Actin exposure upon tissue injury is a targetable wound site-specific protein marker.

BACKGROUND: Identification of wound-specific markers would represent an important step toward damaged tissue detection and targeted delivery of biologically important materials to injured sites. Such delivery could minimize the amount of therapeutic materials that must be administered and limit potential collateral damage on nearby normal tissues. Yet, biological markers that are specific for injured tissue sites remain elusive. METHODS: In this study, we have developed an immunohistological approach for identification of protein epitopes specifically exposed in wounded tissue sites. RESULTS: Using ex-vivo tissue samples in combination with fluorescently-labeled antibodies we show that actin, an intracellular cytoskeletal protein, is specifically exposed upon injury. The targetability of actin in injured sites has been demonstrated in vivo through the specific delivery of anti-actin conjugated particles to the wounded tissue in a lethal rat model of grade IV liver injury. CONCLUSIONS: These results illustrate that identification of injury-specific protein markers and their targetability for specific delivery is feasible. GENERAL SIGNIFICANCE: Identification of wound-specific targets has important medical applications as it could enable specific delivery of various products, such as expression vectors, therapeutic drugs, hemostatic materials, tissue healing, or scar prevention agents, to internal sites of penetrating or surgical wounds regardless of origin, geometry or location.

Benchmarking safety pharmacology regulatory packages and best practice.

INTRODUCTION: The objectives of this survey were to obtain a global information update regarding current industry perspectives that describe Safety Pharmacology programs as they relate to the ICH S7A and S7B regulatory guidelines but also to obtain a broader perspective of other practises practices in the field currently used by companies. Preliminary findings were presented at the 7th Annual Meeting of the Safety Pharmacology Society (SPS) (Edinburgh, Scotland, Sept 19-21, 2007). METHODS: The survey was distributed by the SPS to 125 pharmaceutical companies. Survey topics included (a) an update on ICH S7A and S7B practices, (b) frontloading Safety Pharmacology studies prior to selection of candidate drugs, (c) abuse and dependence-liability studies and (d) an extended evaluation of industry practises practices as assessed by Contract Research Organizations (CROs). RESULTS: Respondents (>94%) include GLP core battery (CV, CNS and respiratory) studies in the drug package submitted to regulatory agencies, and approximately 40% also submit studies on gastrointestinal and renal function. Respondents to the ICH S7B aspects indicate approximately 98% include the hERG assay and QT interval (in vivo) data in submissions, 63% include APD in vitro data and another 23% APD in vivo and other cardiac channel data (26%). SP frontloading is performed by 78% of all responding companies. Respondents indicate that 39% of these non-GLP CV studies are conducted before lead optimization (LO) and 85% during LO and before candidate drug selection. The hERG, CNS selectivity binding screens and rodent behavioral studies are frontloaded by 100%, 90% and 74% of respondents. Responding CROs (26) were surveyed on the services offered including Irwin or Functional Observational Battery (FOB) tests (70%), respiratory studies (85%), in vivo telemeterized dogs (69%) and in vitro CV studies (50%). Only 38% of SP studies are combined with toxicology studies at the CROs. DISCUSSION: The survey results indicate that ICH S7A core battery studies are implemented by most of the responding companies with a clear trend of an enhanced submission of renal and GI studies. The impact of ICH S7B is clear since, all respondents assess cardiac repolarization using cellular hERG (I(Kr)) and whole animal (QT interval) assays as a component of their safety assessment. Responses indicate a diversity of approaches for conducting abuse liability studies, which primarily use the methods of self-administration and drug discrimination. While early SP frontloading of studies seems to vary, the methods used appear to be generic to some extent and include in vitro 'off-target' evaluations and in vivo tests to determine the potential for CNS and cardiovascular issues.

Increased blood pressure in transgenic mice expressing both human renin and angiotensinogen in the renal proximal tubule.

The purpose of this study was to evaluate the physiological significance of a tissue renin-angiotensin system in the proximal tubule of the kidney. To accomplish this, we produced mice that express human renin (hREN) under the control of the kidney androgen-regulated promoter (KAP), which is androgen responsive. One of the lines expressed the hREN transgene primarily in the kidney. Renal expression of the transgene was undetectable in females but could be induced by testosterone treatment. Because the renin-angiotensin system is species specific, we bred KAP2-hREN mice with the mice expressing human angiotensinogen under the same promoter (KAP-hAGT) to produce offspring that expressed both transgenes. We measured mean arterial blood pressure (MAP) in the carotid artery of double-transgenic and control mice using radiotelemetry. Double-transgenic female mice had a normal baseline MAP (116 +/- 4 mmHg, n = 8), which increased by 15 mmHg after 2 wk of testosterone treatment, and returned to baseline after elimination of the testosterone pellet. The change in arterial pressure paralleled the change in plasma testosterone. There was no MAP change in testosterone-treated control littermates. We conclude that dual production of renin and angiotensinogen in the renal proximal tubule can result in a systemic increase in arterial pressure. These data support a role for a tissue-specific renin-angiotensin system in the renal proximal tubule that contributes to the regulation of systemic blood pressure.