Transforming growth factor beta modulates the expression of collagenase and metalloproteinase inhibitor

An update on transforming growth factor-β (TGF-β): sources, types, functions and clinical applicability for cartilage/bone healing

Transforming growth factor-β (TGF-β) has been reviewed for its sources, types of isoforms, biochemical effects on cartilage formation/repair, and its possible clinical applications. Purification of three isoforms (TGF-β-1, β-2 and β-3) and their biochemical characterization revealed mainly their homo-dimer nature, with heterodimers in traces, each monomer comprised of 112 amino acids and MW. of 12 500 Da. While histo-chemical staining by a variety of dyes has revealed precise localization of TGF-β in tissues, immune-blot technique has thrown light on their expression as a function of age (neonatal vs. adult), as also on its quantum in an active and latent state. X-ray crystallographic studies and nuclear magnetic resonance (NMR) analysis have unraveled mysteries of their three-dimensional structures, essential for understanding their functions. Their similarities have led to interchangeability in assays, while differences have led to their specialized clinical applicability. For this purpose, their latent (inactive) form is changed to an active form through enzymatic processes of phosphorylation/glycosylation/transamination/proteolytic degradation. Their functions encompass differentiation and de-differentiation of chondrocytes, synthesis of collagen and proteoglycans (PGs) and thereby maintain homeostasis of cartilage in several degenerative diseases and repair through cell cycle signaling and physiological control. While several factors affecting their performance are already identified, their interplay and chronology of sequences of functions is yet to be understood. For its success in clinical applications, challenges in judicious dealing with the factors and their interplay need to be understood.

hCG, five independent molecules

INTRODUCTION

The hCG amino acid sequence supports 5 glycoproteins. All are called hCG forms. This review examines all 5 molecules, the hormone as produced by the placental syncytiotrophoblast cells, the sulfated hormone produced by the pituitary gonadotrope cells, the hyperglycosylated hCG autocrine made by placental cytotrophoblast cells, and the autocrine cancer promoters hyperglycosylated hCG, hCGß and hyperglycosylated hCGß as made by all malignancies. This review examines all the molecules and multiple proven functions, ranging from evolution to cancer promotion to hormone action.

RESULTS AND DISCUSSION

hCG forms are critical super-growth factors in humans, with an exceptional wide range of functions.

Trefoil factor 2 regulates airway remodeling in animal models of asthma

BACKGROUND

Epithelial denudation and metaplasia are important in the pathogenesis of airway remodeling and asthma. Trefoil factor 2 (TFF2) is a member of a family of peptides involved in protection and healing of the gastrointestinal epithelium but which are also secreted in the airway mucosa.

METHODS

We investigated the role of TFF2 in airway remodeling by histological and morphometric analysis of lung tissue from TFF2-deficient mice subjected to two relevant animal models of asthma: an ovalbumin model of allergic airways disease and an Aspergillus fumigatus antigen sensitization model.

RESULTS

In the ovalbumin model TFF2-deficient mice had increased goblet cell hyperplasia, but not epithelial thickening compared to wild-type (WT) counterparts. In the Aspergillus model TFF2-deficient mice also had increased goblet cell hyperplasia, and epithelial thickness was also increased in the Aspergillus-sensitized mice compared to WT controls. TFF2 deficiency was also associated with increased subepithelial collagen layer thickness.

DISCUSSION

The current study demonstrates a role of TFF2 in airway remodeling in mouse models of airway disease. Further studies into the mechanisms of action of TFF2 and its role in asthma are warranted.

On the dual roles and polarized phenotypes of neutrophils in tumor development and progression

Inconsistencies plague our understanding of the role of neutrophils in cancer and the literature provides evidence for a duality in neutrophil activity on the outcome of cancer. Here, the different effects of neutrophils during the multiple subprocesses of cancer development and progression are overviewed, in order to gain insight into the features of both antitumoral and protumoral tumor-associated neutrophils (TAN). Neutrophils can counteract the progression of malignancies through tumor cytotoxicity, tumor rejection and enhancement of antitumoral immune memory. These cells have recently been phenotypically denominated N1 neutrophils. Recent studies indicate that cytokines, such as TGF-β and IFN-β, are involved in directing neutrophil polarization by the tumor microenvironment. With the opposite polarity, N2 neutrophils may be detrimental for the host and beneficial for tumor growth, invasion and metastasis, e.g. through proteolysis of extracellullar matrix components, promotion of angiogenesis and mediation of immunosuppression.

Cytokine profiles in localized scleroderma and relationship to clinical features

Localized scleroderma (LS) is a disfiguring autoimmune disease of the skin and underlying tissue that mainly affects the pediatric population. Inflammation of the tissue leads to fibrosis and atrophy, causing physical and psychological disability that can continue throughout childhood into adulthood. Available therapies for LS have had variable effects and are associated with morbidity themselves. A better understanding of the pathophysiology of LS, especially during the active inflammatory phase, would lead to more directed and efficacious therapies. As in systemic sclerosis (SSc), the other form of scleroderma, T-helper (Th) cells and their associated cytokines have been suggested to contribute significantly to the pathophysiology of LS supported by the presence of cytokines from these lineages in the sera and tissue of LS patients. It is postulated that the imbalance between Th1/Th2/Th17 cell subsets drives inflammation in the early stages of disease (Th1 and Th17 predominant) and fibrosis in the later stages of scleroderma (Th2 predominant). We review the available experimental data regarding cytokines in LS and compare them to available clinical disease severity and activity features. This provides the platform to launch further investigations into the role of select cytokines in the pathogenesis of LS and to provide directed therapeutic options in the future.

Local administration of autologous synovium-derived cells improve the structural properties of anterior cruciate ligament autograft reconstruction in sheep

BACKGROUND

The structural properties of a tendon autograft deteriorate during the remodeling phase after anterior cruciate ligament (ACL) reconstruction.

HYPOTHESIS

A local application of autologous synovium-derived cells cultured in medium supplemented with transforming growth factor β (TGFβ) may inhibit the deterioration of structural properties of the tendon graft after ACL reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifty-two mature sheep were used. In each animal, the right knee underwent ACL reconstruction using the semitendinosus tendon autograft; then, the animals were divided into 5 groups of 10. No additional treatments were applied in group 1, whereas fibrin sealant was applied around the graft in group 2. In group 3, autologous synovium-derived cells cultured in standard medium were applied around the graft with fibrin sealant, whereas autologous synovium-derived cells cultured in TGFβ-supplemented medium were applied with fibrin sealant in group 4. In group 5, fibrin sealant containing 20 ng of TGFβ was applied around the graft. Each animal was sacrificed at 12 weeks after the surgery. In each group, 7 and 3 sheep were used for biomechanical and histologic evaluations, respectively. The remaining 2 sheep were used to confirm whether the applied cells infiltrated the graft at 1 week after surgery.

RESULTS

Confocal microscope observations showed that the applied cells that were labeled before implantation infiltrated into the superficial portion of the graft at 1 week. Biomechanically, the maximum load and the stiffness of groups 4 and 5 were significantly greater than those of groups 1, 2, and 3. Histologically, necrotic lesions were observed in the core portion of the midsubstance in groups 1 and 2. In groups 3, 4, and 5, no necrotic lesions were found in the midsubstance.

CONCLUSION

A local application of autologous synovium-derived cells cultured in TGFβ-supplemented medium or a fibrin sealant containing TGFβ significantly inhibits the natural deterioration of the structural properties of the tendon graft after ACL reconstruction.

CLINICAL RELEVANCE

Administration of autologous synovium-derived cells cultured in TGFβ-supplemented medium or TGFβ and fibrin glue alone can be a potential cell-based therapy to prevent graft deterioration after transplantation or accelerate mechanical restoration of the deteriorated graft.

Deconstructing fibrosis research: do pro-fibrotic signals point the way for chronic dermal wound regeneration?

Chronic wounds are characterized by inadequate matrix synthesis, no re-epithelialization, infection and ultimately no wound resolution. In contrast, fibrosis is characterized by overproduction of matrix and excess matrix contraction. As research in the fields of chronic wounds and fibrosis surges forward, important parallels can now be drawn between the dysfunctions in fibrotic diseases and the needs of chronic wounds. These parallels exist at both the macroscopic level and at the molecular level. Thus in finding the individual factors responsible for the progression of fibrotic diseases, we may identify new therapeutic targets for the resolution of chronic wounds. The aim of this review is to discuss how recent advances in fibrosis research have found a home in the treatment of chronic wounds and to highlight the benefits that can be obtained for chronic wound treatments by employing a translational approach to molecules identified in fibrosis research.

TGF-β1 gene polymorphism in renal transplant patients with and without gingival overgrowth

BACKGROUND

The incidence of gingival overgrowth among renal transplant patients treated with cyclosporine A ranges from 13% to 84.6%, and the overgrowth is not only esthetic but also a medical problem. We studied the determination of association between TGF-β1 (TGFB1) gene polymorphism and gingival overgrowth in kidney transplant patients medicated with cyclosporin A.

METHODS

Eighty-four kidney transplant patients with gingival overgrowth and 140 control transplant patients without overgrowth were enrolled into the case control study. TGFB1 polymorphism was determined using the PCR-RFLP assay for +869T > C in codon 10 and +915G > C in codon 25 as well as TaqMan real-time PCR assays for promoter -800G>A and -509C > T SNPs.

RESULTS

In kidney transplant patients suffering from gingival overgrowth, mean score of gingival overgrowth was 1.38 ± 0.60, whereas in control subjects it was 0.0. The patients with gingival overgrowth were characterized by similar distribution of TGFB1 genotypes and allele in comparison to subjects without gingival overgrowth. Among 16 potentially possible haplotypes of TGFB1 gene, only four were observed in the studied sample of kidney transplant patients: G_C_T_G, G_T_C_G, G_C_C_C, and A_C_T_G, with similar frequency in patients with and without gingival overgrowth.

CONCLUSION

No association between the TGFB1 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporine A.

Immunopathogenetic and pharmacological aspects of interstitial lung diseases

Interstitial lung diseases (ILDs) are inflammatory diseases characterized by slow and progressive destruction of alveolar-capillary functional units, often leading to respiratory failure and death. A first stage of alveolitis and a following stage of fibrosis provoke an anatomical distortion of the peripheral airways and the interstitium, and for their smoldering evolution and non-specificity of symptoms ILDs may remain undiagnosed and untreated for a long time. In this review we exploited the immunopathogenetic aspects and the therapeutical approaches to this frequently unrecognized and severe disease.

Maternal obesity induces fibrosis in fetal myocardium of sheep

Maternal obesity (MO) has harmful effects on both fetal development and subsequent offspring health. The impact of MO on fetal myocardium development has received little attention. Fibrogenesis is regulated by the transforming growth factor-β (TGF-β)/p38 signaling pathway. Using the well-established model of MO in pregnant sheep, we evaluated the effect of MO on TGF-β/p38 and collagen accumulation in fetal myocardium. Nonpregnant ewes were assigned to a control diet [Con, fed 100% of National Research Council (NRC) nutrient recommendations] or obesogenic diet (OB, fed 150% of NRC recommendations) from 60 days before conception. Fetal ventricular muscle was sampled at 75 and 135 days of gestation (dG). At 75 dG, the expression of precursor TGF-β was 39.9 ± 9.9% higher (P < 0.05) in OB than Con fetal myocardium, consistent with the higher content of phosphorylated Smad3 in OB myocardium. The phosphorylation of p38 tended to be higher in OB myocardium (P = 0.08). In addition, enhanced Smad complexes were bound to Smad-binding elements in 75 dG OB fetal myocardium measured by DNA mobility shift assay (130.2 ± 26.0% higher, P < 0.05). Similar elevation of TGF-β signaling was observed in OB fetal myocardium at 135 dG. Total collagen concentration in OB was greater than Con fetal myocardium (2.42 ± 0.16 vs. 1.87 ± 0.04%, P < 0.05). Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-3 were higher in the Con group compared with OB sheep (43.86 ± 16.01 and 37.23 ± 7.97% respectively, P < 0.05). In summary, MO results in greater fetal heart connective tissue accumulation associated with an upregulated TGF-β/p38 signaling pathway at late gestation; such changes would be expected to negatively impact offspring heart function.

Effects of simulated bleeding in an in vitro nasal fibroblast wound healing model

BACKGROUND

We investigated the effect of simulated bleeding on plasminogen activity, matrix metalloproteinase (MMP) expression, and wound healing using a human fibroblast model.

METHODS

Nasal fibroblasts from three chronic rhinosinusitis (CRS) patients with nasal polyps and three controls were grown in culture and a standardized injury was created using a punch. To mimic bleeding, fibroblasts were stimulated with plasminogen (100 microg/mL), plasminogen + tranexamic acid (TA; 100 microg/mL) or media only. At 24, 48, and 72 hours after injury, we measured urokinase plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) activities and inactive and active MMP-2 and -9 expression.

RESULTS

Injury stimulated the nasal fibroblasts to express uPA and tPA and active and inactive MMP-2 and -9. In CRS patients, plasminogen significantly decreased MMP-9 expression after 48 hours (p < 0.04). In untreated fibroblasts, we observed a decrease in active MMP-9 expression, whereas plasminogen increased active MMP-9 expression after 48 hours (p < 0.04). At 24 hours, active MMP-9 expression was reduced by plasminogen +/- TA (p < 0.02). Plasminogen also stimulated uPA expression in CRS patient fibroblasts after 48 hours (p < 0.04). Fibroblast proliferation occurred when exposed to plasminogen and was strongly modulated by uPA and inactive and active MMP-2. The quality of wound healing was affected by inactive MMP-2, uPA and tPA, simulation, and inhibition of bleeding.

CONCLUSION

Activation of the plasminogen pathway and inactive MMP-2 expression tended to increase both proliferation of nasal fibroblasts and MMP-9 expression as a marker for deterioration of the quality of wound healing.

T Lymphocyte Activation Profiles in Peripheral Blood of Long-Versus Short-Term Residents of Kuwait: Comparison with Asthmatics

Introduction: During the Arabian Gulf Wars of 1991 and 2003, the resident population of Kuwait sustained heavy exposure to environmental toxicants introduced by military activities. No comprehensive studies have been conducted to assess how exposure to the wartime and postwar environment may have altered the fundamental patterns of immune reactivity among Kuwaitis in ways that affect pathogenesis of disease. This present study addresses this issue by characterising immunological features of asthma and allergies in a Kuwaiti population that is unique and possibly correlates with toxicant exposures. Materials and Methods: Twenty-five long-term residents of Kuwait afflicted with bronchial asthma concurrent with rhinitis; and 2 healthy control groups: 18 long-term residents and 10 newcomers to Kuwait were evaluated by 2- and 3-colour flow cytometry for peripheral blood T cell subpopulation frequencies. Results: Relative to healthy, long-term residents, significantly elevated frequencies of all activated cell phenotypes were observed in the blood of the asthmatic group (P <0.05 to P <0.001), except for CD8+HLA-DR+ cells and a presumed T-regulatory (Treg) subpopulation: CD4+CD25high. The asthmatic group was also observed to have larger populations of CD3+ (pan-T cells), CD4+ (T helper cells) and CD8+ (cytotoxic T cells), CD3+CD56 (NKT-like cells) and CD56+CD16+ (NK cells) compared to healthy long-term residents. Compared to healthy recent immigrants, the blood of long-term residents contained elevated levels of CD3+CD56+ (NK-like), CD4+CD45RA+/CD45RO+ (Naive-to-Memory Transitional), but lower CD4+CD25+high (Treg) (P <0.05). Conclusions: Elevated representation of natural killer (NKT)-like and memory phenotypes may predispose long-term residents towards enhanced susceptibility for airway disease; while at the same time, reducing representation of Treg cells which are protective against airway disease, and this may increase vulnerability to these syndromes among the residents of Kuwait. These results may provide insight into the features of immunopathogenesis of asthma and allergies in Kuwait that arise as a result of the special environment of the country. Key words: Asthma, Immune reactivity, Kuwait, Rhinitis, T cells

Immunological aspect of cardiac remodeling: T lymphocyte subsets in inflammation-mediated cardiac fibrosis

Cardiac fibrosis is defined as a progressive accumulation of fibrillar extracellular matrix (ECM) in the myocardium. The regulation of extracellular matrix remodeling is primarily mediated by cardiac fibroblasts (CF). Evidences suggest that various T lymphocyte phenotypes differentially affect organ fibrosis through modulating CF collagen and MMP/TIMP gene expression, MMP activity and cardiac collagen cross-linking, leading to altered ECM composition. In regard to the importance of cytokines in cardiac fibrosis and heart failure, in this review, we will address the role of different T cell subsets in inflammation-mediated cardiac fibrosis, from a distinct perspective of T cell and fibroblast interaction. We conclude that in addition to preventive strategies, therapies based on deviation of Th1/Th2 paradigm, and manipulation of Tregs and Th17 would show promising results in future studies.

The imbalanced expression of matrix metalloproteinases in nephrogenic systemic fibrosis

BACKGROUND

Nephrogenic systemic fibrosis (NSF) occurs in patients with renal dysfunction and gadolinium exposure. Although little is known about the pathogenesis of this disease, increased expression of transforming growth factor-beta has been recently demonstrated. Other fibrosing conditions have been shown to express an imbalance in matrix metalloproteinase (MMP) expression and their corresponding inhibitors. Myofibroblast differentiation, in which cells often express alpha-smooth muscle actin and achieve the ability to contract, is also a hallmark of fibrosis.

OBJECTIVE

We theorized that NSF may overexpress tissue inhibitor of metalloproteinase-1 (TIMP-1), while simultaneously showing decreased expression of MMP-1. As a secondary aim, we sought to evaluate the presence of smooth muscle actin in our samples.

METHODS

We applied immunohistochemistry to 16 skin biopsies from 10 patients with NSF using antibodies to TIMP-1, MMP-1, MMP-2, MMP-9, and alpha-smooth muscle actin. Samples from normal skin, scar, keloid and scleroderma were stained for comparison.

RESULTS

TIMP-1 was strongly expressed in all NSF specimens compared to normal skin. MMP-1 expression was nearly absent in all tested samples. In all 16 NSF cases, the dermal spindle cells did not stain for alpha-smooth muscle actin. MMP-2 and MMP-9 expression was variable but was increased compared to normal skin.

LIMITATIONS

The expression is semiquantitative and based on immunohistochemistry and unconfirmed by other techniques.

CONCLUSIONS

In NSF, TIMP-1 is strongly expressed and MMP-1 is nearly absent, characteristic of the MMP imbalances seen in other fibrosing processes. Using smooth muscle actin immunohistochemistry, there was no evidence of myofibroblast differentiation.

Changes of human menisci in osteoarthritic knee joints

OBJECTIVE

To investigate the changes of knee menisci in osteoarthritis (OA) in human.

METHODS

OA and control menisci were obtained from 42 end-stage OA knees with medial involvement and 28 non-arthritic knees of age-matched donors, respectively. The change of menisci in OA was evaluated by histology, and gene expression of major matrix components and anabolic factors was analyzed in the anterior horn segments by quantitative PCR (qPCR). In those regions of menisci, the rate of collagen neo-synthesis was evaluated by [(3)H]proline incorporation, and the change of matrix was investigated by ultrastructural observation and biomechanical measurement.

RESULTS

In OA menisci, the change in histology was rather moderate in the anterior horn segments. However, despite the modest change in histology, the expression of type I, II, III procollagens was dramatically increased in those regions. The expression of insulin-like growth factor 1 (IGF-1) was markedly enhanced in OA menisci, which was considered to be responsible, at least partly, for the increase in procollagen gene expression. Interestingly, in spite of marked increase in procollagen gene expression, incorporation of [(3)H]proline increased only modestly in OA menisci, and impaired collagen synthesis was suggested. This finding was consistent with the results of ultrastructural observation and biomechanical measurement, which indicated that the change of meniscal matrix was modest in the macroscopically preserved areas of OA menisci.

CONCLUSION

Although the expression of major matrix components was markedly enhanced, matrix synthesis was enhanced only modestly, and the changes of matrix in human OA menisci were rather modest in the non-degenerated areas.

Budesonide treatment of patients with collagenous colitis restores normal eosinophil and T-cell activity in the colon

BACKGROUND

The aim of this study was to assess the activity of eosinophils, neutrophils, and CD4+ as well as CD8+ T-cells in 11 patients with active collagenous colitis (CC) before and after 8 weeks of budesonide treatment (9 mg once daily) compared to 10 healthy individuals.

METHODS

Clinical symptoms were recorded and intestinal biopsy samples were taken and analyzed by flow cytometry. Eosinophils with a high surface expression of CD44 and low CD9 expression were classified as activated. Neutrophil activity was assessed by their expression of CD66b, and CD69 was used as an activation marker for T-cells.

RESULTS

All patients responded to the treatment. The eosinophils in active CC showed increased activity compared to controls. The activity was back to control levels after treatment. Neutrophils were not activated in CC patients before or after treatment. CD8+ T-cells from untreated CC patients had a lower activity than controls, and a tendency of lower activity was observed on CD4+ T-cells. After treatment, the activity was increased on both types of T-cells and was not different from controls.

CONCLUSIONS

In the present study we demonstrated that the inflammation in CC is characterized by activated eosinophils but there is no neutrophil activity. CD4+ and CD8+ T-cells are increased in numbers in active CC but, surprisingly, they had a lower grade of activity than in control subjects. The major finding of this study is that budesonide treatment restores the normal activation of eosinophils and T-cells, accompanied by clinical remission.

Modulation of wound contracture alpha-smooth muscle actin and multispecific vitronectin receptor integrin alphavbeta3 in the rabbit's experimental model

The myofibroblast, a major component of granulation tissue, is a key cell during wound healing, tissue repair and connective tissue remodelling. Persistence of myofibroblasts within a fibrotic lesion leads to excessive scarring impairing function and aesthetics. Various wound-healing cytokines can be modulated by topical application of active agents to promote optimal wound healing and improve scar quality. Thus, the myofibroblast may represent an important target for wound-healing modulation to improve the evolution of conditions such as hypertrophic scars. The purpose of this work is to study the modulation of myofibroblasts and integrin alphavbeta3 in a full thickness wound performed on rabbits treated with different topical agents using: (1) saline, (2) Tegaderm occlusive dressing (3) silver sulfadiazine and (4) moist exposed burn ointment (MEBO). The reepithelialisation was 4 days faster in the MEBO group compared with the other therapies with less oedema formation, delayed contraction, less inflammatory cells and the lowest transepidermal water loss (TEWL) resulting in a soft scar. Although alpha-smooth muscle actin (alpha-SMA) was the highest around day 12 in the MEBO group, wound contraction and myofibroblast's activity were the least for the same period probably because of a downregulation of the integrin alphavbeta3. It seems that the effect of MEBO could be more pronounced on force transmission rather then on force generation. Greater insight into the pathology of scars may translate into non surgical treatments in the future and further work in myofibroblast biology will eventually result in efficient pharmacological tools, improving the evolution of healing and scar formation.

Matrix metalloproteinase inhibition causes luminal narrowing and ring thickening in the cricoid cartilage

OBJECTIVE

Luminal expansion of the cricoid cartilage appears to be stunted by loss of luminal epithelium (LE) and can be enhanced by transforming growth factor-beta3 (TGF-beta3). When both the LE and perichondrium are disrupted, matrix metalloproteinase (MMP) levels within adjacent chondrocytes are diminished but can be restored by exogenous TGF-beta3. Cricoid growth stunting and luminal expansion that occur in the absence and presence of MMP activity, respectively, suggest that MMPs play an important role in normal subglottal development. The study objective was to determine if MMP inhibition affects cricoid expansion and by what mechanism, which will in turn help to define the mechanism of action of TGF-beta3-induced luminal expansion.

STUDY DESIGN

Ex vivo, in vitro whole organ culture of subglottises grown with and without the presence of an MMP inhibitor.

SETTING

Tertiary care facility.

SUBJECTS AND METHODS

Subglottises from 20 neonatal mice were divided into 10 grown with an MMP inhibitor, GM6001, and 10 grown in basic medium alone. The luminal cross-sectional area, apoptosis levels, cell proliferation rates, and presence or absence of cleaved aggrecan fragments were determined.

RESULTS

Subglottises that were exposed to the MMP inhibitor displayed statistically significant luminal narrowing, accompanied by apparent circumferential thickening of the cricoid ring, relatively decreased apoptosis, increased chondrocyte proliferation, and decreased amounts of aggrecan cleavage fragments in the extracellular matrix.

CONCLUSION

Matrix metalloproteinases likely play a significant role in growth of the cricoid cartilage such that their inhibition leads to marked changes in the shape of the ring.

Application of autologous derived-platelet rich plasma gel in the treatment of chronic wound ulcer: diabetic foot ulcer

The treatment of chronic wounds remains problematic, despite new insight into the cellular and molecular basis of wound healing. Although the aetio-pathogenesis of chronic wounds is said to be multi-factorial, it is evident from literature that effective and adequate wound debridement has produced the most consistent effect in chronic wound treatment. There is a growing body of evidence that suggests that wound healing in chronic diabetic foot ulcers is growth factor dependent and that the therapeutic delivery of these growth factors to wounds topically, has the potential ability to accelerate wound healing in conjunction with conventional wound care. Autologous derived platelet concentrate is activated to release growth factors that are stored in the platelet granules. These secretory proteins include cytokines and growth factors such as transforming growth factor-beta, vascular endothelia growth factor, platelet derived growth factor, and so on. The enhancement of soft tissue healing by the application of autologous derived platelet rich plasma gel (APG) is supported by basic science and some clinical studies. This review article will attempt to provide a concise report of current concepts on the use of APG in treating chronic ulcers.

The genotypes of IL-1 beta and MMP-3 are associated with the prognosis of HCV-related hepatocellular carcinoma

BACKGROUND AND AIM

Cytokines and matrix metalloproteinases (MMPs) are involved in tumor growth, invasion, and remote metastasis in various cancers. Recently, functional gene polymorphisms in these cytokines and MMPs have been found, and some reports have revealed an association between these polymorphisms and the prognosis of various cancers. In this study, we examined the relationship between the gene polymorphisms of interleukin 1 beta (IL-1b), IL-1 receptor antagonist (IL-1 RN), transforming growth factor beta 1 (TGF-b1), MMP-1, MMP-3, and MMP-9 and the prognosis of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC).

METHODS

We enrolled 92 HCV-related HCC patients in the study, and gene polymorphisms of IL-1b -31 C/T, IL-1 RN variable number of tandem repeats (VNTR), TGF-b1 +869 C/T, MMP-1 -1,607 1G/2G, MMP-3 -1,171 5A/6A, and MMP-9 -1,562 C/T were analyzed.

RESULTS

In HCC clinical features, TGF-b1 C carriers and MMP-3 5A carriers had significantly larger HCC diameters than TGF-b1 T and MMP-3 6A homozygotes. In HCC prognosis, IL-1b T homozygotes and MMP-3 5A carriers had a significantly poorer prognosis than IL-1b C carriers and MMP-3 6A homozygotes. Those with a combination of IL-1b T homozygosity and MMP-3 5A had synergistically poorer HCC prognosis.

CONCLUSION

The IL-1b -31 T allele and MMP-3 5A allele are cooperative risk factors for poor prognosis in HCC patients, suggesting that these gene polymorphisms might be potential markers for predicting the prognosis of HCC patients.

Pathophysiology and management of the burn scar

Fibroproliferative disorders (FPDs) are common and serious disorders. Hypertrophic scar (HSc) and keloids represent the dermal equivalents of FPD and impose lower mortality but great morbidity. This article reviews current knowledge in the pathophysiology and molecular and cellular characteristics of postburn HSc. Additionally, current treatment modalities and future treatment options based on advancements in the understanding of the pathophysiology of HSc are discussed.

Scar and contracture: biological principles

Dysregulated wound healing and pathologic fibrosis cause abnormal scarring, leading to poor functional and aesthetic results in hand burns. Understanding the underlying biologic mechanisms involved allows the hand surgeon to better address these issues, and suggests new avenues of research to improve patient outcomes. In this article, the authors review the biology of scar and contracture by focusing on potential causes of abnormal wound healing, including depth of injury, cytokines, cells, the immune system, and extracellular matrix, and explore therapeutic measures designed to target the various biologic causes of poor scar.

Differences in pancreatic immunohistochemical staining profiles of TGF-beta1, MMP-2, and TIMP-2 between autoimmune and alcoholic chronic pancreatitis

OBJECTIVES

Tumor growth factor beta (TGF-beta) is an immunosuppressive cytokine and has been implicated in a variety of disease processes, including those in autoimmune disease. Tumor growth factor beta is also involved in fibrosis by regulating matrix metalloproteinases (MMPs) and the tissue inhibitor of MP (TIMP). The purpose of this study was to compare the expression patterns of TGF-beta1, MMP-2, and TIMP-2 between autoimmune chronic pancreatitis (AIP) and alcoholic chronic pancreatitis (ACP) by immunohistochemical staining of pancreatic tissue specimens.

METHODS

Pancreatic tissue specimens were obtained from 16 of 57 patients who had a diagnosis of AIP at the Asan Medical Center. Pancreatic tissue specimens of ACP were obtained from 10 patients who were surgically treated. Immunohistochemical staining was performed with antibodies specific for TGF-beta1, MMP-2, and TIMP-2.

RESULTS

The degree of immunohistochemical staining for TGF-beta1 was significantly weaker in AIP than in ACP in the pancreatic ductal epithelial and mononuclear cells (P = 0.029 and P = 0.018, respectively).

CONCLUSIONS

This finding suggests that there may be a defect in the function of regulatory T (Treg) cells, which normally prevents autoimmune disease progression via a suppressor mechanism. Further studies are needed to identify the type of regulatory T cell involved in this process.

Altered molecular mechanisms of diabetic foot ulcers

The continuously increasing worldwide prevalence of diabetes will be accompanied by a greater incidence of diabetic foot ulcer, a complication in which many of the morphological processes involved in normal wound healing are disrupted. The highly complex and integrated process of wound healing is regulated by a large array of molecular factors. These often have overlapping functions, ensuring a certain degree of tolerance through redundancy. In diabetes, changes to the expression of a large number of molecular factors have been observed, overwhelming this inbuilt redundancy. This results in delayed healing or incomplete healing as in ulceration. Understanding the relationship between altered levels of molecular factors and the inhibited healing process in such ulcers will permit the development of targeted treatments aimed to greatly improve the quality of life of patients, at the same time helping to reduce the huge costs associated with treating this diabetic condition and its long-term consequences. This short review examines how changes in the expression of molecular factors are related to altered morphology in diabetic foot ulceration and very briefly considers treatment strategies at molecular level.

Extracellular matrix in pancreatic islets: relevance to scaffold design and transplantation

Intrahepatic islet transplantation provides a potentially more benign alternative to pancreatic transplantation. However, islet transplants are associated with limited engraftment potential. This inefficiency is likely at least partially attributable to the isolation process, which removes islets from their native environment. Isolation not only disrupts the internal vascularization and innervation of islets, but also fundamentally changes interactions between islet cells and macromolecules of the extracellular matrix (ECM). Signaling interactions between islet cells and ECM are known to regulate multiple aspects of islet physiology, including survival, proliferation, and insulin secretion. Although it is highly likely that disruptions to these interactions during isolation significantly affect transplant outcomes, the true implications of these conditions are not well understood. The following article reviews current understandings and uncertainties in islet-ECM interactions and explains their potential impact on posttransplant engraftment. Topics covered include matrix and receptor compositions in native islets, effects of isolation and culture on islet-ECM interactions, and potential for postisolation restoration of islet-ECM interactions. Greater understanding in these areas may help to reduce isolation and transplantation stresses and improve islet engraftment.

VEGF and inhibitors of TGFbeta type-I receptor kinase synergistically promote blood-vessel formation by inducing alpha5-integrin expression

Vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGFbeta) are potent regulators of angiogenesis. How VEGF and TGFbeta signaling pathways crosstalk is not well understood. Therefore, we analyzed the effects of the TGFbeta type-I-receptor inhibitors (SB-431542 and LY-2157299) and VEGF on endothelial cell (EC) function and angiogenesis. We show that SB-431542 dramatically enhances VEGF-induced formation of EC sheets from fetal mouse metatarsals. Sub-optimal doses of VEGF and SB-431542 synergistically induced EC migration and sprouting of EC spheroids, whereas overexpression of a constitutively active form of TGFbeta type-I receptor had opposite effects. Using quantitative PCR, we demonstrated that VEGF and SB-431542 synergistically upregulated the mRNA expression of genes involved in angiogenesis, including the integrins alpha5 and beta3. Specific downregulation of alpha5-integrin expression or functional blocking of alpha5 integrin with a specific neutralizing antibody inhibited the cooperative effect of VEGF and SB-431542 on EC sprouting. In vivo, LY-2157299 induced angiogenesis and enhanced VEGF- and basic-fibroblast-growth-factor-induced angiogenesis in a Matrigel-plug assay, whereas adding an alpha5-integrin-neutralizing antibody to the Matrigel selectively inhibited this enhanced response. Thus, induction of alpha5-integrin expression is a key determinant by which inhibitors of TGFbeta type-I receptor kinase and VEGF synergistically promote angiogenesis.

Interactions between extracellular matrix and growth factors in wound healing

Dynamic interactions between growth factors and extracellular matrix (ECM) are integral to wound healing. These interactions take several forms that may be categorized as direct or indirect. The ECM can directly bind to and release certain growth factors (e.g., heparan sulfate binding to fibroblast growth factor-2), which may serve to sequester and protect growth factors from degradation, and/or enhance their activity. Indirect interactions include binding of cells to ECM via integrins, which enables cells to respond to growth factors (e.g., integrin binding is necessary for vascular endothelial growth factor-induced angiogenesis) and can induce growth factor expression (adherence of monocytes to ECM stimulates synthesis of platelet-derived growth factor). Additionally, matrikines, or subcomponents of ECM molecules, can bind to cell surface receptors in the cytokine, chemokine, or growth factor families and stimulate cellular activities (e.g., tenascin-C and laminin bind to epidermal growth factor receptors, which enhances fibroblast migration). Growth factors such as transforming growth factor-beta also regulate the ECM by increasing the production of ECM components or enhancing synthesis of matrix degrading enzymes. Thus, the interactions between growth factors and ECM are bidirectional. This review explores these interactions, discusses how they are altered in difficult to heal or chronic wounds, and briefly considers treatment implications.

Integrins in the endometrium

The endometrium expresses many of the same integrins displayed by other tissues. Endometrial epithelial cells maintain the ‘classic’ epithelial integrins, including α2, α3, α6, and β4, while the stroma expresses the fibronectin receptor, α5β1. During the menstrual cycle, the endometrium undergoes dynamic changes in morphology in preparation for implantation. With these histological changes are concomitant alterations in integrin expression that appear to ‘frame’ the window of implantation, by the co-expression of glandular αvβ3 and α4β1 during days 20 to 24 of the menstrual cycle. The changes in integrin expression shift from epithelial to stroma predominance late in the menstrual cycle, extending into early pregnancy. Decidual integrins that appear upregulated in pregnancy include α1β1, α3β1, α6β1 and αvβ3. Markers of uterine receptivity hold promise for a better understanding of the implantation process and may help to explain many different types of infertility. These markers will be essential for monitoring and improving infertility therapies. The importance of integrins in the human endometrium now seems well established and promises to be an area of great clinical and basic science activity in the future.

Relaxin reverses airway remodeling and airway dysfunction in allergic airways disease

Mice deficient in the antifibrotic hormone relaxin develop structural changes in the airway that resemble airway remodeling, and demonstrate exaggerated remodeling changes in models of allergic airways disease (AAD). Relaxin expression in asthma has not been previously studied. We evaluated the efficacy of relaxin in the treatment of established airway remodeling in a mouse model of AAD. Relaxin expression in mouse AAD was also examined by immunohistochemistry and real-time PCR. BALB/c mice with established AAD were treated with relaxin or vehicle control (sc for 14 d), and effects on airway remodeling, airway inflammation, and airway hyperresponsiveness (AHR) were assessed. Relaxin expression was significantly reduced in the airways of mice with AAD compared with controls. Recombinant relaxin treatment in a mouse model of AAD reversed collagen deposition and epithelial thickening, and significantly improved AHR (all P < 0.05 vs. vehicle control), but did not influence airway inflammation or goblet cell hyperplasia. Relaxin treatment was associated with increased matrix metalloproteinase-2 levels, suggesting a possible mechanism for its antifibrotic effects. Endogenous relaxin expression is decreased in murine AAD, whereas exogenous relaxin represents a novel treatment capable of reversing established airway remodeling and AHR.

Serum growth factors in asbestosis patients

Various growth factors, including platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta, have been implicated in the pathogenesis of asbestos-induced disease. PDGF and TGF-beta levels were determined by enzyme-linked immunosorbent assays in the banked serum samples of a cohort of workers with asbestosis, and the relationships of the growth factor levels to the subsequent development of cancer and to the radiographic severity and progression of asbestosis in the cohort were examined. Serum levels of PDGF and TGF-beta were found to be unrelated to the development of cancer, and serum levels of PDGF were found to be unrelated to the severity and progression of asbestosis. However, serum levels of TGF-beta were found to be statistically significantly related to disease severity (p = 0.01), increasing approximately 2.4-fold from ILO radiographic category 0 to category 3, and they were marginally related to disease progression (p = 0.07), in multivariate analysis controlling for other contributory factors including cumulative asbestos exposure. This suggests that serum TGF-beta may be a useful biomarker for asbestos-induced fibrotic disease.

Estrogen receptor alpha attenuates transforming growth factor-beta signaling in breast cancer cells independent from agonistic and antagonistic ligands

To investigate a presumed crosstalk between estrogen receptor alpha (ERalpha) and the TGF-beta signaling pathway in breast cancer, we analyzed the TGF-beta-induced expression of the plasminogen activator inhibitor 1 (PAI-1) gene in ER-positive MCF-7 cells. After siRNA-mediated knock-down of endogenous ERalpha, the transcription level of PAI-1 was upregulated, pointing to an attenuation of TGF-beta signaling by the presence of ERalpha. We verified these findings by a vice versa approach using a primary ER-negative cell model transiently overexpressing either ERalpha or ERbeta. We found that ERalpha, but not ERbeta, led to a strong inhibition of the TGF-beta1 signal, monitored by TGF-beta reporter assays. This attenuation was completely independent of receptor stimulation by beta-estradiol (E2) or inhibition by the pure antagonist ICI 182.780 (ICI). Our results indicate a permanent repression of PAI-1 by ERalpha and suggest a ligand-independent crosstalk between ERalpha and TGF-beta signaling in breast cancer cells.

Temporary fatigue and altered extracellular matrix in skeletal muscle during progression of heart failure in rats

Patients with congestive heart failure (CHF) experience increased skeletal muscle fatigue. The mechanism underlying this phenomenon is unknown, but a deranged extracellular matrix (ECM) might be a contributing factor. Hence, we examined ECM components and regulators in a rat postinfarction model of CHF. At various time points during a 3.5 mo-period after induction of CHF in rats by left coronary artery ligation, blood, interstitial fluid (IF), and muscles were sampled. Isoflurane anesthesia was employed during all surgical procedures. IF was extracted by wicks inserted intermuscularly in a hind limb. We measured cytokines in plasma and IF, whereas matrix metalloproteinase (MMP) activity and collagen content, as well as the level of glycosaminoglycans and hyaluronan were determined in hind limb muscle. In vivo fatigue protocols of the soleus muscle were performed at 42 and 112 days after induction of heart failure. We found that the MMP activity and collagen content in the skeletal muscles increased significantly at 42 days after induction of CHF, and these changes were time related to increased skeletal muscle fatigability. These parameters returned to sham levels at 112 days. VEGF in IF was significantly lower in CHF compared with sham-operated rats at 3 and 10 days, but no difference was observed at 112 days. We conclude that temporary alterations in the ECM, possibly triggered by VEGF, are related to a transient development of skeletal muscle fatigue in CHF.

Deficiency of antiproliferative family protein Ana correlates with development of lung adenocarcinoma

The abundant in neuroepithelium area (ana) gene was originally identified as a member of the tob/btg family of antiproliferative genes. Like the other family members, Ana inhibits growth of NIH3T3 cells when overexpressed. However, whether or not Ana is involved in tumor progression has been elusive. Here, we show that expression of ana is relatively high in the lung, the expression being restricted in type II alveolar epithelial cells. We further show that ana expression is reduced in 97% of the human lung cancer cell lines examined (61/63) and 86% of clinical samples from lung adenocarcinoma patients (36/42). Long-term observation of ana-deficient (ana−/–) mice reveals that 8% of them develop lung tumors (5/66) by 21 months after birth, while 0% of wild-type mice (0/35) develop the same type of tumors. We also show that exogenously expressed ana gene product suppresses the levels of matrix metalloproteinase-2 (MMP-2) and plasminogen activator inhibitor-1 (PAI-1) expression in lung cancer cells. Taken together, we propose that ana functions as a tumor suppressor and that its product inhibits tumor progression as well by suppressing angiogenesis, invasion, and metastasis.

Coculture of osteoclast precursors with rheumatoid synovial fibroblasts induces osteoclastogenesis via transforming growth factor beta-mediated down-regulation of osteoprotegerin

OBJECTIVE

The mechanisms of osteoclast maturation and the role of rheumatoid arthritis (RA) synovial fibroblasts in the control of osteoclastogenesis remain unclear. The purpose of this study was to determine the humoral factors that influence osteoclast differentiation resulting from mutual interactions between osteoclast progenitor cells and synovial fibroblasts.

METHODS

The cloned mouse macrophage cell line RAW 264.7 or isolated human CD14+ monocytes were cocultured with RA or osteoarthritis (OA) synovial fibroblasts in the presence of RANKL. Osteoclasts were visualized by staining for tartrate-resistant acid phosphatase (TRAP), and their functions were evaluated by bone resorption assay. Transforming growth factor beta (TGFbeta) and osteoprotegerin (OPG) levels were measured by enzyme-linked immunosorbent assay. Expression of pSmad2 and Smad7 was analyzed by Western blotting.

RESULTS

RANKL-mediated osteoclast formation was observed in cocultures of RAW cells with RA synovial cells, but not with OA synovial cells. This formation was inhibited by TGFbeta receptor kinase inhibitor or neutralizing TGFbeta antibody. Human CD14+ monocytes showed the same results with RAW 264.7, and bone resorption activity was consistent with osteoclast formation. RA synovial fibroblasts produced TGFbeta in response to cell-cell contact with RAW cells in a RANKL-dependent manner. TGFbeta reduced OPG production by RA synovial fibroblasts, but dose-dependently increased OPG secretion in OA synovial fibroblasts. TGFbeta decreased the expression of pSmad2 and increased the expression of Smad7 in RA synovial fibroblasts, but not OA synovial fibroblasts.

CONCLUSION

Suppression of OPG production by down-regulation of TGFbeta/Smad2 signaling may contribute to RANKL-mediated osteoclastogenesis from RA synovial fibroblasts.

Protective effect of a mixture of Aloe vera and Silybum marianum against carbon tetrachloride-induced acute hepatotoxicity and liver fibrosis

The hepatoprotective effects of ACTIValoe N-931 complex, a mixture of Aloe vera and Silybum marianum, against acute and chronic carbon tetrachloride (CCl(4))-induced liver injuries were investigated. Acute hepatotoxicity was induced by intraperitoneal injection of CCl(4) (50 microl/kg), and ACTIValoe N-931 complex at 85, 170, and 340 mg/kg was administered orally 48, 24, and 2 h before and 6 h after injection of CCl(4). Hepatotoxicity was assessed 24 h after CCl(4) treatment. Liver fibrosis was induced by intraperitoneal injection of CCl(4) for 8 weeks (0.5 ml/kg, twice per week), and mice were treated with ACTIValoe N-931 complex at 85, 170, or 340 mg/kg once a day (p.o.). In both acute hepatotoxicity and liver fibrosis, serum aminotransferase levels and lipid peroxidation were increased and the hepatic glutathione content was decreased. These changes were prevented by ACTIValoe N-931 complex. The ACTIValoe N-931 complex attenuated the increase in tumor necrosis factor-alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), mRNA expressions in acute hepatotoxicity. In antifibrotic experiments, tissue inhibitor of metalloprotease-1 (TIMP-1) mRNA expression was attenuated by treatment with ACTIValoe N-931 complex. The ACTIValoe N-931 complex decreased the hepatic hydroxyproline content and the transforming growth factor-beta1 levels. Our results suggest that the ACTIValoe N-931 complex has hepatoprotective effects in both acute and chronic liver injuries induced by CCl(4).

A synthetic peptide from transforming growth factor-beta1 type III receptor prevents myocardial fibrosis in spontaneously hypertensive rats

AIM

We investigated whether P144, a synthetic peptide from transforming growth factor-beta(1) (TGF-beta(1)) type III receptor betaglycan, exhibits cardiac antifibrotic properties.

METHODS AND RESULTS

The study was carried out in one group of 10-week-old normotensive Wistar-Kyoto rats treated with vehicle (V-WKY), one group of 10-week-old spontaneously hypertensive rats treated with vehicle (V-SHR), and one group of 10-week-old SHR treated with P144 (P144-SHR) for 12 weeks. Two more groups of 10-week-old untreated WKY and SHR were used to assess baseline values of the parameters tested. In addition, the effects of P144 on rat cardiac fibroblasts stimulated with TGF-beta(1) were also studied. Compared with V-WKY, V-SHR exhibited significant increases in the myocardial expression of phosphorylated Smad2, 38 and 42 kDa connective tissue growth factor (CTGF) isoforms, procollagen alpha1 (I) mRNA, and collagen type I protein, as well as in the expression of lysyl oxidase (LOX) mRNA and protein, collagen cross-linking and deposition. P144 administration was associated with significant reduction in all these parameters in P144-SHR. TGF-beta(1)-stimulated fibroblasts exhibited significant increases in phosphorylated Smad2, 38 and 42 kDa CTGF proteins, and procollagen alpha(1) (I) mRNA compared with control fibroblasts. No significant differences were found in these parameters between fibroblasts incubated with TGF-beta(1) and P144 and control fibroblasts.

CONCLUSION

These results show that P144 inhibits TGF-beta(1)-dependent signalling pathway and collagen type I synthesis in cardiac fibroblasts. These effects may be involved in the ability of this peptide to prevent myocardial fibrosis in SHR.

Modulation of tissue transglutaminase in tubular epithelial cells alters extracellular matrix levels: a potential mechanism of tissue scarring

The up-regulation and trafficking of tissue transglutaminase (TG2) by tubular epithelial cells (TEC) has been implicated in the development of kidney scarring. TG2 catalyses the crosslinking of proteins via the formation of highly stable epsilon(gamma-glutamyl) lysine bonds. We have proposed that TG2 may contribute to kidney scarring by accelerating extracellular matrix (ECM) deposition and by stabilising the ECM against proteolytic decay. To investigate this, we have studied ECM metabolism in Opossum kidney (OK) TEC induced to over-express TG2 by stable transfection and in tubular cells isolated from TG2 knockout mice. Increasing the expression of TG2 led to increased extracellular TG2 activity (p<0.05), elevated epsilon(gamma-glutamyl) lysine crosslinking in the ECM and higher levels of ECM collagen per cell by (3)H-proline labelling. Immunofluorescence demonstrated that this was attributable to increased collagen III and IV levels. Higher TG2 levels were associated with an accelerated collagen deposition rate and a reduced ECM breakdown by matrix metalloproteinases (MMPs). In contrast, a lack of TG2 was associated with reduced epsilon(gamma-glutamyl) lysine crosslinking in the ECM, causing reduced ECM collagen levels and lower ECM per cell. We report that TG2 contributes to ECM accumulation primarily by accelerating collagen deposition, but also by altering the susceptibility of the tubular ECM to decay. These findings support a role for TG2 in the expansion of the ECM associated with kidney scarring.

Anti-apoptotic effect of transforming growth factor-beta1 on human articular chondrocytes: role of protein phosphatase 2A

OBJECTIVE

To study whether transforming growth factor-beta1 (TGF-beta1) is able to protect human chondrocytes from apoptosis and to analyze the role of phosphatases in the possible anti-apoptotic effect of TGF-beta1.

METHODS

Cartilage was obtained from patients with osteoarthritis (OA) who were undergoing joint replacement; normal cartilage was obtained from cadavers who had no history of joint disease. Chondrocytes stimulated with tumor necrosis factor-alpha (TNF-alpha) plus Ro 31-8220 (a specific inhibitor of mitogen-activated kinase phosphatase-1 - MKP-1) were employed as an in vitro model of apoptosis. Apoptosis was assessed by flow cytometry and a cell death immunoassay. Protein phosphatase 2A (PP2A) activity was estimated by measuring the absorbance of a molybdate:malachite green:phosphate reaction complex. MKP-1, bcl-2 and bax expressions were quantified by western blot.

RESULTS

In OA cells, TGF-beta1 significantly reduced the percentage of hypo-diploid chondrocytes, as well as the percentage of internucleosomal DNA breakage. However, in normal chondrocytes, TGF-beta1 did not reduce apoptosis, as assessed by both the percentage of hypo-diploid chondrocytes and internucleosomal DNA breakage. MKP-1 expression did not show significant modulation in OA or normal chondrocytes. However, PP2A activity was differentially modulated in normal and OA chondrocytes. In OA chondrocytes, PP2A activity was not altered by TGF-beta1 stimulation; however in normal chondrocytes PP2A activity was significantly activated by TGF-beta1. The preincubation of normal chondrocytes with TGF-beta1 plus the PP2A inhibitor protein, IPP2A, reduced internucleosomal DNA breakage when compared with TGF-beta1 stimulation alone. The bcl-2/bax protein ratio was significantly higher in TGF-beta1 plus IPP2A preincubated normal chondrocytes than in cells stimulated with TGF-beta1 alone.

CONCLUSION

By manipulating the degree of PP2A activity, these results show the major role that PP2A plays in the outcome of TGF-beta1 signal transduction. These data suggest that PP2A could be a pivotal regulator of anti-apoptotic TGF-beta1-induced effects.

Ultraviolet A phototherapy for sclerotic skin diseases: a systematic review

BACKGROUND

Ultraviolet (UV) A-1 phototherapy is now available for a variety of skin diseases. Increasingly since 1995, there have been investigations of the efficacy of UVA-1 (340-400 nm) therapy for sclerotic skin diseases. Most studies undertaken treated patients who had localized scleroderma, but UVA-1 phototherapy is currently also used for other sclerotic skin conditions.

OBJECTIVE

We sought to assess the efficacy, biological effects, and side effects of UVA-1 in a variety of sclerotic skin diseases (localized scleroderma, eosinophilic fasciitis, chronic graft-versus-host disease, lichen sclerosus et atrophicus, scleredema adultorum, necrobiosis lipoidica, POEMS disease, pansclerotic porphyria cutanea tarda, and drug-induced scleroderma-like disorders).

METHODS

The authors searched for publications dated between January 1996 and November 2007 in the computerized bibliographic database, PubMed. PubMed was searched using medical subject heading terms and open searches to retrieve the latest reports.

RESULTS

The evidence based on research concerning the effect of full-spectrum UVA (320-400 nm) and UVA-1 on these skin diseases is still growing, and appears promising. Up until now, good results are shown for all different doses (low, medium, and high) UVA-1 and UVA. There are insufficient data regarding use of high-dose UVA-1 and there are no comparative studies to make a clear assessment regarding the superiority of low-, medium-, or high-dose UVA-1 therapy. Although UVA-1 has various effects on, for instance, fibroblasts and inflammatory cells, the precise mode of action remains obscure. The main short-term side effects of UVA-1 therapy are erythema, pruritus, xerosis cutis, tanning, and recrudescence of herpes simplex infection. More studies are warranted to investigate the potential long-term risk of photoaging and skin cancer. Currently, UVA-1 is considered to be less carcinogenic than psoralen plus UVA (PUVA).

LIMITATIONS

Because of the limited availability of randomized controlled trials and large cohort studies, it is difficult to draw firm conclusions on the long-term efficacy, optimum dose, and best treatment regimens for UVA-1 when administered to patients with sclerosing skin disorders.

CONCLUSIONS

Full-spectrum UVA and UVA-1 phototherapy seem effective in the treatment of sclerotic skin diseases based on data retrieved from the literature. UVA-1 treatment can shorten the active period of localized scleroderma and pseudoscleroderma and prevent further disease progression, including contractures. Further investigations will be needed to determine any additional biological effects of UVA-1. Although long-term side effects are not yet known, UVA-1 might develop into a promising beneficial and well-tolerated treatment in the therapeutic armamentarium for sclerotic skin diseases. Long-term studies in large groups of patients are clearly needed.

Genesis of hepatic fibrosis and its biochemical markers

Liver fibrosis is characterized by an abnormal hepatic accumulation of extracellular matrix (ECM) that results from both increased deposition and reduced degradation of collagen fibres. Fibrotic liver injury results in activation of the hepatic stellate cell (HSC). Surrogate markers are gradually being substituted for biomarkers that reflect the complex balance between synthesis and degradation of the extracellular matrix. Once the hepatic stellate cell is activated, the preceding matrix changes and recurrent injurious stimuli will perpetuate the activated state. The ECM directs cellular differentiation, migration, proliferation and fibrogenic activation or deactivation. The metabolism of the extracellular matrix is closely regulated by matrix metalloproteinases (MMP) and their specific tissue inhibitors (TIMP). Although liver biopsy combined with connective tissue stains has been a mainstay of diagnosis, there is a need for less invasive methods. These diagnostic markers should be considered in combination with liver function tests, ultrasonography and clinical manifestations.

Transgenic expression of matrix metalloproteinase-1 inhibits myocardial fibrosis and prevents the transition to heart failure in a pressure overload mouse model

Hypertension induces dysfunctional matrix remodeling that results in the development of myocardial fibrosis. Myocardial fibrosis adversely affects compliance, electrical activity and cardiac function in patients with hypertensive heart disease. Matrix metalloproteinases (MMPs) are a class of enzymes that regulate the remodeling of the matrix in response to pressure overload. Several studies have shown that the MMP-1/TIMP (tissue inhibitor of matrix metalloproteinase) ratio is decreased in hypertensive heart disease. However, the exact role that MMP-1 has in modulating the fibrotic response to hypertension is largely unknown. We hypothesized that cardiac expression of MMP-1 in mice would protect against the development of dysfunctional matrix remodeling during pressure overload. To investigate this, a suprarenal aortic banding model was utilized. Banded and unbanded MMP-1 transgenic mice were compared with appropriately matched wild-type mice. The banded mice were examined at 2 and 5 weeks after banding. MMP-1 attenuated the development of cardiac fibrosis, prevented left ventricular dilation and preserved cardiac function in mice that were exposed to pressure overload. Thus, MMP-1 protected the heart from the dysfunctional remodeling that occurs in response to chronic hypertension. In conclusion, these results suggest that strategies aimed at improving the MMP-1/TIMP balance in the myocardium may help to prevent the onset and progression of hypertensive heart disease.

Molecular network of cartilage homeostasis and osteoarthritis

This review article presents the current understanding of the molecular basis of articular cartilaginous homeostasis, and outlines potential areas to focus on within the developing field of therapeutics for cartilage disorders. Articular cartilage, an integral component of joints in extremities and the vertebral column, is essential for locomotion. Disturbance of joint development or cartilage homeostasis causes congenital osteocartilaginous dysplasia or osteoarthritic diseases, respectively. Symptomatic treatments and surgical replacement of joints are effective but can also be problematic in terms of quality of life over time. Recently, new insights into the molecular biological basis of chondrocyte differentiation and cartilage homeostasis have been reported. While joint formation is regulated by several growth factors such as Wnts (wingless-related MMTV integration site) and Gdfs (growth and differentiation factors), the pathology of osteoarthritis is now interpreted as the disruption of balance between anabolic and catabolic signals. Current findings in molecular biology on joint development are reviewed concisely to aid in the understanding of the molecular network that governs articular cartilage development and homeostasis.

Review article: epidemiology, pathogenesis and potential treatments of paediatric non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of paediatric liver disease. Similar to NAFLD in adults, NAFLD in children is associated with obesity and insulin resistance and requires liver histology for diagnosis and staging. However, significant histological differences exist between adult and paediatric NAFLD to warrant caution in extrapolation of adult data.

AIM

To review the available data on the epidemiology, pathogenesis, diagnosis and treatment of paediatric NAFLD.

METHODS

Relevant articles were identified by Medline searches using the keywords: nonalcoholic fatty liver disease, steatohepatitis, obesity and children.

RESULTS

The rise in childhood obesity has been accompanied by an increase in paediatric NAFLD. Age, gender and race/ethnicity are significant determinants of risk, and sex hormones, insulin sensitivity and adipocytokines are implicated in the pathogenesis of paediatric NAFLD. There is no consensus for treatment of NAFLD; however, data suggest that diet, exercise and some pharmacological therapies may be of benefit.

CONCLUSIONS

To evaluate and effectively treat paediatric NAFLD, the pathophysiology and natural history of the disease should be clarified and non-invasive methods for screening, diagnosis, and longitudinal assessment developed. Randomized, controlled, double-blind trials of pharmacological therapies in children with biopsy-proven disease are necessary.

Gingival crevicular fluid transforming growth factor-beta1 in cyclosporine and tacrolimus treated renal transplant patients without gingival overgrowth

BACKGROUND

Gingival crevicular fluid (GCF) levels of transforming growth factor-beta(1) (TGF-beta(1)) have been previously investigated in relation to the pathogenesis of cyclosporine-A (CsA)-induced gingival overgrowth (GO) but no clinical data are available regarding the GCF levels of TGF-beta(1) in patients treated with tacrolimus (Tac). However, as gingival inflammation is pronounced at sites of GO and this consequently may lead to an elevation in TGF-beta(1) levels the present study aimed to evaluate gingival crevicular fluid (GCF) TGF-beta(1) levels in renal transplant patients using CsA or Tac without GO.

METHODS

GCF TGF-beta(1) levels were investigated in 30 renal transplant patients without GO medicated with either CsA (n=15) or Tac (n=15). Sixteen gingivitis patients and 15 periodontally healthy subjects were selected as controls. Periodontal status was evaluated by measuring probing depth, plaque index and papilla bleeding index. The TGF-beta(1) levels were analysed by enzyme-linked immunosorbent assay.

RESULTS

Both CsA and Tac groups had significantly elevated GCF TGF-beta(1) total amount compared to gingivitis and healthy groups (p<0.008). GCF TGF-beta(1) total amount of CsA and Tac groups was similar (p>0.008). Gingivitis and healthy groups had also similar GCF TGF-beta(1) total amount (p>0.008).

CONCLUSIONS

Within the limits of the present data it is unlikely that TGF-beta(1) is an exclusive mediator of CsA- or Tac-induced GO. However, pathogenesis of GO is multifactorial and contribution of TGF-beta(1) to the interrelations between cytokines and growth factors with fibrogenic potential cannot be disregarded.

Akt blockade downregulates collagen and upregulates MMP1 in human dermal fibroblasts

Acutely transforming retrovirus AKT8 in rodent T-cell lymphoma (Akt) is a serine/threonine kinase that plays important roles in survival, cell-cycle progression, and cell proliferation, and has recently been implicated in collagen regulation. The aim of this study was to determine the role of Akt in collagen deposition by normal dermal fibroblasts, and to determine the sensitivity of cultured systemic sclerosis (SSc) fibroblasts to Akt inhibition. We show that blockade of Akt using pharmacological inhibitors, small interfering RNA (siRNA), and a dominant-negative Akt mutant led to inhibition of the basal type I collagen production. Furthermore, inhibition of Akt upregulated basal matrix metalloproteinase 1 (MMP1) production and reversed the inhibitory effect of transforming growth factor-beta (TGF-beta) on MMP1 gene expression. In addition, SSc fibroblasts were more sensitive to Akt inhibition, with respect to collagen and MMP1 production. These findings suggest that in human dermal fibroblasts, Akt has dual profibrotic effects, increasing collagen synthesis and decreasing its degradation via downregulation of MMP1. Akt could directly contribute to elevated collagen in SSc fibroblasts and it may represent an attractive target for therapy of SSc fibrosis.