Expression Patterns Of Growth Factors Research Articles

Expresión génica del factor de crecimiento BMP15, GDF9, FGF2 y sus receptores en células foliculares bovinas

Introducción. El crecimiento y la maduración folicular implican una serie de transformaciones de diversos componentes del folículo, como el ovocito, las células de la granulosa y de la teca. Varios factores de crecimiento, incluyendo factor de crecimiento de diferenciación 9 (GDF9), proteína morfogénica ósea 15 (BMP15) y factor de crecimiento de fibroblastos básico (FGF2) son importantes para el desarrollo folicular y maduración de ovocitos, por su capacidad de aumentar la proliferación de las células de la granulosa, teca y el estroma ovárico. Objetivo. Evaluar la expresión de los factores de crecimiento GDF9, BMP15, FGF2 y sus principales receptores: el receptor 1 del factor de crecimiento transformante beta (TGFβ-R1), el receptor de la proteína morfogénica del hueso tipo IB (BMPR-IB) y el receptor del factor de crecimiento fibroblástico 2 (FGFR2) en células foliculares bovinas. Materiales y métodos. Se realizó la extracción de ARN total de pooles de ovocitos (OOs) y células del cumulus (CCs) de complejos cumulus-ovocito (COCs) y del pellet de células foliculares (PCs) provenientes de 70 ovarios obtenidos de 96 vaquillonas para carne, colectados en un frigorífico local. Los patrones de expresión de los factores de crecimiento y sus receptores en las células foliculares bovinas fueron evaluados por retro-transcripción seguida de la reacción en cadena de la polimerasa (RT-PCR). Resultados. La presencia de los transcriptos de ARNm de los genes GDF9, BMP15, FGF2, TGFβ-R1, BMPR-IB y FGFR2 fue detectada por RT-PCR en todas las células estudiadas. Es la primera vez que se reporta en ovocitos bovinos la expresión de los receptores TGFβ-R1 y BMPR-IB. Conclusiones. La presencia de transcriptos de factores de crecimiento y sus receptores en las células estudiadas, indica que estos factores podrían actuar como reguladores paracrinos y autocrinos de la foliculogénesis.

VEGF, FGF-2 and TGFβ expression in the normal and regenerating epidermis of geckos: implications for epidermal homeostasis and wound healing in reptiles.

The skin is a bilayered organ that serves as a key barrier between an organism and its environment. In addition to protecting against microbial invasion, physical trauma and environmental damage, skin participates in maintaining homeostasis. Skin is also capable of spontaneous self-repair following injury. These functions are mediated by numerous pleiotrophic growth factors, including members of the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and transforming growth factor β (TGFβ) families. Although growth factor expression has been well documented in mammals, particularly during wound healing, for groups such as reptiles less is known. Here, we investigate the spatio-temporal pattern of expression of multiple growth factors in normal skin and following a full-thickness cutaneous injury in the representative lizard Eublepharis macularius, the leopard gecko. Unlike mammals, leopard geckos can heal cutaneous wounds without scarring. We demonstrate that before, during and after injury, keratinocytes of the epidermis express a diverse panel of growth factor ligands and receptors, including: VEGF, VEGFR1, VEGFR2, and phosphorylated VEGFR2; FGF-2 and FGFR1; and phosphorylated SMAD2, TGFβ1, and activin βA. Unexpectedly, only the tyrosine kinase receptors VEGFR1 and FGFR1 were dynamically expressed, and only during the earliest phases of re-epithelization; otherwise all the proteins of interest were constitutively present. We propose that the ubiquitous pattern of growth factor expression by keratinocytes is associated with various roles during tissue homeostasis, including protection against ultraviolet photodamage and coordinated body-wide skin shedding.

Transgenerational beneficial effect of Arthrospira (Spirulina) platensis on the rabbit ovaries

Despite the well-known health properties of microalga Arthrospira (Spirulina) platensis, little is known about its effects on female reproduction. The aim of this study was to establish whether including A. platensis in the diet during sexual maturation has an effect on the folliculogenesis and expression patterns of growth factors as bone morphogenetic protein 15 (BMP15) and growth differential factor 9 (GDF9) in the ovaries of the mothers and F1 female offspring in rabbits. The research was conducted using 28 white New Zealand rabbits in total, and seven were individually treated with 350 mg kg-1 of A. platensis at 2 to 6 months of age, prior to the insemination. The morphometric evaluation of the ovaries, RT-PCR, and immunohistochemical analyses of GDF9 and BMP15 expression in the oocytes and cumulus cells of both generations was performed. Arthrospira platensis supplementation led to an increase in the weight of ovaries, in the density of the primary and secondary follicles in the ovaries of treated mothers and their F1 offspring, and in the live body weight of offspring born to the treated mothers. BMP15 expression levels in the oocytes and cumulus cells, and GDF9 expression in the oocytes of treated mothers were enhanced. This increase in BMP15 expression levels was shown to be inherited in the oocytes and cumulus cells of the F1 females born to treated mothers. These data suggests that the A. platensis-supplemented diet during the sexual maturation exerts transgenerational beneficial effects on the folliculogenesis in rabbits.

116 - The Effect of Nicotine Cessation on Bone Marrow Stem Cell Proliferation and Differentiation

BACKGROUND CONTEXT: Cigarette smoking has been correlated with imbalance in bone formation, decreased success rates of bone union, bone graft revascularization and bone mineral density. Furthermore, several animal and in vitro studies found that nicotine affects fusion by modifying osteoblast activity and by changing the expression patterns of growth factors and cytokines. However, data on the period of smoking cessation is still sparse.

Dinitrophenol modulates gene expression levels of angiogenic, cell survival and cardiomyogenic factors in bone marrow derived mesenchymal stem cells

Various preconditioning strategies influence regeneration properties of stem cells. Preconditioned stem cells generally show better cell survival, increased differentiation, enhanced paracrine effects, and improved homing to the injury site by regulating the expression of tissue-protective cytokines and growth factors. In this study, we analyzed gene expression pattern of growth factors through RT-PCR after treatment of mesenchymal stem cells (MSCs) with a metabolic inhibitor, 2,4 dinitrophenol (DNP) and subsequent re-oxygenation for periods of 2, 6, 12 and 24h. These growth factors play important roles in cardiomyogenesis, angiogenesis and cell survival. Mixed pattern of gene expression was observed depending on the period of re-oxygenation. Of the 13 genes analyzed, ankyrin repeat domain 1 (Ankrd1) and GATA6 were downregulated after DNP treatment and subsequent re-oxygenations. Ankrd1 expression was, however, increased after 24h of re-oxygenation. Placental growth factor (Pgf), endoglin (Eng), neuropilin (Nrp1) and jagged 1 (Jag1) were up-regulated after DNP treatment. Gradual increase was observed as re-oxygenation advances and by the end of the re-oxygenation period the expression started to decrease and ultimately regained normal values. Epiregulin (Ereg) was not expressed in normal MSCs but its expression increased gradually from 2 to 24h after re-oxygenation. No change was observed in the expression level of connective tissue growth factor (Ctgf) at any time period after re-oxygenation. Kindlin3, kinase insert domain receptor (Kdr), myogenin (Myog), Tbx20 and endothelial tyrosine kinase (Tek) were not expressed either in normal cells or cells treated with DNP. It can be concluded from the present study that MSCs adjust their gene expression levels under the influence of DNP induced metabolic stress. Their levels of expression vary with varying re-oxygenation periods. Preconditioning of MSCs with DNP can be used for enhancing the potential of these cells for better regeneration.

Patterning Expression of Regenerative Growth Factors Using High Intensity Focused Ultrasound

Temporal and spatial control of growth factor gradients is critical for tissue patterning and differentiation. Reinitiation of this developmental program is also required for regeneration of tissues during wound healing and tissue regeneration. Devising methods for reconstituting growth factor gradients remains a central challenge in regenerative medicine. In the current study we develop a novel gene therapy approach for temporal and spatial control of two important growth factors in bone regeneration, vascular endothelial growth factor, and bone morphogenetic protein 2, which involves application of high intensity focused ultrasound to cells engineered with a heat-activated- and ligand-inducible gene switch. Induction of transgene expression was tightly localized within cell-scaffold constructs to subvolumes of ∼30 mm³, and the amplitude and projected area of transgene expression was tuned by the intensity and duration of ultrasound exposure. Conditions for ultrasound-activated transgene expression resulted in minimal cytotoxicity and scaffold damage. Localized regions of growth factor expression also established gradients in signaling activity, suggesting that patterns of growth factor expression generated by this method will have utility in basic and applied studies on tissue development and regeneration.

Different expression patterns of growth factors in rat fetuses with spina bifida aperta after in utero mesenchymal stromal cell transplantation

Background aimsIn a previous study, we successfully devised a prenatal surgical approach and transplanted mesenchymal stromal cells (MSCs) to fetal rat spinal column to treat retinoic acid–induced neural tube defects in rat. Our results show that MSCs survived, migrated and differentiated into neural lineage cells. We intended to study various growth factor expressions in rat fetal spinal cords with spina bifida aperta after in utero MSC transplantation and the effect of in vivo growth factor introduction for prenatal spina bifida treatment. MethodsPregnant rats were treated with retinoic acid on embryonic day 10 and then received fetal surgery for MSC transplantation and/or lentiviral epidermal growth factor (EGF) injection on embryonic day 16; various growth factor expression in spinal cords from embryonic day 20 fetuses were analyzed by means of quantitative reverse transcriptase–polymerase chain reaction. Terminal deoxynucleotidyl transferase dUTP nick end labeling analysis was performed to observe spinal tissue apoptosis. ResultsGrowth factor expression was dysregulated in spinal cords with spina bifida. After MSC transplantation, we observed significantly increased expression of EGF, fibroblast growth factor (FGF)-8, FGF-2 and FGF-20 in the MSC transplantation group compared with blank injection; Furthermore, EGF expression positively correlated with surviving MSC amounts. Expression of other growth factors was not significantly different. In vivo EGF introduction reduced spinal tissue apoptosis. ConclusionsOur results suggest that intrinsic EGF and FGF-2, FGF-8 and FGF-20 might affect the in vivo fate of transplanted MSCs in a fetal rat spina bifida model. In vivo EGF introduction together with MSC transplantation might serve as a new strategy for prenatal spina bifida treatment.

Bevacizumab Treatment for Meningiomas in NF2: A Retrospective Analysis of 15 Patients

Bevacizumab treatment can result in tumor shrinkage of progressive vestibular schwannomas in some neurofibromatosis 2 (NF2) patients but its effect on meningiomas has not been defined.To determine the clinical activity of bevacizumab against NF2-related meningiomas, we measured changes in volume of meningiomas in NF2 patients who received bevacizumab for treatment of progressive vestibular schwannomas. A radiographic response was defined as a 20% decrease in tumor size by volumetric MRI analysis. In addition, we determined the expression pattern of growth factors associated with tumor angiogenesis in paraffin-embedded tissues from 26 unrelated meningiomas. A total of 48 meningiomas in 15 NF2 patients were included in this study with a median follow up time of 18 months. A volumetric radiographic response was seen in 29% of the meningiomas (14/48). Tumor shrinkage was not durable: the median duration of response was 3.7 months and the median time to progression was 15 months. There was no significant correlation between pre-treatment growth rate and meningioma response in regression models. Tissue analysis showed no correlation between tumor microvascular density and expression of VEGF pathway components. This data suggests that, in contrast to schwannomas, activation of VEGF pathway is not the primary driver of angiogenesis in meningiomas. Our results suggest that a minority of NF2-associated meningiomas shrink during bevacizumab therapy and that these responses were of short duration. These results are comparable to previous studies of bevacizumab in sporadic meningiomas.

Growth factor and cytokine expression of human mesenchymal stromal cells is not altered in an in vitro model of tissue damage

The beneficial effect of human (h) mesenchymal stromal cell (MSC) transplantation in a variety of cell-based intervention strategies is widely believed to be because of paracrine mechanisms. The modification of hMSC cytokine and growth-factor expression patterns were studied following exposure to lipopolysaccharide (LPS) and tissue homogenates (representing tissue debris) from normal and pathologic tissues. Human bone marrow-derived MSC were stimulated with LPS or exposed to homogenate from normal or pathologic rat spinal cord or heart. The expression profiles of a number of cytokines and growth factors were investigated using quantitative reverse transcription (RT)-polymerase chain reaction (PCR) with human-specific primers. The effects of tissue homogenates on hMSC proliferation and migratory behavior were also investigated. Stimulation of hMSC with LPS resulted in an up-regulation of interleukin (IL)-1β, IL-6 and IL-8. However, the pattern of up-regulation varied between donor samples. Furthermore, LPS treatment resulted in a donor-dependent alteration of growth factor expression. Induction of a shift in expression pattern was not observed following exposure to homogenates from either normal or pathologic tissues. Tissue homogenates did stimulate cell proliferation, but not migration. The hMSC expression pattern is apparently stable, even when cells are confronted by debris from different tissue types. However, treatment of hMSC with LPS is able to change the expression of cytokines and growth factors in a donor-dependent manner that may enhance their potential use in regenerative medicine.

Bone Marrow‐Derived Cells Stimulate Healing by Modulating Early Inflammatory Processes

Improvements in healing and vascular growth from acute exogenous bone marrow‐derived cell (BMDC) therapy are apparent by a few days after injury, suggesting that BMDCs modulate early inflammatory events. That MCP‐1 is essential for BMDC mediated healing supports this hypothesis. To examine BMDC impact on inflammatory processes and subsequent growth factor production, BMDCs from healthy (wt), obese diabetic (db) and monocyte chemoattractant protein‐1 (MCP‐1‐) knockout mice were injected into ischemic mouse hindlimbs. (BMDCs from C57Bl/6 but not db or MCP‐1‐ mice stimulate MCP‐1 production and promote limb healing.) Fewer immunolabeled monocytes (day 3) and neutrophils (day 1) were seen in ischemic limbs treated with BMDCs from db and MCP‐1‐ mice than those that received cells from wt mice. However, levels of six pro‐angiogenic growth factors measured by ELISA at days 1, 3, and 5 did not correlate with the extent of monocyte/neutrophil infiltration or healing. We observed a complex temporally regulated pattern of growth factor expression in ischemic muscle that differed depending on cell treatment, but at all time points for all factors differences were at most 2‐fold. Thus, BMDCs may stimulate healing by an immunomodulatory process that only modestly impacts pro‐angiogenic growth factor expression and that may not require their upregulation to induce vascular growth and healing.Support: NIH DK55965

Selective regulation of growth factor expression in cultured cortical astrocytes by neuro-pathological toxins

Astrocytes are integrated in the complex regulation of neurodegeneration and neuronal damage in the CNS. It is well-known that astroglia produces a plethora of growth factors which might be protective for neurons. Growth factors prevent neurons from cell death and promote proliferation and differentiation of precursor cells. Previous data suggest that astrocytes may respond to toxic stimuli by a selective mobilization of guarding molecules. In the present study, we have investigated the potency of different pathological stimuli such as lipopolysaccharides, tumor necrosis factor α, glutamate, and hydrogen peroxide to activate cultured cortical astroglia and stimulate growth factor expression. Astroglial cultures were exposed to the above factors for 24 h at non-toxic concentrations for astrocytes. Growth factor expression was analyzed by real-time PCR, oligo-microarray technique, and ELISA. Insulin-like growth factor-1 was selectively down-regulated by lipopolysaccharides and tumor necrosis factor α, bone morphogenetic protein 6 by all stimuli. In contrast, lipopolysaccharides, tumor necrosis factor α, and glutamate increased leukemia inhibitory factor. Fibroblast growth factor 2 was up-regulated by lipopolysaccharides and tumor necrosis factor α and down-regulated by hydrogen peroxide. Besides hydrogen peroxide, all other stimuli promoted vascular epithelial growth factor A mRNA and protein expression. It appears that lipopolysaccharides but not tumor necrosis factor α effects on vascular epithelial growth factor A depend on the classic NFκB pathway. Our data clearly demonstrate that astroglia actively responses to diverse pathological compounds by a selective expression pattern of growth factors. These findings make astrocytes likely candidates to participate in disease-specific characteristics of neuronal support or damage.

M2087 The Expression Patterns of Growth Factors Are Different in Gallbladder Cancers According to the Gross Type

M2087 The Expression Patterns of Growth Factors Are Different in Gallbladder Cancers According to the Gross Type

Prenatal choline supplementation attenuates neuropathological response to status epilepticus in the adult rat hippocampus

Prenatal choline supplementation (SUP) protects adult rats against spatial memory deficits observed after excitotoxin-induced status epilepticus (SE). To examine the mechanism underlying this neuroprotection, we determined the effects of SUP on a variety of hippocampal markers known to change in response to SE and thought to underlie ensuing cognitive deficits. Adult offspring from rat dams that received either a control or SUP diet on embryonic days 12–17 were administered saline or kainic acid (i.p.) to induce SE and were euthanized 16 days later. SUP markedly attenuated seizure-induced hippocampal neurodegeneration, dentate cell proliferation, and hippocampal GFAP mRNA expression levels, prevented the loss of hippocampal GAD65 protein and mRNA expression, and altered growth factor expression patterns. SUP also enhanced pre-seizure hippocampal levels of BDNF, NGF, and IGF-1, which may confer a neuroprotective hippocampal microenvironment that dampens the neuropathological response to and/or helps facilitate recovery from SE to protect cognitive function.

A hypothetical mechanism of intraepidermal neurite formation in NC/Nga mice with atopic dermatitis

Pruritus is a symptom in atopic dermatitis (AD). Previous studies have reported that increased intraepidermal neurites are observed in AD, suggesting that the neuritogenesis is related to itching in the skin. This study was conducted to reveal the mechanism of intraepidermal neurite formation in AD. In this study, we used conventional (Conv) NC/Nga mice with AD. NC/Nga mice maintained in specific pathogen-free (SPF) condition were used as a control with no AD. Distribution of intraepidermal neurites and expression patterns of growth factors (NGF and amphiregulin (AR)) and cell-cell junctional molecules (E-cadherin, zona occludens 1 (ZO-1) and desmoglein 3 (Dsg3)) were examined in the skins by immunohistochemistry or quantitative RT-PCR. Furthermore, detection of gelatinase activity was performed with in situ zymography. The same experiments were conducted in ICR mice for comparison with NC/Nga mice. Neurite density and expression levels of growth factors and gelatinase were remarkably increased in the epidermis of Conv-NC/Nga mice compared with those of SPF-NC/Nga mice. Decreased expression of E-cadherin and ZO-1 and misexpression of Dsg3 were also observed in the atopic skins. In comparison with ICR mice, increases of neurite density and gelatinase activity were found in the skins of SPF-NC/Nga mice but expression levels of growth factors and cell-cell junctional molecules were unchanged. Increases of growth factors and gelatinase activity may be related to neurite outgrowth in the epidermis of atopic NC/Nga mice. Additionally, abnormal expressions of cell-cell junctional molecules in the epidermis may provide intercellular spaces for the neurite formation.

Differentiated Expression Patterns of Growth Factors in Routine Formalin-Fixed Endomyocardial Biopsies in the Early Postoperative Phase After Heart Transplantation

Background Platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) seem to play a key role in immunological reactions shortly after heart transplantation (HTx). The aim of this study was to analyze the time course of the expression of PDGF A and B, PDGF-receptor α (PDGF-Rα) and β, aFGF, and bFGF on formalin-fixed routine endomyocardial biopsies. Patients and Methods Right ventricular endomyocardial biopsies were obtained from 36 heart transplant recipients up to 2 weeks after HTx. According to the clinical course in the first postoperative year, 3 groups were formed: (1) clinically uneventful course (n = 12); (2) cardiac/systemic infections (n = 12); (3) acute rejection (n = 12). The growth factor expression was examined immunohistochemically. Results In the early phase after HTx, PDGF A, PDGF B, PDGF-Rα, and PDGF-Rβ were predominantly expressed in endothelial cells. The main expression of PDGF-Rα and bFGF was found in cardiomyocytes, endothelial cells, and smooth muscle cells. During the first 2 postoperative weeks, PDGF A, PDGF B, and PDGF-Rβ showed a similar time course of expression: A significantly elevated expression in the first week was followed by a decrease in the second week. In the rejection group, PDGF A was significantly elevated after the first week. Conclusions The increased expression of PDGF in the first postoperative week can be interpreted as an unspecific reaction to peritransplant injury. The prolonged expression of PDGF A, PDGF B, and PDGF-Rβ showed that there were ongoing immunological reactions in the transplant during week 2. The persistence of elevated PDGF A expression might be of prognostic value in terms of a risk factor for either infection or rejection.

Modulation of Growth Factor and Cytokine Expression by Nitric Oxide During Rat Colon Anastomotic Healing

We have previously shown that inhibition of nitric oxide generated by inducible nitric oxide synthase (iNOS) results in impaired colon anastomotic healing. Therefore, we proceeded to assess whether disruption of iNOS activity alters the normal pattern of growth factor expression during anastomotic healing. Two groups of male Sprague-Dawley rats underwent distal colonic division and anastomosis, jugular venous catheterization and subcutaneous placement of polyvinyl alcohol sponges. The first group (n = 10) received q8 hour intravenous injections of 10 mg/kg L-N-iminoethyl-lysine (L-NIL, a selective inhibitor of iNOS), while the second group (n = 12) received equal volumes of saline. On postoperative day 5, animals were sacrificed and anastomotic bursting pressure was determined. Histologic sections of the anastomosis were subjected to in situ hybridization versus mRNA of the proteins listed below. Positive controls were reacted with a poly-thymidine (poly-T) probe versus ubiquitous mRNA poly-adenine tails. Positively stained cells were quantified using a calibrated optical grid encompassing 0.5 mm 2 area centered over the anastomosis. Results are reported as the number of positive cells per 1000 cells positive for poly-T. L-NIL treated animals demonstrated an 18% decrease in wound fluid NO X compared to controls (29.2 ± 1.2 vs. 34.6 ± 2.0 μM, mean ± SEM; P = 0.035). This corresponded to a 17% decrease in anastomotic bursting pressure (153 ± 4 vs. 182 ± 8 mm Hg, mean ± SEM; P < 0.05). L-NIL also markedly increased the number of cells expressing transforming growth factor-β, tumor necrosis factor-α, vascular endothelial growth factor, and both inducible and endothelial forms of nitric oxide synthase. L-NIL had no effect on the expression of basic fibroblast growth factor. The data demonstrate that iNOS inhibition markedly disrupts the profile of cytokine and growth factor mRNA normally expressed during anastomotic healing. This provides in vivo evidence that NO modulates gene expression during anastomotic healing. ( J Gastrointest Surg 2003;7:393–399.)

Downregulation of integrin-linked kinase mRNA expression by nitric oxide in rat glomerular mesangial cells

Inflammatory glomerular diseases are accompanied by changes in the expression patterns of growth factors, mediators and matrix-associated proteins in mesangial cells and by the production of nitric oxide via the cytokine-inducible form of the nitric oxide synthase. Nitric oxide has been shown to act potently on gene transcription. To identify genes that are differentially expressed by endogenously produced nitric oxide, we forced rat mesangial cells to produce high amounts of nitric oxide by exposure to inflammatory cytokines and compared the mRNA expression patterns of cytokine-stimulated mesangial cells with cells that were additionally treated with the nitric oxide synthase inhibitor L-NMMA to block endogenous NO synthesis. We used a modification of a low stringency RT-PCR approach designated as RNA arbitrarily-primed polymerase chain reaction (RAP-PCR). In this way, we identified among others the integrin-linked kinase (ILK) as an NO-regulated gene. The NO-mediated changes in the mRNA and protein expression patterns of ILK were compared to that of “secreted protein acidic and rich in cystein” (SPARC), a gene that was identified as NO-regulated in the same set of experiments (Walpen et al., J. Am. Soc. Nephrol., 11, 468–476). ILK and SPARC mRNA levels by were downregulated by cytokines via endogenously produced nitric oxide in a comparable manner as verified by Northern blot analysis. In contrast, cytokine- induced NO production or administration of exogenous NO-donors strongly reduced SPARC protein levels without altering ILK protein content in mesangial cells over a period up to 72 hours. Blocking de novo protein synthesis showed a short half-life of SPARC (< 2 hours) whereas ILK-protein was stable over a period of 7 hours, indicating that NO-mediated reduction of ILK mRNA levels does not influence protein content of ILK in mesangial cells under the time limitations given under cell culture conditions. However, a role for cytokines/NO in ILK-long-term regulation in chronic inflammatory diseases that may influence phenotypic responses such as apoptosis or cell proliferation remains to be elucidated.

Growth factor expression in cartilage wound healing: temporal and spatial immunolocalization in a rabbit auricular cartilage wound model

Objective The ability of cartilage to regenerate following injury is limited, potentially leading to osteoarthritis. Integrative cartilage repair, necessary for durable restoration of cartilage lesions, can be regarded as a wound healing process. Little is known about the effects of growth factors regulating acute cartilage wound healingin vivo . In this study the temporal expression patterns of growth factors and proteoglycan content in cartilage wound edges in vivo were studied.Design Cartilage wounds were created in rabbit ear cartilage using a 6mm biopsy punch. Specimens were subsequently harvested 1, 3, 7, 14 and 28 days after surgery. Paraffin sections were thionin stained to visualize proteoglycan loss and replacement. Immunohistochemical staining of TGFβ1, TGFβ3, IGF-1, IGF-II and FGF-2 was used to define growth factor expression at the cartilage wound sites.Results Almost no effect of cartilage wounding was observed one day after surgery. A decrease of proteoglycan content, with a maximal loss at day 7, and a subsequent restoration was observed at the wound edges. Growth factor expression increased simultaneously. Maximal immunostaining for IGF1, IGFII, FGF2 and TGF-beta3 was observed at day 7, followed by a gradual decrease. Increased expression of TGFβ1 lasted from day 3 until day 14.Conclusion We have demonstrated the ability of chondrocytes to increase growth factor expression and to restore the rapid decrease in proteoglycan content in the initial phase following acute wounding. A temporal increase in intracellular growth factor expression suggests an autocrine and/or paracrine metabolic stimulation, which can be regarded a sign of chondrocytes repair capacity.

Delayed Changes in Growth Factor Gene Expression during Slow Remyelination in the CNS of Aged Rats

In this study we have examined whether the slower rate of CNS remyelination that occurs with age is associated with a change in growth factor expression patterns, an association that would provide further support for a causal relationship between growth factors and remyelination. Using quantitative in situ hybridization we have shown that there are differences in IGF-I, TGF-β1, and PDGF-A mRNA expression during remyelination of lysolecithin-induced demyelination in the spinal cord of young adult and old adult rats. IGF-I and TGF-β1 mRNA expression in old rats had a delayed and lower peak expression compared to young rats. The initial increase in PDGF-A mRNA expression was delayed in old rats compared to young rats, but after 5 days both age groups had similar patterns of expression, as was the expression pattern of FGF-2 mRNA at all survival times. In neither age group were increases in CNTF, NT-3, or GGF-2 mRNA expression detected. An analysis of the macrophage response using oligonucleotide probes for scavenger receptor-B mRNA indicated that differences in the macrophage response in young and old animals was the likely cause of the age related change in IGF-I and TGF-β1 mRNA expression patterns. On the basis of these data we suggest a model of remyelination in which PDGF is involved in the initial phase of oligodendrocyte progenitor recruitment, while IGF-I and TGF-β1 trigger the differentiation of the recruited cells into myelinating oligodendrocytes.

Increased expression of keratinocyte growth factor represents a stereotypic response to tracheal lumenal insult independent of injury mechanism.

The author hypothesized that keratinocyte growth factor may play a role in mucosal epithelial repair in large conducting airway, and that the nature of the injury, denudation with disruption of the basement membrane by either mechanical or chemical means, versus exfoliation (loss of suprabasal cells only), would be reflected in the growth factor response. This study evaluated the interdependent relationship between respiratory epithelial cells and the surrounding extracellular matrix in response to injury. In human cutaneous models, both keratinocyte growth factor and basic fibroblast growth factor are important in repair process. A sterile tracheal explant culture system was developed that allows for controlled wounding of the epithelial surface using either 1) NaOH, 2) mechanical debridement, or 3) suprabasal exfoliation. Control and injured bovine tracheas were studied by immunohistochemistry up to 24 hours after injury. Keratinocyte growth factor expression was strongly upregulated in epithelium and submucosa of denuded, but not exfoliation cultures, irrespective of means of injury. Disruption of the basement membrane by any means triggers a stereotypic growth factor response paradigm. This growth factor response has a consistent spatial, but variable, temporal relationship that is influenced by the type of injury-mechanical versus chemical. This work demonstrates that the type of injury (denudation vs. exfoliation) affects the expression patterns of growth factors that may be important for airways repair.