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1.
Aust J Gen Pract ; 52(3): 143-148, 2023 03.
Article in English | MEDLINE | ID: mdl-36872092

ABSTRACT

BACKGROUND: The COVID-19 pandemic has revealed the full extent of the crisis in general practice, which has emerged as nothing more than the tip of the iceberg of a health system in crisis. OBJECTIVE: This article introduces the systems and complexity thinking that frame the problems affecting general practice and the systemic challenges inherent in redesigning it. DISCUSSION: The authors show how embedded general practice is in the overall complex adaptive organisation of the health system. They allude to some of the key concerns that need to be dissolved in its redesign to achieve an effective, efficient, equitable and sustainable general practice system within a redesigned overall health system to achieve the best possible desired health experiences for patients.


Subject(s)
COVID-19 , General Practice , Humans , Pandemics , Family Practice
2.
Aust J Gen Pract ; 52(3): 150-157, 2023 03.
Article in English | MEDLINE | ID: mdl-36872093

ABSTRACT

BACKGROUND: The systemic problems and challenges of general practice within the health system require systemic solutions. OBJECTIVE: Noting the complex adaptive nature of health, illness and disease, and its distribution within communities and general practice work, this article suggests a model for general practice that allows the full scope of practice to be developed while creating seamlessly integrated general practice colleges that support general practitioners on their journey to 'mastery' in their chosen discipline. DISCUSSION: The authors discuss the complex dynamics underpinning knowledge and skills development throughout doctors' careers, and the need for policy makers to evaluate health improvement and resourcing based on their interdependencies with all societal activity. To succeed, the profession would have to adopt the principles that form the foundation of generalism and complex adaptive organisations to strengthen its ability to successfully interact with all its stakeholders.


Subject(s)
General Practice , General Practitioners , Humans , Family Practice , Universities
3.
Trials ; 22(1): 726, 2021 Oct 21.
Article in English | MEDLINE | ID: mdl-34674750

ABSTRACT

The efficient community spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the current pandemic of coronavirus disease-2019 (COVID-19), which in severe and critical cases results in progressive pulmonary infection, complicated by respiratory failure, with a high prevalence of acute respiratory distress syndrome. Of all age groups, older adults have the greatest risk of severe COVID-19 and the associated complications. Globally, there are many reports of the rapid spread of COVID-19 among residents of skilled nursing facilities, with high associated rates of morbidity and mortality. With over 1.3 million residents in nursing home care in the USA, there is an urgent need for therapeutic strategies to prevent COVID-19 in these populations.Lilly, in collaboration with the National Institute of Allergy and Infectious Diseases, conducted the BLAZE-2 trial to evaluate the efficacy and safety of the monoclonal antibody bamlanivimab (LY3819253) in preventing SARS-CoV-2 infection and COVID-19, defined as symptomatic infection, in skilled nursing and assisted living facilities. It is a phase 3 randomized, double-blind, placebo-controlled trial, where participants were randomized to bamlanivimab (4200 mg) or placebo and then followed up for 24 weeks. Conducting a trial in the midst of a pandemic in these facilities poses several challenges, including a vulnerable elderly population, travel restrictions, supply chain interruptions, and defining the target population. The operational challenges were addressed by the innovative use of mobile research units which are customized, equipped, and staffed to support BLAZE-2 randomization and participant dosing within the skilled nursing and assisted living facilities. Herein, we describe the design of the study, the analytics behind facility selection, and an innovative operational model.


Subject(s)
Assisted Living Facilities , COVID-19 , Aged , Clinical Trials as Topic , Humans , Post-Exposure Prophylaxis , SARS-CoV-2
4.
Sci Rep ; 11(1): 15529, 2021 07 30.
Article in English | MEDLINE | ID: mdl-34330963

ABSTRACT

Diabetes mellitus (DM) is the leading cause of chronic kidney disease and diabetic nephropathy is widely studied. In contrast, the pathobiology of diabetic urinary bladder disease is less understood despite dysfunctional voiding being common in DM. We hypothesised that diabetic cystopathy has a characteristic molecular signature. We therefore studied bladders of hyperglycaemic and polyuric rats with streptozotocin (STZ)-induced DM. Sixteen weeks after induction of DM, as assessed by RNA arrays, wide-ranging changes of gene expression occurred in DM bladders over and above those induced in bladders of non-hyperglycaemic rats with sucrose-induced polyuria. The altered transcripts included those coding for extracellular matrix regulators and neural molecules. Changes in key genes deregulated in DM rat bladders were also detected in db/db mouse bladders. In DM rat bladders there was reduced birefringent collagen between detrusor muscle bundles, and atomic force microscopy showed a significant reduction in tissue stiffness; neither change was found in bladders of sucrose-treated rats. Thus, altered extracellular matrix with reduced tissue rigidity may contribute to voiding dysfunction in people with long-term DM. These results serve as an informative stepping stone towards understanding the complex pathobiology of diabetic cystopathy.


Subject(s)
Diabetes Mellitus, Experimental/metabolism , Urinary Bladder/metabolism , Animals , Enzyme-Linked Immunosorbent Assay , Male , Microscopy, Atomic Force , Oligonucleotide Array Sequence Analysis , Rats , Rats, Wistar , Transcriptome/genetics , Transcriptome/physiology
5.
JAMA ; 326(1): 46-55, 2021 07 06.
Article in English | MEDLINE | ID: mdl-34081073

ABSTRACT

Importance: Preventive interventions are needed to protect residents and staff of skilled nursing and assisted living facilities from COVID-19 during outbreaks in their facilities. Bamlanivimab, a neutralizing monoclonal antibody against SARS-CoV-2, may confer rapid protection from SARS-CoV-2 infection and COVID-19. Objective: To determine the effect of bamlanivimab on the incidence of COVID-19 among residents and staff of skilled nursing and assisted living facilities. Design, Setting, and Participants: Randomized, double-blind, single-dose, phase 3 trial that enrolled residents and staff of 74 skilled nursing and assisted living facilities in the United States with at least 1 confirmed SARS-CoV-2 index case. A total of 1175 participants enrolled in the study from August 2 to November 20, 2020. Database lock was triggered on January 13, 2021, when all participants reached study day 57. Interventions: Participants were randomized to receive a single intravenous infusion of bamlanivimab, 4200 mg (n = 588), or placebo (n = 587). Main Outcomes and Measures: The primary outcome was incidence of COVID-19, defined as the detection of SARS-CoV-2 by reverse transcriptase-polymerase chain reaction and mild or worse disease severity within 21 days of detection, within 8 weeks of randomization. Key secondary outcomes included incidence of moderate or worse COVID-19 severity and incidence of SARS-CoV-2 infection. Results: The prevention population comprised a total of 966 participants (666 staff and 300 residents) who were negative at baseline for SARS-CoV-2 infection and serology (mean age, 53.0 [range, 18-104] years; 722 [74.7%] women). Bamlanivimab significantly reduced the incidence of COVID-19 in the prevention population compared with placebo (8.5% vs 15.2%; odds ratio, 0.43 [95% CI, 0.28-0.68]; P < .001; absolute risk difference, -6.6 [95% CI, -10.7 to -2.6] percentage points). Five deaths attributed to COVID-19 were reported by day 57; all occurred in the placebo group. Among 1175 participants who received study product (safety population), the rate of participants with adverse events was 20.1% in the bamlanivimab group and 18.9% in the placebo group. The most common adverse events were urinary tract infection (reported by 12 participants [2%] who received bamlanivimab and 14 [2.4%] who received placebo) and hypertension (reported by 7 participants [1.2%] who received bamlanivimab and 10 [1.7%] who received placebo). Conclusions and Relevance: Among residents and staff in skilled nursing and assisted living facilities, treatment during August-November 2020 with bamlanivimab monotherapy reduced the incidence of COVID-19 infection. Further research is needed to assess preventive efficacy with current patterns of viral strains with combination monoclonal antibody therapy. Trial Registration: ClinicalTrials.gov Identifier: NCT04497987.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Neutralizing/therapeutic use , Antiviral Agents/therapeutic use , COVID-19/prevention & control , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal, Humanized/adverse effects , Antibodies, Monoclonal, Humanized/immunology , Antiviral Agents/adverse effects , Antiviral Agents/immunology , Assisted Living Facilities , COVID-19/epidemiology , Double-Blind Method , Drug Approval , Female , Health Personnel , Humans , Immunization, Passive , Incidence , Infusions, Intravenous , Male , Middle Aged , SARS-CoV-2/isolation & purification , Severity of Illness Index , Skilled Nursing Facilities , Young Adult
6.
Pediatr Nephrol ; 35(6): 1069-1079, 2020 06.
Article in English | MEDLINE | ID: mdl-31970483

ABSTRACT

BACKGROUND: Total serum 25-hydroxyvitamin D [25(OH)D] is considered the best marker of vitamin D status and used routinely in clinical practice. However, 25(OH)D is predominantly bound to vitamin D-binding protein (VDBP), and it has been reported that the free-25(OH)D and 25(OH)D loosely bound to albumin fraction correlates better with clinical outcomes. METHODS: We assessed total-25(OH)D, measured free-25(OH)D, and calculated free-25(OH)D and their relationship with VDBP and biomarkers of mineral metabolism in 61 children (22 CKD 2-3, 18 dialysis, and 21 post-transplant). RESULTS: Total-25(OH)D concentrations were comparable across the three groups (p = 0.09), but free- and bioavailable-25(OH)D (free- and albumin-25(OH)D) were significantly lower in the transplant group (both: p = 0.01). Compared to CKD and dialysis patients, the transplant group had significantly higher VDBP concentrations (p = 0.03). In all three groups, total-25(OH)D concentrations were positively associated with measured free-, calculated free-, and bioavailable-25(OH)D. Multivariable regression analysis showed that total-25(OH)D was the only predictor of measured free-25(OH)D concentrations in the dialysis group (ß = 0.9; R2 = 90%). In the transplant group, measured free-25(OH)D concentrations were predicted by both total-25(OH)D and VDBP concentrations (ß = 0.6, - 0.6, respectively; R2 = 80%). Correlations between parathyroid hormone with total-25(OH)D and measured and calculated free-25(OH)D were only observed in the transplant group (all: p < 0.001). CONCLUSIONS: In transplanted patients, VDBP concentrations were significantly higher compared to CKD and dialysis patients, and consequently, free-25(OH)D concentrations were lower, despite a comparable total-25(OH)D concentration. We suggest that free-25(OH)D measures may be required in children with CKD, dialysis, and transplant, with further research required to understand its association with markers of mineral metabolism.


Subject(s)
Renal Insufficiency, Chronic/blood , Vitamin D-Binding Protein/blood , Vitamin D/analogs & derivatives , Adolescent , Biomarkers/blood , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Kidney Transplantation , Male , Renal Dialysis , Renal Insufficiency, Chronic/complications , Vitamin D/blood , Vitamin D Deficiency/blood , Vitamin D Deficiency/complications
7.
Elife ; 82019 12 06.
Article in English | MEDLINE | ID: mdl-31808745

ABSTRACT

Heterogeneity of lymphatic vessels during embryogenesis is critical for organ-specific lymphatic function. Little is known about lymphatics in the developing kidney, despite their established roles in pathology of the mature organ. We performed three-dimensional imaging to characterize lymphatic vessel formation in the mammalian embryonic kidney at single-cell resolution. In mouse, we visually and quantitatively assessed the development of kidney lymphatic vessels, remodeling from a ring-like anastomosis under the nascent renal pelvis; a site of VEGF-C expression, to form a patent vascular plexus. We identified a heterogenous population of lymphatic endothelial cell clusters in mouse and human embryonic kidneys. Exogenous VEGF-C expanded the lymphatic population in explanted mouse embryonic kidneys. Finally, we characterized complex kidney lymphatic abnormalities in a genetic mouse model of polycystic kidney disease. Our study provides novel insights into the development of kidney lymphatic vasculature; a system which likely has fundamental roles in renal development, physiology and disease.


Subject(s)
Kidney/metabolism , Lymphangiogenesis/genetics , Lymphatic Vessels/metabolism , Polycystic Kidney Diseases/genetics , Animals , Gene Expression Regulation, Developmental , Genetic Heterogeneity , Humans , Kidney/embryology , Kinetics , Lymphatic Vessels/embryology , Mammals/embryology , Mammals/genetics , Mammals/metabolism , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Polycystic Kidney Diseases/embryology , Polycystic Kidney Diseases/metabolism , Spatio-Temporal Analysis , Vascular Endothelial Growth Factor C/genetics , Vascular Endothelial Growth Factor C/metabolism
8.
J Pathol ; 246(4): 485-496, 2018 12.
Article in English | MEDLINE | ID: mdl-30125361

ABSTRACT

Planar cell polarity (PCP) pathways control the orientation and alignment of epithelial cells within tissues. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the normal differentiation of kidney glomeruli and tubules. Vangl2 has also been implicated in modifying the course of acquired glomerular disease, and here, we further explored how Vangl2 impacts on glomerular pathobiology in this context. Targeted genetic deletion of Vangl2 in mouse glomerular epithelial podocytes enhanced the severity of not only irreversible accelerated nephrotoxic nephritis but also lipopolysaccharide-induced reversible glomerular damage. In each proteinuric model, genetic deletion of Vangl2 in podocytes was associated with an increased ratio of active-MMP9 to inactive MMP9, an enzyme involved in tissue remodelling. In addition, by interrogating microarray data from two cohorts of renal patients, we report increased VANGL2 transcript levels in the glomeruli of individuals with focal segmental glomerulosclerosis, suggesting that the molecule may also be involved in certain human glomerular diseases. These observations support the conclusion that Vangl2 modulates glomerular injury, at least in part by acting as a brake on MMP9, a potentially harmful endogenous enzyme. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.


Subject(s)
Cell Polarity , Glomerulosclerosis, Focal Segmental/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Kidney Glomerulus/metabolism , Membrane Proteins/metabolism , Nephrosis, Lipoid/metabolism , Nerve Tissue Proteins/metabolism , Podocytes/metabolism , Adult , Animals , Case-Control Studies , Cells, Cultured , Disease Models, Animal , Enzyme Activation , Female , Glomerulosclerosis, Focal Segmental/genetics , Glomerulosclerosis, Focal Segmental/pathology , Glomerulosclerosis, Focal Segmental/physiopathology , Humans , Intracellular Signaling Peptides and Proteins/genetics , Kidney Glomerulus/pathology , Kidney Glomerulus/physiopathology , Male , Matrix Metalloproteinase 9/metabolism , Membrane Proteins/genetics , Mice, Inbred C57BL , Mice, Knockout , Middle Aged , Nephrosis, Lipoid/genetics , Nephrosis, Lipoid/pathology , Nephrosis, Lipoid/physiopathology , Nerve Tissue Proteins/deficiency , Nerve Tissue Proteins/genetics , Podocytes/pathology , Signal Transduction , Young Adult
9.
Cell Death Discov ; 4: 13, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29531810

ABSTRACT

Kidney function is directly linked to the number of nephrons which are generated until 32-36 weeks gestation in humans. Failure to make nephrons during development leads to congenital renal malformations, whilst nephron loss in adulthood occurs in progressive renal disease. Therefore, an understanding of the molecular processes which underlie human nephron development may help design new treatments for renal disease. Mesenchyme to epithelial transition (MET) is critical for forming nephrons, and molecular pathways which control rodent MET have been identified. However, we do not know whether they are relevant in human kidney development. In this study, we isolated mesenchymal cell lines derived from human first trimester kidneys in monolayer culture and investigated their differentiation potential. We found that the mesenchymal cells could convert into osteogenic, but not adipogenic or endothelial lineages. Furthermore, addition of lithium chloride led to MET which was accompanied by increases in epithelial (CDH1) and tubular (ENPEP) markers and downregulation of renal progenitor (SIX2, EYA1, CD133) and mesenchymal markers (HGF, CD24). Prior to phenotypic changes, lithium chloride altered Wnt signalling with elevations in AXIN2, GSK3ß phosphorylation and ß-catenin. Collectively, these studies provide the first evidence that lithium-induced Wnt activation causes MET in human kidneys. Therapies targeting Wnts may be critical in the quest to regenerate nephrons for human renal diseases.

10.
J Am Soc Nephrol ; 27(1): 69-77, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26038530

ABSTRACT

Polycystic kidney diseases (PKD) are genetic disorders characterized by progressive epithelial cyst growth leading to destruction of normally functioning renal tissue. Current therapies have focused on the cyst epithelium, and little is known about how the blood and lymphatic microvasculature modulates cystogenesis. Hypomorphic Pkd1(nl/nl) mice were examined, showing that cystogenesis was associated with a disorganized pericystic network of vessels expressing platelet/endothelial cell adhesion molecule 1 and vascular endothelial growth factor receptor 3 (VEGFR3). The major ligand for VEGFR3 is VEGFC, and there were lower levels of Vegfc mRNA within the kidneys during the early stages of cystogenesis in 7-day-old Pkd1(nl/nl) mice. Seven-day-old mice were treated with exogenous VEGFC for 2 weeks on the premise that this would remodel both the VEGFR3(+) pericystic vascular network and larger renal lymphatics that may also affect the severity of PKD. Treatment with VEGFC enhanced VEGFR3 phosphorylation in the kidney, normalized the pattern of the pericystic network of vessels, and widened the large lymphatics in Pkd1(nl/nl) mice. These effects were associated with significant reductions in cystic disease, BUN and serum creatinine levels. Furthermore, VEGFC administration reduced M2 macrophage pericystic infiltrate, which has been implicated in the progression of PKD. VEGFC administration also improved cystic disease in Cys1(cpk/cpk) mice, a model of autosomal recessive PKD, leading to a modest but significant increase in lifespan. Overall, this study highlights VEGFC as a potential new treatment for some aspects of PKD, with the possibility for synergy with current epithelially targeted approaches.


Subject(s)
Polycystic Kidney Diseases/drug therapy , Vascular Endothelial Growth Factor C/therapeutic use , Animals , Mice , Polycystic Kidney Diseases/etiology , Vascular Endothelial Growth Factor C/physiology
11.
Stat Med ; 34(20): 2794-819, 2015 Sep 10.
Article in English | MEDLINE | ID: mdl-25924975

ABSTRACT

Availability of individual patient-level data (IPD) broadens the scope of network meta-analysis (NMA) and enables us to incorporate patient-level information. Although IPD is a potential gold mine in biomedical areas, methodological development has been slow owing to limited access to such data. In this paper, we propose a Bayesian IPD NMA modeling framework for multiple continuous outcomes under both contrast-based and arm-based parameterizations. We incorporate individual covariate-by-treatment interactions to facilitate personalized decision making. Furthermore, we can find subpopulations performing well with a certain drug in terms of predictive outcomes. We also impute missing individual covariates via an MCMC algorithm. We illustrate this approach using diabetes data that include continuous bivariate efficacy outcomes and three baseline covariates and show its practical implications. Finally, we close with a discussion of our results, a review of computational challenges, and a brief description of areas for future research.


Subject(s)
Biomarkers , Diabetes Mellitus/therapy , Medical Records , Meta-Analysis as Topic , Algorithms , Bayes Theorem , Humans , Middle Aged , Outcome Assessment, Health Care/statistics & numerical data
12.
J Am Soc Nephrol ; 26(12): 3021-34, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25896609

ABSTRACT

Glomerular disease often features altered histologic patterns of extracellular matrix (ECM). Despite this, the potential complexities of the glomerular ECM in both health and disease are poorly understood. To explore whether genetic background and sex determine glomerular ECM composition, we investigated two mouse strains, FVB and B6, using RNA microarrays of isolated glomeruli combined with proteomic glomerular ECM analyses. These studies, undertaken in healthy young adult animals, revealed unique strain- and sex-dependent glomerular ECM signatures, which correlated with variations in levels of albuminuria and known predisposition to progressive nephropathy. Among the variation, we observed changes in netrin 4, fibroblast growth factor 2, tenascin C, collagen 1, meprin 1-α, and meprin 1-ß. Differences in protein abundance were validated by quantitative immunohistochemistry and Western blot analysis, and the collective differences were not explained by mutations in known ECM or glomerular disease genes. Within the distinct signatures, we discovered a core set of structural ECM proteins that form multiple protein-protein interactions and are conserved from mouse to man. Furthermore, we found striking ultrastructural changes in glomerular basement membranes in FVB mice. Pathway analysis of merged transcriptomic and proteomic datasets identified potential ECM regulatory pathways involving inhibition of matrix metalloproteases, liver X receptor/retinoid X receptor, nuclear factor erythroid 2-related factor 2, notch, and cyclin-dependent kinase 5. These pathways may therefore alter ECM and confer susceptibility to disease.


Subject(s)
Extracellular Matrix/genetics , Extracellular Matrix/metabolism , Kidney Diseases/genetics , Kidney Glomerulus/metabolism , Albuminuria/genetics , Albuminuria/metabolism , Animals , Collagen Type I/genetics , Collagen Type I/metabolism , Cyclin-Dependent Kinase 5/metabolism , Extracellular Matrix/ultrastructure , Female , Fibroblast Growth Factor 2/genetics , Fibroblast Growth Factor 2/metabolism , Genetic Predisposition to Disease , Glomerular Basement Membrane/ultrastructure , Kidney Diseases/metabolism , Liver X Receptors , Male , Matrix Metalloproteinases/metabolism , Metalloendopeptidases/genetics , Metalloendopeptidases/metabolism , Mice , Mice, Inbred Strains , NF-E2-Related Factor 2/metabolism , Nerve Growth Factors/genetics , Nerve Growth Factors/metabolism , Netrins , Oligonucleotide Array Sequence Analysis , Orphan Nuclear Receptors/metabolism , RNA/analysis , Sex Factors , Signal Transduction , Tenascin/genetics , Tenascin/metabolism
13.
Pharm Stat ; 13(1): 94-100, 2014.
Article in English | MEDLINE | ID: mdl-24446072

ABSTRACT

Unmeasured confounding is a common problem in observational studies. Failing to account for unmeasured confounding can result in biased point estimators and poor performance of hypothesis tests and interval estimators. We provide examples of the impacts of unmeasured confounding on cost-effectiveness analyses using observational data along with a Bayesian approach to correct estimation. Assuming validation data are available, we propose a Bayesian approach to correct cost-effectiveness studies for unmeasured confounding. We consider the cases where both cost and effectiveness are assumed to have a normal distribution and when costs are gamma distributed and effectiveness is normally distributed. Simulation studies were conducted to determine the impact of ignoring the unmeasured confounder and to determine the size of the validation data required to obtain valid inferences.


Subject(s)
Bayes Theorem , Data Interpretation, Statistical , Computer Simulation , Confounding Factors, Epidemiologic , Cost-Benefit Analysis , Humans , Models, Statistical
14.
Pharm Stat ; 13(1): 55-70, 2014.
Article in English | MEDLINE | ID: mdl-24038897

ABSTRACT

The Drug Information Association Bayesian Scientific Working Group (BSWG) was formed in 2011 with a vision to ensure that Bayesian methods are well understood and broadly utilized for design and analysis and throughout the medical product development process, and to improve industrial, regulatory, and economic decision making. The group, composed of individuals from academia, industry, and regulatory, has as its mission to facilitate the appropriate use and contribute to the progress of Bayesian methodology. In this paper, the safety sub-team of the BSWG explores the use of Bayesian methods when applied to drug safety meta-analysis and network meta-analysis. Guidance is presented on the conduct and reporting of such analyses. We also discuss different structural model assumptions and provide discussion on prior specification. The work is illustrated through a case study involving a network meta-analysis related to the cardiovascular safety of non-steroidal anti-inflammatory drugs.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Bayes Theorem , Meta-Analysis as Topic , Cardiovascular Diseases/chemically induced , Drug Discovery , Humans
15.
J Am Soc Nephrol ; 25(1): 33-42, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24009238

ABSTRACT

Vascular growth factors play an important role in maintaining the structure and integrity of the glomerular filtration barrier. In healthy adult glomeruli, the proendothelial survival factors vascular endothelial growth factor-A (VEGF-A) and angiopoietin-1 are constitutively expressed in glomerular podocyte epithelia. We demonstrate that this milieu of vascular growth factors is altered in streptozotocin-induced type 1 diabetic mice, with decreased angiopoietin-1 levels, VEGF-A upregulation, decreased soluble VEGF receptor-1 (VEGFR1), and increased VEGFR2 phosphorylation. This was accompanied by marked albuminuria, nephromegaly, hyperfiltration, glomerular ultrastructural alterations, and aberrant angiogenesis. We subsequently hypothesized that restoration of angiopoietin-1 expression within glomeruli might ameliorate manifestations of early diabetic glomerulopathy. Podocyte-specific inducible repletion of angiopoietin-1 in diabetic mice caused a 70% reduction of albuminuria and prevented diabetes-induced glomerular endothelial cell proliferation; hyperfiltration and renal morphology were unchanged. Furthermore, angiopoietin-1 repletion in diabetic mice increased Tie-2 phosphorylation, elevated soluble VEGFR1, and was paralleled by a decrease in VEGFR2 phosphorylation and increased endothelial nitric oxide synthase Ser(1177) phosphorylation. Diabetes-induced nephrin phosphorylation was also reduced in mice with angiopoietin-1 repletion. In conclusion, targeted angiopoietin-1 therapy shows promise as a renoprotective tool in the early stages of diabetic kidney disease.


Subject(s)
Angiopoietin-1/metabolism , Diabetic Nephropathies/metabolism , Diabetic Nephropathies/therapy , Molecular Targeted Therapy , Angiopoietin-1/deficiency , Angiopoietin-1/genetics , Angiopoietin-2/genetics , Angiopoietin-2/metabolism , Animals , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Experimental/therapy , Diabetic Nephropathies/pathology , Humans , Intracellular Signaling Peptides and Proteins/deficiency , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Male , Membrane Proteins/deficiency , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Mice, Mutant Strains , Podocytes/metabolism , Podocytes/pathology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction , Vascular Endothelial Growth Factor Receptor-1/metabolism , Vascular Endothelial Growth Factor Receptor-2/metabolism
16.
Pediatr Nephrol ; 29(4): 665-72, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24221350

ABSTRACT

Strategies to facilitate repair or generate new nephrons are exciting prospects for acute and chronic human renal disease. Repair of kidney injury involves not just local mechanisms but also mobilisation of progenitor/stem cells from intrarenal niches, including papillary, tubular and glomerular locations. Diverse markers characterise these unique cells, often including CD24 and CD133. Extrarenal stem cells may also contribute to repair, with proposed roles in secreting growth factors, transfer of microvesicles and exosomes and immune modulation. Creating new nephrons from stem cells is beginning to look feasible in mice in which kidneys can be dissociated into single cells and will then generate mature renal structures when recombined. The next step is to identify the correct human markers for progenitor cells from the fetus or mature kidney with similar potential to form new kidneys. Intriguingly, development can continue in vivo: whole foetal kidneys and recombined organs engraft, develop a blood supply and grow when xenotransplanted, and there are new advances in decellularised scaffolds to promote differentiation. This is an exciting time for human kidney repair and regeneration. Many of the approaches and techniques are in their infancy and based on animal rather than human work, but there is a rapid pace of discovery, and we predict that therapies based on advances in this field will come into clinical practice in the next decade.


Subject(s)
Kidney/cytology , Stem Cells/cytology , Tissue Engineering/methods , Tissue Engineering/trends , Animals , Humans , Transplantation, Heterologous/methods , Transplantation, Heterologous/trends
17.
Pharm Stat ; 13(1): 13-24, 2014.
Article in English | MEDLINE | ID: mdl-23897858

ABSTRACT

Safety assessment is essential throughout medical product development. There has been increased awareness of the importance of safety trials recently, in part due to recent US Food and Drug Administration guidance related to thorough assessment of cardiovascular risk in the treatment of type 2 diabetes. Bayesian methods provide great promise for improving the conduct of safety trials. In this paper, the safety subteam of the Drug Information Association Bayesian Scientific Working Group evaluates challenges associated with current methods for designing and analyzing safety trials and provides an overview of several suggested Bayesian opportunities that may increase efficiency of safety trials along with relevant case examples.


Subject(s)
Bayes Theorem , Clinical Trials as Topic , Drug-Related Side Effects and Adverse Reactions , Research Design , Humans , Meta-Analysis as Topic , Risk Assessment , Sample Size
18.
Kidney Int ; 83(6): 1118-29, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23447063

ABSTRACT

Normally, the glomerular filtration barrier almost completely excludes circulating albumin from entering the urine. Genetic variation and both pre- and postnatal environmental factors may affect albuminuria in humans. Here we determine whether glomerular gene expression in mouse strains with naturally occurring variations in albuminuria would allow identification of proteins deregulated in relatively 'leaky' glomeruli. Albuminuria increased in female B6 to male B6 to female FVB/N to male FVB/N mice, whereas the number of glomeruli/kidney was the exact opposite. Testosterone administration led to increased albuminuria in female B6 but not female FVB/N mice. A common set of 39 genes, many expressed in podocytes, were significantly differentially expressed in each of the four comparisons: male versus female B6 mice, male versus female FVB/N mice, male FVB/N versus male B6 mice, and female FVB/N versus female B6 mice. The transcripts encoded proteins involved in oxidation/reduction reactions, ion transport, and enzymes involved in detoxification. These proteins may represent novel biomarkers and even therapeutic targets for early kidney and cardiovascular disease.


Subject(s)
Albuminuria/etiology , Kidney Glomerulus/metabolism , Testosterone/metabolism , Albuminuria/genetics , Albuminuria/pathology , Albuminuria/urine , Animals , Blood Pressure , Cells, Cultured , Female , Gene Expression Profiling , Gene Expression Regulation , Genotype , Glomerular Filtration Barrier/metabolism , Kidney Glomerulus/pathology , Male , Mice , Mice, Inbred C57BL , Permeability , Phenotype , Podocytes/metabolism , RNA, Messenger/metabolism , Sex Factors , Species Specificity
19.
PLoS One ; 8(2): e56273, 2013.
Article in English | MEDLINE | ID: mdl-23409162

ABSTRACT

Cardiovascular disease (CVD) is increasingly recognised as a complication of childhood chronic kidney disease (CKD) even in the absence of diabetes and hypertension. We hypothesized that an alteration in angiopoietin-1 and -2, growth factors which regulate endothelial and vascular function could be involved. We report that the endothelial survival factor, angiopoietin-1 is low in children with pre-dialysis CKD whereas the pro-inflammatory angiopoietin-2 is elevated in children on dialysis. In dialysis patients, angiopoietin-2 positively correlated with time on dialysis, systolic blood pressure, and carotid artery intima media thickness. Elevated angiopoietin-2 levels in dialysis versus pre-dialysis CKD patients were also associated with an anti-angiogenic (high soluble VEGFR-1 and low VEGF-A) and pro-inflammatory (high urate, E-selectin, P-selectin and VCAM-1) milieu. Ang-2 was immunodetected in arterial biopsy samples whilst the expression of VEGF-A was significantly downregulated in dialysis patients. Serum urate correlated with angiopoietin-2 levels in dialysis patients and addition of uric acid was able to induce rapid release of angiopoietin-2 from cultured endothelial cells. Thus, angiopoietin-2 is a marker for cardiovascular disease in children on chronic dialysis and may act as an anti-angiogenic and pro-inflammatory effector in this context. The possibility that the release of angiopoietin-2 from endothelia is mediated by urate should be explored further.


Subject(s)
Angiopoietin-2/blood , Cardiovascular Diseases/complications , Renal Dialysis , Renal Insufficiency, Chronic/blood , Renal Insufficiency, Chronic/therapy , Adolescent , Angiopoietin-2/metabolism , Arteries/metabolism , Arteries/pathology , Biomarkers/blood , Cell Adhesion Molecules/blood , Cell Adhesion Molecules/chemistry , Child , Female , Human Umbilical Vein Endothelial Cells/drug effects , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Male , Renal Insufficiency, Chronic/pathology , Solubility , Time Factors , Uric Acid/pharmacology , Vascular Endothelial Growth Factor A/blood , Vascular Endothelial Growth Factor Receptor-1/blood
20.
J Biopharm Stat ; 23(1): 26-42, 2013.
Article in English | MEDLINE | ID: mdl-23331219

ABSTRACT

Patients and prescribers need to be fully informed regarding the safety profile of approved medications. This includes knowledge and information regarding whether an adverse event of interest exhibits a potential dose-response relationship. In order to thoroughly evaluate whether an adverse event rate increases with increasing dose level, evidence from multiple clinical trials needs to be combined and analyzed. The various clinical trials that need to be combined often include different dose levels. If one evaluates the dose-response relationship by including only the trials with all of the common dose levels, this will lead to the exclusion of potentially several clinical trials as well as dose levels, and thus the loss of important information. Other methods, such as crudely pooling patients on the same dose level across different studies, are subject to bias due to the breakdown of randomization. It is preferable to include all studies and relevant dose levels, even if all studies do not contain the same dose levels. Bayesian methodology has been shown to be useful in the context of indirect and mixed treatment comparison methods, to combine information from different therapies in different studies in order to make treatment effect inferences. This type of approach is foundational to the models presented here, but instead of modeling different dose arms in different studies, we extend the methodology to allow for assessment of the dose-response relationship across multiple clinical trials. In this paper, we propose three Bayesian indirect/mixed treatment comparison models to assess adverse event dose-response relationships. These three models are designed to handle binary responses and time to event responses. We apply the methods to real data sets and demonstrate that our proposed methods are useful in discovering potential dose-response relationships.


Subject(s)
Drug-Related Side Effects and Adverse Reactions , Models, Theoretical , Pharmaceutical Preparations/administration & dosage , Bayes Theorem , Dose-Response Relationship, Drug , Humans , Randomized Controlled Trials as Topic/methods , Treatment Outcome
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