A clinical model of dermal wound angiogenesis

Ozonated Oils and Cutaneous Wound Healing

Wound tissue repair is a complex and dynamic process of restoring cellular structures and tissue layers. Improvement in this process is necessary to effectively treat several pathologies characterized by a chronic delayed wound closure, such as in diabetes, and the investigation of new approaches aimed to ameliorate the wound healing process is under continuous evolution. Recently, the usage of vegetable matrices in the form of ozonated oils has been proposed, and several researchers have shown positive effects on wound healing, due to the bactericidal, antiviral, and antifungal properties of these ozonated oils. In the present review, we intend to summarize the actual state of the art of the topical usage of ozonated oil in cutaneous wounds with special emphasis to the importance of the ozonated degree of the oil.

Mechanical Forces in Tumor Angiogenesis

A defining hallmark of cancer and cancer development is upregulated angiogenesis. The vasculature formed in tumors is structurally abnormal, not organized in the conventional hierarchical arrangement, and more permeable than normal vasculature. These features contribute to leaky, tortuous, and dilated blood vessels, which act to create heterogeneous blood flow, compression of vessels, and elevated interstitial fluid pressure. As such, abnormalities in the tumor vasculature not only affect the delivery of nutrients and oxygen to the tumor, but also contribute to creating an abnormal tumor microenvironment that further promotes tumorigenesis. The role of chemical signaling events in mediating tumor angiogenesis has been well researched; however, the relative contribution of physical cues and mechanical regulation of tumor angiogenesis is less understood. Growing research indicates that the physical microenvironment plays a significant role in tumor progression and promoting abnormal tumor vasculature. Here, we review how mechanical cues found in the tumor microenvironment promote aberrant tumor angiogenesis. Specifically, we discuss the influence of matrix stiffness and mechanical stresses in tumor tissue on tumor vasculature, as well as the mechanosensory pathways utilized by endothelial cells to respond to the physical cues found in the tumor microenvironment. We also discuss the impact of the resulting aberrant tumor vasculature on tumor progression and therapeutic treatment.

A phase I study of gemcitabine + dasatinib (gd) or gemcitabine + dasatinib + cetuximab (GDC) in refractory solid tumors

PURPOSE

This study was conducted to define the maximum tolerated dose (MTD), recommended phase two dose (RPTD), and toxicities of gemcitabine + dasatinib (GD) and gemcitabine + dasatinib + cetuximab (GDC) in advanced solid tumor patients.

METHODS

This study was a standard phase I 3 + 3 dose escalation study evaluating two combination regimens, GD and GDC. Patients with advanced solid tumors were enrolled in cohorts of 3-6 to either GD or GDC. Gemcitabine was dosed at 1000 mg/m² weekly for 3 of 4 weeks, dasatinib was dosed in mg PO BID, and cetuximab was dosed at 250 mg/m² weekly after a loading dose of cetuximab of 400 mg/m². There were two dose levels for dasatinib: (1) gemcitabine + dasatinib 50 mg ± cetuximab, and (2) gemcitabine + dasatinib 70 mg ± cetuximab. Cycle length was 28 days. Standard cycle 1 dose-limiting toxicity (DLT) definitions were used. Eligible patients had advanced solid tumors, adequate organ and marrow function, and no co-morbidities that would increase the risk of toxicity. Serum, plasma, and skin biopsy biomarkers were obtained pre- and on-treatment.

RESULTS

Twenty-five patients were enrolled, including 21 with pancreatic adenocarcinoma. Three patients received prior gemcitabine. Twenty-one patients were evaluable for toxicity and 16 for response. Four DLTs were observed: Grade (Gr) 3 neutropenia (GDC1, n = 1), Gr 3 ALT (GD2, n = 2), and Gr 5 pneumonitis (GDC2, n = 1). Possible treatment-emergent adverse events (TEAEs) in later cycles included: Gr 3-4 neutropenia (n = 7), Gr 4 colitis (n = 1), Gr 3 bilirubin (n = 2), Gr 3 anemia (n = 2), Gr 3 thrombocytopenia (n = 2), Gr 3 edema/fluid retention (n = 1), and Gr 3 vomiting (n = 3). Six of 16 patients (3 of whom were gemcitabine-refractory) had stable disease (SD) as best response, median duration = 5 months (range 1-7). One gemcitabine-refractory patient had a partial response (PR). Median PFS was 2.9 months (95% CI 2.1, 5.8). Median OS was 5.8 months (95% CI 4.1, 11.8). Dermal wound biopsies demonstrated that dasatinib resulted in a decrease of total and phospho-Src levels, and cetuximab resulted in a decrease of EGFR and ERBB2 levels.

CONCLUSIONS

The MTD/RPTD of GD is gemcitabine 1000 mg/m² weekly for 3 of 4 weeks and dasatinib 50 mg PO BID. The clinical activity of GD seen in this study was modest, and does not support its further investigation in pancreatic cancer.

Understanding the Hawthorne effect in wound research-A scoping review

The Hawthorne Effect (HE) is considered a methodological artefact in research, although its definition and influence on research outcomes lack consensus. This review explored how this term has been mentioned and discussed in the area of wound research. A scoping review was conducted on ProQuest Central, Scopus, EbscoHost, and online databases of indexed wound journals using the methodological framework by Arksey and Malley. A review protocol was applied to detail key terms, truncation and Boolean operators, and inclusion and exclusion criteria. Search findings were reported using PRISMA guidelines. A total of 38 articles reporting primary evidence were identified. Three themes emerged from the review: wound researchers' awareness of HE, the acknowledgement of the existence or otherwise of HE, and the mentioning of HE in passing. These results reflect a lack of attention to and understanding and awareness of the HE in the area of wound research. It is suggested that the HE receives more attention as a methodological concern, and its potential influence is considered and mitigated when planning future studies. Recommendations are provided to minimise the impact of the HE on the rigour of the research and confidence afforded to research findings.

A Phase I Trial of the IGF-1R Antibody Ganitumab (AMG 479) in Combination with Everolimus (RAD001) and Panitumumab in Patients with Advanced Cancer

PURPOSE

This study evaluated the maximum tolerated dose or recommended phase II dose (RPTD) and safety and tolerability of the ganitumab and everolimus doublet regimen followed by the ganitumab, everolimus, and panitumumab triplet regimen.

MATERIALS AND METHODS

This was a standard 3 + 3 dose escalation trial. Doublet therapy consisted of ganitumab at 12 mg/kg every 2 weeks; doses of everolimus were adjusted according to dose-limiting toxicities (DLTs). Panitumumab at 4.8 mg/kg every 2 weeks was added to the RPTD of ganitumab and everolimus. DLTs were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity. Pretreatment and on-treatment skin biopsies were collected to assess insulin-like growth factor 1 receptor and mammalian target of rapamycin (mTOR) target modulation.

RESULTS

Forty-three subjects were enrolled. In the doublet regimen, two DLTs were observed in cohort 1, no DLTs in cohort -1, and one in cohort -1B. The triplet combination was discontinued because of unacceptable toxicity. Common adverse events were thrombocytopenia/neutropenia, skin rash, mucositis, fatigue, and hyperglycemia. In the doublet regimen, two patients with refractory non-small cell lung cancer (NSCLC) achieved prolonged complete responses ranging from 18 to >60 months; one treatment-naïve patient with chondrosarcoma achieved prolonged stable disease >24 months. In dermal granulation tissue, the insulin-like growth factor receptor and mTOR pathways were potently and specifically inhibited by ganitumab and everolimus, respectively.

CONCLUSION

The triplet regimen of ganitumab, everolimus, and panitumumab was associated with unacceptable toxicity. However, the doublet of ganitumab at 12 mg/kg every 2 weeks and everolimus five times weekly had an acceptable safety profile and demonstrated notable clinical activity in patients with refractory NSCLC and sarcoma.

IMPLICATIONS FOR PRACTICE

This trial evaluated the maximum tolerated dose or recommended phase II dose and safety and tolerability of the ganitumab and everolimus doublet regimen followed by the ganitumab, everolimus, and panitumumab triplet regimen. Although the triplet regimen of ganitumab, everolimus, and panitumumab was associated with unacceptable toxicity, the doublet of ganitumab at 12 mg/kg every 2 weeks and everolimus at five times weekly had an acceptable safety profile and demonstrated notable clinical activity in patients with refractory non-small cell lung cancer and sarcoma.

Models of wound healing: an emphasis on clinical studies

BACKGROUND

The healing of wounds has always provided challenges for the medical community whether chronic or acute. Understanding the processes which enable wounds to heal is primarily carried out by the use of models, in vitro, animal and human. It is generally accepted that the use of human models offers the best opportunity to understand the factors that influence wound healing as well as to evaluate efficacy of treatments applied to wounds.

OBJECTIVES

The objective of this article is to provide an overview of the different methodologies that are currently used to experimentally induce wounds of various depths in human volunteers and examines the information that may be gained from them.

METHODS

There is a number of human volunteer healing models available varying in their invasiveness to reflect the different possible depth levels of wounds.

RESULTS

Currently available wound healing models include sequential tape stripping, suction blister, abrasion, laser, dermatome, and biopsy techniques. The various techniques can be utilized to induce wounds of variable depth, from removing solely the stratum corneum barrier, the epidermis to even split-thickness or full thickness wounds.

CONCLUSION

Depending on the study objective, a number of models exist to study wound healing in humans. These models provide efficient and reliable results to evaluate treatment modalities.

Direct Evidence of Target Inhibition with Anti-VEGF, EGFR, and mTOR Therapies in a Clinical Model of Wound Healing

PURPOSE

In early clinical testing, most novel targeted anticancer therapies have limited toxicities and limited efficacy, which complicates dose and schedule selection for these agents. Confirmation of target inhibition is critical for rational drug development; however, repeated tumor biopsies are often impractical and peripheral blood mononuclear cells and normal skin are often inadequate surrogates for tumor tissue. Based upon the similarities of tumor and wound stroma, we have developed a clinical dermal granulation tissue model to evaluate novel targeted therapies.

EXPERIMENTAL DESIGN

A 4-mm skin punch biopsy was used to stimulate wound healing and a repeat 5-mm punch biopsy was used to harvest the resulting granulation tissue. This assay was performed at pretreatment and on-treatment evaluating four targeted therapies, bevacizumab, everolimus, erlotinib, and panitumumab, in the context of three different clinical trials. Total and phosphorylated levels VEGFR2, S6RP, and EGFR were evaluated using ELISA-based methodologies.

RESULTS

Significant and consistent inhibition of the VEGF pathway (using VEGFR2 as the readout) was observed in granulation tissue biopsies from patients treated with bevacizumab and everolimus. In addition, significant and consistent inhibition of the mTOR pathway (using S6RP as the readout) was observed in patients treated with everolimus. Finally, significant inhibition of the EGFR pathway (using EGFR as the readout) was observed in patients treated with panitumumab, but this was not observed in patients treated with erlotinib.

CONCLUSIONS

Molecular analyses of dermal granulation tissue can be used as a convenient and quantitative pharmacodynamic biomarker platform for multiple classes of targeted therapies.

A Phase I/biomarker study of bevacizumab in combination with CNTO 95 in patients with advanced solid tumors

PURPOSE

Inhibition of tumor angiogenesis is an effective mechanism to limit tumor growth; dual inhibition may result in additional benefit. Bevacizumab is a monoclonal antibody directed against vascular endothelial growth factor (VEGF), and intetumumab is a fully humanized monoclonal antibody that blocks αv integrins when complexed with β integrins. We evaluated the safety, tolerability, and efficacy of the combination of bevacizumab plus intetumumab in patients with refractory solid tumors. We also explored the effects of these agents on plasma-based biomarkers and wound angiogenesis.

METHODS

Patients with refractory solid tumors, Karnofsky performance status ≥70%, and adequate organ function were eligible. Plasma samples and wound biopsies were obtained at baseline and on-treatment.

RESULTS

Twelve patients were enrolled and received study drug. No tumor responses were noted. Observed toxicities included three cases of transient uveitis likely related to intetumumab and one case of reversible posterior leukoencephalopathy syndrome likely related to bevacizumab. Biomarker analysis revealed changes in soluble endoglin, soluble E-cadherin, and soluble E-selectin as well as PlGF and VEGF-D while on treatment. There was no observed impact of bevacizumab plus intetumumab on the phosphorylated or total levels of paxillin in wound tissue; however, an increase in the ratio of phospho/total paxillin levels was noted.

CONCLUSIONS

Bevacizumab and intetumumab can be administered safely in combination. Bevacizumab plus intetumumab treatment resulted in changes in the plasma levels of several extracellular matrix interacting proteins and angiogenic factors.

A phase I study of ABT-510 plus bevacizumab in advanced solid tumors

Targeting multiple regulators of tumor angiogenesis have the potential to improve treatment efficacy. Bevacizumab is a monoclonal antibody directed against vascular endothelial growth factor and ABT-510 is a synthetic analog of thrombospondin, an endogenous angiogenesis inhibitor. Dual inhibition may result in additional benefit. We evaluated the safety, tolerability, and efficacy of the combination of bevacizumab plus ABT-510 in patients with refractory solid tumors. We also explored the effects of these agents on plasma-based biomarkers and wound angiogenesis. Thirty-four evaluable subjects were enrolled and received study drug. Therapy was well tolerated; minimal treatment-related grade 3/4 toxicity was observed. One patient treated at dose level 1 had a partial response and five other patients treated at the recommended phase II dose had prolonged stable disease for more than 1 year. Biomarker evaluation revealed increased levels of D-dimer, von Willebrand factor, placental growth factor, and stromal-derived factor 1 in response to treatment with the combination of bevacizumab and ABT-510. Data suggest that continued evaluation of combination antiangiogenesis therapies may be clinically useful.

Alpha-v integrins as therapeutic targets in oncology

Integrins are heterodimeric cell adhesion receptors that mediate intercellular communication through cell-extracellular matrix interactions and cell-cell interactions. Integrins have been demonstrated to play a direct role in cancer progression, specifically in tumor cell survival, tumor angiogenesis, and metastasis. Therefore, agents targeted against integrin function have potential as effective anticancer therapies. Numerous anti-integrin agents, including monoclonal antibodies and small-molecule inhibitors, are in clinical development for the treatment of solid and hematologic tumors. This review focuses on the role of alpha(v) integrins in cancer progression, the current status of integrin-targeted agents in development, and strategies for the clinical development of anti-integrin therapies.

The healing effects of autologous platelet gel on acute human skin wounds

OBJECTIVE

To compare the healing of full-thickness skin punch wounds treated with topical autologous platelet gel (APG) vs conventional therapy (antibiotic ointment and/or occlusive dressings) in healthy volunteers.

METHODS

A prospective, single-blind, pilot study comprising 80 full-thickness skin punch wounds (4 mm diameter) was conducted on the thighs of 8 healthy volunteers. With each subject serving as his or her own control (5 punch sites per leg), APG was applied topically on one thigh, and an antibiotic ointment and/or a semiocclusive dressing was applied on the other thigh. Healing was monitored for spontaneous wound closure by clinical assessment and by digital photographs over 6 months. Over 35 days, 64 serial dermal biopsy specimens (6 mm diameter) were analyzed (using hematoxylin-eosin, Mason trichrome, CD-34, and Ki-67 stains) to measure differences between treated and control sites for cellularity, granulation formation, vascularity, epithelialization, and cellular replication.

RESULTS

Over a 42-day period, the APG-treated sites had statistically increased wound closure compared with controls by visual clinical assessment and by digital planimetry photographic measurements (P<or=.02). On day 17, the percentage of closure was 81.1% +/- 2.5% (mean +/- SE) for the APG-treated sites and 57.2% +/- 5.9% for the control sites. Also, the APG wound closure velocities were significantly faster than those of the controls (P = .001). Histologically, over time, the APG-treated sites had similar cellularity, cellular replication, granulation tissue, vascularity, and epithelialization compared with controls. However, when the platelet count in the gel was more than 6 times the baseline intravascular platelet count in some subjects, epithelialization and granulation formation appeared 3 days earlier in the APG-treated group. Furthermore, in vitro testing of supplemental APG showed increased endothelial cell proliferation compared with controls (P<.04).

CONCLUSION

This pilot study provides preliminary evidence that topical APG may hasten wound closure in full-thickness dermal wounds in healthy individuals.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00199992.

The use of vascular biomarkers and imaging studies in the early clinical development of anti-tumour agents targeting angiogenesis

Recent findings about the pathomechanisms of tumour angiogenesis have led to new therapeutic options in the treatment of malignant tumours. During the development of anti-angiogenic drugs, reporting ranged from healing cancer to completely ineffective drugs. In 2003 the first anti-angiogenic drug was approved. Several anti-angiogenic drugs are still in the clinical phase of development. In contrast to identifying the maximal tolerable dose, determination of the optimal biological dose--reaching biological activity at lower doses--has become the main target in the early development of anti-angiogenic agents. This has been evaluated by different biomarker techniques. As a new standard in anti-tumour treatment, a better understanding of imaging in the treatment monitoring for anti-angiogenic agents is important. Studies of tumour angiogenesis by tissue sampling rely on invasive procedures, adequate sampling and painstaking estimation of histological microvessel density. Attempts to develop wound healing assays to correlate angiogenesis in wounds with angiogenesis in tumour have been made but are still considered invasive and correlation of healthy with malignant tissue is still of limited validity. Several soluble markers of tumour angiogenesis were detected in various malignant diseases and were evaluated for assessing their use as surrogate markers in tumour angiogenesis. Further, soluble markers were investigated for visualizing them as imaging tools. Combining both, new soluble markers and imaging techniques, developing anticancer drugs and monitoring of therapy success becomes a dynamic process in which finally the patients' individual response can be achieved soon. Time-consuming delays for anatomically based restaging procedures can be avoided. Characterization of soluble biomarkers as well as different imaging techniques such as ultrasound, computed tomography (CT), magnetic resonance imaging and positron emission tomography combined with or without CT are reviewed in this manuscript.

Oxygen transport and exchange in the microcirculation

The cardiovascular system is responsible for maintaining an adequate convective delivery of oxygen to the smallest branches of the network of blood vessels-the microcirculation-from which oxygen passes to the parenchymal cells by passive diffusion. The aim of this brief review is to trace the development of the study of oxygen transport from the point of view of the microcirculation. August Krogh performed measurements that allowed him to use his keen insight to draw conclusions about oxygen transport that remained the foundations of this field for decades. After an extended period of neglect, Duling rekindled interest in the field of oxygen transport by discovering that substantial amounts of oxygen diffused from the arteriolar network. Subsequent investigations confirmed this finding ill various vascular beds and extended these studies to capillaries and venules. The important contributions of computational modeling and new techniques in intravital microscopy continue to lead to more advances in our understanding of the role of the microcirculation in the supply of oxygen to tissues. Current work is applying the concepts and principles learned in normal tissues to pathophysiological situations, as well as increasing our understanding of artificial oxygen carriers, oxygen sensing, and the connections between nitric oxide and oxygen transport.