Endothelial Cell Derived Extracellular Vesicles and Hematopoiesis.

Extracellular vesicles (EVs) have been recognized as a novel way of cell-to-cell communication in the last several decades. It is believed that EVs exert their functions on nearby or distant cells through transfer of the cargo that they carry. In this review, we focus on EVs produced by endothelial cells, with emphasis on their role in hematopoiesis. We first describe how endothelial cells interact with hematopoietic stem/progenitor cells during development and in disease conditions. We then discuss EVs, ranging from their subtypes to isolation methods and analysis of EVs. With the above background information, we next review the literature related to endothelial cell derived EVs (ECEVs), including physiological functions and their clinical uses. In the last sections, we summarize the current results about the effect of ECEVs on hematopoiesis under physiological and stress conditions.

Salsalate: a pleotropic anti-inflammatory drug in the treatment of diabetes, obesity, and metabolic diseases.

Type two Diabetes Mellitus (T2DM) is a rising epidemic. Available therapeutic strategies have provided glycaemic control via HbA1c reduction but fail to provide clinically meaningful reduction in microvascular and macrovascular (cardiac, renal, ophthalmological, and neurological) complications. Inflammation is strongly linked to the pathogenesis of T2DM. Underlying inflammatory mechanisms include oxidative stress, endoplasmic reticulum stress amyloid deposition in the pancreas, lipotoxicity, and glucotoxicity. Molecular signalling mechanisms in chronic inflammation linked to obesity and diabetes include JANK, NF-kB, and AMPK pathways. These activated pathways lead to a production of various inflammatory cytokines, such as Interleukin (IL-6), tumor necrosis factor (TNF)-alpha, and C-reactive protein (CRP), which create a chronic low-grade inflammation and ultimately dysregulation of glucose homeostasis in the liver, skeletal muscle, and smooth muscle. Anti-inflammatory agents are being tested as anti-diabetic agents such as the IL-1b antagonist, Anakinra, the IL-1b inhibitor, Canakinuma, the IL-6 antagonists such as Tocilizumab, Rapamycin (Everolimus), and the IKK-beta kinase inhibitor, Salsalate. Salsalate is a century old safe anti-inflammatory drug used in the treatment of arthritis. Long-term safety and efficacy of Salsalate in the treatment of T2DM have been evaluated, which showed improved fasting plasma glucose and reduced HbA1C levels as well as reduced pro-inflammatory markers in T2DM patients. Current publication summarizes the literature review of pathophysiology of role of inflammation in T2DM and clinical efficacy and safety of Salsalate in the treatment of T2DM.

Muscle injury induces a transient senescence-like state that is required for myofiber growth during muscle regeneration.

Cellular senescence is the irreversible arrest of normally dividing cells and is driven by the cell cycle inhibitors Cdkn2a, Cdkn1a, and Trp53. Senescent cells are implicated in chronic diseases and tissue repair through their increased secretion of pro-inflammatory factors known as the senescence-associated secretory phenotype (SASP). Here, we use spatial transcriptomics and single-cell RNA sequencing (scRNAseq) to demonstrate that cells displaying senescent characteristics are "transiently" present within regenerating skeletal muscle and within the muscles of D2-mdx mice, a model of Muscular Dystrophy. Following injury, multiple cell types including macrophages and fibrog-adipogenic progenitors (FAPs) upregulate senescent features such as senescence pathway genes, SASP factors, and senescence-associated beta-gal (SA-ß-gal) activity. Importantly, when these cells were removed with ABT-263, a senolytic compound, satellite cells are reduced, and muscle fibers were impaired in growth and myonuclear accretion. These results highlight that an "acute" senescent phenotype facilitates regeneration similar to skin and neonatal myocardium.

Fibrinogen-Coated Albumin Nanospheres Prevent Thrombocytopenia-Related Bleeding.

Thrombocytopenia (TCP) may cause severe and life-threatening bleeding. While this may be prevented by platelet transfusions, transfusions are associated with potential complications, do not always work (platelet refractory) and are not always available. There is an urgent need for a synthetic alternative. We evaluated the ability of fibrinogen-coated nanospheres (FCNs) to prevent TCP-related bleeding. FCNs are made of human albumin polymerized into a 100-nm sphere and coated with fibrinogen. We hypothesized that FCNs would bind to platelets through fibrinogen-GPIIb/IIIa interactions, contributing to hemostasis in the setting of TCP. We used two murine models to test these effects: in the first model, BALB/c mice received 7.25 Gy total-body irradiation (TBI); in the second model, lower dose TBI (7.0 Gy) was combined with an anti-platelet antibody (anti-CD41) to induce severe TCP. Deaths in both models were due to gastrointestinal or intracranial bleeding. Addition of antiplatelet antibody to 7.0 Gy TBI significantly worsened TCP and increased mortality compared to 7.0 Gy TBI alone. FCNs significantly improved survival compared to saline control in both models, suggesting it ameliorated TCP-related bleeding. Additionally, in a saphenous vein bleeding model of antibody-induced TCP, FCNs shortened bleeding times. There were no clinical or histological findings of thrombosis or laboratory findings of disseminated intravascular coagulation after FCN treatment. In support of safety, fluorescence microscopy suggests that FCNs bind to platelets only upon platelet activation with collagen, limiting activity to areas of endothelial damage. To our knowledge, this is the first biosynthetic agent to demonstrate a survival advantage in TCP-related bleeding.

Bridging the gaps: using an NHP model to predict single dose radiation absorption in humans.

Purpose: Design and characterization of a radiation biodosimetry device are complicated by the fact that the requisite data are not available in the intended use population, namely humans exposed to a single, whole-body radiation dose. Instead, one must turn to model systems. We discuss our studies utilizing healthy, unexposed humans, human bone marrow transplant patients undergoing total body irradiation (TBI), non-human primates subjected to the same irradiation regimen received by the human TBI patients and NHPs given a single, whole-body dose of ionizing radiation.Materials and Methods: We use Bayesian linear mixed models to characterize the association between NHP and human expression patterns in radiation response genes when exposed to a common exposure regimen and across exposure regimens within the same species.Results: We show that population average differences in expression of our radiation response genes from one to another model system are comparable to typical differences between two randomly sampled members of a given model system and that these differences are smaller, on average, for linear combinations of the probe data and for the model-based combinations employed for dose prediction as part of a radiation biodosimetry device.Conclusions: Our analysis suggests that dose estimates based on our gene list will be accurate when applied to humans who have received a single, whole-body exposure to ionizing radiation.

Role of Tau Acetylation in Alzheimer's Disease and Chronic Traumatic Encephalopathy: The Way Forward for Successful Treatment.

Progressive neurodegenerative diseases plague millions of individuals both in the United States and across the world. The current pathology of progressive neurodegenerative tauopathies, such as Alzheimer's disease (AD), Pick's disease, frontotemporal dementia (FTD), and progressive supranuclear palsy, primarily revolves around phosphorylation and hyperphosphorylation of the tau protein. However, more recent evidence suggests acetylation of tau protein at lysine 280 may be a critical step in molecular pathology of these neurodegenerative diseases prior to the tau hyperphosphorylation. Secondary injury cascades such as oxidative stress, endoplasmic reticulum stress, and neuroinflammation contribute to lasting damage within the brain and can be induced by a number of different risk factors. These injury cascades funnel into a common pathway of early tau acetylation, which may serve as the catalyst for progressive degeneration. The post translational modification of tau can result in production of toxic oligomers, contributing to reduced solubility as well as aggregation and formation of neurofibrillary tangles, the hallmark of AD pathology. Chronic Traumatic Encephalopathy (CTE), caused by repetitive brain trauma is also associated with a hyperphosphorylation of tau. We postulated acetylation of tau at lysine 280 in CTE disease could be present prior to the hyperphosphorylation and tested this hypothesis in CTE pathologic specimens. We also tested for ac-tau 280 in early stage Alzheimer's disease (Braak stage 1). Histopathological examination using the ac tau 280 antibody was performed in three Alzheimer's cases and three CTE patients. Presence of ac-tau 280 was confirmed in all cases at early sites of disease manifestation. These findings suggest that tau acetylation may precede tau phosphorylation and could be the first "triggering" event leading to neuronal loss. To the best of our knowledge, this is the first study to identify acetylation of the tau protein in CTE. Prevention of tau acetylation could possibly serve as a novel target for stopping neurodegeneration before it fully begins. In this study, we highlight what is known about tau acetylation and neurodegeneration.

Intra-Abdominal Hemorrhage Complicating Electrothermal Arterial Injury During Pelvic Surgery: A Case Report.

Iatrogenic vascular injury is a potentially serious complication of surgical procedures. Here we report a case of delayed fatal intra-abdominal hemorrhage because of electrocautery injury of a right external iliac artery. The decedent, a 31-year-old woman, died suddenly on postoperative day 1 after a laparoscopic staging operation for an ovarian tumor. Her past medical history included a recent diagnosis of a microinvasive carcinoma in the background of a mucinous cystic neoplasm of the right ovary. Postmortem examination revealed a young woman with evidence of emergency intervention, recent laparoscopic pelvic surgery, and pale hypostasis limited to the back surfaces of the body. The internal examination confirmed the postmortem computed tomography findings of a large amount of blood in the pelvic and abdominal cavities and evidence of recent surgical intervention. The soft tissues around the aorta and major pelvic vessels showed electrocautery change and marked perivascular hemorrhage preferentially surrounding the right external iliac artery. Histological examination of the vascular bundle showed an electrocautery injury of the arterial wall: transmural necrosis, acute inflammation, and hemorrhage. In this report, we offer an approach to a postmortem examination in postoperative deaths with emphasis on deaths due to iatrogenic vascular injuries and discuss the rationale for determining the manner of death.

Performance of [18F]flutemetamol amyloid imaging against the neuritic plaque component of CERAD and the current (2012) NIA-AA recommendations for the neuropathologic diagnosis of Alzheimer's disease.

INTRODUCTION: Performance of the amyloid tracer [18F]flutemetamol was evaluated against three pathology standard of truth (SoT) measures including neuritic plaques (CERAD "original" and "modified" and the amyloid component of the 2012 NIA-AA guidelines). METHODS: After [18F]flutemetamol imaging, 106 end-of-life patients who died underwent postmortem brain examination for amyloid plaque load. Blinded positron emission tomography scan interpretations by five independent electronically trained readers were compared with pathology measures. RESULTS: By SoT, sensitivity and specificity of majority image interpretations were, respectively, 91.9% and 87.5% with "original CERAD," 90.8% and 90.0% with "modified CERAD," and 85.7% and 100% with the 2012 NIA-AA criteria. DISCUSSION: The high accuracy of either CERAD criteria suggests that [18F]flutemetamol predominantly reflects neuritic amyloid plaque density. However, the use of CERAD criteria as the SoT can result in some false-positive results because of the presence of diffuse plaques, which are accounted for when the positron emission tomography read is compared with the 2012 NIA-AA criteria.

Phase 3 trial of flutemetamol labeled with radioactive fluorine 18 imaging and neuritic plaque density.

IMPORTANCE: In vivo imaging of brain ß-amyloid, a hallmark of Alzheimer disease, may assist in the clinical assessment of suspected Alzheimer disease. OBJECTIVE: To determine the sensitivity and specificity of positron emission tomography imaging with flutemetamol injection labeled with radioactive fluorine 18 to detect ß-amyloid in the brain using neuropathologically determined neuritic plaque levels as the standard of truth. DESIGN, SETTING, AND PARTICIPANTS: Open-label multicenter imaging study that took place at dementia clinics, memory centers, and hospice centers in the United States and England from June 22, 2010, to November 23, 2011. Participants included terminally ill patients who were 55 years or older with a life expectancy of less than 1 year. INTERVENTIONS: Flutemetamol injection labeled with radioactive fluorine 18 (Vizamyl; GE Healthcare) administration followed by positron emission tomography imaging and subsequent brain donation. MAIN OUTCOMES AND MEASURES: Sensitivity and specificity of flutemetamol injection labeled with radioactive fluorine 18 positron emission tomography imaging for brain ß-amyloid. Images were reviewed without and with computed tomography scans and classified as positive or negative for ß-amyloid by 5 readers who were blind to patient information. In patients who died, neuropathologically determined neuritic plaque levels were used to confirm scan interpretations and determine sensitivity and specificity. RESULTS: Of 176 patients with evaluable images, 68 patients (38%) died during the study, were autopsied, and had neuritic plaque levels determined; 25 brains (37%) were ß-amyloid negative; and 43 brains (63%) were ß-amyloid positive. Imaging was performed a mean of 3.5 months (range, 0 to 13 months) before death. Sensitivity without computed tomography was 81% to 93% (median, 88%). Median specificity was 88%, with 4 of 5 of the readers having specificity greater than 80%. When scans were interpreted with computed tomography images, sensitivity and specificity improved for most readers but the differences were not significant. The area under the receiver operating curve was 0.90. There were no clinically meaningful findings in safety parameters. CONCLUSIONS AND RELEVANCE: This study showed that flutemetamol injection labeled with radioactive fluorine 18 was safe and had high sensitivity and specificity in an end-of-life population. In vivo detection of brain ß-amyloid plaque density may increase diagnostic accuracy in cognitively impaired patients.

A translatable predictor of human radiation exposure.

Terrorism using radiological dirty bombs or improvised nuclear devices is recognized as a major threat to both public health and national security. In the event of a radiological or nuclear disaster, rapid and accurate biodosimetry of thousands of potentially affected individuals will be essential for effective medical management to occur. Currently, health care providers lack an accurate, high-throughput biodosimetric assay which is suitable for the triage of large numbers of radiation injury victims. Here, we describe the development of a biodosimetric assay based on the analysis of irradiated mice, ex vivo-irradiated human peripheral blood (PB) and humans treated with total body irradiation (TBI). Interestingly, a gene expression profile developed via analysis of murine PB radiation response alone was inaccurate in predicting human radiation injury. In contrast, generation of a gene expression profile which incorporated data from ex vivo irradiated human PB and human TBI patients yielded an 18-gene radiation classifier which was highly accurate at predicting human radiation status and discriminating medically relevant radiation dose levels in human samples. Although the patient population was relatively small, the accuracy of this classifier in discriminating radiation dose levels in human TBI patients was not substantially confounded by gender, diagnosis or prior exposure to chemotherapy. We have further incorporated genes from this human radiation signature into a rapid and high-throughput chemical ligation-dependent probe amplification assay (CLPA) which was able to discriminate radiation dose levels in a pilot study of ex vivo irradiated human blood and samples from human TBI patients. Our results illustrate the potential for translation of a human genetic signature for the diagnosis of human radiation exposure and suggest the basis for further testing of CLPA as a candidate biodosimetric assay.

CHF5074 reduces biomarkers of neuroinflammation in patients with mild cognitive impairment: a 12-week, double-blind, placebo-controlled study.

As neuroinflammation is an early event in the pathogenesis of Alzheimer' s disease, new selective antiinflammatory drugs could lead to promising preventive strategies. We evaluated the safety, tolerability, pharmacokinetics and pharmacodynamics of CHF5074, a new microglial modulator, in a 12-week, double-blind, placebo-controlled, parallel groups, ascending dose study involving 96 MCI patients. Subjects were allocated into three successive study cohorts to receive ascending, titrated doses of CHF5074 (200, 400 or 600 mg/day) or placebo. Vital signs, cardiac safety, neuropsychological performance and safety clinical laboratory parameters were assessed on all subjects. Plasma samples were collected throughout the study for measuring drug concentrations, soluble CD40 ligand (sCD40L) and TNF-α. At the end of treatment, cerebrospinal fluid (CSF) samples were optionally collected after the last dose to measure drug levels, ß- amyloid1-42 (Aß42), tau, phospho-tau181, sCD40L and TNF-α. Ten patients did not complete the study: one in the placebo group (consent withdrawn), two in the 200-mg/day treatment group (consent withdrawn and unable to comply) and seven in the 400-mg/day treatment group (five AEs, one consent withdrawn and one unable to comply). The most frequent treatment-emergent adverse events were diarrhea, dizziness and back pain. There were no clinically significant treatmentrelated clinical laboratory, vital sign or ECG abnormalities. CHF5074 total body clearance depended by gender, age and glomerular filtration rate. CHF5074 CSF concentrations increased in a dose-dependent manner. At the end of treatment, mean sCD40L and TNF-α levels in CSF were found to be inversely related to the CHF5074 dose (p=0.037 and p=0.001, respectively). Plasma levels of sCD40L in the 600-mg/day group were significantly lower than those measured in the placebo group (p=0.010). No significant differences between treatment groups were found in neuropsychological tests but a positive dose-response trend was found on executive function in APOE4 carriers. This study shows that CHF5074 is well tolerated in MCI patients after a 12-week titrated treatment up to 600 mg/day and dose-dependently affects central nervous system biomarkers of neuroinflammation.

Safety and pharmacology of ponezumab (PF-04360365) after a single 10-minute intravenous infusion in subjects with mild to moderate Alzheimer disease.

OBJECTIVE: Ponezumab (PF-04360365) is a humanized anti-amyloid beta (Aß) monoclonal antibody designed for treatment of Alzheimer disease (AD). A single 2-hour intravenous infusion of 0.1 to 10 mg/kg was previously shown to be safe and well tolerated in subjects with mild to moderate AD, with measurable effects on plasma and cerebrospinal fluid Aß. This phase I, dose-escalation, open-label study evaluated the safety, pharmacokinetics, and pharmacodynamics of a single 10-minute intravenous infusion. METHODS: Subjects with mild to moderate AD received ponezumab 1 mg/kg (n = 3), 3 mg/kg (n = 3), 5 mg/kg (n = 4), or 10 mg/kg (n = 5). They were followed up as outpatients for 6 months. RESULTS: All subjects completed the trial. Ponezumab was safe and well tolerated with no deaths, withdrawals, or drug-related moderate, severe, or serious adverse events. Mild drug-related adverse events included headache (3 patients) and lethargy and hypoesthesia (both in 1 patient). No infusion reactions, clinically meaningful laboratory abnormalities, vital sign changes, electrocardiographic changes, or antidrug antibodies were detected. There was no evidence of brain microhemorrhage, vasogenic edema, encephalitis, or other imaging abnormality. Cognitive function showed no treatment-related trends. Ponezumab displayed approximately dose-proportional increases in plasma exposure. Steady-state volume of distribution was 113 to 172 mL/kg, clearance was 2.7 to 3.0 mL/d/kg, and terminal half-life was 35 to 52 days. Plasma maximum observed concentration and the area under the plasma concentration-time profile from time 0 extrapolated to infinite time of Aß(1-x) and Aß(1-40) increased dose-dependently. CONCLUSIONS: Administration of ponezumab as a 10-minute infusion was safe and well tolerated and produced effects on plasma Aß species comparable with a 2-hour infusion. Shorter infusions may provide more flexibility, comfort, and convenience for patients and caregivers.

Radiation injury treatment network (RITN): healthcare professionals preparing for a mass casualty radiological or nuclear incident.

PURPOSE: To describe the history, composition, and activities of the Radiation Injury Treatment Network (RITN). The Radiation Injury Treatment Network® is a cooperative effort of the National Marrow Donor Program and the American Society for Blood and Marrow Transplantation. The goals of RITN are to educate hematologists, oncologists, and stem cell transplant practitioners about their potential involvement in the response to a radiation incident and provide treatment expertise. Injuries to the marrow system readily occur when a victim is exposed to ionising radiation. This focus therefore leverages the expertise of these specialists who are accustomed to providing the intensive supportive care required by patients with a suppressed marrow function. Following a radiological incident, RITN centres may be asked to: Accept patient transfers to their institutions; provide treatment expertise to practitioners caring for victims at other centres; travel to other centres to provide medical expertise; or provide data on victims treated at their centres. Moving forward, it is crucial that we develop a coordinated interdisciplinary approach in planning for and responding to radiological and nuclear incidents. The ongoing efforts of radiation biologists, radiation oncologists, and health physicists can and should complement the efforts of RITN and government agencies. CONCLUSION: RITN serves as a vital partner in preparedness and response efforts for potential radiological and nuclear incidents.

An ear punch model for studying the effect of radiation on wound healing.

PURPOSE: Radiation and wound combined injury represents a major clinical challenge because of the synergistic interactions that lead to higher morbidity and mortality than either insult would produce singly. The purpose of this study was to develop a mouse ear punch model to study the physiological mechanisms underlying radiation effects on healing wounds. MATERIALS AND METHODS: Surgical wounds were induced by a 2 mm surgical punch in the ear pinnae of MRL/MpJ mice. Photographs of the wounds were taken and the sizes of the ear punch wounds were quantified by image analysis. Local radiation to the ear was delivered by orthovoltage X-ray irradiator using a specially constructed jig that shields the other parts of body. RESULTS: Using this model, we demonstrated that local radiation to the wound area significantly delayed the healing of ear punch wounds in a dose-dependent fashion. The addition of sublethal whole body irradiation (7 Gy) further delayed the healing of ear punch wounds. These results were replicated in C57BL/6 mice; however, wound healing in MRL/MpJ mice was accelerated. CONCLUSIONS: These data indicate that the mouse ear punch model is a valuable model to study radiation and wound combined injury.

Hematopoietic cell infusion for the treatment of nuclear disaster victims: new data from the Chernobyl accident.

PURPOSE: To present previously unavailable data on the use of stem cell administration to aid recovery of victims of the Chernobyl disaster. On 26 April 1986, an accident at Unit 4 of the Chernobyl Nuclear Power Plant took place during the planned test of one of the safety systems. The diagnosis of acute radiation syndrome (ARS) was confirmed in 134 individuals exposed to high levels of radiation. There were nine patients heretofore unreported in the scientific literature who underwent intraosseous injections of allogeneic bone marrow cells in Kyiv. CONCLUSIONS: Transplantation was associated with significantly shortened time to recovery of granulocyte and platelet counts in these patients. While current guidelines would certainly include the use of cytokines, these data provide an indication of the effectiveness of stem cell transplant to treat victims of radiation exposure.

Are γ-secretase inhibitors detrimental for Alzheimer's disease patients?

The recent failure of semagacestat in two large Phase III studies questions the value of γ-secretase inhibitors in treating Alzheimer's disease. Understanding the reasons of this setback may be important for the future research on effective treatments for this devastating disease.

Minireview: Nuclear receptors, hematopoiesis, and stem cells.

Nuclear receptors (NRs) regulate a panoply of biological processes, including the function and development of cells within the hematopoietic and immune system, such as erythrocytes, monocytes, and lymphocytes. Significantly less is known regarding the function of NRs in regulating the fate of hematopoietic stem cells (HSCs), the self-renewing, pluripotent cells that give rise to the entirety of the blood and immune systems throughout the lifetime of an individual. Several recent studies suggest, either directly or indirectly, a role for members of the NR family in regulating the differentiation and self-renewal of HSCs, embryonic stem cells, and induced pluripotent stem cells. Herein, we review in detail the function of specific NRs in controlling HSC and other stem cell fate and propose a framework through which these observations can be translated into therapeutic amplification of HSCs for clinical purposes.

Rationale for transdermal drug administration in Alzheimer disease.

Transdermal patches are used for the treatment of various diseases including neurologic and psychiatric disorders such as Parkinson disease (PD), major depression, and attention deficit hyperactivity disorder. They are believed to offer many advantages over conventional oral therapies. By providing smoother, continuous drug delivery and steadier plasma levels, patches may reduce the incidence of side effects, thus making optimal therapeutic doses easier to attain and potentially improving treatment efficacy and compliance. Drug delivery systems such as patches that are more patient- and caregiver-friendly may enable patients to continue treatment for longer periods and to attain greater, more sustained treatment benefits. To date, approved therapies for Alzheimer disease (AD), including cholinesterase inhibitors and memantine, are orally administered. Potential advantages associated with patches provide a therapeutic rationale to offer additional benefits in AD patients. Rivastigmine is well suited to patch administration because it is a small, potent molecule that is both lipophilic and hydrophilic. A rivastigmine patch has been developed and may provide a promising new approach to dementia therapy.

The effects of ZD6474, an inhibitor of VEGF signaling, on cutaneous wound healing in mice.

BACKGROUND: ZD6474 is an inhibitor of the VEGFR-2 receptor tyrosine kinase with additional activity against EGFR-1 receptor tyrosine kinases that has been shown to inhibit tumor growth and wound-induced neovascularization in pre-clinical studies and phase I clinical trials. The purpose of this study was to determine the effects of ZD6474 on breaking strength in a murine model of cutaneous wound healing. MATERIALS AND METHODS: Balb/C mice were given ZD6474 (50 or 100 mg/kg p.o.) or vehicle starting 7 days before wounding. Two full-thickness incisions were made in each mouse and closed using suture. On post-wounding day 7 or 28, laser Doppler blood flow measurements were made, and the breaking strength of the wounded skin was determined. Microvessel density measurements were performed using computer image analysis of CD31-stained sections. RESULTS: Compared with controls, mice treated with ZD6474 showed a significantly reduced dose-dependent decline in breaking strength, both at POD 7 (P < 0.001) and at POD 28 (P < 0.005). Histologically, the ZD6474-treated mice showed a qualitative reduction in the degree of fibrosis and epithelial proliferation at the wound site, but no significant difference was noted between the 50 mg/kg and 100 mg/kg ZD6474-treated groups. Also, microvessel density measurements demonstrated no significant difference between groups. CONCLUSION: In a murine model of wound healing, ZD6474 treatment did not prevent wound healing, but was associated with a reduced skin breaking strength compared with vehicle-treated controls at both 7 and 28 days post-wounding. These observations may have clinical relevance for the perioperative management of patients treated with inhibitors of angiogenesis.