Real world study of sacituzumab govitecan in metastatic triple-negative breast cancer in the United Kingdom

BACKGROUND

Treatment options for pre-treated patients with metastatic triple-negative breast cancer (mTNBC) remain limited. This is the first study to assess the real-world safety and efficacy of sacituzumab govitecan (SG) in the UK.

METHODS

Data was retrospectively collected from 16 tertiary UK cancer centres. Pts had a diagnosis of mTNBC, received at least two prior lines of treatment (with at least one being in the metastatic setting) and received at least one dose of SG.

RESULTS

132 pts were included. Median age was 56 years (28-91). All patients were ECOG performance status (PS) 0-3 (PS0; 39, PS1; 76, PS2; 16, PS3;1). 75% (99/132) of pts had visceral metastases including 18% (24/132) of pts with CNS disease. Median PFS (mPFS) was 5.2 months (95% CI 4.5-6.6) with a median OS (mOS) of 8.7 months (95% CI 6.8-NA). The most common adverse events (AEs) were fatigue (all grade; 82%, G3/4; 14%), neutropenia (all grade; 55%, G3/4; 29%), diarrhoea (all grade; 58%, G3/4, 15%), and nausea (all grade; 38%, G3/4; 3%). SG dose reduction was required in 54% of pts.

CONCLUSION

This study supports significant anti-tumour activity in heavily pre-treated pts with mTNBC. Toxicity data aligns with clinical trial experience.

Urogenital symptoms in mitochondrial disease: overlooked and undertreated

Background and purpose

Bowel symptoms are well documented in mitochondrial disease. However, data concerning other pelvic organs is limited. A large case–control study has therefore been undertaken to determine the presence of lower urinary tract symptoms (LUTS) and sexual dysfunction in adults with genetically confirmed mitochondrial disease.

Methods

Adults with genetically confirmed mitochondrial disease and control subjects were recruited from a specialist mitochondrial clinic. The presence and severity of LUTS and their impact on quality of life, in addition to sexual dysfunction and bowel symptoms, were captured using four validated questionnaires. Subgroup analysis was undertaken in patients harbouring the m.3243A>G MT‐TL1 mitochondrial DNA mutation. A subset of patients underwent urodynamic studies to further characterize their LUTS.

Results

Data from 58 patients and 19 controls (gender and age matched) were collected. Adults with mitochondrial disease had significantly more overactive bladder (81.5% vs. 56.3%, P = 0.039) and low stream (34.5% vs. 5.3%, P = 0.013) urinary symptoms than controls. Urodynamic studies in 10 patients confirmed that bladder storage symptoms predominate. Despite high rates of LUTS, none of the patient group was receiving treatment. Female patients and those harbouring the m.3243A>G MT‐TL1 mutation experienced significantly more sexual dysfunction than controls (53.1% vs. 11.1%, P = 0.026, and 66.7% vs. 26.3%, P = 0.011, respectively).

Conclusions

Lower urinary tract symptoms are common but undertreated in adult mitochondrial disease, and female patients and those harbouring the m.3243A>G MT‐TL1 mutation experience sexual dysfunction. Given their impact on quality of life, screening for and treating LUTS and sexual dysfunction in adults with mitochondrial disease are strongly recommended.

The care of dying people in 16th- and 17th-century England

Between the years 1500 and 1700, mortality was higher and exposure to death is greater than in the modern day. Through analysis of primary texts from the chosen period, we explored the principles behind the care of the dying in the context of medicine, spirituality, and society. Results showed that a "holy death" was a cultural norm and medicine was subsidiary: hope was for the salvation of the soul, not the body. This was part of an approach that focused on symptom relief, irrespective of disease classification, demonstrating an early holistic approach to death and dying.

The Red Kangaroo pericardium as a material source for the manufacture of percutaneous heart valves

BACKGROUND

The kangaroo pericardium might be considered to be a good candidate material for use in the manufacture of the leaflets of percutaneous heart valves based upon the unique lifestyle. The diet consists of herbs, forbs and strubs. The kangaroo pericardium holds an undulated structure of collagen.

MATERIAL AND METHOD

A Red Kangaroo was obtained after a traffic fatality and the pericardium was dissected. Four compasses were cut from four different sites: auricular (AUR), atrial (ATR), sternoperitoneal (SPL) and phrenopericardial (PPL). They were investigated by means of scanning electron microscopy, light microscopy and transmission electron microscopy.

RESULTS

All the samples showed dense and wavy collagen bundles without vascularisation from both the epicardium and the parietal pericardium. The AUR and the ATR were 150±25μm thick whereas the SPL and the PPL were thinner at 120±20μm. The surface of the epicardium was smooth and glistening. The filaments of collagen were well individualized without any aggregation, but the banding was poorly defined and somewhat blurry.

CONCLUSION

This detailed morphological analysis of the kangaroo pericardium illustrated a surface resistant to thrombosis and physical characteristics resistant to fatigue. The morphological characteristics of the kangaroo pericardium indicate that it represents an outstanding alternative to the current sources e.g., bovine and porcine. However, procurement of tissues from the wild raises supply and sanitary issues. Health concerns based upon sanitary uncertainty and reliability of supply of wild animals remain real problems.

Autologous bilayered self-assembled skin substitutes (SASSs) as permanent grafts: a case series of 14 severely burned patients indicating clinical effectiveness

Split-thickness skin autografts (AGs) are the standard surgical treatment for severe burn injuries. However, the treatment of patients with substantial skin loss is limited by the availability of donor sites for skin harvesting. As an alternative to skin autografts, our research group developed autologous self-assembled skin substitutes (SASSs), allowing the replacement of both dermis and epidermis in a single surgical procedure. The aim of the study was to assess the clinical outcome of the SASSs as a permanent coverage for full-thickness burn wounds. Patients were recruited through the Health Canada's Special Access Program. SASSs were grafted on debrided full-thickness wounds according to similar protocols used for AGs. The graft-take and the persistence of the SASS epithelium over time were evaluated. 14 patients received surgical care with SASSs. The mean percentage of the SASS graft-take was 98 % (standard deviation = 5) at 5 to 7 d after surgery. SASS integrity persisted over time (average follow-up time: 3.2 years), without noticeable deficiency in epidermal regeneration. Assessment of scar quality (skin elasticity, erythema, thickness) was performed on a subset of patients. Non-homogeneous pigmentation was noticed in several patients. These results indicated that the SASS allowed the successful coverage of full-thickness burns given its high graft-take, aesthetic outcome equivalent to autografting and the promotion of long-term tissue regeneration. When skin donor sites are in short supply, SASSs could be a valuable alternative to treat patients with full-thickness burns covering more than 50 % of their total body surface area.

Translating the combination of gene therapy and tissue engineering for treating recessive dystrophic epidermolysis bullosa

The combination of gene therapy and tissue engineering is one of the most promising strategies for the treatment of recessive dystrophic epidermolysis bullosa (RDEB). RDEB is a rare genetic disease characterised by mutations in the COL7A1 gene, encoding type VII collagen (COLVII), which forms anchoring fibrils at the dermal-epidermal junction of the skin. This disease causes severe blistering and only palliative treatments are offered. In this study, the base of a strategy combining gene therapy and a tissue-engineered skin substitute (TES), which would be suitable for the permanent closure of skin wounds, was set-up. As a high transduction efficiency into fibroblasts and/or keratinocytes seems to be a prerequisite for a robust and sustained correction of RDEB, different envelope pseudotyped retroviral vectors and the transduction enhancer EF-C were tested. When green fluorescent protein (GFP) was used as a reporter gene to evaluate the retroviral-mediated gene transfer, the fibroblast infection efficiency was 30 % higher with the Ampho pseudotyped vector as compared with the other pseudotypes. At least a 3.1-fold and a 1.3-fold increased transduction were obtained in fibroblasts and keratinocytes, respectively, with EF-C as compared with polybrene. A continuous and intense deposit of haemagglutinin (HA)-COLVII was observed at the dermal-epidermal junction of self-assembled TESs made of cells transduced with a HA-tagged COL7A1 vector. Furthermore, HA-tagged basal epidermal cells expressing keratin 19 were observed in TESs, suggesting stem cell transduction. This approach could be a valuable therapeutic option to further develop, in order to improve the long-term life quality of RDEB patients.

Protein-polyelectrolyte complexes to improve the biological activity of proteins in layer-by-layer assemblies

A standard method of protein immobilization is proposed, based on the use of protein-polyelectrolyte complexes (PPCs) as building blocks for layer-by-layer assembly. Thicker multilayers, with a higher polyelectrolyte fraction, are obtained with PPCs compared to single protein molecules. Biological activity is not only maintained, but specific activity is also higher, as demonstrated for lysozyme-poly(styrene sulfonate) complexes. This is attributed to the more hydrated state of the assemblies. This new method of protein immobilization opens up perspectives for biotechnology and biomedical applications.

Microstructural alterations owing to handling of bovine pericardium to manufacture bioprosthetic heart valves: A potential risk for cusp dehiscence

INTRODUCTION

Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis.

MATERIAL AND METHOD

Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

RESULTS

The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles.

CONCLUSION

Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated.

Correlation between structural changes and acute thrombogenicity in transcatheter pericardium valves after crimping and balloon deployment

INTRODUCTION

Transcathether heart valve replacement has gained considerable acceptance during the last decades. It is now part of the armamentarium for aortic valve replacement. The procedure proved to be highly efficient. However the issues of the blood compatibility and tissue durability were not raised and the adverse events were probably under-reported, according to observations of thrombosis after deployment.

MATERIAL AND METHOD

Bovine pericardium leaflets were sewn inside a 26mm diameter stainless steel stent to manufacture these valves (one control and two experimental). The correlation between the trauma and the acute thombogenicity of bovine pericardium leaflets, after crimping and ballooning, was investigated via an in vitro blood flow with labeled platelets. These leaflets were processed for histology: scanning electron microscopy, light microscopy, and transmission electron microscopy.

RESULTS

The control specimens showed a regular pericardium structure with some blood cells deposited on the collagen fibrous surface (inflow) and scarce blood cells deposited on the serous surface (outflow). After crimping and ballooning, the structure of the pericardium was severely injured, eventually with delaminations and ruptures. The blood cell uptake was considerably increased compared to the control.

CONCLUSION

It would therefore be appropriate to pay more attention to the design of the valves. Specifically, the incorporation of a buffer tissue or fabric between the pericardium and the metallic stent is suggested. The issue of ballooning deserves detailed and in depth investigation regarding the lifetime of the device.

Transcatheter heart valve crimping and the protecting effects of a polyester cuff

INTRODUCTION

Prior to deployment, the percutaneous heart valves must be crimped and loaded into sheaths of diameters that can be as low as 6mm for a 23mm diameter valve. However, as the valve leaflets are fragile, any damage caused during this crimping process may contribute to reducing its long-term durability in vivo.

MATERIAL AND METHOD

Bovine pericardium percutaneous valves were manufactured as follows. The leaflets were sutured on a nitinol frame. A polyester cuff fabric served as a buffer between the pericardium and the stent. Two valves were crimped and one valve was used as control. The valves were examined in gross observation and micro-CT scan and then the leaflets were processed for histology and analyzed in scanning electron microscopy, light microscopy and transmission electron microscopy.

RESULT

Crimping of the valves resulted in the increase thickness of the leaflets and there was no evidence of additional delamination. The heavy prints of the stents were irregularly distributed on the outflow surface in the crimped devices and were shallow and did not penetrate throughout the thickness of the leaflets. However, the wavy microscopy of collagen fiber bundles was well preserved. They were found to remain individualized without any agglutination as shown by the regular banding appearance.

CONCLUSION

Crimping of self-deployable valves per se caused only minor damages to the leaflets. However, the procedure could be refined in order to minimize areas of high pressure and swelling of the tissue that can be accompanied with flow surface disruption and increase of the hydraulic conductance. The incorporation of a polyester buffer serves to prevent the deleterious effects that may be caused if the pericardium tissue were in direct contact with the nitinol stent.

Effect of intense pulsed light treatment on human skin in vitro: analysis of immediate effects on dermal papillae and hair follicle stem cells

BACKGROUND

Hair follicles house a permanent pool of epithelial stem cells. Intense pulsed light (IPL) sources have been successfully used for hair removal, but long-term hair reduction may require several treatments. Many questions remain regarding the impact of IPL treatment on the structure of the hair follicle, more specifically on hair follicular stem cells and dermal papilla cells, a group of specialized cells that orchestrate hair growth.

OBJECTIVES

To characterize the destruction of human hair follicles and surrounding tissues following IPL treatment, with more attention paid to the bulge and the bulb regions.

METHODS

Human scalp specimens of Fitzpatrick skin phototype II were exposed ex vivo to IPL pulses and were then processed for histological analysis, immunodetection of stem cell-associated keratin 19, and revelation of the endogenous alkaline phosphatase activity expressed in dermal papilla cells.

RESULTS

Histological analysis confirmed that pigmented structures, such as the melanin-rich matrix cells of the bulb in anagen follicles and the hair shaft, are principally targeted by IPL treatment, while white hairs and epidermis remained unaffected. Damage caused by heat sometimes extended over the dermal papilla cells, while stem cells were mostly spared.

CONCLUSIONS

IPL epilation principally targets pigmented structures. Our results suggest that, under the tested conditions, collateral damage does not deplete stem cells. Damage at the dermal papilla was observed only with high-energy treatment modalities. Extrapolated to frequently treated hairs, these observations explain why some hairs grow back after a single IPL treatment.

Isolation and characterization of human airway fibroblasts in culture

Asthma is considered an airway inflammatory disorder characterized by variable airflow obstruction and airway hyperresponsiveness (1). The inflammatory component of asthma has been studied extensively over the past few years, but, more recently, the potential contribution of airway wall remodeling to functional and clinical changes has been emphasized (2,3). Although the methods of sampling of bronchial tissue were previously limited, being obtained mostly from autopsic or surgical specimens, they have improved recently.

Skin substitutes and wound healing

Medical science has vastly improved on the means and methods available for the treatment of wounds in the clinic. The production and use of various types of skin substitutes has led to dramatic improvements in the odds of survival for severely burned patients, but they have also shown promise for many other applications, including cases involving chronic wounds that are not life threatening. Nowadays, more than 20 products are commercially available, more are undergoing clinical trials and a large number of new models are being investigated in various research laboratories worldwide. Many of the current products do not contain any living cells and vary in their capacity to harness the innate capacity of the body to heal itself. Others include living cells, of allogeneic or autologous origin, and are often referred to as 'cellular therapy' or 'tissue-engineered' products. Modifications and improvements are currently investigated that aim at improving the healing potential of those products through the use of recombinant growth factors and additional features such as microvascularization. Fundamental research into wound healing and scar-free regeneration raises the hope that we will eventually be able to restore almost completely the appearance and function of skin after the healing of wounds.

Reliability of reconstructed β-orientation maps in titanium alloys

This paper demonstrates that parent beta-orientation maps of titanium alloys can reliably be reconstructed from inherited alpha maps in most cases. Important aspects of the calculation that ensure an accurate determination of the parent orientation as well as a reliable restitution of the beta boundaries are discussed. The limits of the reconstruction method, according to the inherited alpha microstructure are also pointed out. Finally, the method is applied to a beta metastable titanium alloy, which contained enough retained beta phase so that its orientation could be measured by EBSD. The comparison between the measured and the reconstructed beta maps shows the efficiency of the method.

Determination of parent orientation maps in advanced titanium-based alloys

In the past few years, reconstruction methods have been developed and applied successfully to restore the beta microtexture in titanium alloys. This contribution shows how these methods are extended to other transformations often encountered in advanced titanium alloys: the alpha (hcp)-->gamma (tetragonal) and the beta (bcc)-->O (orthorhombic) transformation. The efficiency of the restitution depends on specific crystallographic features of the investigated phase transformations. Therefore, the paper outlines these crystallographic specificities for some advanced titanium alloys. To illustrate the capability of the method to reconstruct the parent phase, different restored parent microtextures of these alloys are presented. The results show that the reconstruction methods are an efficient tool to study the microstructure and texture modifications induced by these phase transformations.

The antiwrinkle effect of topical concentrated 2-dimethylaminoethanol involves a vacuolar cytopathology

BACKGROUND

The 'cosmeceutical' agent 2-dimethylaminoethanol (DMAE) is a tertiary amine found in high concentration in numerous topical antiwrinkle preparations.

OBJECTIVES

We hypothesized that a 337 mmol L(-1) (3%) DMAE reservoir applied to the skin could reproduce the cytopathology induced by other amines by maintaining a millimolar drug concentration within a certain depth of the skin layers, and that vacuolar cell expansion could account for the very rapid effect on the apparent skin fullness.

METHODS

Morphological and functional assays were applied to cultured rabbit dermal fibroblasts treated with tertiary amines in vitro. A morphological verification of the vacuolization caused by topical DMAE was also attempted in vivo using the inner skin of the rabbit ear and in vitro using primary cultures of human cutaneous epithelial cells.

RESULTS

Fibroblasts responded to DMAE (2.5-10 mmol L(-1)) by massive vacuolization (0.5-4 h; phase contrast observations). Triethanolamine, another chemical frequently used topically, was also active in this respect (10 mmol L(-1)). The vacuolar adenosine triphosphatase inhibitor bafilomycin A1 prevented DMAE- or triethanolamine-induced vacuolization; adding bafilomycin A1 or cell washout slowly reversed the established vacuolization induced by DMAE. Further effects of DMAE in cultured fibroblasts included a moderate cytotoxicity (10 mmol L(-1)) that was abated by bafilomycin A1 cotreatment, a concentration-dependent mitotic arrest (2.5 mmol L(-1)) and transient and mild effects on cell ploidy. The epidermis of the rabbit external ear was significantly thickened and exhibited clear perinuclear swelling indicative of vacuolization in response to 3% DMAE (1 h; paraffin tissue sections). Cultured human cutaneous epithelial cells responded to DMAE by vacuolization (inhibited by bafilomycin A1 cotreatment).

CONCLUSIONS

The vacuolar cytopathology induced by concentrated organic amines may be the cellular basis of the antiwrinkle effect of DMAE.

Carvedilol inhibits right ventricular hypertrophy induced by chronic hypobaric hypoxia

Right ventricular hypertrophy induced by chronic hypoxia is mainly due to a mechanical stress upon the ventricular wall secondary to pulmonary arterial hypertension. However, the hypoxic chronic activation of the sympathetic nervous system can contribute to the development of right ventricular hypertrophy either via myocardial adrenergic receptors and/or a vasoconstriction and remodeling of pulmonary arteries. To highlight the specific role of the sympathetic nervous system on hypoxia-induced right ventricular hypertrophy and particularly the efficiency of carvedilol, our study compared physiological, myocardial, and pulmonary arterial morphometric data in rats treated by alpha-(prazosin), or beta-(propranolol) or alphabeta-(carvedilol) antagonist and exposed to chronic hypobaric hypoxia (2 weeks at 380 mmHg barometric pressure). In chronic hypoxia, both systolic right ventricular pressure and Fulton's ratio (right/(left+septum) ventricular weight) were lower in rats treated by prazosin (-16.7 and -13.6%), propranolol (-28.6 and -12.7%) and carvedilol (-15.9 and -14.3%) respectively when compared to glucose (p<0.05). Surprisingly, prazosin was unable to reduce right ventricular hypertrophy induced by chronic hypoxia, whereas, left ventricular weight increased. Wall thickness index of pulmonary arteries increased in chronic hypoxia and was reduced by carvedilol. In conclusion, the hypoxia-induced activation of the adrenergic system participates in the development of right ventricular hypertrophy. Carvedilol is effective in reducing hypoxia-induced right ventricular hypertrophy, pulmonary arterial hypertension, and muscularization of pulmonary arteries.

Mechanism of potentiation by polyphenols of contraction in human vein-engineered media

The potential of natural dietary polyphenols in the treatment of vascular diseases originating from veins has been suggested in the literature. However, the mechanisms involved to explain the effects of polyphenols are not yet elucidated. Therefore, the aim of this study was to investigate the mechanisms by which polyphenols from red wine (Provinols) modulated contraction in human veins. We took advantage of a human model previously reported as a new tool for pharmacological research, using tissue-engineered techniques allowing the production of vascular media based exclusively on human smooth muscle cells. Thus human tissue-engineered vascular media (TEVM) were produced with cells originating from umbilical cord vein. TEVM were treated with either vehicle or Provinols. Results showed that treatment of TEVM with Provinols significantly potentiated the contractile responses induced by histamine and bradykinin. The potentiating effect of Provinols was not associated with an enhancement of histamine-induced increase in cytosolic calcium; rather, it implied the presence of a Ca2+-independent signaling pathway. Pharmacological studies indicated that action of Provinols took place at the level of phospholipase A2-Rho-kinase pathway and was associated with an enhancement of myosin light chain kinase activity. These results, obtained using the human TEVM, bring new insights to explain the regulation of venous contraction by polyphenols.

Production of tissue-engineered three-dimensional human bronchial models

We have reported morphological and functional features of cells isolated from human bronchial biopsies. Both epithelial and fibroblastic cells were isolated from the same biopsies using collagenase. A few models have been established to study normal bronchial response to various agents and to understand the mechanisms responsible for some disorders, such as asthma. We produced three-dimensional bronchial equivalents in culture, using human epithelial and fibroblastic cells. We previously showed that peripheral anchorage can prevent the dramatic collagen contraction in gels seeded with fibroblasts when properly adapted to the size and type of cultured tissues. Our bilayered bronchial constructs were anchored and cultured under submerged conditions and at the air-liquid interface. Three culture media were compared. Serum-free medium supplemented with retinoic acid (5 x 10(-8) M) was found to be the best for maintenance of bronchial cell properties in the reconstructed bronchial tissue. Immunohistological and ultrastructural analyses showed that these equivalents present good structural organization, allowing ciliogenesis to occur in culture. Moreover, human bronchial goblet cells could differentiate and secrete mucus with culture time. Laminin, a major constituent of the basement membrane and basal cells, was also detected at the mesenchymoepithelial interface. Such models will be useful for studying human bronchial properties in vitro.

A tissue-engineered endothelialized dermis to study the modulation of angiogenic and angiostatic molecules on capillary-like tube formation in vitro

BACKGROUND

Because angiogenesis is a major feature of different physiological and pathological situations, the identification of factors that stimulate or inhibit this process and the elucidation of their mechanisms of action are most certainly of clinical relevance. We have produced a new model of endothelialized reconstructed dermis that promotes the spontaneous formation of a human capillary-like network and its stabilization in vitro for a period longer than 1 month.

OBJECTIVES

The aim of this work was to describe the three-dimensional structure of the capillary-like network. Thereafter we strove to study, quantitatively and qualitatively, the influence of angiogenic and angiostatic drugs on capillary-like tube (CLT) formation in vitro in the model.

METHODS

The endothelialized dermis was prepared by coculturing two human cell types, dermal fibroblasts and umbilical vein endothelial cells, in a collagen sponge biomaterial.

RESULTS

The visualization by confocal microscopy of the tubes present in the model showed that the endothelial structures were not cord-like but rather CLTs with well-defined lumina. Moreover, these tubes were organized in a complex network of branching structures. When angiogenic factors (vascular endothelial growth factor 10 ng mL-1 or basic fibroblast growth factor 10 ng mL-1) were added to the model, 1.8 and 1.4 times more capillaries, respectively, were observed, whereas the addition of progesterone (10 microg x mL(-1)) reduced by 2.4 times the number of tubes compared with the control.

CONCLUSIONS

These results suggest that this model is a highly efficient assay for the screening of potentially angiogenic and angiostatic compounds.

Effects of acute liver injury on blood coagulation

The mechanisms leading to the hemostatic changes of acute liver injury are poorly understood. To study these further we have assessed coagulation and immune changes in patients with acute paracetamol overdose and compared the results to patients with chronic cirrhosis and normal healthy controls. The results demonstrate that in paracetamol overdose coagulation factors (F)II, V, VII and X were reduced to a similar degree and were significantly lower than FIX and FXI (mean levels 0.28, 0.16, 0.13, 0.19, 0.51 and 0.72 IU mL(-1), respectively). In cirrhosis, by contrast, FII, FV, FVII, FIX and FX were equally reduced whilst FXI was lower than the other factors (mean levels 0.64, 0.69, 0.62, 0.60, 0.66 and 0.40 IU mL-1, respectively). FVIII was raised in paracetamol overdose patients but normal in those with cirrhosis (mean levels 1.95 and 1.01 IU mL(-1), respectively). Interleukin-6 and tumor necrosis factor-alpha levels were raised in both patient groups, but higher levels were found in paracetamol overdose, compared to cirrhosis. Thrombin-antithrombin and soluble tissue factor levels were higher in those with acute liver injury but normal in cirrhosis. Antithrombin levels were reduced in both acute liver injury and cirrhosis. From these data we put forward a novel mechanism for the coagulation changes in acute paracetamol induced liver injury. We propose that immune activation leads to tissue factor-initiated consumption of FII, FV, FVII and FX, but that levels of FIX and FXI are better preserved because antithrombin inhibits the thrombin induced positive feedback loop that activates these latter factors.

Collagen fibril network and elastic system remodeling in a reconstructed skin transplanted on nude mice

Wound healing of deep and extensive burns can induce hypertrophic scar formation, which is a detrimental outcome for skin functionality. These scars are characterized by an impaired collagen fibril organization with fibril bundles oriented parallel to each other, in contrast with a basket weave pattern arrangement in normal skin. We prepared a reconstructed skin made of a collagen sponge seeded with human fibroblasts and keratinocytes and grown in vitro for 20 days. We transplanted it on the back of nude mice to assess whether this reconstructed skin could prevent scar formation. After transplantation, murine blood vessels had revascularized one-third of the sponge thickness on the fifth day and were observed underneath the epidermis at day 15. The reconstructed skin extracellular matrix was mostly made of human collagen I, organized in loosely packed fibrils 5 days after transplantation, with a mean diameter of 45 nm. After 40-90 days, fibril bundles were arranged in a basket weave pattern while their mean diameter increased to 56 nm, therefore exactly matching mouse skin papillary dermis organization. Interestingly, we showed that an elastic system remodeling was started off in this model. Indeed, human elastin deposits were organized in thin fibrils oriented perpendicular to epidermis at day 90 whereas elastic system usually took years to be re-established in human scars. Our reconstructed skin model promoted in only 90 days the remodeling of an extracellular matrix nearly similar to normal dermis (i.e. collagen fibril diameter and arrangement, and the partial reconstruction of the elastic system).

Mechanisms of wound reepithelialization: hints from a tissue-engineered reconstructed skin to long-standing questions

Wound closure of epithelial tissues must occur efficiently to restore rapidly their barrier function. We have developed a tissue-engineered wound-healing model composed of human skin keratinocytes and fibroblasts to better understand the mechanisms of reepithelialization. It allowed us to quantify the reepithelialization rate, which was significantly accelerated in the presence of fibrin or platelet-rich plasma. The reepithelialization of these 6 mm excisional wounds required the contribution of keratinocyte proliferation, migration, stratification, and differentiation. The epidermis regenerated progressively from the surrounding wound margins. After 3 days, the neoepidermis showed a complete spectrum of changes. Near the wound margin, the differentiation of the neoepidermis (keratins 1/10, filaggrin, and loricrin) and regeneration of the dermoepidermal junction (laminin 5 and collagen IV) were more advanced than toward the wound center, where the proliferative index was significantly increased. The spatial distribution of keratinocytes distinguished by particular features suggests two complementary mechanisms of reepithelialization: 1) the passive displacement of the superficial layers near the wound margin that would rapidly regenerate a barrier function and 2) the crawling of keratinocytes over each other at the tip of the progressing neoepidermis. Therefore, this study brings a new perspective to long-standing questions concerning wound reepithelialization.

Characterization of a 150 kDa accessory receptor for TGF-beta 1 on keratinocytes: direct evidence for a GPI anchor and ligand binding of the released form

Transforming growth factor-beta (TGF-beta) is a key modulator of epidermal development and homeostasis, and has been shown to potently regulate keratinocyte migration and function during wound repair. There are three cloned TGF-beta receptors termed type I, type II, and type III that are found on most cell types. The types I and II are the signaling receptors, while the type III is believed to facilitate TGF-beta binding to the types I and II receptors. Recently, we reported that in addition to these receptors, human keratinocytes express a 150 kDa TGF-beta 1 binding protein (r150) which forms a heteromeric complex with the TGF-beta signaling receptors. This accessory receptor was described as glycosyl phosphatidylinositol-specific anchored based on its sensitivity to phosphatidylinositol phospholipase C (PIPLC). In the present study, we demonstrate that the GPI-anchor is contained in r150 itself and not on a tightly associated protein and that it binds TGF-beta 1 with an affinity similar to those of the types I and II TGF-beta signaling receptors. Furthermore, the PIPLC released (soluble) form of this protein is capable of binding TGF-beta 1 independently from the signaling receptors. In addition, we provide evidence that r150 is released from the cell surface by an endogenous phospholipase C. Our observation that r150 interacts with the TGF-beta signaling receptors, together with the finding that the soluble r150 binds TGF-beta 1 suggest that r150 in either its membrane anchored or soluble form may potentiate or antagonize TGF-beta signaling. Elucidating the mechanism by which r150 functions as an accessory molecule in TGF-beta signaling may be critical to understanding the molecular mechanisms underlying the regulation of TGF-beta action in keratinocytes.

Selective culture of epithelial cells from primary breast carcinomas using irradiated 3T3 cells as feeder layer

The main drawback of the selective culture of human mammary epithelial cells from primary breast cancer is the overgrowth of tumor-associated stromal fibroblasts. This drawback may be overcome by using, in primary culture, lethally irradiated 3T3 cells which act as a feeder layer to maintain tumor-derived epithelial cell proliferation. These 3T3 cells, exposed to 60 Gy at confluence, form a specific cellular substrate which constitutes an obstacle to fibroblast attachment. Enzyme-disaggregated breast cells from six primary breast carcinomas were cocultured over lethally irradiated but living 3T3 cells. The method led to the purification of tumor-derived epithelial cells from all six cancer samples, and long-term culture was obtained in one. The epithelial nature of these purified tumor-derived epithelial cells was demonstrated by their general morphology and by the expression of cytokeratins and Epithelial Membrane Antigen. These results confirm the stimulatory effect of a this stromal feeder layer on breast epithelial cell growth and show that this stromal feeder layer can also control the fibroblast overgrowth. Our results provide an alternative approach in the selective culture of epithelial cells from primary breast carcinoma.

Fetal and adult human skin fibroblasts display intrinsic differences in contractile capacity

One of the differences between fetal and adult skin healing is the unique ability of fetal wounds to heal without contracture and scar formation. Studies have shown that the ratio between the three isoforms of TGFbeta is different in adult and fetal wounds. Thus, we analyzed the capacity of adult and fetal human skin fibroblasts to contract collagen gels after stimulation with TGFbeta isoforms. In control medium, fetal fibroblasts had a contractile capacity similar to that of adult fibroblasts. However, the growth capacity of fetal fibroblasts was completely inhibited, in contrast to adult fibroblasts. When cells were treated with TGFbeta, fetal fibroblasts showed an inhibition of their contractile capacity whereas adult fibroblasts further contracted gels. The contractile response was similar for all isoforms of TGFbeta although TGFbeta3 always had the strongest effect. We considered that the regulation of cell contractile capacity by TGFbeta may be dependent on receptor expression for this cytokine, on myofibroblast differentiation of the cells, or in cell links with matrix. Since TGFbeta receptor analysis did not show differences in receptor affinity, we studied the expression of alpha-smooth muscle (SM) actin, a fibroblast contractile marker and of three integrins, the cell surface receptors specific of the attachment of the fibroblasts with collagen matrix. We observed that the expression of alpha-SM actin and alpha3 and beta1 integrin subunits was increased when TGFbeta was added to the medium of adult fibroblasts whereas the levels of the alpha1 and alpha2 subunits were unchanged. In contrast, fetal fibroblasts treated with TGFbeta showed a decrease of alpha1, alpha2, and beta1 integrin expression but no change in alpha3 integrin and in alpha-SM actin expression. These results indicate that intrinsic differences between fetal and adult fibroblasts might explain their opposite responses to TGFbeta stimuli. The variations in their alpha-SM actin and integrin expression patterns represent potentially important mechanisms used by fetal fibroblasts to regulate their response to cytokines, and likely contribute to the resultant differences in the quality of wound repair.

Production of bioengineered cancer tissue constructs in vitro: epithelium-mesenchyme heterotypic interactions

A few models have been established to study cancer cells in vitro. However, the cellular interactions have rarely been studied specifically using bioengineered cancer constructs combining human carcinoma cells and tumor-associated fibroblasts. We developed an in vitro model of tridimensional bioengineered cancer tissue constructs (bCTC) by seeding mammary epithelial cancer cells or normal keratinocytes over a mesenchymal layer containing tumor-derived fibroblastic cells or normal skin fibroblasts. After the introduction of epithelial cells, each construct was cultured for another 10 d. Histologic analyses showed that carcinoma cell lines could invade the subjacent mesenchymal layer and that the capacity to migrate was related to the invasive potential of cancer cells and the type of fibroblasts used, while noninvasive populations did not. Of the tested epithelial cells, MDA-MB-231 and, to a lesser degree, HDQ-P1 cell lines were invasive, and the invasion was deeper into the mesenchymal component containing tumor-derived fibroblasts. However, with normal skin fibroblasts, the mesenchymal layer was degraded twice faster than with tumor-derived fibroblastic cells. MDA-MB-231 cells and normal keratinocytes induced the highest level of gelatinase B, and the level was lowest with the MCF-7 cell line. The activated form of gelatinase B was, however, induced to the highest levels in the keratinocyte-seeded bCTC containing tumor-derived but not normal fibroblasts. MDA-MB-231 was the only epithelial cancer cell line whose activity of gelatinase A was reduced when cocultured with tumor-derived fibroblasts but not under normal fibroblast stimulation. Finally, a 50/48-kDa gelatinase band has been observed in bCTCs with noninvasive epithelial cells only. Our study demonstrates the selective secretion of gelatinases according to the phenotype of the cells seeded in the various bCTCs.

A human tissue-engineered vascular media: a new model for pharmacological studies of contractile responses

Our method for producing tissue-engineered blood vessels based exclusively on the use of human cells, i.e., without artificial scaffolding, has previously been described (1). In this report, a tissue-engineered vascular media (TEVM) was specifically produced for pharmacological studies from cultured human vascular smooth muscle cells (VSMC). The VSMC displayed a differentiated phenotype as demonstrated by the re-expression of VSMC-specific markers and actual tissue contraction in response to physiological stimuli. Because of their physiological shape and mechanical strength, rings of human TEVM could be mounted on force transducers in organ baths to perform standard pharmacological experiments. Concentration-response curves to vasoconstrictor agonists (histamine, bradykinin, ATP, and UTP) were established, with or without selective antagonists, allowing pharmacological characterization of receptors (H1, B2, and P2Y1, and pyrimidinoceptors). Sustained agonist-induced contractions were associated with transient increases in cytosolic Ca2+ concentration, suggesting sensitization of the contractile machinery to Ca2+. ATP caused both Ca2+ entry and Ca2+ release from a ryanodine- and caffeine-sensitive store. Increased cyclic AMP or cyclic GMP levels caused relaxation. This human TEVM displays many of functional characters of the normal vessel from which the cells were originally isolated, including contractile/relaxation responses, cyclic nucleotide sensitivity, and Ca2+ handling mechanisms comparable to those of the normal vessel from which the cells were originally isolated. These results demonstrate the potential of this human model as a versatile new tool for pharmacological research.

The mixed lineage kinase leucine-zipper protein kinase exhibits a differentiation-associated localization in normal human skin and induces keratinocyte differentiation upon overexpression

Leucine-zipper protein kinase/dual leucine zipper bearing kinase/mitogen-activated protein kinase-upstream kinase is a recently described protein serine/threonine kinase which belongs to the mixed lineage kinase family. The overall pattern of expression of the leucine-zipper protein kinase/dual leucine zipper bearing kinase/mitogen-activated protein kinase-upstream kinase gene in embryonic and adult mouse tissues suggested that this kinase could be involved in the regulation of epithelial cell proliferation and differentiation. In order to get more insights into the potential role of leucine-zipper protein kinase in these cellular processes, we characterized its expression in normal human skin, both at the mRNA and protein levels. In situ hybridization, western blotting, and indirect immunofluorescence studies were conducted to localize leucine-zipper protein kinase on various human skin tissues. This is one of the first reports that leucine-zipper protein kinase has a very precise pattern of expression in human skin epithelia, as both mRNA and protein are restricted to the granular layer of the epidermis and inner root sheath of hair follicles. Detection of leucine-zipper protein kinase protein on skin from various body sites, donors of different ages as well as on reconstructed human skin always reveals that leucine-zipper protein kinase is present only in the very differentiated keratinocytes of epidermis and hair follicles. To determine directly whether leucine-zipper protein kinase exhibits any effect on cell growth and differentiation, keratinocytes were transfected with an expression vector harboring the leucine-zipper protein kinase cDNA. The presence of this construct in keratinocytes results in growth arrest together with a concomitant increase in filaggrin expression. Collectively, our results indicate that leucine-zipper protein kinase plays an active part in cellular processes related to terminal differentiation of epidermal keratinocytes.

Can we produce a human corneal equivalent by tissue engineering?

Tissue engineering is progressing rapidly. Bioengineered substitutes are already available for experimental applications and some clinical purposes such as skin replacement. This review focuses on the development of reconstructed human cornea in vitro by tissue engineering. Key elements to consider in the corneal reconstruction, such as the source for epithelial cells and keratocytes, are discussed and the various steps of production are presented. Since one application of this human model is to obtain a better understanding of corneal wound healing, the mechanisms of this phenomenon as well as the function played both by membrane-bound integrins and components from the extracellular matrix have also been addressed. The analysis of integrins by immunohistofluorescence labelling of our reconstructed human cornea revealed that beta(1), alpha(3), alpha(5), and alpha(6) integrin subunits were expressed but alpha(4) was not. Laminin, type VII collagen and fibronectin were also detected. Finally, the future challenges of corneal reconstruction by tissue engineering are discussed and the tremendous applications of such tissue produced in vitro for experimental as well as clinical purposes are considered.

Influence of endothelial cells on structure, biochemistry and functionality of epidermis reconstructed on synthetic porous membrane

The model of keratinocytes cultured on a synthetic porous membrane at the air-liquid interface leads to the formation of a pluristratified and cornified epidermis with histological and biochemical characteristics near those observed in vivo. In the present study, we evaluated the effect of proliferative endothelial cells on epidermalization. Keratinocytes were grown in three culture conditions: in defined medium (DM; control), in medium previously conditioned by proliferative endothelial cells (CM) and in medium with proliferative endothelial cells (pEC). The structures of reconstructed epidermis were analyzed by electron microscopy, their biochemistry by DNA, protein and cytokine analyses and finally their functionality was evaluated by estradiol and water absorption testing. Ultrastructural analysis showed a well-developed and cornified epidermis for each culture condition. In addition, living epidermis was thinner in the presence of endothelial cells, revealing faster epidermal differentiation. DNA and protein analyses were in accordance with these results. Secreted soluble factors varied according to culture conditions. At 37 degreesC, the permeability of reconstructed epidermis in DM, in CM or with pEC was 5- to 10-fold higher than that of native human epidermis with both tracers. Laminin coating of the inserts led to similar absorption results except for the DM where the barrier function to estradiol was decreased 2-fold. At 32 degreesC, reconstructed and native epidermis were, respectively, 1.5- and 2-fold less permeable to estradiol compared to 37 degreesC. In conclusion, this model is adequate for fundamental and pharmacological studies since it allows the study of interactions between two cell types without their direct contact as well as percutaneous absorption tests directly performed in the modified culture chamber.