Generation of contractile force by cultured Dupuytren's disease and normal palmar fibroblasts

The Molecular Pathogenesis of Dupuytren Disease: Review of the Literature and Suggested New Approaches to Treatment

BACKGROUND

Ever since the classification of Dupuytren disease into the proliferative, involutional, and residual stages, extensive research has been performed to uncover the molecular underpinnings of the disease and develop better treatment modalities for patients. The aim of this article is to systematically review the basic science literature pertaining to Dupuytren disease and suggest a new approach to treatment.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review was conducted using the MEDLINE database to identify basic science literature on Dupuytren pathophysiology falling under 1 or more of the following categories: (1) Molecular alterations, (2) Structural alterations, and (3) Genetic predisposition.

RESULTS

A total of 177 articles were reviewed of which 77 studies met inclusion criteria. Articles were categorized into respective sections outlined in the study methods.

CONCLUSION

The pathophysiological changes involved in Dupuytren's disease can be divided into a number of molecular and structural alterations with genetic predisposition playing a contributory role. Understanding these changes can allow for the development of biologics which may disrupt and halt the disease process.

Angiotensin receptors in Dupuytren's tissue: Implications for the pharnnacological treatment of Dupuytren's disease

The role of Angiotensin II as a pro-fibrotic mediator has been established in models of cardiac, hepatic and renal fibrosis. The administration of Angiotensin-Converting Enzyme (ACE) – inhibitors to these models results in a reduction in the myofibroblast population and collagen synthesis. In rodent excisionat wound-healing experiments, an ACE inhibitor reduced the rate of wound contraction, collagen deposition and angiogenesis. Using immunohistochemistry, the presence of Angiotensin I receptors was identified within tissue samples from patients with Dupuytren's disease. These were found to be co-localised with areas of myofibrobtast expression. This co-localisation has implications for the potential of pharmacological regulation of Dupuytren's disease. Further research is necessary to confirm whether the use of ACE-inhibitors can modulate this disease process, which until now has not been responsive to safe, effective pharmacological treatment.

Dupuytren's Contracture Cosegregation with Limb-Girdle Muscle Dystrophy

Limb-girdle muscular dystrophies (LGMDs) is a heterogeneous group of muscular dystrophies that mostly affect the pelvic and shoulder girdle muscle groups. We report here a case of neuromuscular disease associated with Dupuytren's contracture, which has never been described before as cosegregating with an autosomal dominant type of inheritance. Dupuytren's contracture is a common disease, especially in Northern Europe. Comorbid conditions associated with Dupuytren's contracture are repetitive trauma to the hands, diabetes, and seizures, but it has never before been associated with neuromuscular disease. We hypothesize that patients may harbor mutations in genes with functions related to neuromuscular disease and Dupuytren's contracture development.

The mechanical environment in Dupuytren's contracture determines cell contractility and associated MMP-mediated matrix remodeling

Matrix metalloproteinases (MMPs) are expressed in Dupuytren's contracture and play a role in matrix remodeling. We tested the role of tension on contractility and MMP expression in Dupuytren's nodule and cord cells. Cells were subjected to pre-determined loading patterns of known repeatable magnitudes (static load, unloading, and overloading) and tested for MMP gene expression (MMP-1, -2, -9, -13, and TIMP-1, -2) and force generation using a tension-culture force monitor. Matrix remodeling was assessed by addition of cytochalasin D and residual matrix tension was quantified. Nodule compared to cord and control cells demonstrate greater force generation and remodeling (p < 0.05). Nodule cells subjected to a reduced load and overloading led to threefold increase of MMP-1, -2, and -9 compared to static load, whilst cord and control cells only showed a twofold increase of MMP-9. Nodule cells subjected to overloading showed a twofold increase in TIMP-2 expression, whilst cord and control cells showed a twofold increase in TIMP-1 expression. Nodule cells differ from cord cells by increased force generation in response to changes in the mechanical environment and related MMP/TIMP-mediated matrix remodeling. In turn this may lead to permanent matrix shortening and digital contracture. Interventional therapies should be aimed at nodule cells to prevent contraction and subsequent permanent matrix remodeling.

Correction of contracture and recurrence rates of Dupuytren contracture following invasive treatment: the importance of clear definitions

PURPOSE

To call attention to the wide variety of definitions for recurrence that have been employed in studies of different invasive procedures for the treatment of Dupuytren contracture and how this important limitation has contributed to the wide range of reported results.

METHODS

This study reviewed definitions and rates of contracture correction and recurrence in patients undergoing invasive treatment of Dupuytren contracture. A literature search was carried out in January 2011 using the terms "Dupuytren" AND ("fasciectomy" OR "fasciotomy" OR "dermofasciectomy" OR "aponeurotomy" OR "aponeurectomy") and limited to studies in English.

RESULTS

The search returned 218 studies, of which 21 had definitions, quantitative results for contracture correction and recurrence, and a sample size of at least 20 patients. Definitions for correction of contracture and recurrence varied greatly among articles and were almost always qualitative. Percentages of patients who achieved correction of contracture (ie, responder rate) when evaluated at various times after completion of surgery ranged from 15% to 96% for fasciectomy/aponeurectomy. Responder rates were not reported for fasciotomy/aponeurotomy. Recurrence rates ranged from 12% to 73% for patients treated with fasciectomy/aponeurectomy and from 33% to 100% for fasciotomy/aponeurotomy. Review of these reports underscored the difficulty involved in comparing correction of contracture and recurrence rates for different surgical interventions because of differences in definition and duration of follow-up.

CONCLUSIONS

Clearly defined objective definitions for correction of contracture and for recurrence are needed for more meaningful comparisons of results achieved with different surgical interventions.

CLINICAL RELEVANCE

Recurrence after surgical intervention for Dupuytren contracture is common. This study, which evaluated reported rates of recurrence following surgical treatment of Dupuytren contracture, provides clinicians with practical information regarding expected long-term outcomes of surgical treatment choices.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic and decision analysis III.

Recent Surgical and Medical Advances in the Treatment of Dupuytren's Disease - A Systematic Review of the Literature

Dupuytren’s disease (DD) is a type of fibromatosis which progressively results in the shortening and thickening of the fibrous tissue of the palmar fascia. This condition which predominantly affects white-northern Europeans has been identified since 1614. DD can affect certain activities of daily living such as face washing, combing hair and putting hand in a glove. The origin of Dupuytren’s contracture is still unknown, but there are a number of treatments that doctors have come across throughout the years. Historically surgery has been the mainstay treatment for DD but not the only one. The objective is to make a structured review of the most recent advances in treatment of DD including the surgical and medical interventions. We have looked at the most relevant published articles regarding the various treatment options for DD. This review has taken 55 articles into consideration which have met the inclusion criteria. The most recent treatments used are multi-needle aponeurotomy, extensive percutaneous aponeurotomy and lipografting, injecting collagenase Clostridium histolyticum, INF-gamma and shockwave therapy as well as radiotherapy. Each of these treatments has certain advantages and drawbacks and cannot be used for every patient. In order to prevent this condition, spending more time and money in the topic is required to reach better and more consistent treatments and ultimately to eradicate this disease.

Elevated transforming growth factor β and mitogen-activated protein kinase pathways mediate fibrotic traits of Dupuytren's disease fibroblasts

Background

Dupuytren's disease is a fibroproliferative disorder of the palmar fascia. The treatment used to date has mostly been surgery, but there is a high recurrence rate. Transforming growth factor β (TGF-β) has been implicated as a key stimulator of myofibroblast activity and fascial contraction in Dupuytren's disease.

Results

We studied Dupuytren's fibroblasts in tissues ex vivo and in cells cultured in vitro and found increased TGF-β expression compared to control fibroblasts. This correlated not only with elevated expression and activation of downstream Smad effectors but also with overactive extracellular signal-regulated kinase 1/2 (ERK1/2)/mitogen-activated protein (MAP) kinase signalling. Treatment with the TGF-β type I receptor kinase inhibitor SB-431542 and bone morphogenetic protein 6 (BMP6) led to inhibition of elevated Smad and ERK1/2/MAP kinase signalling as well as to inhibition of the increased contractility of Dupuytren's fibroblasts. BMP6 attenuated TGF-β expression in Dupuytren's fibroblasts, but not in control fibroblasts. Platelet-derived growth factor (PDGF) expression was strongly promoted by TGF-β in Dupuytren's fibroblasts and was curbed by SB-431542 or BMP6 treatment. High basal expression of phosphorylated ERK1/2 MAP kinase and fibroproliferative markers was attenuated in Dupuytren's fibroblasts by a selective PDGF receptor kinase inhibitor. Cotreatment of Dupuytren's fibroblasts with SB-431542 and the mitogen-activated protein kinase kinase 1 inhibitor PD98059 was sufficient to abrogate proliferation and contraction of Dupuytren's fibroblasts.

Conclusions

Both TGF-β and ERK1/2 MAP kinase pathways cooperated in mediating the enhanced proliferation and high spontaneous contraction of Dupuytren's fibroblasts. Our data indicate that both signalling pathways are prime targets for the development of nonsurgical intervention strategies to treat Dupuytren's disease.

Calcium-dependent signaling in Dupuytren's disease

BACKGROUND

Previous studies suggest that Dupuytren's disease is caused by fibroblast and myofibroblast contractility. Cell contractility in smooth muscle cells is caused by calcium-dependent and calcium-independent signaling mechanisms. In the calcium-dependent pathway, calcium/calmodulin activates myosin light chain kinase (MLCK). In this study, the effects of calcium/calmodulin inhibition with the FDA-approved drug fluphenazine on Dupuytren's fibroblast contractility and MLCK expression were tested.

METHODS

Fibroblast lines from the palmar fascia of patients with Dupuytren's disease were explanted and used for in vitro study. The effect of fluphenazine on Dupuytren's fibroblast migration was determined using a scratch migration assay, and contractility was determined using fibroblast-populated collagen lattice (FPCL) assays. Immunohistochemical staining of MLCK in different samples of Dupuytren's tissue and normal fascia were compared.

RESULTS

Fluphenazine demonstrated a dose-dependent inhibition of Dupuytren's fibroblast migration, with the maximum inhibition of migration observed at 20 μM (69.8 ± 1.9%). Fluphenazine also inhibited FPCL contraction in a dose-dependent manner. Maximal inhibition was observed at a fluphenazine concentration of 20 μM (52.5 ± 6.1%). Immunohistological staining illustrated that MLCK was predominantly expressed throughout the cytoplasm of select fibroblasts within Dupuytren's nodules, yet was absent in the fibroblasts of Dupuytren's cords and normal palmar fascia.

CONCLUSIONS

Fluphenazine inhibits Dupuytren's fibroblast contractility and migration through inhibition of MLCK in vitro. However, the inconsistent expression of MLCK throughout Dupuytren's tissue suggests that calcium-dependent signaling may not be a primary mode of contracture formation. Fluphenazine inhibition of MLCK is not likely to be a target for the treatment of Dupuytren's disease.

Dupuytren's fibroblast contractility by sphingosine-1-phosphate is mediated through non-muscle myosin II

PURPOSE

Previous studies suggest that Dupuytren's disease is caused by fibroblast and myofibroblast contractility within Dupuytren's nodules; however, the stimulus for cell contractility is unknown. Sphingosine-1-phosphate (S1P) is a serum-derived lysophospholipid mediator that enhances cell contractility by activating the S1P receptor, S1P(2). It is hypothesized that S1P stimulates Dupuytren's fibroblast contractility through S1P(2) activation of non-muscle myosin II (NMMII). This investigation examined the role of S1P and NMMII activation in Dupuytren's disease progression and suggests potential targets for treatment.

METHODS

We enmeshed Dupuytren's fibroblasts into fibroblast-populated collagen lattices (FPCLs) and assayed S1P-stimulated FPCL contraction in the presence of the S1P(2) receptor inhibitor JTE-013, the Rho kinase inhibitor Y-27632, the myosin light chain kinase inhibitor ML-7, and the NMMII inhibitor blebbistatin. Tissues from Dupuytren's fascia (n = 10) and normal palmar fascia (n = 10) were immunostained for NMMIIA and NMMIIB.

RESULTS

Sphingosine-1-phosphate stimulated FPCL contraction in a dose-dependent manner. Inhibition of S1P(2) and NMMII prevented S1P-stimulated FPCL contraction. Rho kinase and myosin light chain kinase inhibited both S1P and control FPCL contraction. Dupuytren's nodule fibroblasts robustly expressed NMMIIA and NMMIIB, compared with quiescent-appearing cords and normal palmar fascia.

CONCLUSIONS

Sphingosine-1-phosphate promotes Dupuytren's fibroblast contractility through S1P(2), which stimulates activation of NMMII. NMMII isoforms are ubiquitously expressed throughout Dupuytren's nodules, which suggests that nodule fibroblasts are primed to respond to S1P stimulation to cause contracture formation. S1P-promoted activation of NMMII may be a target for disease treatment.

Post-transcriptional regulation of alpha-smooth muscle actin determines the contractile phenotype of Dupuytren's nodular cells

The objective was to study Dupuytren's myofibroblast cells in constrained collagen matrices in order to more closely emulate their in vivo environment and, to correlate their contractility with alpha-smooth muscle actin (alpha-SMA) expression and determine if dermal fibroblasts regulate Dupuytren's myofibroblast phenotype. Isotonic and isometric force contraction by cells isolated from Dupuytren's nodules, palmar and non-palmar skin fibroblasts was measured in collagen matrices. The effect of co-culturing nodule cells with dermal fibroblasts on isometric contraction was examined. Isometric contraction was correlated with levels of alpha-SMA mRNA by pcr and protein by Western blotting, and alpha-SMA distribution assessed by immunofluorescence. Dupuytren's nodule cells exhibited similar levels of isotonic contraction to both palmar and non-palmar dermal fibroblasts. However, nodule cells generated high levels of isometric force (mean: 3.5 dynes/h), which continued to increase over 24 h to a maximum of 173 dynes. In contrast, dermal fibroblasts initially exhibited low levels of contraction (mean: 0.5 dynes/h) and reached tensional homeostasis on average after 15 h (range: 4-20 h), with a maximum force of 52 dynes. Although all three cell types had similar alpha-SMA mRNA levels, increased levels of alpha-SMA protein were observed in nodule cells compared to dermal fibroblasts. alpha-SMA localised to stress fibres in 35% (range: 26-50%) of nodule cells compared to only 3% (range:0-6%) of dermal fibroblasts. Co-cultures of Dupuytren's cells and dermal fibroblasts showed no contractile differences. The contractile phenotype of Dupuytren's myofibroblasts is determined by increased alpha-SMA protein distributed in stress fibres, not by cellular mRNA levels. Dupuytren's cell contractility is not influenced by dermal fibroblasts.

Myofibroblast distribution in Dupuytren's cords: correlation with digital contracture

PURPOSE

Dupuytren's tissue has typically been described as being composed of myofibroblast-rich palmar nodules and relatively acellular tendon-like cords. We aimed to determine myofibroblast distribution (alpha-smooth muscle actin [alpha-SMA] positive cells) within Dupuytren's tissue and to correlate histologically defined alpha-SMA-positive nodules with digital contracture and recurrent disease.

METHODS

One hundred and three digital Dupuytren's cords (72 fasciectomy, 31 dermofasciectomy) were stained with anti-alpha-SMA antibody. The presence of alpha-SMA-positive nodules, their surface area, and alpha-SMA-positive cells were quantified throughout excised Dupuytren's tissue. Clinical data on diathesis, flexion deformity, and previous surgeries were collected.

RESULTS

Cords were nodular (66%) or non-nodular (34%). Nodular cords contained 1 (55%), 2 (33%), or 3 or more nodules (12%) composed of localized collections of cells. The mean total nodule surface area was 23 mm(2) (range, 1.3-105 mm(2)). Nodules contained the highest number of alpha-SMA-positive cells (mean 97%, 2374 cells/mm(2)) compared to peri-nodular areas (mean 32%, 763 cells/mm(2)), and more distant cord (mean 8%, 495 cells/mm(2)). Non-nodular cords contained 9% to 17% alpha-SMA-positive cells (mean 475-663 cells/mm(2)), with higher numbers distally. There was greater digital contracture in patients with non-nodular cords. Thirty-six of 38 proximal interphalangeal (PIP) joint-marked samples had a nodule that co-localized with the PIP joint. Nodule size did not correlate with flexion deformity or with primary or recurrent disease.

CONCLUSIONS

We found that two thirds of digital cords were nodular. Nodules were hypercellular, the majority being alpha-SMA-positive cells. Nodules varied in size and co-localized with the PIP joint. Cord was relatively cellular throughout; a proportion of these cells were alpha-SMA-positive and cells aligned with collagen fibers. Non-nodular cords correlated with significantly greater digital flexion contracture. We propose that cells in nodular cords contract and deposit extracellular matrix components. The matrix is then remodeled in shortened configuration, and as fixed flexion deformity develops, stress shielding eventually leads to myofibroblast apoptosis, and cord becomes less cellular.

Periostin differentially induces proliferation, contraction and apoptosis of primary Dupuytren's disease and adjacent palmar fascia cells

Dupuytren's disease, (DD), is a fibroproliferative condition of the palmar fascia in the hand, typically resulting in permanent contracture of one or more fingers. This fibromatosis is similar to scarring and other fibroses in displaying excess collagen secretion and contractile myofibroblast differentiation. In this report we expand on previous data demonstrating that POSTN mRNA, which encodes the extra-cellular matrix protein periostin, is up-regulated in Dupuytren's disease cord tissue relative to phenotypically normal palmar fascia. We demonstrate that the protein product of POSTN, periostin, is abundant in Dupuytren's disease cord tissue while little or no periostin immunoreactivity is evident in patient-matched control tissues. The relevance of periostin up-regulation in DD was assessed in primary cultures of cells derived from diseased and phenotypically unaffected palmar fascia from the same patients. These cells were grown in type-1 collagen-enriched culture conditions with or without periostin addition to more closely replicate the in vivo environment. Periostin was found to differentially regulate the apoptosis, proliferation, alpha smooth muscle actin expression and stressed Fibroblast Populated Collagen Lattice contraction of these cell types. We hypothesize that periostin, secreted by disease cord myofibroblasts into the extra-cellular matrix, promotes the transition of resident fibroblasts in the palmar fascia toward a myofibroblast phenotype, thereby promoting disease progression.

Transforming growth factor-beta1 stimulation enhances Dupuytren's fibroblast contraction in response to uniaxial mechanical load within a 3-dimensional collagen gel

PURPOSE

A function of fibroblasts is the generation of cytomechanical force within their surrounding extracellular matrix. Abnormalities in force generation may be the cause of many pathologic conditions including scarring, and some fibroproliferative disorders such as Dupuytren's disease, which is the focus of this report.

METHODS

This work investigated the cytomechanical responses of Dupuytren's-derived fibroblasts to externally applied mechanical force using a culture force monitor model, with and without stimulation with the fibrosis-linked cytokine, transforming growth factor-beta1 (TGF-beta1). We compared these responses with cytomechanical responses of fibroblasts derived from the transverse carpal ligament.

RESULTS

Dupuytren's fibroblasts display a significantly greater ability to contract a collagen matrix compared with control fibroblasts, with a maximum generated force of 131 dynes (p < .001). These cells did not exhibit a characteristic plateau phase in the contraction, which indicates a delay in achieving tensional homeostasis from Dupuytren's-derived cells. After being subjected to uniaxial overload and underload, Dupuytren's fibroblasts responded by increased force generation, whereas control fibroblasts responded by a reduction in force in response to an overload, and contraction in response to an underload. These changes were exacerbated by the addition of the profibrotic factor TGF-beta1, with a significant increase in generated force for all cell types, in particular during the early phase of fibroblast attachment and contraction, and a positive contraction gradient in response to overloading forces.

CONCLUSIONS

These data suggest that cells derived from this fibrotic disease display characteristic abnormalities in force generation profiles. Their default response to loading or underloading is contraction, or increased force generation. This work highlights the role of TGF-beta1 as a mechano-transduction cytokine, which has an influence on the early phase cell of force generation, as well as a role in mechanical responses of cells to external mechanical stimuli. This, in turn, may influence the progression of Dupuytren's disease and the high rates of recurrence seen postoperatively.

A complete expression profile of matrix-degrading metalloproteinases in Dupuytren's disease

PURPOSE

Dupuytren's disease (DD) is a common fibrotic condition of the palmar fascia, leading to deposition of collagen-rich cords and finger contractions. The metzincin superfamily contains key enzymes in the turnover of collagen and other extracellular matrix macromolecules. A number of broad-spectrum matrix metalloproteinase inhibitors, used in cancer clinical trials, caused side effects of DD-like contractures. We tested the hypothesis that changes in the expression of specific metalloproteinases underlie or contribute to the fibrosis and contracture seen in DD.

METHODS

We collected tissue from patients with DD and used normal palmar fascia as a control. We profiled the expression of the entire matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinases (TIMP), and a disintegrin and metalloproteinase domain with thrombospondin motif (ADAMTS) gene families in these tissues using real-time reverse-transcription polymerase chain reaction.

RESULTS

A number of metalloproteinases and inhibitors are regulated in DD. The expression of 3 key collagenases, MMP1, MMP13, and MMP14 is increased significantly in the DD nodule, as is the expression of the collagen biosynthetic enzyme ADAMTS14. The expression of MMP7, an enzyme with broad substrate specificity, is increased in the DD nodule and remains equally expressed in the DD cord. TIMP1 expression is increased significantly in DD nodule compared with normal palmar fascia.

CONCLUSIONS

This study measured the expression of all MMP, ADAMTS, and TIMP genes in DD. Contraction and fibrosis may result from: (1) increased collagen biosynthesis mediated by increased ADAMTS-14; (2) an increased level of TIMP-1 blocking MMP-1- and MMP-13-mediated collagenolysis; and (3) contraction enabled by MMP-14-mediated pericellular collagenolysis (and potentially MMP-7), which may escape inhibition by TIMP-1. The complete expression profile will provide a knowledge-based approach to novel therapeutics targeting these genes.

Contractile forces generated by striae distensae fibroblasts embedded in collagen lattices

Striae distensae are characterized by linear, smooth bands of atrophic-appearing skin that are reddish at first and finally white. They are due to stretching of the skin, as in rapid weight gain, or mechanical stress, as in weight lifting. The pathogenesis of striae distensae is unknown but probably relates to changes in the fibroblast phenotype. In order to characterize striae distensae fibroblasts, alpha-smooth muscle actin expression and contractile forces were studied. Five healthy women with early erythematous striae and five healthy women with older striae were selected. Paired biopsies were taken from the center of lesional striae and adjacent normal skin. Fibroblasts were obtained by an explant technique and expanded in vitro in Dulbecco's modified Eagle's medium. Contractile forces generated by fibroblasts in collagen lattices were measured with the Glasbox device developed in our laboratory. Alpha-smooth muscle actin expression was studied by immunofluorescence labeling of cells and by flow cytometry. Fibroblasts from early striae distensae were the richest cells in alpha-smooth muscle actin filaments and generated the highest contractile forces. Their peak contractile force was 26% greater than normal fibroblasts. There was a 150% higher level of alpha-smooth muscle actin content in fibroblasts from early striae distensae compared with fibroblasts from normal skin. In contrast, there was no significant difference in force generation between old striae fibroblasts and normal fibroblasts with cells expressing no alpha-smooth muscle actin. The contractile properties of fibroblasts from striae distensae varies depending on the stage of the disease. In early striae distensae, fibroblasts acquire a more contractile phenotype, corresponding to that of myofibroblasts.

Dupuytren's contracture; increased cellularity--proliferation, is there equality?

BACKGROUND

Dupuytren's disease is a chronic inflammatory process which causes contractures of the fingers by shortening and thickening the palmar fascia. During the proliferative phase, fibroblasts transform into myofibroblasts apparently under the influence of several different factors. The disease usually develops slowly, but in some patients it tends to develop aggressively. The pathogenesis of Dupuytren's disease remains unsolved. In this study, we analyzed some histological characteristics that seem to predict rapid recurrence.

MATERIAL AND METHODS

21 patients were divided into two groups. In 11 patients the disease was classified as aggressive because it had recurred within two years after an operation. In 10 cases it was non-aggressive, as no recurrence had been seen. Five control samples were taken from healthy palmar aponeurosis. The differences in cellularity, collagen, Ki-67, MSA, alpha-SMA and tenascin between the specimens were analyzed using immunohistochemistry.

RESULTS

Alpha-SMA and Ki-67 were present more often in the aggressive specimens. Immunohistochemical stainings for macrophages and lymphocytes were negative.

CONCLUSION

There may be differences in the histology and/or immunohistochemical appearance of pathological palmar connective tissue cords in aggressive and normal Dupuytren's disease. Further studies are needed to elucidate the pathogenesis of this disease.

Comparing the contractile properties of human fibroblasts in leg ulcers with normal fibroblasts

OBJECTIVE

The tissue contraction phenomenon associated with wound healing is of prime importance for wound closure. Contractile properties of human fibroblasts from chronic venous leg ulcers were compared with those of normal fibroblasts using in vitro models.

METHOD

Biopsies were taken from the uninvolved skin of the thigh, the epithelialised ulcer edge and the non-epithelialised ulcer centre in four patients (average age: 78 years). Fibroblasts were obtained by an explant technique and expanded in vitro in Dulbecco's Modified Eagle's Medium supplemented with 10% foetal calf serum and used for the assays at their fourth passage. Intracellular alpha-smooth muscle actin expression (alphaSM-actin) was studied by immunofluorescence labelling of cells cultured in monolayer. Contractile properties were evaluated using three-dimensional collagen lattices.

RESULTS

Fibroblasts from the ulcer centre were the richest cells in actin filaments. Both populations of venous ulcer fibroblasts contracted more rapidly and to a greater extent than normal fibroblasts. The peak contractile forces developed by fibroblasts from the ulcer centre and the ulcer edge were 30% and 18% greater than normal fibroblasts respectively.

CONCLUSION

Some functions of fibroblasts, in particular the generation of contractile forces and the formation of cytoplasmic actin filaments, seem not to be affected in chronic venous ulcers.

DECLARATION OF INTEREST

This study was supported by the Fondation Coloplast pour la Qualite de la Vie of France.

The Contractile Properties and Responses to Tensional Loading of Dupuytren???s Disease???Derived Fibroblasts Are Altered: A Cause of the Contracture?

Dupuytren's disease causes disability because of the development of finger flexion deformities, with distinct nodule and cord formation. This results in physical shortening of the diseased fascial tissue through a combination of cell-mediated contraction and matrix remodeling. It is this fixed tissue fabric shortening that prevents finger extension. In this experimental study, the relative contractile properties of Dupuytren nodule- and cord-derived fibroblasts were quantified in a culture force monitor model, in comparison with normal carpal ligament fibroblasts. Nine nodule, 10 cord, and four carpal ligament fibroblast cell lines were studied; each cell line was derived from a separate patient. The contractile forces generated by nodule and cord fibroblasts were significantly greater than the force generated by carpal ligament fibroblasts. There were also significant differences between nodule- and cord-derived fibroblasts, with the nodule cells demonstrating the greatest contractile force generation. The contraction profiles of both cord and nodule Dupuytren fibroblasts demonstrated delays in the attainment of tensional homeostasis, with an absence of a plateau phase by 20 hours. After the contraction phase, cell-seeded constructs were subjected to a series of four uniaxial mechanical overloads and cellular responses were monitored during each subsequent 30-minute period. Dupuytren nodule and cord fibroblast responses were significantly altered, compared with carpal ligament fibroblasts, exhibiting an increased and opposite response. Dupuytren fibroblasts, particularly nodule fibroblasts, exhibited increased force generation and a delay in reaching tensional homeostasis. The data suggest that these cells have an inherently higher basal tension and contractile ability. This results in increased shortening of the matrix, and the delay in reaching tensional homeostasis might exacerbate this response. These results represent a theoretical framework regarding the fundamental processes involved in the pathogenesis and progression of clinical flexion deformities in Dupuytren disease.

Tamoxifen decreases fibroblast function and downregulates TGF(beta2) in dupuytren's affected palmar fascia

BACKGROUND

Dupuytren's contracture is a fibroproliferative disorder that is associated with increased collagen deposition. Isoforms of transforming growth factor beta (TGF(beta)), normally TGF(beta1) and TGF(beta2), are involved in the progressive fibrosis of Dupuytren's disease. It has been suggested that downregulation of TGF(beta) may be useful in the treatment of the condition. Tamoxifen, a synthetic nonsteroidal antiestrogen, is known to modulate the production of TGF(beta). This study examined the role of tamoxifen in decreasing fibroblast function and downregulating TGF(beta2).

METHODS

Primary cultures of fibroblasts were obtained from Dupuytren's affected fascia and carpal tunnel affected fascia as a control. Collagen lattices were prepared and populated with the fibroblasts. The fibroblast-populated collagen lattices (FPCL) were then measured for contraction every 24 h for 5 days. Supernatant was obtained from the culture medium following completion of the FPCL portion of the experiment and used for a TGF(beta2) immunoassay.

RESULTS

Dupuytren's affected fibroblasts contracted the FPCLs significantly more than carpal tunnel control fibroblasts. Treating the fibroblasts with tamoxifen caused a decreased contraction rate in both Dupuytren's affected fibroblasts and carpal tunnel controls. There was increased TGF(beta2) expression in the Dupuytren's affected fascia group compared to the carpal tunnel control group. Tamoxifen decreased TGF(beta2) expression in Dupuytren's affected fascia group but not in the carpal tunnel control group.

CONCLUSION

TGF(beta) appears to be the key cytokine in the fibrogenic nature of Dupuytren's disease. Tamoxifen treatment has been demonstrated to decrease the function of fibroblasts derived from Dupuytren's affected fascia and downregulated TGF(beta2) production in these same fibroblasts. These data suggest a method to manipulate and control Dupuytren's contracture in the clinical setting.

Effect of telmisartan on angiotensin II-mediated collagen gel contraction by adult rat cardiac fibroblasts

The possible contributions of the angiotensin receptor subtypes 1 and 2 on the angiotensin II-induced collagen gel contraction by adult rat cardiac fibroblasts were studied using the specific angiotensin receptor type 1 and 2 antagonists telmisartan and P-186, respectively. Cardiac fibroblasts (from normal male adult rats) from passage 2 were cultured to confluency and added to a hydrated collagen gel, with or without angiotensin II, angiotensin II plus telmisartan, or angiotensin II plus P-186 in Dulbecco's Modified Eagle's Medium containing 5% fetal bovine serum for 1, 2, or 3 days. Control gels containing adult rat cardiac fibroblasts showed a significant amount of contraction after 3 days of incubation, causing a contraction to 67.9 +/- 7.1% of the area after 1 day. Angiotensin II (10(-7) M) stimulated (p < or = 0.05) the contraction of collagen mediated by cardiac fibroblasts after 1, 2, or 3 days. Telmisartan (10(-7) M) completely blocked the angiotensin II-induced collagen contraction by cardiac fibroblasts. P-186 (10(-7) M) had no effect on the angiotensin II-induced collagen contraction by cardiac fibroblasts. Addition of telmisartan and P-186 alone did not affect the collagen gel contraction by cardiac fibroblasts. Our data demonstrate that the effects of angiotensin II on the collagen gel contraction by adult rat cardiac fibroblasts are angiotensin II type 1 receptor mediated because they were abolished by the specific angiotensin II type 1 receptor antagonist telmisartan but not by the specific angiotensin II type 2 receptor antagonist P-186.

The effect of interferon-alpha2b on an in vitro model Dupuytren's contracture

The effects of interferon-alpha2b (IFN-alpha2b) on Dupuytren's and control palmar fibroblasts were evaluated using the fibroblast-populated collagen lattice model. Three paired strains of Dupuytren's and control fibroblasts were exposed to IFN-alpha2b for 96 hours before incorporation into triplicate collagen lattices. Contraction of the lattices was recorded and Northern blot analysis of cytoskeletal mRNA was performed. Comparisons of Dupuytren's and control fibroblasts revealed significantly increased contractility of the Dupuytren's fibroblasts in 2 of the 3 strains. Treatment with IFN-alpha2b significantly inhibited contraction in both Dupuytren's and control fibroblasts. In Dupuytren's fibroblasts, treatment with IFN-alpha2b significantly down-regulated mRNA expression for cytoplasmic beta-actin and gamma-actin.

Pharmacologic regulation of Dupuytren's fibroblast contraction in vitro

Dupuytren's disease is associated with contraction of specialized fibroblasts present in the diseased palmar fascia. Pharmacologic agents were evaluated for their ability to promote or inhibit contraction of Dupuytren's fibroblasts in vitro using a collagen lattice contraction assay. In the first part of the study, lysophosphatidic acid (LPA), serotonin, angiotensin II, and prostaglandin F2 alpha were tested for their ability to promote Dupuytren's fibroblast contraction. Lysophosphatidic acid was found to significantly promote Dupuytren's fibroblast contraction as compared with controls. This response to LPA is dose dependent, with a half-maximal response of 0.07 microM. Angiotensin II, serotonin, and prostaglandin F2 alpha at 1 mM, induced a significant amount of contraction as compared to controls, but the amount of contraction was at least six times less than that observed for LPA. In the second part of the study, prostaglandins E1 and E2 or the calcium blockers nifedipine and verapamil were tested for their ability to inhibit LPA-promoted contraction. It was found that both types of inhibitors partially block LPA-promoted contraction of Dupuytren's fibroblasts. The effect of the various pharmacologic agents on normal palmar fibroblasts was not evaluated. The focus of this study was to examine the regulation of contraction of Dupuytren's fibroblasts. This study demonstrates that LPA is a potent agonist of Dupuytren's fibroblast contraction and that this contraction can be inhibited by specific pharmacologic agents. These findings provide a rational basis for investigating further the clinical use of the calcium channel blockers nifedipine or verapamil and prostaglandins E1 and E2 to control Dupuytren's disease and possibly other fibrotic conditions.

Correlation of alpha-smooth muscle actin expression and contraction in Dupuytren's disease fibroblasts

We studied 11 nodules from patients with Dupuytren's contracture to determine whether alpha-smooth muscle actin expression in Dupuytren's fibroblasts is related to the generation of contractile force. Tissue was placed into explant culture and fibroblast strains were obtained. The mean percent of cultured Dupuytren's fibroblasts expressing alpha-smooth muscle actin, as determined by immunofluorescence, was 14 +/- 8 and ranged from 1% to 26%. The ability of Dupuytren's fibroblasts to generate contractile force was determined by using a previously described collagen lattice contraction assay. We observed a significant positive correlation between the expression of alpha-smooth muscle actin and the generation of contractile force in cell strains of Dupuytren's fibroblasts. In addition, six fibroblast strains from palmar fascia of individuals undergoing carpal tunnel release were examined. In six strains of palmar fibroblasts the mean percent of cells expressing alpha-smooth muscle actin was 5 +/- 3 and ranged from 1% to 9%. Six Dupuytren's fibroblast strains, in which more than 15% of the cells expressed alpha-smooth muscle actin, were significantly more contractile than the palmar fibroblasts. These results suggest that Dupuytren's fibroblasts can acquire smooth muscle characteristics and that the acquisition of a smooth muscle-like phenotype correlates with increased contractility.