Scarring and Skin Fibrosis Reversal with Regenerative Surgery and Stem Cell Therapy

Skin scarring and fibrosis affect millions of people worldwide, representing a serious clinical problem causing physical and psychological challenges for patients. Stem cell therapy and regenerative surgery represent a new area of treatment focused on promoting the body's natural ability to repair damaged tissue. Adipose-derived stem cells (ASCs) represent an optimal choice for practical regenerative medicine due to their abundance, autologous tissue origin, non-immunogenicity, and ease of access with minimal morbidity for patients. This review of the literature explores the current body of evidence around the use of ASCs-based regenerative strategies for the treatment of scarring and skin fibrosis, exploring the different surgical approaches and their application in multiple fibrotic skin conditions. Human, animal, and in vitro studies demonstrate that ASCs present potentialities in modifying scar tissue and fibrosis by suppressing extracellular matrix (ECM) synthesis and promoting the degradation of their constituents. Through softening skin fibrosis, function and overall quality of life may be considerably enhanced in different patient cohorts presenting with scar-related symptoms. The use of stem cell therapies for skin scar repair and regeneration represents a paradigm shift, offering potential alternative therapeutic avenues for fibrosis, a condition that currently lacks a cure.

Adipose derived stem cells and platelet rich plasma improve the tissue integration and angiogenesis of biodegradable scaffolds for soft tissue regeneration

Current surgical reconstruction for soft tissue replacement involves lipotransfer to restore soft tissue replacements but is limited by survival and longevity of the fat tissue. Alternative approaches to overcome these limitations include using biodegradable scaffolds with stem cells with growth factors to generate soft tissue. Adipose derived stem cells (ADSCs) offer great potential to differentiate into adipose, and can be delivered using biodegradable scaffolds. However, the optimal scaffold to maximise this approach is unknown. This study investigates the biocompatibility of nanocomposite scaffolds (POSS-PCL) to deliver ADSCs with and without the addition of growth factors using platelet rich plasma (PRP) in vivo. Rat ADSCs were isolated and then seeded on biodegradable scaffolds (POSS-PCL). In addition, donor rats were used to isolate PRP to modify the scaffolds. The implants were then subcutaneously implanted for 3-months to assess the effect of PRP and ADSC on POSS-PCL scaffolds biocompatibility. Histology after explanation was examined to assess tissue integration (H&E) and collagen production (Massons Trichome). Immunohistochemistry was used to assess angiogenesis (CD3, α-SMA), immune response (CD45, CD68) and adipose formation (PPAR-γ). At 3-months PRP-ADSC-POSS-PCL scaffolds demonstrated significantly increased tissue integration and angiogenesis compared to PRP, ADSC and unmodified scaffolds (p < 0.05). In addition, PRP-ADSC-POSS-PCL scaffolds showed similar levels of CD45 and CD68 staining compared to unmodified scaffolds. Furthermore, there was increased PPAR-γ staining demonstrated at 3-months with PRP-ADSC-POSS-PCL scaffolds (p < 0.05). POSS-PCL nanocomposite scaffolds provide an effective delivery system for ADSCs. PRP and ADSC work synergistically to enhance the biocompatibility of POSS-PCL scaffolds and provide a platform technology for soft tissue regeneration.

Breast Reconstruction with a Tissue Engineering and Regenerative Medicine Approach (Systematic Review)

Current techniques for breast reconstruction include an autologous-tissue flap or an implant-based procedure, although both can impose further morbidity. This systematic review aims to explore the existing literature on breast reconstruction using a tissue engineering approach; conducted with the databases Medline and Embase. A total of 28 articles were included, mainly comprising of level-5 evidence with in vitro and animal studies focusing on utilizing scaffolds to support the migration and growth of new tissue; scaffolds can be either biological or synthetic. Biological scaffolds were composed of collagen or a decellularized tissue matrix scaffold. Synthetic scaffolds were primarily composed of polymers with customisable designs, adjusting the internal morphology and pore size. Implanting cells, including adipose-derived stem cells, with combined use of basic fibroblast growth factor has been studied in an attempt to enhance tissue regeneration. Lately, a level-4 evidence human case series was reported; successfully regenerating 210 mL of tissue using an arterio-venous pedicled fat flap within a tissue engineering chamber implanted on the chest wall. Further research is required to evaluate whether the use of cells and other growth factors could adjust the composition of regenerated tissue and improve vascularity; the latter a major limiting factor for creating larger volumes of tissue.

Argon plasma surface modification promotes the therapeutic angiogenesis and tissue formation of tissue-engineered scaffolds in vivo by adipose-derived stem cells

Background

Synthetic implants are being used to restore injured or damaged tissues following cancer resection and congenital diseases. However, the survival of large tissue implant replacements depends on their ability to support angiogenesis that if limited, causes extrusion and infection of the implant. This study assessed the beneficial effect of platelet-rich plasma (PRP) and adipose-derived stem cells (ADSCs) on synthetic biomaterials in combination with argon plasma surface modification to enhance vascularisation of tissue-engineered constructs.

Methods

Non-biodegradable polyurethane scaffolds were manufactured and modified with plasma surface modification using argon gas (PM). Donor rats were then used to extract ADSCs and PRP to modify the scaffolds further. Scaffolds with and without PM were modified with and without ADSCs and PRP and subcutaneously implanted in the dorsum of rats for 3 months. After 12 weeks, the scaffolds were excised and the degree of tissue integration using H&E staining and Masson’s trichrome staining, angiogenesis by CD31 and immune response by CD45 and CD68 immunohistochemistry staining was examined.

Results

H&E and Masson’s trichrome staining showed PM+PRP+ADSC and PM+ADSC scaffolds had the greatest tissue integration, but there was no significant difference between the two scaffolds (p < 0.05). The greatest vessel formation after 3 months was shown with PM+PRP+ADSC and PM+ADSC scaffolds using CD31 staining compared to all other scaffolds (p < 0.05). The CD45 and CD68 staining was similar between all scaffolds after 3 months showing the ADSCs or PRP had no effect on the immune response of the scaffolds.

Conclusions

Argon plasma surface modification enhanced the effect of adipose-derived stem cells effect on angiogenesis and tissue integration of polyurethane scaffolds. The combination of ADSCs and argon plasma modification may improve the survival of large tissue implants for regenerative applications.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1195-z) contains supplementary material, which is available to authorized users.

Comparison of the mechanical properties of different skin sites for auricular and nasal reconstruction

Background

Autologous and synthetic nasal and auricular frameworks require skin coverage. The surgeon’s decides on the appropriate skin coverage for reconstruction based on colour matching, subcutaneous tissue thickness, expertise and experience. One of the major complications of placing subcutaneous implants is the risk of extrusion (migration through the skin) and infection. However, knowledge of lessening the differential between the soft tissue and the framework can have important implications for extrusion. This study compared the mechanical properties of the skin commonly used as skin sites for the coverage in auricular and nasal reconstruction.

Methods

Using ten fresh human cadavers, the tensile Young’s Modulus of the skin from the forehead, forearm, temporoparietal, post-auricular and submandibular neck was assessed. The relaxation rate and absolute relaxation level was also assessed after 90 min of relaxation.

Results

The submandibular skin showed the greatest Young’s elastic modulus in tension of all regions (1.28 MPa ±0.06) and forearm showed the lowest (1.03 MPa ±0.06). The forehead demonstrated greater relaxation rates among the different skin regions (7.8 MPa⁻⁰⁷ ± 0.1). The forearm showed the lowest rate of relaxation (4.74 MPa⁻⁰⁷ ± 0.1). The forearm (0.04 MPa ±0.004) and submandibular neck skin (0.04 MPa ±0.005) showed similar absolute levels of relaxation, which were significantly greater than the other skin regions (p < 0.05).

Conclusions

This study provides an understanding into the biomechanical properties of the skin of different sites allowing surgeons to consider this parameter when trying to identify the optimal skin coverage in nasal and auricular reconstruction.

Electronic supplementary material

The online version of this article (doi:10.1186/s40463-017-0210-6) contains supplementary material, which is available to authorized users.

A Review of Current Regenerative Medicine Strategies that Utilize Nanotechnology to Treat Cartilage Damage

Background:

Cartilage is an important tissue found in a variety of anatomical locations. Damage to cartilage is particularly detrimental, owing to its intrinsically poor healing capacity. Current reconstructive options for cartilage repair are limited, and alternative approaches are required. Biomaterial science and Tissue engineering are multidisciplinary areas of research that integrate biological and engineering principles for the purpose of restoring premorbid tissue function. Biomaterial science traditionally focuses on the replacement of diseased or damaged tissue with implants. Conversely, tissue engineering utilizes porous biomimetic scaffolds, containing cells and bioactive molecules, to regenerate functional tissue. However, both paradigms feature several disadvantages. Faced with the increasing clinical burden of cartilage defects, attention has shifted towards the incorporation of Nanotechnology into these areas of regenerative medicine.

Methods:

Searches were conducted on Pubmed using the terms “cartilage”, “reconstruction”, “nanotechnology”, “nanomaterials”, “tissue engineering” and “biomaterials”. Abstracts were examined to identify articles of relevance, and further papers were obtained from the citations within.

Results:

The content of 96 articles was ultimately reviewed. The literature yielded no studies that have progressed beyond in vitro and in vivo experimentation. Several limitations to the use of nanomaterials to reconstruct damaged cartilage were identified in both the tissue engineering and biomaterial fields.

Conclusion:

Nanomaterials have unique physicochemical properties that interact with biological systems in novel ways, potentially opening new avenues for the advancement of constructs used to repair cartilage. However, research into these technologies is in its infancy, and clinical translation remains elusive.

Nanoscale Surface Modifications of Medical Implants for Cartilage Tissue Repair and Regeneration

BACKGROUND

Natural cartilage regeneration is limited after trauma or degenerative processes. Due to the clinical challenge of reconstruction of articular cartilage, research into developing biomaterials to support cartilage regeneration have evolved. The structural architecture of composition of the cartilage extracellular matrix (ECM) is vital in guiding cell adhesion, migration and formation of cartilage. Current technologies have tried to mimic the cell's nanoscale microenvironment to improve implants to improve cartilage tissue repair.

METHODS

This review evaluates nanoscale techniques used to modify the implant surface for cartilage regeneration.

RESULTS

The surface of biomaterial is a vital parameter to guide cell adhesion and consequently allow for the formation of ECM and allow for tissue repair. By providing nanosized cues on the surface in the form of a nanotopography or nanosized molecules, allows for better control of cell behaviour and regeneration of cartilage. Chemical, physical and lithography techniques have all been explored for modifying the nanoscale surface of implants to promote chondrocyte adhesion and ECM formation.

CONCLUSION

Future studies are needed to further establish the optimal nanoscale modification of implants for cartilage tissue regeneration.

An update on the Application of Nanotechnology in Bone Tissue Engineering

Background:

Natural bone is a complex and hierarchical structure. Bone possesses an extracellular matrix that has a precise nano-sized environment to encourage osteoblasts to lay down bone by directing them through physical and chemical cues. For bone tissue regeneration, it is crucial for the scaffolds to mimic the native bone structure. Nanomaterials, with features on the nanoscale have shown the ability to provide the appropriate matrix environment to guide cell adhesion, migration and differentiation.

Methods:

This review summarises the new developments in bone tissue engineering using nanobiomaterials. The design and selection of fabrication methods and biomaterial types for bone tissue engineering will be reviewed. The interactions of cells with different nanostructured scaffolds will be discussed including nanocomposites, nanofibres and nanoparticles.

Results:

Several composite nanomaterials have been able to mimic the architecture of natural bone. Bioceramics biomaterials have shown to be very useful biomaterials for bone tissue engineering as they have osteoconductive and osteoinductive properties. Nanofibrous scaffolds have the ability to provide the appropriate matrix environment as they can mimic the extracellular matrix structure of bone. Nanoparticles have been used to deliver bioactive molecules and label and track stem cells.

Conclusion:

Future studies to improve the application of nanomaterials for bone tissue engineering are needed.

A prospective study of the use of botulinum toxin injections in the treatment of Raynaud's syndrome associated with scleroderma

Raynaud's syndrome contributes to the pain, paraesthesia, ulceration, and gangrene of scleroderma. Botulinum toxin has been shown to improve digital perfusion in patients with Raynaud's. This is the first study to objectively assess hand function following this treatment in patients with scleroderma. Twenty patients were treated with 100 units of botulinum toxin injected into the hand. An assessment of hand function and symptoms was performed prior to injection and then 8-12 weeks later. The outcomes assessed were change in pain, appearance, cold intolerance, pinch and power grip, ranges of movement, and Disabilities of the Arm, Shoulder and Hand (DASH) score. In total, 80% of patients reported an overall improvement in their symptoms, reduction in pain, and improved DASH score and 65% reported improvement in cold intolerance. Overall, 90% showed an improvement in pinch grip and 65% an improvement in power grip. Objective parameters were statistically significantly improved; however, subjective outcomes only showed a trend. We have found botulinum toxin to be an effective treatment for Raynaud's syndrome secondary to scleroderma.

Surface and mechanical analysis of explanted Poly Implant Prosthèse silicone breast implants

BACKGROUND

The recent events surrounding Poly Implant Prosthèse (PIP) breast implants have renewed the debate about the safety profile of silicone implants. The intentional use of industrial-grade instead of certified medical-grade silicone is thought to be responsible for reportedly higher frequencies of implant rupture in vivo. The differences in mechanical and viscoelastic properties between PIP and medical-grade silicone implant shells were investigated. Surface characterization of shells and gels was carried out to determine structural changes occurring after implantation.

METHODS

Breast implants were obtained from women at the Royal Free Hospital (London, UK). PIP implants were compared with medical-grade control silicone implants. Tensile strength, tear resistance and elongation at break were assessed using a tensile tester. Surfaces were analysed using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Spearman correlation analyses and Kruskal-Wallis one-way statistical tests were performed for mechanical data.

RESULTS

There were 18 PIP and four medical-grade silicone implants. PIP silicone shells had significantly weaker mechanical strength than control shells (P < 0·009). There were negative correlations between mechanical properties of PIP shells and implantation times, indicative of deterioration of PIP shells over time in vivo (r(s) = -0·75, P = 0·009 for tensile strength; r(s) = -0·76, P = 0·001 for maximal strain). Comparison of ATR-FTIR spectra of PIP and control silicones demonstrated changes in material characteristics during the period of implantation suggestive of time-dependent bond breakage and degradation of the material.

CONCLUSION

This study demonstrated an increased weakness of PIP shells with time and therefore supports the argument for prophylactic removal of PIP breast implants.

Adipose-derived stem cells for clinical applications: a review

The use of stem cells derived from adipose tissue as an autologous and self-replenishing source for a variety of differentiated cell phenotypes, provides a great deal of promise for reconstructive surgery. In this article, we review available literature encompassing methods of extraction of pluripotent adipose stem cells (ASCs) from lipoaspirate locations, their storage, options for culture, growth and differentiation, cryopreservation and its effect on stem cell survival and proliferation, and new technologies involving biomaterials and scaffolds. We will conclude by assessing potential avenues for developing this incredibly promising field.

The psychological management of facial transplantation

Facial transplantation is a major advance in reconstructive surgery, providing enormous potential benefit in terms of improved function and cosmesis. Managing the challenges it brings depends on understanding both technical and psychological issues. Research on the psychological aspects of organ transplantation is a starting point; however, issues of altered appearance and identity, adjustment to change, the management of suboptimal adherence to immunosuppression, and how we present and understand risk, particularly related to immunosuppression and rejection, must all be addressed before the procedure becomes a clinical option. This review addresses the psychological issues highlighted in the Royal College of Surgeons Working Party Report on facial transplantation, describing how these have been addressed in the development of a clinical program.

Systemic sclerosis as a model of chronic rejection in facial composite tissue transplantation

INTRODUCTION

Chronic rejection remains a potential significant long-term problem of facial allograft transplantation. Scleroderma parallels chronic rejection in terms of its immunological pathophysiology and its histopathological processes. Through the analysis of facial changes in scleroderma we demonstrate how chronic facial allograft rejection may present and progress.

METHODS

129 consecutive patients with a clinical diagnosis of scleroderma were recruited into the study. Static facial disease assessment was carried out through the analysis of digital photographs. Facial motion dysfunction was assessed using a modified House-Brackmann Grading Scale and an established maximal static response assay. Psychological evaluation comprised the Derriford Appearance Scale short-form (DAS), the Noticeability and Worry score and the Hospital Anxiety and Depression Scale (HADS).

RESULTS

Static disease severity as measured using an observer-rated disfigurement scale revealed all grades of disease in the scleroderma cohort - from mild through to severe. Significant positive correlations were seen between observer rated disfigurement and DAS24, Noticeability and Worry scores. No significant relationship could be seen between the indices of facial motion impairment and psychological scores.

CONCLUSIONS

Progressive facial deterioration seen over time in scleroderma provides a comprehensive spectrum of static and dynamic facial changes which may be encountered in chronic facial graft rejection. This study provides valuable insight into the potentially significant long-term sequelae of allogenic reconstructive transplantation.

The use of dextran post free tissue transfer

Dextran has been used in microsurgery to reduce the risk of free tissue transfer loss. A number of regimens which vary considerably in dosage and timing have been published in the literature. Using a postal questionnaire, a survey was conducted to delineate the current practise of UK plastic surgeons. Data were received from 161 plastic surgeons in 51 units (response rate of 61%). Forty-five percent of microsurgeons routinely use dextran post-operatively whilst 29% use alternative thromboprophylaxis. The indications, post-operative regimes and duration of administration of dextran vary significantly amongst surgeons and units. The reported success rates of free tissue transfer and digital replants were 97 and 85.1%, respectively, and was not significantly affected by the use of dextran. We conclude that there is considerable variation amongst UK plastic surgeons regarding thromboprophylaxis post microsurgery. Our data suggest that the use of dextrans does not affect free tissue transfer success rates.

Hyperbaric oxygen as adjuvant therapy in the management of necrotizing fasciitis

BACKGROUND

Necrotizing fasciitis (NF) is an uncommon but serious infection of fascia and skin associated with considerable morbidity and mortality. One modality proposed for improving the outcome of this condition is hyperbaric oxygen (HBO) therapy. This is a form of medical treatment that involves intermittent inhalation of 100% oxygen under pressures exceeding the atmosphere. The aim of this article is to review current practice and evidence for the use of HBO as adjunctive therapy in the management of NF.

METHODS

A survey of published English literature through searches of Medline and PubMed was carried out using the following key words: "necrotizing fasciitis," "Fournier's gangrene," "necrotizing soft tissue infections," "hyperbaric oxygen therapy," "and hyperbaric oxygen chambers."

RESULTS

The results of studies on the use of HBO therapy in NF are inconsistent. Some studies have demonstrated that HBO can improve patient survival and decrease the number of debridements required to achieve wound control, whereas others have failed to show any beneficial effect.

CONCLUSIONS

Encouraging results have been achieved with the addition of HBO therapy to standard treatment regimes, thus justifying further research in this field. More robust evidence by way of a prospective randomized trial is necessary before widespread and routine use of HBO in the management of NF can be recommended.

Postoperative monitoring of free flaps in UK plastic surgery units

Monitoring free-tissue transfers in the postoperative period is valuable for detection of failing flaps. As well as conventional methods, a myriad of sophisticated techniques have been reported in the literature. Using a postal questionnaire, a survey was conducted to delineate current protocols employed in UK plastic surgery units. Data were received from 148 plastic surgeons in 51 units. All surgeons used clinical assessment, although there was significant disparity in the duration and frequency of postoperative monitoring. Adjuvant techniques such as laser Doppler flowmetry were routinely used by less than 20% of surgeons. We conclude that there is considerable variation in postoperative monitoring of free flaps, with significant clinical and resource implications. A protocol based on robust evidence is thus recommended.

Hirudo Medicinalis and the plastic surgeon

Medicinal leech therapy is an ancient craft that dates back to ancient Egypt and the beginnings of civilisation. The popularity of Hirudo Medicinalis has varied throughout history, reaching such a peak in Europe in the early 19th century that supplies were exhausted. During the latter half of the 19th century, their use fell out of favour, as they did not fit in with the emerging concepts of modern medicine. Leeches have enjoyed a renaissance in the world of reconstructive microsurgery during recent years, and their first reported use in alleviating venous engorgement following flap surgery was reported in this journal [M Derganc, F Zdravic, Venous congestion of flaps treated by application of leeches, Br J Plast Surg 13 (1960) 187]. Contemporary plastic and reconstructive surgeons in units throughout the United Kingdom and Ireland continue to use leeches to aid salvage of failing flaps. We carried out a survey of all 62 plastic surgery units in the United Kingdom and the Republic of Ireland to assess the current extent of use, and to investigate current practice. We have shown that the majority of plastic surgery units in the UK and Ireland use leeches post-operatively and that the average number of patients requiring leech therapy was 10 cases per unit per year. Almost all units use antibiotic prophylaxis, but the type of antibiotic and combination used is variable. We outline current practice and suggest a protocol for the use of leeches. Whilst the use of leeches is widespread, the plastic surgery community has progressed little in defining indications for their use or in achieving an accepted protocol for their application in units throughout the UK and Ireland.

Historical Article: Hirudo medicinalis : ancient origins of, and trends in the use of medicinal leeches throughout history

Blood letting and the therapeutic use of Hirudo medicinalis date back to ancient Egypt and the beginning of civilisation. Their popularity has varied over the years, reaching such a peak in Europe between 1825 and 1850 that supplies were exhausted. Towards the end of the century they fell out of favour and, during this period, the leech, once used by the physicians of emperors and influential academic surgeons, became associated with lay therapists and quackery. Leeches have enjoyed a renaissance in reconstructive microsurgery during the last 15 years, having been used by maxillofacial [Br. J. Oral Maxillofac. Surg 41 (2003) 44] and other reconstructive surgeons to aid salvage of compromised microvascular free tissue transfers [Laryngoscope 108 (1998) 1129; Br. J. Plast. Surg. 34 (1984) 358], replanted digits [Int. J. Microsurg. 3 (1981) 265], ears [Ann. Plast. Surg. 43 (1999) 427], lips [Plast. Reconstr. Surg. 102 (1998) 358; J. Reconstr. Microsurg. 9 (1993) 327] and nasal tips [Br. J. Oral Maxillofac. Surg. 36 (1998) 462]. Peer-reviewed evidence suggests that the survival of compromised, venous-congested tissues is improved by early application of a leech [J. Reconstr. Microsurg. 12 (1996) 165; Arch. Otolaryngol. Head Neck Surg. 114 (1988) 1395; Br. J. Plast. Surg. 45 (1992) 235]. Leeches have also recently been used to treat a wide range of conditions, including periorbital haematomas [Br. J. Ophthalmol. 75 (1991) 755], severe macroglossia [Otolaryngol. Head Neck Surg. 125 (2001) 649; J. Laryngol. Otol. 109 (1995) 442] and purpura fulminans [Ann. Plast. Surg. 35 (1995) 300]. The first medicinal leech farm, Biopharm, was set up in Swansea in 1981 by Dr Roy Sawyer, and now supplies leeches to hospitals all over the world. In this paper, we summarise the history of treatment with Hirudo medicinalis from its origin to the present day, and take a brief look at the possible future of the annelid.

Non-vital, prosthetic, and virtual reality models of microsurgical training

Many microsurgical training models exist. These can be broadly classified into living and non-living. The latter type can be further sub-classified into non-vital, prosthetic, and virtual reality models. We review each model within these sub-groups with reference to the ideal properties of a training model. The most important attribute of any model is that the skills acquired from it must translate efficiently into microsurgical skill in the clinical situation. We believe that non-vital and prosthetic models are an important complement to living ones in training and maintaining the skills of all microsurgeons. As virtual reality technology improves, virtual models may succeed the rat as the microsurgical training tool of choice.

Donor modification leads to prolonged survival of limb allografts

Chronic immunosuppression is essential for maintaining human hand transplant survival because composite tissue allografts are as susceptible to rejection as visceral organ allografts. Limb allografts comprise different types of tissues with varying antigenicities, and the immunosuppressive doses required for these allografts are as high or higher than those required for solid organ allotransplantation. In particular, bone marrow is an early target of the host immune response. This study reports on donor limb modification of the marrow compartment leading to prolonged survival of limb allografts. Chimeric limb allografts comprising a Lewis rat vascularized allograft and Brown Norway rat bone marrow were created. These chimeric limbs were transplanted into three recipients: (1) Buffalo rats (n = 12), where the chimeric limb was allogeneic for both vascular graft and bone marrow; (2) Lewis rats (n = 12), where the limb was allogeneic for marrow alone; and (3) Brown Norway rats (n = 12), where the limb was allogeneic for graft alone. This study found that Brown Norway recipients elicited significantly reduced cell-mediated and humoral immune responses in comparison with the Buffalo and Lewis recipients (p < 0.001 and p < 0.01, respectively). The Buffalo and Lewis recipients both elicited high cell-mediated and humoral responses. The Brown Norway recipients also had prolonged survival of limb tissue allograft in comparison with the other experimental groups.

The Soho nail bomb: the UCH experience. University College Hospital

This paper documents the clinical course of the casualties treated at University College Hospital, following the detonation of a terrorist nail bomb in a public house in Soho, London. The need for adequate primary debridement is paramount, including consideration of definitive primary limb amputation.

Delayed penile replantation after prolonged warm ischemia

We report a case of microsurgical replantation of traumatic self-amputation of penis after prolonged warm ischemia as a result of delayed presentation. At 12 weeks postoperative follow-up evaluation, the patient exhibited good urinary flow, spontaneous erection, and a normal response to pharmacological stimulation.

Abdominoplasty wound-healing complications: assisted closure using foam suction dressing

Abdominoplasty dehiscence, with or without skin necrosis, is a difficult reconstructive problem, which historically entailed protracted management with poor aesthetic outcome. The use of a foam suction dressing in combination with rapid serial wound closure achieves effective delayed primary closure of the abdominoplasty wound with an acceptable aesthetic result. This approach allows effective wound control and functioning, as a mechanical closure device enables rapid closure by serially reducing the foam dressing size with wound closure laterally. This technique has been used in four cases; successful closure was achieved within 8 days, resulting in a stable linear abdominoplasty scar in each case.

Injection of allogeneic bone marrow cells into the portal vein of swine in utero

The ability to safely manipulate the immune system of the developing fetus carries the hope of effective treatment strategies for certain congenital disorders that can be diagnosed during gestation. One possible intervention is the induction of specific transplantation tolerance to an adult donor who could provide tissue after birth without the need for immunosuppression. Although the introduction of allogeneic stem cells to a developing immune system has been shown to result in hematopoietic chimerism, donor-specific transplantation tolerance has not been demonstrated in a large animal model. In previous reports of in utero stem-cell transplantation, the cells were injected into the fetus by an intraperitoneal route. We sought to improve upon this technique of cell transplantation by developing a method for the safe delivery of allogeneic stem cells directly into the hepatic circulation of fetal swine. In the second phase of our study, we determined if adult allogeneic bone marrow cells delivered to the fetus by this intravascular route could result in result in hematopoietic chimerism and donor-specific transplantation tolerance. A method of successful intravascular injection was designed in which a laparotomy was performed on a sow at midgestation (50-55 days) to administer 1 cc of inoculum into the portal vein of each fetus using transuterine ultrasound guidance and a 25-gauge spinal needle. In one sow, 10 piglets were injected with saline to test safety, and 8 piglets were born. For transplantation of stem cells to the fetuses, donor bone marrow was harvested from a genetically defined miniature swine. In one sow the marrow was injected without T-cell depletion resulting in abortion. In the third sow, the marrow was depleted of T-cells to less than 0.01% using magnetic beads conjugated to anti-CD3 monoclonal antibodies. No chimerism was detected in these offspring. Only in the fourth sow where the T-cell depletion was reduced to about 1% of the cells in the inoculum did one animal demonstrate chimerism. This piglet showed reproducible blood chimerism (0.95% donor cells) detected by flow cytometry measurement of monoclonal antibodies to the donor MHC. In addition, this animal demonstrated hyporesponsiveness to donor lymphocytes in an MLR assay while reacting strongly to third-party stimulator cells. A split-thickness skin graft from the donor was accepted, and a third-party graft was rapidly rejected.

Quantitative and qualitative effects of chemical peeling on photo-aged skin: an experimental study

Chemical peel reverses the visible stigmata of photo aging in human skin. The qualitative and, in particular, the quantitative changes in the dermis that effect this transformation are unclear. This study used a recognized photo-aged animal model, the Skh:HR-1 hairless mouse, to quantify and qualify the changes that occurred in collagen and glycosaminoglycan content after chemical peel. One hundred Skh:HR-1 hairless mice were photo-aged by use of chronic ultraviolet B irradiation for 14 weeks. After irradiation the animals were randomly distributed into five groups of 20 mice each: group 1, control; group 2, 50% glycolic acid peel; group 3, 30% trichloroacetic acid peel; group 4, 50% trichloroacetic acid peel; group 5, phenol peel (Baker-Gordon formula). The respective peeling agent was applied to the dorsal skin of each animal while it was fully anesthetized. Punch biopsies were taken at several times after peel for histological and biochemical analysis. Glycosaminoglycan content was assessed at 14, 28, and 60 days using a colorimetric assay. Collagen content per unit volume increased initially 3 days after the procedure in all chemical peel groups, declining on day 7, and peaking again on day 28. Significant elevations (p < 0.04) were seen in the 30% trichloroacetic acid, 50% trichloroacetic acid, and phenol peels on days 3 and 28 in comparison with controls. This increase in collagen content was not maintained and returned to control values by 60 days. Glycosaminoglycan content per unit volume was elevated initially after peel with significant elevation (p < 0.02) in the 50% trichloroacetic acid and phenol groups on days 14 and 28. This increase in glycosaminoglycan content was not maintained beyond 28 days and declined to control values by day 60 in all groups. Histological examination demonstrated an increase in dermal thickness in the 50% trichloroacetic acid and phenol groups in comparison with controls by day 60. Under polarized light all chemical peel groups at day 60 demonstrated a reorganization of collagen in the reticular and papillary dermis. The elastotic masses that are pathognomonic of photo aging were present in the control group but were absent in the peel groups and demonstrated a reorganization of the elastic fibers in the dermis. This effect was deeper in the dermis in the deeper peel groups (50% trichloroacetic acid and phenol peel). The beneficial effects of chemical peel were due to a combination of two findings; a reorganization in dermal structural elements and an increase in dermal volume. These effects were more pronounced in the deeper peel groups.

Neonatal induction of tolerance to skeletal tissue allografts without immunosuppression

Vascularized allogeneic skeletal tissue transplantation without the need for host immunosuppression would increase reconstructive options for treating congenital and acquired defects. Because the immune system of a fetus or neonate is immature, it may be possible to induce tolerance to allogeneic skeletal tissues by alloantigen injection during this permissive period. Within 12 hours after birth, 17 neonatal Lewis rats were injected through the superficial temporal vein with 3.5 to 5 million Brown Norway bone marrow cells in 0.1 ml normal saline. Ten weeks after the injection, peripheral blood from the Lewis rats was analyzed for the presence of Brown Norway cells to determine hemopoietic chimerism. The Lewis rats then received a heterotopic, vascularized limb tissue transplant (consisting of the knee, the distal femur, the proximal tibia, and the surrounding muscle on a femoral vascular pedicle) from Brown Norway rat donors to determine their tolerance to the allogeneic tissue. A positive control group (n = 6) consisted of syngeneic transplants from Lewis rats into naive Lewis rats to demonstrate survival of transplants. A negative control group (n = 6) consisted of Brown Norway transplants into naive Lewis rats not receiving bone marrow or other immunosuppressive treatment. The animals were assessed for transplant viability 30 days after transplantation using histologic and bone fluorochrome analysis. All the syngeneic controls (Lewis to Lewis) remained viable throughout the experiment, whereas all the Brown Norway to Lewis controls had rejected. Ten of the 17 allografts transplanted into bone marrow recipients were viable at 30 days, with profuse bleeding from the ends of the bone graft and the surrounding graft muscle. The percent of chimerism correlated with survival, with 3.31 percent (SD = 1.9) of peripheral blood, Brown Norway chimerism present in the prolonged survival groups and 0.75 percent (SD = 0.5) of Brown Norway chimerism in the rejected graft group. This study demonstrated prolonged survival of allogeneic skeletal tissue without immunosuppression after early neonatal injection of allogeneic bone marrow in a rat model.

Prolonged survival of musculoskeletal xenografts with combined cyclosporine and 15-deoxyspergualin

This study was undertaken to evaluate the feasibility of performing vascularized musculoskeletal xenografts between mice and rats using immunosuppression. Vascularized musculoskeletal grafts were harvested from the hind limb of C57BL/6J (B6) mice, transplanted heterotopically into Lewis rats, and revascularized by microanastomoses of the graft artery and the recipient femoral artery and the graft vein to the recipient femoral vein. Recipient rats were divided into four groups. Group 1 received no immunosuppression (n = 10), group 2 was treated with cyclosporine (10 mg/kg/day; n = 10), group 3 was treated with 15-deoxyspergualin (5 mg/kg/day; n = 10), and group 4 received both cyclosporine and 15-deoxyspergualin (n = 10). Graft survival was directly examined on postoperative days 4, 7, and 14. In vitro assays were performed using mixed lymphocyte reactions and anti-donor cytotoxic antibody assays to assess the recipient's immune response. Grafts were examined by histology and immunohistochemistry. All grafts in group 1 were rejected by day 4. In groups 2 and 3, all grafts were rejected by day 7. In group 4, however, 8 of 10 recipients had viable grafts on day 14. Data from mixed lymphocyte reactions showed that cell-mediated immune responses were uniformly suppressed in groups 2, 3, and 4 compared with group 1. However, anti-donor antibody production was only partly suppressed in groups 2 and 3, suggesting that graft rejection was primarily caused by circulating cytotoxic anti-donor antibodies in groups 1, 2, and 3. Histologic observations in groups 1, 2, and 3 confirmed the important role of the humoral mechanism in xenograft rejection. Furthermore, immunohistochemical results demonstrated that the small vessels in the rejected grafts showed anti-rat immunoglobulin and complement depositions. Only a combination therapy of cyclosporine and 15-deoxyspergualin attenuated the rejection of xenografts.

Effect of early mobilization on healing of nerve repair: histologic observations in a canine model

The effect of early mobilization on the healing of nerve repair was studied in a canine model. Median and ulnar nerves in the left wrist of 16 adult mongrel dogs were transected and immediately repaired. No motion of the repaired forelimb was allowed in the immobilized group (n = 10), while controlled passive motion between 30 and 90 degrees of wrist flexion was begun on the first postoperative day for 10 minutes twice daily in the mobilized group (n = 6). The pattern of revascularization and collagen formation at neurorrhaphy was examined by transillumination of India ink-injected specimen and by conventional histologic sections. Revascularization of nerve repair was found to occur by ingrowth of capillaries from proximal and distal nerve ends, which typically crossed the neurorrhaphy by 3 weeks in the immobilized group. Following early mobilization, there was a persistent "hypovascular zone" at the nerve repair site for up to 6 weeks. In addition, more scar tissue was generated by early motion according to gross observation and quantitative collagen analysis. Early mobilization, therefore, seems to impede nerve regeneration by delaying revascularization and enhancing scar formation.

A comparative study of nerve healing in adult, neonatal, and fetal rabbits

This experiment quantitatively compared the human equivalent of a nerve repair following surgical division in the fetal, adult, and early childhood period of development using a rabbit as an experimental animal model. Twelve time-dated pregnant New Zealand White rabbits at 24 days' gestation (term = 31 days) underwent hysterotomy; one hind limb was delivered through the uterine opening. The sciatic nerve was divided and repaired by primary neurorrhaphy using two 11-0 epineural sutures. Sciatic nerve repair was also performed in 10 neonatal and 10 adult New Zealand White rabbits. Following repair, each group was assessed using electromyography examination, measuring distal motor latency and amplitude at 1, 2, 3, and 4 months postrepair. There was no difference in any of the groups in distal motor latency. The amplitude rose incrementally in all groups, and the fetal group had significantly higher amplitudes (p < 0.02) at 1, 2, 3, and 4 months in comparison with the adult group. There was no statistically significant difference between fetal and neonatal nerve repairs at any of the time periods. At the completion of the study, the nerve repair sites were harvested for histologic estimation of mean myelinated fiber density and fiber diameter distribution distal and proximal to the repair site. A greater percentage of myelinated axons crossed the repair site in the fetal group (83 percent) in comparison with the adult group (63 percent) (p < 0.03). Our study also demonstrated significant increases in the number of larger myelinated fibers crossing the repair site in comparison with the neonatal and adult groups (p < 0.04). This study found that fetal nerve healing following surgical repair is superior to that found in adult animals and results in a higher number of larger myelinated fibers crossing the repair site in comparison with adult and neonatal repairs.

Cell transplantation from limb allografts

A murine model of skeletal tissue transplantation was developed to study the allograft rejection process in mice for limb allograft transplantation. Muscle, bone, and skin have been shown to be strong antigenic stimuli in vascularized allograft models, and cells from these sources were used for transplantation. Using enzymatic digestion, keratinocytes, myocytes, and osteocytes were harvested from B10.A mice tissues, dissociated into single cells, and then grown in culture for 14 to 21 days. Each cell type was marked with an intracellular fluorescent marker before transplantation of the cells into pockets in the rectus abdominis muscle of a syngenic host. All cell types remained viable and were detectable 2 weeks following transplantation when examined histologically and observed under a fluorescent microscope. Transplanted osteocytes were found to produce bone 8 weeks following transplantation. These results demonstrate that individual cells transplanted into muscle pockets survive and have the ability to produce extracellular matrix in this mouse model of skeletal tissue transplantation. Use of this model will allow transplantation of the cellular components comprising limb allografts to study the relative antigenicities and the rejection of the separate cells with the advanced immunologic techniques available for mice. A better understanding of immunologic responses to these individual tissue components may enable specific donor tissue or host immune modification to achieve skeletal tissue transplantation without immunosuppression. These findings are particularly valuable to the field of tissue engineering where allogeneic cells may be used in cell/polymer constructs for reconstructive procedures.

Tissue engineered neocartilage using plasma derived polymer substrates and chondrocytes

This study demonstrates that fibrin monomers can be polymerized into moldable gels and used for the encapsulation of isolated chondrocytes. This biologically derived scaffold will maintain three-dimensional spatial support, allowing new tissue development in a subcutaneous space. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were combined with cyroprecipitate and polymerized with bovine thrombin to create a fibrin glue gel with a final cell density of 12.5 x 10(6) cells/ml. The polymer-chondrocyte constructs were implanted subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analysis including deoxyribonucleic acid (DNA) and glycosaminoglycan quantitation confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from 12 implantation sites consisting of chondrocytes alone or fibrin glue substrates did not demonstrate any gross or histologic evidence of neocartilage formation. Moldable autogenous fibrin glue polymer systems have a potential to serve as alternatives to current proprietary polymer systems used for tissue engineering cartilage as well as autogenous grafts and alloplastic materials used for facial skeletal and soft-tissue augmentation.

Prolonged survival in fetal rabbit surgery

Timing and outcome of antenatal surgical intervention is being explored using fetal animal models. Models that are currently used range from larger animals with fewer offspring and higher cost to smaller animals with larger litters and lower cost. The rabbit is an ideal "small" animal model for experimentation in the third trimester, with a large litter, short gestation and a relatively large fetus. This paper reports methods by which prolonged survival (greater than 110 days) may be achieved in as many as 60% of operated fetuses following complex fetal surgery in the rabbit.

Craniofacial skeletal fixation using biodegradable plates and cyanoacrylate glue

This study examined the feasibility of fixation of craniofacial bone using Lactosorb biodegradable plates adhered to bone with butyl-2-cyanoacrylate adhesive (Histoacryl) in a pig. The stability and bone-healing characteristics of this rigid fixation method were studied and compared with standard rigid fixation using metal plates and screws on osteotomy sites in the frontal bones and infraorbital rims. Rectangular osteotomies (2.0 x 3.0 cm) were performed on the right and left sides of the frontal bone and wedge-shaped osteotomies (1.5 x 1.7 cm) were made on the left and right infraorbital rims in seven Yorkshire pigs. Metal plates were applied with screws to the osteotomies on one side, and the other side was fixed with a biodegradable plate and butyl-2-cyanoacrylate. The animals were sacrificed at 8 weeks, and both sides were compared biomechanically and histologically. Radiographic, biomechanical, and histologic analyses were performed to evaluate skeletal stability, contour, accurate positioning of bony fragments, bone healing, and maximum torque to failure of the repair sites. Clinical and radiographic observations demonstrated stability of the bone fragments without any evidence of displacement. According to Student's t test for paired data, no statistical difference was found in the maximum torque to failure of fragments fixed with biodegradable plates and glue compared with those fixed with metal plates and screws (p > 0.05), whether or not a gap existed at the osteosynthesis site. Although the sample size was small, no differences were noted between the two types of treatment groups. This study demonstrates that rigid internal fixation of osteotomized cranial bone fragments using biodegradable plates and butyl-2-cyanoacrylate is as effective as metal plate and screw fixation in this animal model.

Prolonged general anesthesia for experimental craniofacial surgery in fetal swine

A protocol utilizing high preoperative doses of altrenogest (Regu-Mate) and a "balanced" general anesthesia regimen consisting of isoflurane at subanesthetic doses supplemented with intravenous doses of sodium thiopental was developed to prevent preterm labor, minimize intracranial fetal cerebral edema, and decrease postpartum mortality of fetal swine after undergoing complex in utero craniofacial procedures. A total of 20 fetal piglets at 75% gestation were exposed to prolonged (> 3 h) anesthesia conditions of which 7 piglets were randomly selected to undergo experimental craniofacial procedures consisting of periosteal stripping of frontal and parietal bone segments with/without extensive coronal suture fusion procedures. Neither sows nor piglets were lost to anesthetic complications during the initial laparotomy or subsequent cesarean delivery. None of the sows experienced uterine sepsis or underwent preterm labor. The overall survival rate for all piglets exposed to prolonged anesthesia conditions was 95% at 4 weeks and 45% at 11 weeks after surgery. The experimental group's survival was 85.7% at 4 weeks and 28.5% at 11 weeks after surgery.

Surgical model to assess the effects and optimal timing of craniofacial fixation

An in utero swine model of craniofacial deformity was developed as a potential alternative to neonatal models currently used for evaluating the optimal timing and long-term effects of rigid fixation techniques on a growing cranium. At 75% gestation, seven fetal piglets were randomly selected to undergo periosteal stripping of frontal and parietal bone segments with and without extensive coronal suture fusion procedures with cyanoacrylate adhesive. Fetal swine were killed postpartum at 4 and 11 weeks after fusion to assess craniofacial deformity. Piglets undergoing coronal fusion had slight deviation of the nose-snout toward the side of fusion and taller cranial vaults. The vertical cranial index of the experimental fusion group was 0.34 in comparison to a vertical index of 0.27 for the controls, suggesting abnormal vertical height expansion. There was no difference in the horizontal cranial index of either control or experimental fusion groups. Neither sows nor piglets were lost to anesthetic complications, uterine sepsis, or preterm labor during the initial laparotomy or subsequent cesarean delivery.

Injectable cartilage using polyethylene oxide polymer substrates

This study demonstrates that polyethylene oxide gels, which are biocompatible and biodegradable synthetic polymers, can be utilized for the encapsulation of isolated chondrocytes and maintenance of three-dimensional spatial support for new tissue development. Chondrocytes isolated from the glenohumeral and humeroradioulnar joints of a calf were added to a 20% polyethylene oxide solution in Ham's F-12 medium to generate a final cellular density of 10 x 10(6)/mL. The polymer-chondrocyte constructs were injected through a 22-gauge needle in 500-microliters aliquots subcutaneously in 12 nude mice and incubated for 6 and 12 weeks in vivo. Histologic and biochemical analyses including deoxyribonucleic acid and glycosaminoglycan quantitative analyses confirmed the presence of actively proliferating chondrocytes with production of a well-formed cartilaginous matrix in the transplanted samples. Control specimens from eight implantation sites consisting of chondrocytes alone or polyethylene oxide substrates did not demonstrate any gross or histologic evidence of neocartilage formation. These findings demonstrate the potential use of an injectable and moldable polymer substrate that can support cell proliferation and matrix synthesis after subcutaneous transplantation for neocartilage generation. The use of functional biologic tissue substitutes may serve as an alternative solution to current methods of augmentation or reconstruction of structural craniofacial contour deformities.

A 1-year prospective study of burns in an Irish paediatric burns unit

Burns are the fourth leading cause of injury death in children in the USA, accounting for 1300 paediatric deaths annually. The majority of paediatric burns mortality and morbidity result from simple domestic accidents that are preventable. A prospective study of paediatric burns from 1 January 1992 to 1 January 1993 was undertaken at our burns unit to outline the profile of the Irish paediatric burns problem. A total of 336 burns were referred to our unit over the 12 months (80 per cent self-referrals, 15 per cent tertiary referrals from district hospitals and 5 per cent GP referrals). Sixteen per cent (57) of the patients required admission and 33 per cent (112) required prolonged dressings as outpatients. Mortality and morbidity rates were comparable to other centres at 1.8 per cent and 39 per cent respectively. The demographic analysis of the patient population was similar to that seen in other studies from developed countries but there were some notable differences. First, there was an alarmingly high incidence of serious sunburn injuries, especially among young infants. Most parents were unaware of the association between childhood sunburn and the development of skin cancer in later life. Second, 90 per cent of the accidents occurred in the home and almost all were preventable. A parent or guardian was present in 87 per cent of cases but parental knowledge of the appropriate first aid measures was poor. It is suggested that a public health education campaign on this issue would help in reducing the incidence and severity of paediatric burn injuries in Ireland.

Bacterial growth in saline implants: in vitro and in vivo studies

The survival of bacteria was evaluated in custom-made saline breast implants with integral injection ports in vitro and in 10 New Zealand White rabbits for Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Serratia marcescens. Pseudomonas and Serratia survived in vitro in saline-filled implants and multiplied 24-fold and 22-fold, respectively, from the initial inocula of 300 colony-forming units per cubic centimeter in 21 days. Serratia alone survived in saline implants placed on the dorsum of rabbits, proliferated 80-fold in 7 days, and tapered to 10-fold at the end of 3 weeks. Chemical analysis revealed the presence of glucose in fluid from the implants in the animal study (mean, 1.2 mg per deciliter; standard error of mean [SEM], 0.6) after 21 days and from human subjects (mean, 3.8 mg per deciliter; SEM, 1.0) after 8 months to 10 years. Serratia incubated in human breast implant fluid samples proliferated 7-fold to 30-fold greater than in the saline control in a nonaerated environment. We conclude that some bacteria are able to proliferate in saline in breast implants. Furthermore, their survival may be facilitated by a substance (i.e., glucose) that diffuses across the implant outer shell.

Cervical spine injuries in patients with facial fractures: a 1-year prospective study

A total of 582 consecutive patients with facial fractures were investigated prospectively for evidence of a concomitant cervical spine injury. Of them, 1.04% (6) were found to have a cervical spine injury, all having occurred in road traffic accidents. Only two of the injuries were diagnosable on standard, three-view, plain cervical spine radiographs. Four were diagnosable from computerized tomography scan, while the remaining two required stress views under radiographic screening for definitive diagnosis.

Bupivacaine and Kaltostat reduces post-operative donor site pain

A prospective double blind controlled trial was carried out to examine the differences in post-operative split skin graft donor site pain between sites dressed with three differently treated types of dressing; a dry calcium alginate dressing (Kaltostat Britcair), a saline moistened Kaltostat dressing and a bupivacaine hydrochloride (0.5%) moistened Kaltostat dressing. There was a significant reduction in post-operative pain in the Kaltostat and bupivacaine group (group 3) at 24 and 48 h when compared to the other two groups (p < 0.04). There was no difference in ease of removal of dressings or the quality of wound healing on day 10 between the three groups. This study demonstrates a significant reduction in post-operative pain in bupivacaine soaked Kaltostat without reducing the beneficial effects of Kaltostat on donor site healing and we recommend its use in clinical practice.