy was associated with the largest increase in fibroblast-malignant interactions. Comparing the SMI data with orthogonal single-nucleus RNA-sequencing and digital spatial profiling data, we identified CLCF1-CNTFR as the fibroblast-malignant interaction most associated with resistance to chemoradiotherapy in PDAC. CLCF1 is a gp130-family cytokine that activates Jak-STAT signaling and acts as a potent neurotrophic factor. Notably, the CLCF1-CNTRF (fibroblast-malignant) interaction has prominent pro-oncogenic effects in lung adenocarcinoma and an engineered CNTFR decoy receptor with therapeutic potential has been developed. To functionally validate the role of the CLCF1-CNTFR (fibroblast-malignant) interaction in mediating resistance to cytotoxic therapy, we created CRISPR-engineered cancer-fibroblast tumoroids and modulated expression of this ligand-receptor pair. Pancreatic cancer cell viability in the presence of 5-fluorouracil was better maintained with increased CLCF1-CNTFR signaling.

CONCLUSION

In this study, we integrated ultra high-plex single-cell spatial transcriptomics, optimal transport ligand-receptor predictions, and genetically-engineered stromal tumoroids to identify and validate CLCF1-CNTFR as an important intercellular mechanism of resistance to chemoradiotherapy in PDAC-pioneering a paradigm for translating single-cell spatial biology to clinical oncology.

Five-Year Cost-Effectiveness Modeling of Primary Care-Based, Nonmydriatic Automated Retinal Image Analysis Screening Among Low-Income Patients With Diabetes

BACKGROUND

Artificial intelligence-based technology systems offer an alternative solution for diabetic retinopathy (DR) screening compared with standard, in-office dilated eye examinations. We performed a cost-effectiveness analysis of Automated Retinal Image Analysis System (ARIAS)-based DR screening in a primary care medicine clinic that serves a low-income patient population.

METHODS

A model-based, cost-effectiveness analysis of two DR screening systems was created utilizing data from a recent study comparing adherence rates to follow-up eye care among adults ages 18 or older with a clinical diagnosis of diabetes. In the study, the patients were prescreened with an ARIAS-based, nonmydriatic (undilated), point-of-care tool in the primary care setting and were compared with patients with diabetes who were referred for dilated retinal screening without prescreening, as is the current standard of care. Using a Markov model with microsimulation resulting in a total of 600 000 simulated patient experiences, we calculated the incremental cost-utility ratio (ICUR) of the two screening approaches, with regard to five-year cost-effectiveness of DR screening and treatment of vision-threatening DR.

RESULTS

At five years, ARIAS-based screening showed similar utility as the standard of care screening systems. However, ARIAS reduced costs by 23.3%, with an ICUR of $258 721.81 comparing the current practice to ARIAS.

CONCLUSIONS

Primary care-based ARIAS DR screening is cost-effective when compared with standard of care screening methods.

Guidelines for Genetic Testing and Management of Alport Syndrome

Genetic testing for pathogenic COL4A3-5 variants is usually undertaken to investigate the cause of persistent hematuria, especially with a family history of hematuria or kidney function impairment. Alport syndrome experts now advocate genetic testing for persistent hematuria, even when a heterozygous pathogenic COL4A3 or COL4A4 is suspected, and cascade testing of their first-degree family members because of their risk of impaired kidney function. The experts recommend too that COL4A3 or COL4A4 heterozygotes do not act as kidney donors. Testing for variants in the COL4A3-COL4A5 genes should also be performed for persistent proteinuria and steroid-resistant nephrotic syndrome due to suspected inherited FSGS and for familial IgA glomerulonephritis and kidney failure of unknown cause.

Consensus statement on standards and guidelines for the molecular diagnostics of Alport syndrome: refining the ACMG criteria

The recent Chandos House meeting of the Alport Variant Collaborative extended the indications for screening for pathogenic variants in the COL4A5, COL4A3 and COL4A4 genes beyond the classical Alport phenotype (haematuria, renal failure; family history of haematuria or renal failure) to include persistent proteinuria, steroid-resistant nephrotic syndrome, focal and segmental glomerulosclerosis (FSGS), familial IgA glomerulonephritis and end-stage kidney failure without an obvious cause. The meeting refined the ACMG criteria for variant assessment for the Alport genes (COL4A3-5). It identified 'mutational hotspots' (PM1) in the collagen IV α5, α3 and α4 chains including position 1 Glycine residues in the Gly-X-Y repeats in the intermediate collagenous domains; and Cysteine residues in the carboxy non-collagenous domain (PP3). It considered that 'well-established' functional assays (PS3, BS3) were still mainly research tools but sequencing and minigene assays were commonly used to confirm splicing variants. It was not possible to define the Minor Allele Frequency (MAF) threshold above which variants were considered Benign (BA1, BS1), because of the different modes of inheritances of Alport syndrome, and the occurrence of hypomorphic variants (often Glycine adjacent to a non-collagenous interruption) and local founder effects. Heterozygous COL4A3 and COL4A4 variants were common 'incidental' findings also present in normal reference databases. The recognition and interpretation of hypomorphic variants in the COL4A3-COL4A5 genes remains a challenge.

Effect of workpiece curvature on the tool influence function during hemispherical sub-aperture tool glass polishing

The influence of workpiece curvature on the tool influence function spot during polishing of fused silica glass with cerium oxide slurry, while using a rotating hemispherical pad-foam tool for a wide variety of process conditions (tool displacement, inclination angle, and rotation rate), has been investigated. (Workpiece curvature ranged from 500 mm radius concave to 43 mm radius convex.) The TIF spot decreases in diameter and increases in the peak removal rate on more convex workpieces. In contrast, the TIF spot increases both in diameter and peak removal rate on more concave workpieces. For the range of workpiece curvatures investigated, both the spot size and the peak removal rate changed significantly, as much as 2 times. An elastic sphere-sphere contact mechanics model, which utilizes both a modified displacement (that leads to a change in the applied load) as well as a mismatch factor (that influences the pressure distribution shape), has been developed. The model was validated using both offline load-displacement measurements and finite-element analysis simulations. The model quantitatively describes the measured change in the relative contact diameter and relative pressure distribution, as well as semiquantitively describes the change in the relative volumetric removal rate on a large variety of TIF spots. The change in the volumetric removal rate for convex workpieces is a result of the balance between a decreasing spot size (reducing removal) and an increasing peak pressure (increasing removal), which usually results in relatively small changes in volumetric removal. In the case of concave workpieces, the volumetric removal rate change is also governed by a similar balance, but the spot size increase contribution dominates, resulting in a significant increase in volumetric removal rate. Understanding these trends can enable methods to add greater determinism during the fabrication of freeform optics by adjusting polishing parameters (such as dwell time) while the tool translates along a workpiece surface with different local curvatures.

Mechanisms influencing and prediction of tool influence function spots during hemispherical sub-aperture tool polishing on fused silica

Sub-aperture tool polishing of precision optics requires a detailed understanding of the local material removal [tool influence function (TIF)] at the contact spot between the workpiece and tool to achieve high removal determinism and hence precision of the optic relative to the desired/design surface figure. In this study, the mechanisms influencing and the quantitative prediction of the removal rate and shape of TIF spots during polishing of fused silica glass with cerium oxide slurry using a rotating hemispherical pad-foam tool for a wide variety of process conditions (including tool properties, kinematics, and applied displacements) are investigated. The TIF volumetric removal rate can be estimated utilizing the average relative velocity and contact area using a simple analytical model. In addition, stability of the volumetric removal rate for fixed process conditions is shown to be greatly dependent on the pad preparation and amount of tool use (affecting both pad topography and slurry buildup), whose general behavior shows an increase in removal rate followed by stabilization with polishing time. The determination of the TIF removal shape is more complex. An extended version of the Preston removal model is developed to explain a comprehensive set of measured TIF removal shapes to within ∼22%. This model incorporates a number of phenomena impacting the TIF removal shape including: (a) temporal and spatial dependent relative velocity between the workpiece and tool; (b) an elastic mechanics based, as well as hydrodynamic, pressure distribution; (c) a spatially dependent friction coefficient possibly caused by both reduced slurry replenishment in low velocity regions and pad slurry islands (100 µm scale) and porosity (millimeter scale); and (d) a shear-based removal mechanism on the periphery of the contact spot.

Inflammatory cytokines promote clonal hematopoiesis with specific mutations in ulcerative colitis patients

Epidemiological sequencing studies have revealed that somatic mutations characteristic of myeloid neoplasms can be detected in the blood of asymptomatic individuals decades prior to presentation of any clinical symptoms. This premalignant condition is known as clonal hematopoiesis of indeterminate potential (CHIP). Despite the fact these mutant clones become readily detectable in the blood of elderly individuals (∼10% of people over the age of 65), the overall rate of disease progression remains relatively low. Thus, in addition to genetic mutations, there are likely environmental factors that contribute to clonal evolution in people with CHIP. One environmental stress that increases with age is inflammation. Although chronic inflammation is detrimental to the long-term function of normal hematopoietic stem cells, several recent studies in animal models have indicated hematopoietic stem cells with CHIP mutations may be resistant to these deleterious effects. However, direct evidence indicating a correlation between increased inflammation and accelerated CHIP in humans is currently lacking. In this study, we sequenced the peripheral blood cells of a cohort of patients with ulcerative colitis, an autoimmune disease characterized by increased levels of pro-inflammatory cytokines. This analysis revealed that the inflammatory environment of ulcerative colitis promoted CHIP with a distinct mutational spectrum, notably positive selection of clones with DNMT3A and PPM1D mutations. We also show a specific association between elevated levels of serum interferon gamma and DNMT3A mutations. These data add to our understanding of how cell extrinsic factors select for clones with specific mutations to promote clonal hematopoiesis.

Efficacy of Vedolizumab for Refractory Pouchitis of the Ileo-anal Pouch: Results From a Multicenter US Cohort

BACKGROUND AND AIMS

Inflammation of the pouch after ileal pouch-anal anastomosis (IPAA) can significantly impact quality of life and be difficult to treat. We assessed the effectiveness and safety of vedolizumab in Crohn's disease (CD) of the pouch and chronic antibiotic-dependent or antibiotic-refractory pouchitis.

METHODS

This was a retrospective, multicenter cohort study at 5 academic referral centers in the United States. Adult patients with endoscopic inflammation of the pouch who received vedolizumab were included. The primary outcome was clinical response at any time point. Secondary outcomes included clinical remission, endoscopic response, and remission. Univariate analysis and multivariate analysis were performed for the effect of the following variables on clinical response: fistula, onset of pouchitis less than 1 year after IPAA, younger than 35 years old, gender, previous tumor necrosis factor inhibitor-alpha use, and BMI >30.

RESULTS

Eighty-three patients were treated with vedolizumab for inflammation of the pouch between January 2014 and October 2017. Median follow-up was 1.3 years (interquartile range 0.7-2.1). The proportion of patients that achieved at least a clinical response was 71.1%, with 19.3% achieving clinical remission. Of the 74 patients with a follow-up pouchoscopy, the proportion of patients with endoscopic response and mucosal healing was 54.1% and 17.6%, respectively. Patients who developed pouchitis symptoms less than 1 year after undergoing IPAA were less likely to respond to vedolizumab, even after controlling for other risk factors.

CONCLUSIONS

Vedolizumab is safe and effective in the management of CD of the pouch and chronic pouchitis. Further studies are needed to compare vedolizumab with other biologic therapies for pouchitis and CD of the pouch.

Prenatal exposure to betamethasone causes intergenerational impairment of epididymal development in the rat

BACKGROUND

Studies on epididymal toxicology are scarce. Betamethasone (BM) is a glucocorticoid used in clinical practice for antenatal therapy. We previously reported changes to testicular morphology, altered sperm quality, and fertility in adult rats following intrauterine administration of BM.

OBJECTIVES

Given that high levels of corticosteroids during gestation lead to fetal androgen depletion, and the essential role of testosterone during epididymal development, here we investigated epididymal morphology and physiology in the F1 and F2 male offspring of female rats treated with BM during gestation.

MATERIALS AND METHODS

Pregnant rats were randomly divided into two experimental groups: control (saline vehicle, n = 11) and BM-treated group (0.1 mg/kg betamethasone 21-phosphate disodium, n = 13). Rats received an intramuscular injection of vehicle or BM on gestational days 12, 13, 18, and 19. This encompasses the beginning of the critical window of male rat reproductive tract development. A subset of three males from each litter (n = 5 litters/group) was used: One rat per litter was euthanized at puberty, one was euthanized at adulthood, while the others were mated with a non-treated female to obtain the F2 generation. The same protocol described for the F1 was applied for F2, except for the mating protocol.

RESULTS

In both F1 and F2 generations, prenatal BM exposure resulted in delayed differentiation of the cauda epididymal epithelium, characterized by increased cribriform appearance on PND 45, and displayed weaker or non-detectable Cx43 immunostaining. Furthermore, in the F1 generation only, immunostaining of TP63, a transcription factor expressed in basal cells, appeared more intense with a greater number of TP63-positive cells observed in the cauda epididymis. In adults, the epithelial area was reduced in the F1 BM rats. The contractile activity of isolated epididymal ducts was comparable between groups.

DISCUSSION AND CONCLUSION

Prenatal BM exposure leads to intergenerational impairment in the development and structure of the rat epididymis.

Ustekinumab Is Effective for the Treatment of Crohn's Disease of the Pouch in a Multicenter Cohort

BACKGROUND

Crohn's disease (CD) of the pouch and chronic pouchitis occur in approximately 10% of patients after ileal pouch-anal anastomosis (IPAA) for refractory ulcerative colitis (UC) or UC-related dysplasia. The efficacy of anti-tumor necrosis factor (anti-TNF) agents and vedolizumab have been reported for the treatment of CD of the pouch and chronic pouchitis, but little is known regarding the use of ustekinumab in these settings. Our primary aim was to evaluate the efficacy of ustekinumab for these conditions.

METHODS

This is a retrospective, multicenter cohort study evaluating the efficacy of ustekinumab in patients with CD of the pouch and chronic pouchitis. Clinical response or remission was judged by the treating physician's assessment at 6 months.

RESULTS

Fifty-six patients (47 with CD of the pouch and 9 with chronic pouchitis) were included the study. Of these, 73% had previously been treated with either anti-TNF therapy, vedolizumab, or both after IPAA. Among patients with CD of the pouch and chronic pouchitis, 83% demonstrated clinical response 6 months after induction with ustekinumab. Responders demonstrated significantly less pouch inflammation on endoscopy when compared with nonresponders (29% vs 100%; P = 0.023). Higher mean body mass index at induction (26.3 vs 23.7; P = 0.033) and male sex (83% vs 30%; P = 0.014) were significant predictors of nonresponse to ustekinumab in those with CD of the pouch.

CONCLUSION

In this refractory patient population, ustekinumab appears to be a safe and effective treatment for chronic pouchitis and CD of the pouch in biologic-naïve patients and those with prior anti-TNF or vedolizumab therapy failure. 10.1093/ibd/izx005_video1 izy302.video1 5844889626001.

De-novo Inflammatory Bowel Disease After Bariatric Surgery: A Large Case Series

BACKGROUND

Case reports of inflammatory bowel diseases [IBD] have been reported in patients with a history of bariatric surgery. Our aim was to characterize patients who were diagnosed with IBD after having undergone bariatric surgery.

METHODS

Electronic medical records were reviewed at two institutions to identify patients who developed de-novo Crohn's disease or ulcerative colitis [UC] after bariatric surgery. Data on demographics, type of bariatric surgical procedure, IBD subtype, phenotype and medication usage were obtained. The incidence rate of de-novo IBD after bariatric surgery [per 100000 person-years] and standardized incidence ratio [SIR] were estimated from a prospective bariatric surgery database.

RESULTS

A total of 44 patients with de-novo IBD after bariatric surgery were identified [31 Crohn's disease, 12 UC, one IBD unclassified]. Most patients were female [88.6%], with median age at IBD onset of 44 years [IQR, 37-52] and median time to IBD diagnosis after bariatric surgery of 7 years [IQR, 3-10]. Sixty-eight per cent underwent Roux-en-Y gastric bypass. In the prospective database, the incidence of IBD in patients who underwent bariatric surgery was 26.7 per 100000 person-years [4.5 for UC and 22.3 for Crohn's disease]. The age-adjusted SIR ranged from 3.56 in the 40-49 year age group to 4.73 in the 30-39 year age group.

CONCLUSION

We described a case series of patients developing de-novo IBD after bariatric surgery. There appears to be a numerically higher incidence of Crohn's disease in this population. Confirmation of causality is required in larger patient cohorts.

Insect transformation with piggyBac: getting the number of injections just right

The insertion of exogenous genetic cargo into insects using transposable elements is a powerful research tool with potential applications in meeting food security and public health challenges facing humanity. piggyBac is the transposable element most commonly utilized for insect germline transformation. The described efficiency of this process is variable in the published literature, and a comprehensive review of transformation efficiency in insects is lacking. This study compared and contrasted all available published data with a comprehensive data set provided by a biotechnology group specializing in insect transformation. Based on analysis of these data, with particular focus on the more complete observational data from the biotechnology group, we designed a decision tool to aid researchers' decision-making when using piggyBac to transform insects by microinjection. A combination of statistical techniques was used to define appropriate summary statistics of piggyBac transformation efficiency by species and insect order. Publication bias was assessed by comparing the data sets. The bias was assessed using strategies co-opted from the medical literature. The work culminated in building the Goldilocks decision tool, a Markov-Chain Monte-Carlo simulation operated via a graphical interface and providing guidance on best practice for those seeking to transform insects using piggyBac.

Effects of polysaccharide intercellular adhesin (PIA) in an ex vivo model of whole blood killing and in prosthetic joint infection (PJI): A role for C5a

BACKGROUND

A major complication of using medical devices is the development of biofilm-associated infection caused by Staphylococcus epidermidis where polysaccharide intercellular adhesin (PIA) is a major mechanism of biofilm accumulation. PIA affects innate and humoral immunity in isolated cells and animal models. Few studies have examined these effects in prosthetic joint infection (PJI).

METHODS

This study used ex vivo whole blood modelling in controls together with matched-serum and staphylococcal isolates from patients with PJI.

RESULTS

Whole blood killing of PIA positive S. epidermidis and its isogenic negative mutant was identical. Differences were unmasked in immunosuppressed whole blood pre-treated with dexamethasone where PIA positive bacteria showed a more resistant phenotype. PIA expression was identified in three unique patterns associated with bacteria and leukocytes, implicating a soluble form of PIA. Purified PIA reduced whole blood killing while increasing C5a levels. In clinically relevant staphylococcal isolates and serum samples from PJI patients; firstly complement C5a was increased 3-fold compared to controls; secondly, the C5a levels were significantly higher in serum from PJI patients whose isolates preferentially formed PIA-associated biofilms.

CONCLUSIONS

These data demonstrate for the first time that the biological effects of PIA are mediated through C5a in patients with PJI.

Haemophilia Experiences, Results and Opportunities (HERO) study: treatment-related characteristics of the population

The HERO (Haemophilia Experiences, Results and Opportunities) quantitative surveys collected information on characteristics and perceptions of adult persons with haemophilia (PWH) and parents of children with haemophilia. The aim of this article is to describe the perceptions of PWH and parents on psychosocial aspects related to treatment. Two online surveys (one for PWH, one for parents) were conducted in 10 countries. Among 675 PWH respondents, 77% reported having responsibility for their own care; 72% of 561 parent respondents had the main responsibility for their son. PWH were most commonly treated on demand (45% of 648 adults using factor concentrate), with 32% on regular prophylaxis and 23% treated on demand with short-term prophylaxis (e.g. for sports/physiotherapy). Children were most often treated with prophylaxis (65% of 549 children using factor concentrate), with 26% treated on demand and 8% treated on demand with short-term prophylaxis. Factor was generally used as instructed at home. Some respondents (41% PWH; 30% parents) had difficulties/concerns with factor availability/affordability. PWH reported more bleeds in the last 12 months than parents reporting their son's bleeds (mean 17.8 vs. 8.7). Both PWH and parents generally perceived that overall, their (their son's) haemophilia was well controlled. Results differed by country. The HERO study captured new, patient-based data regarding many facets of life relevant to PWH, including treatment. The information conveyed in this article largely represents new insights regarding perceptions of treatment and provides initial benchmark statistics for further research.

Haemophilia Experiences, Results and Opportunities (HERO) Study: influence of haemophilia on interpersonal relationships as reported by adults with haemophilia and parents of children with haemophilia

Evidence delineating the effects of haemophilia on interpersonal relationships is sparse and largely outdated, failing to reflect the impact of current treatment strategies. HERO (Haemophilia Experiences, Results and Opportunities) was commenced to garner a more comprehensive understanding of psychosocial issues facing persons with haemophilia (PWH). This article describes the findings of the quantitative HERO survey relating to the influence of haemophilia on interpersonal relationships of adult PWH, and parents/caregivers of children with haemophilia. Separate questionnaires were completed by adult PWH and parents of minor children from 10 countries, including satisfaction with support from partners, family, friends and other social contacts; disclosure of haemophilia and carrier status and family dynamics. A total of 675 PWH and 561 parents completed the survey. Over half of PWH (57%) and parents (84%) were married. Most PWH were satisfied with support from partners (94%), family (90%) and friends (85%), with lower percentages reported among those with inhibitors. Most parents were likewise satisfied with support from partners (88%) and family (83%). Whereas PWH were reticent to disclose their diagnosis beyond family and friends, parents were more likely to share their son's diagnosis, and most were satisfied with the support from their son's peers (74%), teachers (83%) and other adults in supervisory roles (85%). PWH and parents surveyed were satisfied overall with the support they received from partners, family, friends and social contacts. Relationships are affected by haemophilia in various ways, and particularly affected in terms of disease burden, age and social life.

Expert guidelines for the management of Alport syndrome and thin basement membrane nephropathy

Few prospective, randomized controlled clinical trials address the diagnosis and management of patients with Alport syndrome or thin basement membrane nephropathy. Adult and pediatric nephrologists and geneticists from four continents whose clinical practice focuses on these conditions have developed the following guidelines. The 18 recommendations are based on Level D (Expert opinion without explicit critical appraisal, or based on physiology, bench research, or first principles-National Health Service category) or Level III (Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees-U.S. Preventive Services Task Force) evidence. The recommendations include the use of genetic testing as the gold standard for the diagnosis of Alport syndrome and the demonstration of its mode of inheritance; the need to identify and follow all affected members of a family with X-linked Alport syndrome, including most mothers of affected males; the treatment of males with X-linked Alport syndrome and individuals with autosomal recessive disease with renin-angiotensin system blockade, possibly even before the onset of proteinuria; discouraging the affected mothers of males with X-linked Alport syndrome from renal donation because of their own risk of kidney failure; and consideration of genetic testing to exclude X-linked Alport syndrome in some individuals with thin basement membrane nephropathy. The authors recognize that as evidence emerges, including data from patient registries, these guidelines will evolve further.

Nanodiscs in the studies of membrane-bound cytochrome P450 enzymes

Cytochromes P450 from eukaryotes and their native redox partners cytochrome P450 reductases both belong to the class of monotopic membrane proteins containing one transmembrane anchor. Incorporation into the lipid bilayer significantly affects their equilibrium and kinetic properties and plays an important role in their interactions. We describe here the detailed protocols developed in our group for the functional self-assembly of mammalian cytochromes P450 and cytochrome P450 reductases into Nanodiscs with controlled lipid composition. The resulting preparations are fully functional, homogeneous in size, composition and oligomerization state of the heme enzyme, and show an improved stability with respect to P420 formation. We provide a brief overview of applications of Nanodisc technology to the biophysical and biochemical mechanistic studies of cytochromes P450 involved in steroidogenesis, and of the most abundant xenobiotic-metabolizing human cytochrome P450 CYP3A4.

Clinical practice recommendations for the treatment of Alport syndrome: a statement of the Alport Syndrome Research Collaborative

We present clinical practice recommendations for the treatment of children with Alport syndrome who are not enrolled in clinical trials. Our goal is to promote early initiation of a standard therapeutic approach that will facilitate assessment of the safety and efficacy of the protocol. The treatment protocol is based on the reduction of proteinuria, intraglomerular pressure, and renal fibrosis via interference with the renin-angiotensin-aldosterone system.

Modeling asthma exacerbations through lung function in children

BACKGROUND

Formal economic evaluation using a model-based approach is playing an increasingly important role in health care decision making.

OBJECTIVE

To develop a model by using an objective measure of lung function-- prebronchodilator FEV(1) as a percent of predicted (FEV(1)% predicted)--as the primary independent factor to predict the frequency of adverse events related to the exacerbation of asthma on a population level.

METHODS

We developed a Markov simulation model of childhood asthma by using data from the Childhood Asthma Management Program. The primary outcomes were the result of asthma exacerbations defined as hospitalizations, emergency department (ED) visits, and the need for oral corticosteroid therapy. Predicted monthly frequencies for each acute event were based on negative binomial regression equations estimated from the placebo arm of the Childhood Asthma Management Program with covariates of age, prebronchodilator FEV(1)% predicted, time in study, prior hospitalizations, and prior nocturnal awakenings.

RESULTS

Simulated versus observed mean number of acute events were similar within the placebo and treatment groups. While the trial demonstrated treatment effects of 48% reduction in hospitalizations, 46% reduction in ED visits, and 44% reduction in the need for oral corticosteroid therapy at 48 months, the model simulated similar reductions of 49% in hospitalizations, 41% in ED visits, and 46% in the need for oral corticosteroid therapy.

CONCLUSIONS

Our findings suggest that longitudinal intervention effects may be modeled through FEV(1)% predicted to estimate hospitalizations, ED visits, and need for oral corticosteroid therapy in childhood asthma for planning and evaluation purposes.

Economic evaluation of plerixafor for stem cell mobilization

INTRODUCTION

Autologous peripheral stem cell transplantation (ASCT) with high-dose chemotherapy is a preferred treatment for relapsed non- Hodgkin lymphoma (NHL) patients. Estimated failure rates with current stem cell mobilization (SCM) regimens are 5% to 30%. Granulocyte colony-stimulating factor (G-CSF) with plerixafor (G P) is superior to G-CSF alone for SCM in heavily pretreated NHL patients.

OBJECTIVES

To conduct a cost-utility evaluation of G P versus G-CSF as a method for SCM in patients with diffuse large B-cell lymphoma (DLBCL), the most common subtype of NHL.

METHODS

A Markov model simulated the care process of DLBCL patients undergoing ASCT using data from the Washington University site of the plerixafor phase III study. Other data and utilities were taken from the literature. Costs were Medicare allowable. Using microsimulation we estimated the incremental cost-utility ratio (ICUR) over the patient's remaining lifetime.

RESULTS

The expected lifetime cost of providing care for DLBCL patients using G P was $25,567 more than G-CSF, but they accumulated 1.74 more quality-adjusted life-years (QALYs) for an ICUR of $14,735 per QALY. In sensitivity analyses this result was robust to clinically relevant changes in assumptions.

CONCLUSIONS

Using G P for SCM in ASCT of patients with DLBCL meets accepted standards of cost-effectiveness, primarily because of its effectiveness in SCM.

A comparison of surgical intervention and stereotactic body radiation therapy for stage I lung cancer in high-risk patients: a decision analysis

OBJECTIVE

We sought to compare the relative cost-effectiveness of surgical intervention and stereotactic body radiation therapy in high risk patients with clinical stage I lung cancer (non-small cell lung cancer).

METHODS

We compared patients chosen for surgical intervention or SBRT for clinical stage I non-small cell lung cancer. Propensity score matching was used to adjust estimated treatment hazard ratios for the confounding effects of age, comorbidity index, and clinical stage. We assumed that Medicare-allowable charges were $15,034 for surgical intervention and $13,964 for stereotactic body radiation therapy. The incremental cost-effectiveness ratio was estimated as the cost per life year gained over the patient's remaining lifetime by using a decision model.

RESULTS

Fifty-seven patients in each arm were selected by means of propensity score matching. Median survival with surgical intervention was 4.1 years, and 4-year survival was 51.4%. With stereotactic body radiation therapy, median survival was 2.9 years, and 4-year survival was 30.1%. Cause-specific survival was identical between the 2 groups, and the difference in overall survival was not statistically significant. For decision modeling, stereotactic body radiation therapy was estimated to have a mean expected survival of 2.94 years at a cost of $14,153 and mean expected survival with surgical intervention was 3.39 years at a cost of $17,629, for an incremental cost-effectiveness ratio of $7753.

CONCLUSIONS

In our analysis stereotactic body radiation therapy appears to be less costly than surgical intervention in high-risk patients with early stage non-small cell lung cancer. However, surgical intervention appears to meet the standards for cost-effectiveness because of a longer expected overall survival. Should this advantage not be confirmed in other studies, the cost-effectiveness decision would be likely to change. Prospective randomized studies are necessary to strengthen confidence in these results.

Molecular testing for adult type Alport syndrome

Background

Alport syndrome (AS) is a progressive renal disease with cochlear and ocular involvement. The majority of AS cases are X-linked (XLAS) and due to mutations in the COL4A5 gene. Although the disease may appear early in life and progress to end stage renal disease (ESRD) in young adults, in other families ESRD occurs in middle age. Few of the more than four hundred mutations described in COL4A5 are associated with adult type XLAS, but the families may be very large.

Methods

We classified adult type AS mutation by prevalence in the US and we developed a molecular assay using a set of hybridization probes that identify the three most common adult type XLAS mutations; C1564S, L1649R, and R1677Q.

Results

The test was validated on samples previously determined to contain one or none of these mutations. In the US, the test's clinical specificity and sensitivity are estimated to be higher than 99% and 75% respectively. Analytical specificity and sensitivity are above 99%.

Conclusion

This test may be useful for presymptomatic and carrier testing in families with one of the mutations and in the diagnosis of unexplained hematuria or chronic kidney disease.

A set of SAS macros for calculating and displaying adjusted odds ratios (with confidence intervals) for continuous covariates in logistic B-spline regression models

In clinical and epidemiologic research to investigate dose-response associations, non-parametric spline regression has long been proposed as a powerful alternative to conventional parametric regression approaches, since no underlying assumptions of linearity have to be fulfilled. For logistic spline models, however, to date, little standard statistical software is available to estimate any measure of risk, typically of interest when quantifying the effects of one or more continuous explanatory variable(s) on a binary disease outcome. In the present paper, we propose a set of SAS macros which perform non-parametric logistic regression analysis with B-spline expansions of an arbitrary number of continuous covariates, estimating adjusted odds ratios with respective confidence intervals for any given value with respect to a supplied reference value. Our SAS codes further allow to graphically visualize the shape of the association, retaining the exposure variable under consideration in its initial, continuous form while concurrently adjusting for multiple confounding factors. The macros are easily to use and can be implemented quickly by the clinical or epidemiological researcher to flexibly investigate any dose-response association of continuous exposures with the risk of binary disease outcomes. We illustrate the application of our SAS codes by investigating the effect of body-mass index on risk of cancer incidence in a large, population-based male cohort.

Prospective study of the association of gamma-glutamyltransferase with cancer incidence in women

Although several epidemiologic studies have shown that gamma-glutamyltransferase (GGT) is associated with cardiovascular disease and all-cause mortality, its relationship with cancer incidence remains widely unexplored. In experimental models the ability of cellular GGT to modulate crucial redox-sensitive functions has been established, and it may thus play a role in tumor progression. In the present study, we investigated the association of GGT with overall and site-specific cancer incidence in a population-based cohort of 92,843 Austrian women with 349,674 serial GGT measurements, prospectively followed-up for a median of 13.5 years. The relationship between GGT and cancer incidence was analyzed using adjusted Cox regression models with age as underlying time metric with age as underlying time metric including GGT concentrations at baseline and incorporating repeated GGT measurements as a time-dependent variable. During follow-up, 4,884 incidence cancers were observed. Compared to normal low GGT (<17.99 U/L), cancer risk was elevated for all other GGT categories (p for trend < 0.0001), with adjusted hazard ratios (95% confidence intervals) of 1.06 (0.99-1.13) for GGT levels between 18.00 and 35.99 U/L (normal high), 1.12 (1.02-1.22) for GGT levels between 36.00 and 71.99 U/L (elevated) and 1.43 (1.28-1.61) for highly elevated GGT (>72.00 U/L). Very similar results were seen when GGT was analyzed as a time-dependent variable. In cancer-site specific models, elevated GGT statistically significantly increased the risk for malignant neoplasms of digestive organs, the respiratory system/intrathoracic organs, breast and female genital organs and lymphoid and haematopoietic cancers (all, p < 0.006). Our study is the first to demonstrate in a large population-based cohort that high GGT levels significantly increased cancer risk in women.

Association of gamma-glutamyltransferase and risk of cancer incidence in men: a prospective study

Although several epidemiologic studies have shown that gamma-glutamyltransferase (GGT) is independently associated with cardiovascular disease and all-cause mortality, its relationship with cancer incidence remains widely unexplored. In several experimental models, the ability of cellular GGT to modulate crucial redox-sensitive functions has been established, and it thus may play a role in tumor progression, as has been repeatedly suggested. We prospectively investigated the association between GGT and risk of overall and site-specific cancer incidence in a large population-based cohort of 79,279 healthy Austrian men with serial GGT measurements. Median follow-up was 12.5 years. Adjusted Cox proportional hazards models were calculated to evaluate GGT as an independent predictor for cancer incidence, and nonparametric regression splines were fitted to flexibly capture the dose-response relationship. Elevated GGT significantly increased overall cancer risk, showing a clear dose-response relationship (P for GGT log-unit increase < 0.0001; P for trend < 0.0001). In comparison with the reference GGT concentration (25 units/L), we found adjusted relative risks (95% confidence intervals) equalling 1.19 (1.15-1.22) for GGT concentrations of 60 units/L, 1.32 (1.28-1.36) for 100 units/L, 1.67 (1.60-1.75) for 200 units/L, and 2.30 (2.14-2.47) for 400 units/L. In cancer site-specific models, GGT was significantly associated with malignant neoplasms of digestive organs, the respiratory system/intrathoracic organs, and urinary organs (all P < 0.0001). Age of participants significantly modified the association of GGT and cancer risk (P < 0.001), revealing markedly stronger associations in participants ages </=65 years. Our findings, for the first time, show that elevated GGT is significantly associated with increased cancer risk in men.

Communicating about haemophilia within the family: the importance of context and of experience

This study examines communication within families affected by haemophilia, focusing especially on communication about carrier status. A qualitative study using semi-structured interviews with family members in the UK revealed recurrent patterns in communication strategies and styles. Participants drew a marked contrast between the nature of communication within the clinic and within the home. In families, it is notable that communication usually occurs within the context of concrete experience of the condition. Noticeable differences existed in families with obligate carriers when compared with families with non-obligate carrier daughters. In families with affected sons, daughters may have more experience of haemophilia and consequently more understanding of their possible carrier status than in families with an affected father. Families also typically make value judgements and comments on coping strategies when they communicate about the condition. Readiness to receive information is very variable, and depends upon factors such as personality and life stage. Information may seem to be successfully communicated but the recipient may sometimes actually comprehend much less, only understanding more fully later or when the information becomes directly relevant to them. Periodic checking of understanding of different family members, and the provision of written information, may be helpful.

Hyperbaric oxygenation ameliorates indomethacin-induced enteropathy in rats by modulating TNF-alpha and IL-1beta production

The effect of hyperbaric oxygenation (HBO2) was investigated in a rat model of indomethacin-induced enteropathy. Enteropathy was induced by two subcutaneous injections of indomethacin (7.5 mg/kg) 24 hr apart. Six groups of rats (n=8) were treated with and without HBO2 (100% oxygen at 2.3 atm absolute) for 1 hr once or twice a day for 2 or 5 days. Disease activity index (DAI) and total ulcer length were measured. Other rats were randomized into two groups (n=16) with and without HBO2 (1 hr once a day) and four rats were killed in each group at 12, 24, 48, and 72 hr after the final injection of indomethacin. Serum and intestinal mucosal TNF-alpha, IL-1beta, myeloperoxidase (MPO), and iNOS expression was measured. HBO2 treatment significantly attenuated indomethacin -induced intestinal ulceration and improved DAI. Indomethacin increased MPO activity and iNOS expression, and these were reduced by HBO2 treatment, with a concomitant reduction in TNF-alpha and IL-1beta. Our data suggest that HBO2 treatment has a beneficial effect on indomethacin-induced enteropathy and this effect is possibly mediated by decreased production of TNF-alpha and IL-1beta.

Safety and efficacy of retreating follicular non-Hodgkin’s lymphoma (NHL) with 90Y ibritumomab tiuxetan

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Background: There is no data regarding safety and efficacy of treating follicular NHL patients with a second course of 90Y ibritumomab tiuxetan (Zevalin). Methods: Patients with follicular NHL who received 2 courses of Zevalin therapy were identified nationally, and data was retrospectively collected. Results: 10 patients (pts) (mean age 62.5 years, 48–91) were identified. Prior to the first Zevalin, all pts received chemotherapy (mean 2.4 courses, 1–5), 3/10 auto-PBSCT, and 4/10 external beam radiotherapy(ebRT). After the initial course of treatment, the mean time to nadir for the anemia was 7.9 weeks (wks)(4–13), neutropenia was 6.7 wks (4–10); and thrombocytopenia was 5.2 wks (4–8). 1 pt required growth factor support and transfusions; 2 had an incomplete recovery of platelet count at 23 and 30 wks (76,000 and 126,000/μl). Hematologic toxicity and grades are in the table below. Prior to the second course of Zevalin 2 pts received ebRT, 1 received 131I tositumomab, and 3 received chemotherapy (1–5 regimens). The median time to the second Zevalin course was 613 days (183–1,300). After the second course of Zevalin, the mean time to nadir for the anemia was 8.2 wks (2–25); neutropenia was 6.7 wks (4–10); and thrombocytopenia was 5.5 wks (4–7). 4/10 pts required growth factor support, 2 required transfusions, 3 had incomplete recovery of platelet count and early progression, 2 pts had a maximum recovery of their platelet count at 29 and 40 wks (143,000 and 144,000/μl). There were no infectious or bleeding complications with either course of Zevalin. No secondary myelodysplastic syndrome or acute leukemia were reported. Conclusions: Retreating patients with follicular NHL with a second course of Zevalin is tolerable with substantial evidence of clinical efficacy. This data warrants further evaluation of Zevalin retreatment in a clinical trial.

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Zebrafish: a genetic model for hemostasis and thrombosis

Here we review the zebrafish hemostatic system, its relevance to mammalian hemostasis, and its efficacy as a vertebrate genetic model to further the understanding of hemostasis and thrombosis.