Publications

BACKGROUND

A-kinase anchoring proteins (AKAPs) are scaffolding molecules that coordinate and integrate G-protein signaling events to regulate development, physiology, and disease. One family member, AKAP13, encodes for multiple protein isoforms that contain binding sites for protein kinase A (PKA) and D (PKD) and an active Rho-guanine nucleotide exchange factor (Rho-GEF) domain. In mice, AKAP13 is required for development as null embryos die by embryonic day 10.5 with cardiovascular phenotypes. Additionally, the AKAP13 Rho-GEF and PKD-binding domains mediate cardiomyocyte hypertrophy in cell culture. However, the requirements for the Rho-GEF and PKD-binding domains during development and cardiac hypertrophy are unknown.

METHODOLOGY/PRINCIPAL FINDINGS

To determine if these AKAP13 protein domains are required for development, we used gene-trap events to create mutant mice that lacked the Rho-GEF and/or the protein kinase D-binding domains. Surprisingly, heterozygous matings produced mutant mice at Mendelian ratios that had normal viability and fertility. The adult mutant mice also had normal cardiac structure and electrocardiograms. To determine the role of these domains during β-adrenergic-induced cardiac hypertrophy, we stressed the mice with isoproterenol. We found that heart size was increased similarly in mice lacking the Rho-GEF and PKD-binding domains and wild-type controls. However, the mutant hearts had abnormal cardiac contractility as measured by fractional shortening and ejection fraction.

CONCLUSIONS

These results indicate that the Rho-GEF and PKD-binding domains of AKAP13 are not required for mouse development, normal cardiac architecture, or β-adrenergic-induced cardiac hypertrophic remodeling. However, these domains regulate aspects of β-adrenergic-induced cardiac hypertrophy.

In this issue of Blood, Leonhardt et al report that neovascularization during graft-versus-host disease (GVHD) is regulated by av integrins and the micro RNA miR-100.

BACKGROUND

The long-term consequences of unsuccessful interferon-α based hepatitis C treatment on liver disease progression and survival have not been fully explored.

METHODS AND FINDINGS

We performed retrospective analyses to assess long-term clinical outcomes among treated and untreated patients with hepatitis C virus in two independent cohorts from a United States Veterans Affairs Medical Center and a University Teaching Hospital. Eligible patients underwent liver biopsy during consideration for interferon-α based treatment between 1992 and 2007. They were assessed for the probability of developing cirrhosis and of dying during follow-up using Cox proportional hazards models, stratified by pretreatment liver fibrosis stage and adjusted for known risk factors for cirrhosis and characteristics affecting treatment selection. The major predictor was a time-dependent covariate for treatment outcome among four patient groups: 1) patients with sustained virological response to treatment; 2) treatment relapsers; 3) treatment nonresponders; and 4) never treated patients. Treatment nonresponders in both cohorts had a statistically significantly increased hazard of cirrhosis compared to never treated patients, as stratified by pretreatment liver fibrosis stage and adjusted for clinical and psychosocial risk factors that disproportionately affect patients who were ineligible for treatment (Veterans Affairs HR=2.35, CI 1.18-4.69, mean follow-up 10 years, and University Hospital HR=5.90, CI 1.50-23.24, mean follow-up 7.7 years). Despite their increased risk for liver disease progression, the overall survival of nonresponders in both cohorts was not significantly different from that of never treated patients.

CONCLUSION

These unexpected findings suggest that patients who receive interferon-α based therapies but fail to clear the hepatitis C virus may have an increased hazard of cirrhosis compared to untreated patients.

Strategies to effectively treat people with CKD have been identified by conventional clinical research. Despite this evidence, awareness, screening, detection, diagnosis, risk factor control, treatment, and outcomes remain substandard. Translating clinical evidence into actionable measures that reduce the burden of CKD is a pressing need. Expansion from a "bench-to-bedside" paradigm (conventional type 1 translation) to research that encompasses "clinic and community" is the core concept of type 2 translation. Specifically, this is the discipline of identifying factors and using strategies that lead to adoption, maintenance, and sustainability of science-based interventions in practice. This review identifies key elements of type 2 translational research and highlights the current scope of this type of research for CKD. For type 2 translation to achieve the goals of providing high-quality care and better health outcomes, key facilitators (e.g., theory-based frameworks, adaptable interventions, and inclusion of sustainability and evaluation metrics) and essential elements (e.g., multidisciplinary team care, health information technology, and stakeholder engagement) must be integrated. The National Institute of Diabetes and Digestive and Kidney Diseases recently funded five proposals that aim to improve outcomes for people with CKD, focusing on diverse components of the healthcare continuum: patient safety and transitions; delivery of high-quality, evidence-based CKD care; and elimination of disparities. The need for type 2 translational research in CKD is urgent because of preventable human suffering and unsustainable costs of providing care. Focus on the theory, framework, and approaches we have suggested may help us meet that challenge.