Isolation of a nonmitogenic angiogenesis factor from wound fluid

Tenascin-C: A Key Regulator in Angiogenesis during Wound Healing

(1) Background: Injury repair is a complex physiological process in which multiple cells and molecules are involved. Tenascin-C (TNC), an extracellular matrix (ECM) glycoprotein, is essential for angiogenesis during wound healing. This study aims to provide a comprehensive review of the dynamic changes and functions of TNC throughout tissue regeneration and to present an up-to-date synthesis of the body of knowledge pointing to multiple mechanisms of TNC at different restoration stages. (2) Methods: A review of the PubMed database was performed to include all studies describing the pathological processes of damage restoration and the role, structure, expression, and function of TNC in post-injury treatment; (3) Results: In this review, we first introduced the construction and expression signature of TNC. Then, the role of TNC during the process of damage restoration was introduced. We highlight the temporal heterogeneity of TNC levels at different restoration stages. Furthermore, we are surprised to find that post-injury angiogenesis is dynamically consistent with changes in TNC. Finally, we discuss the strategies for TNC in post-injury treatment. (4) Conclusions: The dynamic expression of TNC has a significant impact on angiogenesis and healing wounds and counters many negative aspects of poorly healing wounds, such as excessive inflammation, ischemia, scarring, and wound infection.

Angiogenesis in Wound Repair: Too Much of a Good Thing?

Angiogenesis, or the growth of new blood vessels from the preexisting vasculature, is a visible and important component of wound repair. When tissue damage occurs, disruption of the vasculature structure leads to hypoxia. The restoration of normoxia is essential for appropriate and durable tissue repair. Angiogenesis in wounds is regulated by endogenous proangiogenic mediators, which cause rapid growth of a new vascular bed that is much denser than that of normal tissue. Such rapid growth of the capillary bed results in capillaries that are abnormal, and the newly formed vessels are tortuous, dilated, and immature. During wound resolution, this substantial neocapillary bed is pruned back to normal density with attendant maturation. Many poorly healing wounds, including nonhealing ulcers and scars, exhibit an aberrant angiogenic response. The fine-tuning of capillary regrowth in wounds is an area of significant therapeutic potential.

Tissue reaction and anti-biofilm action of new biomaterial composed of latex from Hancornia speciosa Gomes and silver nanoparticles

In this work, the natural latex extracted from Harconia speciosa was incorporated with silver nanoparticles (AgNP) to compose a functional biomaterial associating the intrinsic angiogenic activity of the latex and the antimicrobial activity of AgNP. Tissue reaction after subcutaneous implantation in dorsum of rats of membranes without AgNP and with 0.05%, 0.4% AgNP was compared at 3, 7 and 25 days. No statistically significant difference in the tissue response of the different biomaterials was observed, indicating that AgNP did not interfere with the inflammatory reaction (p > 0.05) or with the angiogenic activity of latex. Biomembranes were also tested against bacterial biofilm formation by Staphylococcus aureus and the antimicrobial activity of the new biomaterial can be found with bacteria crenation (0.05% AgNP) and no biofilm deposition (0.4% AgNP). Therefore, this biomaterial has interesting properties for the tissue repair process and may be feasible for future applications as dressing.

Plasma and wound fluid levels of eight proangiogenic proteins are elevated after colorectal resection

BACKGROUND

Colorectal resection is associated with 3-5 wk long elevations in the plasma levels of at least 11 proangiogenic proteins that may stimulate tumor angiogenesis post-surgery. The increases during the first week after surgery may be related to the acute inflammatory response; the cause(s) of the week 2-5 increases is unknown. The wounds are a possible source because of the important role that angiogenesis plays in the healing process. The main hypothesis of the study is that wound fluid levels of the proteins studied will be elevated well beyond plasma levels which, in turn, are elevated from preoperative baseline levels.

AIM

To determine plasma and wound fluid levels of 8 proangiogenic proteins after colorectal resection for cancer and benign pathology.

METHODS

Blood and wound fluid samples were taken simultaneously on postoperative (postop) day 1, 3, and later time points until wound drain removal in 35 colorectal cancer patients and 31 benign disease patients undergoing colorectal resection in whom closed wound drains had been placed in either the pelvis or the subcutaneous space of the abdominal incision. Postop plasma levels were compared to preop plasma and postop wound fluid levels (separate analyses for cancer and benign groups).

RESULTS

Sixty-six colorectal disease patients were studied (35 cancer, 31 benign pathology). Most patients underwent minimally invasive surgery (open surgery in 11% of cancer and 6% of benign patients). The majority in the cancer group had rectal resections while in the benign group sigmoid or right colectomy predominated. Plasma levels of all 8 proteins were significantly elevated from baseline (P < 0.05) at all post-operative time points in the cancer group and at 90% of time points (29/32) in the benign group. Wound levels of all 8 proteins were 3-106 times higher (P < 0.05) than plasma levels at 87-90 percent of postop time points; of note, wound levels were more than 10 times higher at 47-50% of time points.

CONCLUSION

Plasma protein levels were elevated for 3 weeks after surgery; wound fluid levels were much greater than corresponding blood levels. Healing wounds may be the source of the plasma increases.

The Effect of Light on Tissue Repair

Electrotherapeutic modalities are widely used by physiotherapists to accelerate repair and reduce pain. It is important that the underlying mechanisms and effects that they produce are fully understood, together with any underlying adverse effects which may arise from their use. Light therapy is a relatively new addition to the physiotherapy arsenal and the mechanisms of action have not yet been fully identified. There is clinical evidence suggesting that it is effective in promoting tissue repair and pain relief. This, together with some recent laboratory evidence showing light to be effective in stimulating cells that are involved in the repair process to produce wound mediators, is described. The weight of evidence suggests that, if used correctly, light therapy can induce bioeffects which are beneficial to the patient.

Soluble E-cadherin promotes tumor angiogenesis and localizes to exosome surface

The limitations of current anti-angiogenic therapies necessitate other targets with complimentary mechanisms. Here, we show for the first time that soluble E-cadherin (sE-cad) (an 80-kDa soluble form), which is highly expressed in the malignant ascites of ovarian cancer patients, is a potent inducer of angiogenesis. In addition to ectodomain shedding, we provide further evidence that sE-cad is abundantly released in the form of exosomes. Mechanistically, sE-cad-positive exosomes heterodimerize with VE-cadherin on endothelial cells and transduce a novel sequential activation of β-catenin and NFκB signaling. In vivo and clinical data prove the relevance of sE-cad-positive exosomes for malignant ascites formation and widespread peritoneal dissemination. These data advance our understanding of the molecular regulation of angiogenesis in ovarian cancer and support the therapeutic potential of targeting sE-cad. The exosomal release of sE-cad, which represents a common route for externalization in ovarian cancer, could potentially be biomarkers for diagnosis and prognosis.

A soluble form E-cadherin is highly expressed in ovarian cancer. Here, the authors show that soluble E-cadherin is released by ovarian cancer cells packaged in exosomes and promotes tumor angiogenesis through β-catenin and NFkB signaling activation.

Wearable Technology for Chronic Wound Monitoring: Current Dressings, Advancements, and Future Prospects

Chronic non-healing wounds challenge tissue regeneration and impair infection regulation for patients afflicted with this condition. Next generation wound care technology capable of in situ physiological surveillance which can diagnose wound parameters, treat various chronic wound symptoms, and reduce infection at the wound noninvasively with the use of a closed loop therapeutic system would provide patients with an improved standard of care and an accelerated wound repair mechanism. The indicating biomarkers specific to chronic wounds include blood pressure, temperature, oxygen, pH, lactate, glucose, interleukin-6 (IL-6), and infection status. A wound monitoring device would help decrease prolonged hospitalization, multiple doctors' visits, and the expensive lab testing associated with the diagnosis and treatment of chronic wounds. A device capable of monitoring the wound status and stimulating the healing process is highly desirable. In this review, we discuss the impaired physiological states of chronic wounds and explain the current treatment methods. Specifically, we focus on improvements in materials, platforms, fabrication methods for wearable devices, and quantitative analysis of various biomarkers vital to wound healing progress.

Angiogenesis and wound repair: when enough is enough

All animals heal, and the ability to heal is requisite for human health. One aspect of repair that has always been considered to be essential for adequate healing is the creation of a new vasculature via angiogenesis. As adult skin wounds heal, a period of rapid and robust capillary growth creates a vascular bed that has many fold more capillaries than does normal tissue. Over time, most of the newly formed capillaries regress, resulting in a final vascular density similar to that of normal skin. Certainly, new capillaries are necessary to bring nutrients, immune cells, and oxygen to healing wounds. Yet, the presumed functional importance of an overabundance of capillaries has recently been challenged, creating questions about whether excess capillary growth is truly necessary for healing. In particular, studies of wounds that heal exceptionally quickly and with less scar formation, such as those in fetal skin and oral mucosa, show that these tissues heal with a reduced angiogenic burst composed of more mature vessels that provide better oxygenation. The level of angiogenesis in wounds often correlates with the inflammatory response, largely because inflammatory cells produce an abundance of proangiogenic mediators. Both the selective reduction of inflammation and the selective reduction of angiogenesis have now been suggested as ways to improve scarring. These concepts link excessive inflammation and the production of a dense but poorly perfused capillary bed to inferior healing outcomes.

Wound Fluids: A Window Into the Wound Environment?

Wound healing of the skin is a complex biologic process involving temporal interactions between numerous types of cells, extracellular matrix molecules, and soluble factors. The process of repair can be viewed as involving 3 or 4 phases: homeostasis, inflammation, synthesis, and remodeling. These phases occur at different times and differ in their cellular, biochemical, and physiologic requirements. Disruption of one or more of these interactions can significantly interfere with the repair process. Such comorbidities as age, nutrition, immune status, and underlying disease status (eg, diabetes or venous stasis) contribute additional intricacy to the repair process. Because of this complexity, care of chronic wounds remains highly individualized, and it should not come as a surprise that treatment of these wounds as a group with single target therapies have met with only modest success. A major hurdle in the progression toward improved treatment regimens has been the lack of objective biochemical and physiological landmarks that can be used to assess wound status. Collection and biochemical characterization of wound fluids presents the opportunity to noninvasively obtain information reflecting the status of the wound and of specific biomarkers. This review discusses the collection of wound fluid and highlights biomarkers that may be useful to this end.

TIMAP promotes angiogenesis by suppressing PTEN-mediated Akt inhibition in human glomerular endothelial cells

The function of TIMAP, an endothelial cell (EC)-predominant protein phosphatase 1-regulatory subunit, is poorly understood. We explored the potential role of TIMAP in the Akt-dependent regulation of glomerular EC proliferation, survival, and in vitro angiogenesis. To deplete TIMAP, the EC were transfected with TIMAP-specific or nonspecific small interfering (si) RNA. The rate of electrical impedance development across subconfluent EC monolayers, a measure of the time-dependent increase in EC number, was 93 ± 2% lower in TIMAP-depleted than in control EC. This effect on cell proliferation was associated with reduced DNA synthesis and increased apoptosis: TIMAP silencing reduced 5-ethynyl-2'-deoxyuridine incorporation by 38 ± 2% during the exponential phase of EC proliferation, and cleaved caspase 3 as well as caspase 3 activity increased in TIMAP-depleted relative to control cells. Furthermore, TIMAP depletion inhibited the formation of angiogenic sprouts by glomerular EC in three-dimensional culture. TIMAP depletion strongly diminished growth factor-stimulated Akt phosphorylation without altering ERK1/2 phosphorylation, suggesting a specific effect on the PI3K/Akt/PTEN pathway. Endogenous TIMAP and PTEN colocalized in EC and coimmunoprecipitated from EC lysates. The inhibitory PTEN phosphorylation on S370 was significantly reduced in TIMAP-depleted compared with control EC, while phosphorylation of PTEN on the S380/T382/T383 cluster remained unchanged. Finally, the PTEN inhibitor bpV(phen) fully reversed the suppressive effect of TIMAP depletion on Akt phosphorylation. The data indicate that in growing EC, TIMAP is necessary for Akt-dependent EC proliferation, survival, and angiogenic sprout formation and that this effect of TIMAP is mediated by inhibition of the tumor suppressor PTEN.

Crosstalk between VEGF and novel angiogenic protein regulates tumor angiogenesis and contributes to aggressiveness of breast carcinoma

We have identified and characterized a novel proangiogenic glycoprotein (NAP) with molecular weight of 67 kDa from synovial fluid of rheumatoid arthritis patients. Proteomic analysis of the protein revealed 29% sequence coverage with maximum identity for human retinoblastoma binding protein 2. N-terminal amino acid sequence showed no identity to recently discovered protein sequences. NAP was also identified in both normal and tumor cell lines by Western blotting. NAP is a permeability factor as verified by miles permeability assay. The proangiogenic potential of NAP was identified using shell less CAM, rat cornea and tumor on CAM assays. NAP induces expression of VEGF and Flt-1 gene as verified by promoter reporter gene analysis. Further NAP induces proliferation of endothelial cells and formation of tube like structures. NAP is also involved in migration and invasion of tumor cells. Clinical data revealed the presence of NAP in breast cancer biopsies. We have developed monoclonal antibody (mAb), and specific ELISA, which confirmed the presence of NAP in the cytosol of tumor cells. The mAb effect was evaluated with established angiogenic assays. Further, we investigated the detailed mechanism by which NAP induces angiogenesis. NAP is phosphorylated by VEGF induced activation of MAPK and JNK pathways through VEGFR2 phosphorylation. NAP involves JNK pathway predominantly with further activation of NFκB in downstream processing of VEGF activation. Together these findings establish that NAP displays angiogenic properties and promotes efficient neovascularization both in vitro and in vivo models. These observations suggest that anti-NAP-mAb can be targeted for antiangiogenic therapy of cancer.

Effect of a combination of medium chain triglycerides, linoleic acid, soy lecithin and vitamins A and E on wound healing in rats

PURPOSE

The aim of the study was to determine the effect of a combination of medium chain triglycerides (caprylic, capric, caproic and lauric acids), linoleic acid (essential fatty acid), vitamins A and E and soy lecithin, through a morphometric study, on the wound healing kinetics of experimental cutaneous ulcers.

METHODS

A total of 45 male Wistar rats were used, in which a skin flap of total thickness with an area of 4 cm2 was removed. The animals were divided randomly into 3 groups of 15 rats each, Control, Reference and Test groups, which were treated topically with 0.9% NaCl, a preparation of clostebol combined with neomycin sulfate and the test formulation, respectively. The wound areas were measured by digital planimetry at days zero, 3, 7 and 12 postoperative. Based on the wound area, we determined the degree of tissue repair and mean rate of repair at different time intervals.

RESULTS

At day 3, an expansion of the wound area was observed in the Reference group and slight contraction in the Control and Test groups. On the subsequent days, the healing process, according to the degree of repair, proceeded in a linear manner, such that, at day 12, the healed area reached 77.95% of the initial ulcerated region in the Control group, 78.40% in the Reference group and 83.49% in the Test group, showing no significant differences. The overall mean rate of repair was equally similar at 12 days of treatment: 25.79 mm2/dia in the Control group, 25.42 mm2/dia in the Reference group and 27.38 mm2/dia in the Test group.

CONCLUSION

The test preparation, applied topically on the experimentally induced cutaneous ulcers in rats, did not accelerate the process of tissue repair by secondary union.

Secretion of toxic oxygen products by macrophages: regulatory cytokines and their effects on the oxidase

We are attempting to identify cytokines that regulate macrophage secretion of reactive oxygen intermediates (ROI) and to analyse the biochemical basis of their effects. In both humans and mice, interferon-gamma (IFN-gamma) appears to be the chief factor secreted by clonally unselected lymphocytes that enhances macrophage oxidative metabolism and antiprotozoal activity. In vivo administration of recombinant IFN-gamma enhances the ROI secretory capacity of monocytes in humans, and the secretion of ROI and killing of protozoa by peritoneal macrophages in mice. A protein secreted by murine tumours and certain non-malignant cells exerts opposing effects. This macrophage deactivation factor (MDF) both blocks the induction of activation by IFN-gamma and reverses pre-existent activation. MDF action is non-toxic and selective, suppressing the secretion of ROI, killing of intracellular protozoa, and expression of Ia antigen, without inhibiting secretion of several other products, or synthesis of protein, ingestion of particles or adherence to culture vessels. The suppressive effect of MDF is reversed over several days after its removal. This reversal is hastened by IFN-gamma. Profound suppression of oxidative metabolism accompanies the differentiation of murine monocytes into Kupffer cells. The capacity of Kupffer cells to secrete ROI and kill intracellular protozoa remains deficient even after exposure to IFN-gamma. Thus, four states of macrophage activation can provisionally be discerned: the transition of mouse peritoneal macrophages from the non-activated to the activated state is accompanied by a ninefold increase in affinity of the superoxide-producing enzyme for NADPH, without a marked increase in cellular Vmax or content of cytochrome b559. The MDF-induced transition of mouse peritoneal macrophages from the activated to the deactivated state is accompanied by both an increase in Km and a decrease in apparent V max of the oxidase. There are no changes in the phorbol myristate acetate receptor number or affinity, glucose transport, NADPH levels, cytochrome b559 content, catalase (EC 1.11.1.6) GSH, GSH peroxidase (EC 1.11.1.9), GSH reductase (EC 1.6.4.2) or myeloperoxidase, consistent with the suppressed ROI secretory capacity and antiprotozoal activity of these cells. The Kupffer cell, whose non-responsiveness to IFN-gamma may mark it as inactivated, appears to lack detectable NADPH oxidase activity, despite the probable presence of cytochrome b559, and in this regard differs from both non-activated and deactivated macrophages.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell interactions in post-traumatic fibrosis

Models of reparative fibrosis, or wound healing, disclose a basic spatial relationship between inflammatory cells, fibroblasts, dividing fibroblasts and angiogenic endothelial cells. Many components of the extracellular fluid, especially steep gradients of PO2, PCO2, pH, glucose and lactate, have been measured. After components of coagulation play out their role in the first few days after injury, macrophages sense excitatory substances and signs of respiratory distress, and secrete chemoattractants for endothelial cells and fibroblasts. If excitatory substances (such as silica) are eliminated, active fibrosis ends with the restoration of the energy supply. Some of the mitogens and chemoattractants acting as intercellular messengers between these cells have been isolated and identified.

Chronische Wunde

Underlying disease may impair normal wound healing, leading to chronic, poorly healing wounds. Efficient treatment strategies require identification and treatment of the underlying disease as well as directed correction of the wound healing defect. A thorough knowledge of tissue repair mechanisms at the cellular and molecular level will help to achieve these goals. This review focuses on new developments in wound healing research and the resulting non-operative therapeutic implications.

Nerve growth factor as an angiogenic factor

Nerve growth factor (NGF), a neurotrophin that plays a crucial role in promoting neurotrophic and neurotropic effects in sympathetic neurons, has recently been identified as a novel angiogenic molecule, which exerts a variety of effects in the cardiovascular system and on endothelial cells. In fact, NGF may contribute to maintenance, survival, and function of endothelial cells by autocrine and/or paracrine mechanisms. This review summarizes the involvement of NGF in the regulation of angiogenesis in both normal and pathological conditions.

Influence of the application of platelet-enriched plasma in oral mucosal wound healing

PURPOSE

The aim of this study was to describe and quantify the therapeutic value of platelet concentrate on the capillary density in oral mucosal wound healing.

MATERIAL AND METHODS

The subjects included 10 healthy edentulous patients who underwent bilaterally a sinus floor elevation procedure and a buccal onlay graft with autologous iliac crest bone for maxillary reconstruction. During surgery, platelet-rich plasma (PRP) was prepared from a blood sample taken from the patient. After randomization in a split-mouth design, at one side PRP was administered in the wound and at the contralateral side a placebo. At baseline, microvascular capillary density was scored with the orthogonal polarization spectral (OPS) imaging technique and repeated measurements were performed postoperatively on a daily basis until the tenth day, after which measurements were continued weekly until the fifth postoperative week.

RESULTS

Ten patients, five males and five females, were included in the study with a mean age of 54.2+/-9.1 years for females and 57.6+/-6.9 years for males. Donor platelet counts from whole blood had a mean value of 248.5+/-13.5 x 10(9)/l, while the value of platelet counts in the PRP had a mean of 975.9+/-97.9 x 10(9)/l. Wound healing was significantly accelerated in the PRP-treated mucosal wounds during the first 10 postoperative days. After the second week, no obvious differences between the PRP or placebo side could be noted.

CONCLUSION

PRP has a strong stimulant effect on capillary regeneration in wound healing. These effects are mainly noticeable during the early stages of wound healing.

Lactate stimulates endothelial cell migration

The significance of the high lactate levels that characterize healing wounds is not fully understood. Lactate has been shown to enhance collagen synthesis by fibroblasts and vascular endothelial growth factor (VEGF) production by macrophages and endothelial cells. VEGF has been shown to induce endothelial cell migration. However, it has not been shown whether accumulated lactate correlates with the biological activity of VEGF. Therefore, we investigated the effect of lactate on migration of endothelial cells. Human umbilical vein endothelial cells and human microvascular endothelial cells were cultured to subconfluent monolayers in standard six-well tissue culture plates. Following a 24-hour serum starvation, cells were treated with the indicated concentrations of l-lactate. Cell migration was assessed using a modified Boyden chamber. VEGF protein in the cell culture supernatant was measured by enzyme-linked immunoassay. Lactate-enhanced VEGF protein synthesis in a time- and dose-dependent manner. Lactate added into the bottom well did not stimulate cellular migration from the upper well. However, lactate when added together with endothelial cells to the bottom well of the Boyden chamber increased cellular migration in a dose-dependent manner. This effect was blocked by anti-VEGF and by cycloheximide. Lactate enhances VEGF production in endothelial cells, although lactate, itself, is not a chemoattractant. We conclude that the lactate-mediated increase in cellular migration is regulated by VEGF.

What can wound fluids tell us about the venous ulcer microenvironment?

Research into the healing of venous leg ulcers is increasing as they are a common problem. The wound fluid bathing an ulcer is thought to reflect the wound microenvironment, and the properties of wound fluids have been studied in attempts to find ways to promote healing. After a brief summary of normal wound healing, this article reviews some of the research that has been carried out on venous ulcer wound fluid, with respect to its biochemistry, proteolytic nature, growth factor profile, and effects on cell cultures. Some of the problems and pitfalls inherent in performing and interpreting wound fluid studies are discussed. Finally, a proposal is made for standardizing research on wound fluids that would improve comparisons between different studies.

Chronic wound fluid suppresses proliferation of dermal fibroblasts through a Ras-mediated signaling pathway

Wound fluid collected from chronic venous leg ulcers (chronic wound fluid (CWF)) has been shown to inhibit the growth of dermal fibroblasts by interfering with cell-cycle progression from G1 into S phase. Specifically, CWF was shown to downregulate the levels of hyperphosphorylated retinoblastoma tumor-suppressor gene (Rb) and cyclin D1, known to be critical for entering the S phase of the cell cycle. To further elucidate the effects of CWF, a Ras-mediated signaling pathway involving the mitogen-activated protein kinase kinase (MEK), known to modulate the expression of these cell-cycle-regulatory proteins, was examined. Transient transfection of dermal fibroblasts with constitutively active Ras abrogated the growth suppressive effects of CWF on hyperphosphorylated Rb (ppRb) and cyclin D1. In contrast, an MEK inhibitor PD 98059 mimicked the effects of CWF on these cell-cycle-regulatory proteins. Concurrent treatment with PD 98059 and CWF produced additive effects. Taken together, these results suggest that CWF inhibits the growth of dermal fibroblasts at least in part by decreasing the level of active Ras, resulting in decreased levels of ppRb and cyclin D1. Therefore, a Ras-dependent signaling pathway may mediate the growth inhibitory effect of CWF, and reconstitution of Ras activity may overcome this growth inhibitory effect.

Disappearance of the post-lesional laminin immunopositivity of brain vessels is parallel with the formation of gliovascular junctions and common basal lamina. A double-labelling immunohistochemical study

Previous studies revealed that during development the laminin immunopositivity gradually disappeared from the brain vessels, but temporarily re-appeared in them around lesions. The question of the present study was the correlation between the post-lesional vascular immunopositivity to laminin and the glial reaction. Following stab wounds, double fluorescent immunohistochemical labelling was performed against laminin (using a polyclonal antiserum against laminin 1) and glial fibrillary acidic protein. A number of vessels exhibited intense immunopositivity to laminin within the lesioned tissue. Where these laminin immunopositive vessels entered the perilesional brain substance, the astroglia formed contacts on them, and the separate vascular and glial basal laminae fused. The disappearance of the post-lesional laminin immunopositivity seemed to coincide with these phenomena. When monoclonal antibodies were applied against the beta1 and gamma1 laminin chains, vessels proved to be immunopositive at the lesion, but none in the intact brain tissue. No immunoreactivity was detected in the cases of alpha2 and beta2 chains. The results suggest that the disappearance of laminin immunopositivity may be attributed to that the epitopes become inaccessible for antibodies owing to the formation of gliovascular junctions and common basal lamina between astroglia and vessel. The possible role of an alteration in the laminin composition and the effect of fixation are discussed.

Role of ADP-ribosylation in wound repair. The contributions of Thomas K. Hunt, MD

Nearly 36 years ago Thomas K. Hunt, with Patrick Twomey, was the first to report that the level of lactate significantly increases in healing wounds. This observation convinced him that lactate, besides being the by-product of glycolysis, must have a regulatory role in the healing process. He set out to investigate this observation and found it to be so. This article is written in recognition of his foresight. It summarizes the salient findings emanating from this fundamental observation and describes the biochemical principles by which most of the lactate action may be explained. Down-regulation of the ubiquitous protein modification reaction called ADP-ribosylation turned out to be a basic signal behind the role of lactate in wound healing.

Spatial and temporal localization of transforming growth factor-beta1, bone morphogenetic protein-2, and platelet-derived growth factor-A in healing tooth extraction sockets in a rabbit model

PURPOSE

The purpose of this study was to test the hypothesis that spatial and temporal localization of growth factors transforming growth factor (TGF)-beta1, bone morphogenetic protein (BMP)-2, and platelet derived growth factor (PDGF)-A in a rabbit tooth extraction model correlate with the histologic events contributing toward healing.

MATERIALS AND METHODS

Twenty-four male New Zealand White rabbits were used in the study. Incisor teeth were extracted from both jaws, and the healing extraction socket with the surrounding jaw bone was harvested at 48 hours, 4 days, and 1, 2, 4, 8, 12, and 16 weeks. Tissues were fixed, decalcified, and processed for hematoxylin and eosin and immunohistochemical staining. The sections were stained to detect TGF-beta1, BMP-2, and PDGF-A. Stained sections were then imaged, and an automated computer program was used to detect the brown 3,3'-diaminobenzidine regions representing the location of growth factors of interest. The data were collected in terms of percentage area and intensity of stain, and an analysis of variance was conducted (Tukey-Kramer and Scheffe's test) for statistical comparison between different time points, jaws, and growth factors. These results were also compared with hematoxylin and eosin-stained histologic specimens obtained at similar time points.

RESULTS

Spatial and temporal differences in localization of TGF-beta1, BMP-2, and PDGF-A were observed across all time frames in both jaws. Statistically significant differences in percentage area and intensity of brown diaminobenzidine stain were detected temporally between TGF-beta1, BMP-2, and PDGF-A (P < or =.0001).

CONCLUSION

The results of this study showed positive correlation between histologic events and the spatial and temporal localization of TGF-beta1, BMP-2, and PDGF-A in a rabbit tooth extraction model.

Differential angiogenic and proliferative activity of surgical and burn wound fluids

BACKGROUND

Invasive surgical wounds exhibit the rapid production of a robustly proangiogenic environment. To compare the immediate angiogenic environment of wounds of different types, the angiogenic activity of fluid derived from burn injuries and wounds confined to the dermis was examined and compared with that of deeper surgical wounds.

METHODS

The angiogenic activity of surgical wound fluid (SWF) (n = 7), skin graft wound fluid (SGF) (n = 3), and burn wound fluid (BWF) (n = 4) was assessed by measuring endothelial cell (EC) proliferative activity, EC chemotactic activity, and angiogenic activity in the rat corneal assay. The fibroblast growth factor-2 (FGF-2) level of each wound fluid was determined by enzyme-linked immunosorbent assay.

RESULTS

SWF exhibited significant EC proliferative activity, SGF exhibited intermediate activity, and BWF displayed no EC proliferative activity. Seventy-one percent of SWF samples, 33% of SGF, and 0% of BWF contained significant EC chemotactic activity. Each wound fluid sample that demonstrated significant chemotactic activity also evoked a positive corneal angiogenic response. SWF contained 914 +/- 170 pg/mL of FGF-2, whereas SGF and BWF contained just 164 +/- 54 pg/mL and 37 +/- 7 pg/mL of FGF-2, respectively.

CONCLUSION

The results suggest that injuries confined to the dermis, whether thermal or excisional, elicit a less robust initial angiogenic stimulus than deep surgical wounds.

In vivo imaging of physiological angiogenesis from immature to preovulatory ovarian follicles

To develop a model for the study of physiological angiogenesis, we transplanted ovarian follicles onto striated muscle tissue and analyzed the process of microvascularization in vivo using repeated fluorescence microscopy. Follicles were mechanically isolated from unstimulated as well as pregnant mare's serum gonadotropin (PMSG)- or PMSG/luteinizing hormone (LH)-stimulated Syrian golden hamster ovaries and were transplanted as free grafts into dorsal skinfold chambers of untreated or synchronized hamsters. Follicles lacking thecal cell layers did not vascularize regardless whether harvested from unstimulated or PMSG-stimulated animals, but underwent granulosa cell apoptosis, as indicated in vivo by nuclear condensation and fragmentation of bisbenzimide-stained follicular tissue. In contrast, all follicles at 48 hours after PMSG treatment with a multilayered thecal shell exhibited initial signs of angiogenesis within 3 days. Vascularization was completed within 7 to 10 days, comprising a dense glomerulum-like microvascular network. Nature and extent of vascularization of follicles harvested at 72 hours after either PMSG or PMSG/LH treatment did not notably differ from each other when transplanted into the respective synchronized animals. However, follicles with PMSG/LH treatment revealed significantly larger microvessel diameters and higher capillary blood perfusion compared to follicles with sole PMSG treatment, probably reflecting the adaptation to the increased functional demand upon the LH surge. Using the unique experimental approach of ovarian follicle transplantation in the dorsal skinfold chamber of Syrian golden hamsters, we could show in vivo the developmental stage-dependent vascularization of follicular grafts with sustained potential to meet their metabolic demand by increased blood perfusion.

Role of leukocytes and endothelial cells in the development of angiogenesis in inflammation and wound healing

The basic signs and symptoms of inflammation and wound healing have been appreciated for thousands of years. However, the specific cells involved and their roles in this complex environment are still being elucidated today. In 1926, the origin of the phagocytic mononuclear ameboid wandering cell (macrophage) had not been determined. One popular theory was that the cells were differentiated from the endothelial cells of the nearby blood vessels, whereas others believed that the cells came from the peripheral blood or resting wandering cells. The purpose of this article is to review the seminal article published by Lang regarding this topic nearly 75 years ago. In addition, this article will review what is now known with regard to the role of the macrophage and endothelial cells in the development of angiogenesis, which is arguably the most critical component of successful inflammatory process or wound healing.

Lactate elicits vascular endothelial growth factor from macrophages: a possible alternative to hypoxia

Macrophages respond to various stimuli to produce angiogenic factors but few mechanistic details are known. We examined the effects of hypoxia, lactate and nicotinamide on the expression of vascular endothelial growth factor by cultured macrophages. These agents were chosen because they down-regulate polyadenosine diphosphoribose levels. Following exposure, conditioned media were analyzed for vascular endothelial growth factor protein. Nicotinamide adenine dinucleotide, polyadenosine diphosphoribose, and vascular endothelial growth factor mRNA were measured in the cellular fraction. Angiogenic capacity of the conditioned media was tested in rabbit corneas and Matrigel implants. All three agents, hypoxia, lactate and nicotinamide, elicited significantly increased levels of vascular endothelial growth factor mRNA and vascular endothelial growth factor in the conditioned media, and these levels were paralleled by their angiogenic activity. Polyadenosine diphosphoribose in the cellular fraction was correspondingly depressed. Anti-vascular endothelial growth factor antibody inhibited most of the angiogenic response whereas anti-basic fibroblast growth factor antibody had little effect. We propose that redox changes associated with the alteration of cellular nicotinamide adenine dinucleotide and polyadenosine diphosphoribose are involved in lactate-mediated VEGF expression.

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis

BACKGROUND

We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate.

METHODS

After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 micrograms/application), heparin (250 micrograms/application) or suramin (250 micrograms/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n = 48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed.

RESULTS

Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs.

CONCLUSIONS

These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.

General principles of wound healing

Wound healing is a complex process involving different biologic and immunologic systems. Despite improvements in diagnostics and therapy, wound failures remain a clinical problem. The approach to a nonhealed wound is an interdisciplinary challenge that should not be underestimated. Better understanding of the complex wound-healing cascade helps our approach to wound healing and its possible failure. Manipulations of the involved immunologic features offer future therapeutic strategies.

The chick embryo chorioallantoic membrane as an in vivo wound healing model

The chick embryo chorioallantoic membrane (CAM) was used as an in vivo wound healing model. A full excision of a 1 mm2 CAM area was filled by a granulation tissue after 96-120 h, which eventually formed a scar in 75% of the cases. In the remaining 25%, a solution of continuity was left which, however, was smaller in size than the one observed immediately after the excision. Under the microscope, the CAM area involved in the repair process showed: i. hyperplasia of the chorionic epithelium; ii. about three times as many microvessels and fibroblasts in the mesenchyme as in the normal adjacent control regions; iii. an inflammatory infiltrate mostly consisting of macrophages; and iv. a strong positivity for fibronectin in the extracellular matrix. The validity of this experimental model appears to be confirmed by the fact that we were able to reproduce all the critical events controlling the wound healing process, such as re-epithelization, angiogenesis, formation of an inflammatory infiltrate and deposition of one of the main constituents of the extracellular matrix, such as fibronectin.

The effect of the platelet derived wound healing formula and the nerve growth factor on the experimentally injured spinal cord

The main purpose of this study is to investigate the effect of platelet derived wound healing formula (PDWHF) and nerve growth factor (NGF) in the treatment of experimental spinal cord injury. PDWHF is a conglomerate of growth factors which include platelet derived growth factor (PDGF), platelet derived angiogenesis factor (PDAF), transforming growth factor-beta (TGF beta) and platelet factor IV (PF4). Complete spinal cord transection was performed at T12 in rats and the treatment of the spinal cord injury was achieved by filling the dead space with type 1 collagen gel impregnated with PDWHF, or with 2.5S-NGF. Controls were treated with only type 1 collagen gel. Animals were sacrificed at 1, 2 or 3 months. Histopathologically, tissue autolysis and cavity formation by phagocytosis expanded 1-3 mm into the cord stumps and the volume of cavitation was less in the two treated groups. In the NGF group, a greater number of surviving nerve cells were observed in this region. Most of the control animals formed only thin, short axonal bundles, however, increased axonal regrowth was noted in animals treated with trophic factors, especially in the NGF group. The NGF group formed thick axonal bundles and abundant neuroma. Increased angiogenesis was observed in the collagen gel matrix and the injured spinal cord parenchyma, in the PDWHF group. Recent studies have shown that mammalian adult CNS possesses the ability for structural and/or functional plasticity following injury under appropriate circumstances. In this in vivo study, exogenous NGF appeared to induce axomal outgrowth and nerve cell survival. PDWHF produced notable angiogenesis which seemed to improve the extracellular microenvironment. This may be important for the delivery of exogenous trophic factors, nutrients and for the changes of extracellular matrices to support nerve cells and axons.

Multiple giant disseminated pyogenic granuloma in three patients burned by boiling milk

BACKGROUND

Pyogenic granuloma is a common benign skin tumor. The multiple disseminated form of the disease is relatively rare.

METHODS

We examined three patients who developed giant pyogenic granuloma after burns from boiling milk. The patients were a 1.5-year-old boy, a 5-year-old girl, and a 35-year-old woman, All three patients had second-degree burns over their face and trunk.

RESULTS

In these patients, pyogenic granuloma had developed over the previously burned areas 2-3 weeks after exposure. The general condition of the patients remained good and all lesions involuted spontaneously. In a 6-month follow-up period no relapse of the lesions was seen.

CONCLUSIONS

The cause for development of multiple giant pyogenic granulomas after burns from milk remains unknown, but milk proteins or other components of milk, microorganisms, or the burn itself may be causative factors.

Shifts in the concentrations of magnesium and calcium in early porcine and rat wound fluids activate the cell migratory response

Accruing evidence indicates that the levels of extracellular Mg2+ and Ca2+ can have a distinct impact on the adhesive and migratory activities of many cell types. The physiological relevance of these observations, however, has remained largely unexplored. In the present study, wound fluids collected throughout the early stages of cutaneous wound repair were examined for possible Mg2+ and Ca2+ fluctuations. Early in the process, when cell migration into the wound site is initiated, Mg2+ is elevated and Ca2+ is reduced (Mg2+:Ca2+ = 1). As wound healing progresses, wound fluid concentrations of Mg2+ and Ca2+ begin to return to normal plasma levels (Mg2+:Ca2+ = 0.4). When macrophages, keratinocytes, fibroblasts, and endothelial cells were exposed to dialyzed wound fluid, the migration stimulated by undialyzed wound fluid was lost. Addition back to dialyzed wound fluid of 24 h, postinjury concentrations of Mg2+ and Ca2+ restored all migratory stimulus. This observed migration is approximately twofold greater than when normal plasma Mg2+ and Ca2+ concentrations are present. Changes in the levels of Mg2+ and Ca2+ in wound fluid occur during the same period that inflammatory cells, keratinocytes, fibroblasts, and neovasculature have been shown to migrate during wound healing in vivo. Together, these data suggest that the impact of these changes on integrins and E-cadherin may play a direct role in the activation and maintenance of the migratory phenotypes of the cells involved in the wound healing process.

Sequential changes in the cell mediators of peritoneal and wound fluids after surgery

The concentrations of cell mediators in the peritoneal and wound fluids of patients who underwent abdominal surgery or mastectomy were determined sequentially and compared with the concomitant changes in blood components. The level of interleukin-6 (IL-6) in the peritoneal and wound fluids was significantly higher than the plasma level after gastrectomy (P < 0.001), cholecystectomy (P < 0.05), and mastectomy (P < 0.05), although the level of plasma IL-6 was also higher postoperatively than before surgery (P < 0.001, P < 0.05). Significantly higher levels of tumor necrosis factor-alpha were detected in the peritoneal and wound fluids (P < 0.01, P < 0.05, respectively) after surgery despite its absence in plasma. A platelet-specific protein and a protein specific for fibroblasts were also measured. Thus, mediators derived from various cells were shown to be present in human peritoneal and wound fluids, indicating that the local production of these mediators plays an important role in the process of tissue repair.

Effects of nicardipine on tube formation of bovine vascular endothelial cells in vitro

BACKGROUND AND PURPOSE

The purpose of this study was to assess the effect of nicardipine, a Ca2+ channel blocker, on angiogenesis in vitro.

METHODS

Bovine carotid artery endothelial cells were cultured between type I collagen gel layers with 10(-9) to 10(-5) M nicardipine. The morphological changes were monitored by phase-contrast microscopy and photographed. The total length of tubular structures was measured with an image analyzer system. Endothelial proliferation and migration assays were also performed with the same doses of nicardipine.

RESULTS

Cultured endothelial cells form tubular structures between collagen gel layers. Tube formation of endothelial cells was suppressed by culture with 10(-9) to 10(-5) M nicardipine in a dose-dependent manner. Migration of endothelial cells was also suppressed by the same doses of nicardipine. However, proliferation of endothelial cells was not enhanced.

CONCLUSIONS

Nicardipine acts as an inhibitor of angiogenesis in vitro by inhibiting the migration of endothelial cells. This result suggests that nicardipine may have therapeutic potential in angiogenic disorders such as tumor growth, atherogenesis, and diabetic retinopathy.

Modern wound dressings: a systematic approach to wound healing

The advent of modern wound care management constitutes one of the most innovative applications of medical device technology. The foundation for wound care recent advances has been built upon the developments achieved in polymer technology over the last three decades. New and unique materials have been engineered to provide properties with significant technical and clinical benefits. These new wound care products were made possible by the convergence of three interrelated disciplines: (1) more complete understanding of the underlying principles of dermal wound healing processes, (2) new elastomeric polymers capable of being fabricated into protective dressings, and (3) advances in breathable adhesive technology. The following discussion provides a critical review of the current status of technology and the worldwide opportunities for improved wound management products. Particular attention is focused on the clinical applications of the newer, breathable dressing products, which approximate a temporary synthetic artificial skin.

Angiogenic activity of fibrin degradation products is located in fibrin fragment E

The source of angiogenic activity of fibrin degradation products has been sought in a series of experiments, applying degradation products from different types of fibrin and fibrinogen to the chick chorioallantoic membrane. The presence of platelets or fibronectin during clotting was not essential for activity, and neither was crosslinking. Fibrinogen degradation products were non-stimulatory, as was serum. Molecular sieve column chromatography indicated a range of active fragments. Admixture of active fibrin degradation products with antifibrin fragment E, but not D, antiserum neutralized activity. Preparations containing only fibrin fragment E retained activity. A commercial preparation of fibrinogen fragment E was inactive until treated with thrombin. These experiments point to fibrin fragment E being the source of angiogenic activity, with thrombin cleavage being the essential step in generating activity.

Endothelial cell chemotactic factor derived from human glioma cell lines

✓ The authors report a study of the human umbilical vein endothelial cell chemotactic factor derived from human malignant glioma cell lines. The endothelial cell chemotactic activity of serum-free conditioned medium from cultures of U-373MG, U-251MG, or U-105MG cell lines was measured using a 48-well microchemotaxis chamber. The best response was from U-373MG, which was selected for further study. Chemotactic activity was contained in materials unadsorbed and adsorbed to the heparin-affinity column. Because the higher activity was seen in the unadsorbed material, it was used for characterization and partial isolation. The chemotactic activity was decreased under the condition of tumor protein synthesis inhibition. Heating, exposure to acid, and trypsin digestion also decreased the activity. The factor was found to be a protein with a relative molecular weight of greater than 200 kD; it has no mitogenic activity for endothelial cells in vitro and, partially purified, it was not identical to any other known endothelial cell chemotactic or mitogenic factor. Fibronectin was not detected, and anti-fibronectin antibody failed to inhibit the activity of the factor. These results suggest that malignant glioma cells produce a yet unknown endothelial cell chemotactic factor.