[Academic Careers in Medicine: a Sex-Related Analysis of Career Goals]

AIM OF THE STUDY

For female and male physicians of the clinical-academic mid-level staff, working conditions as well as the attitude towards profession and career play a decisive role. For years, there has been an increasing proportion of women in medicine. Despite this increase, a significant sex incongruence is still evident, especially in academic medicine. The aim of this work was to analyze current opinions of female and male physicians on sex-related aspects for career.

METHODS

By means of an online survey, medical mid-level staff from university and peripheral hospitals were asked about professional biographical as well as career-related topics and the data analyzed in terms of the sexes.

RESULTS

Compared to their male counterparts, female physicians had lower career goals and mainly aimed to qualify as senior physicians. Women planned to have families and raise children earlier in their careers. Men were more likely to have their professional careers in mind during the same time period. Although only just under 47% of respondents considered an academic career to be worthwhile, 65% continued to rate the acquisition of an academic title highly. When evaluating equal treatment by superiors, female physicians tended to feel disadvantaged in their professional careers compared to male physicians. Thus, physicians rated the treatment by their respective superiors as characterized by the quality of the work (44% for both genders of superiors) or dependent on sympathy (female superiors 30%; male superiors 24%). Female physicians, however, saw a preference for male colleagues in 37% of male superiors.

CONCLUSION

Despite a significantly larger proportion of women in medicine for decades, there is still an incongruence in sexes in favor of men in management positions. The professional and private goals of women and men differ significantly depending on their age decade. The academic career per se is increasingly losing importance, although the acquisition of academic degrees still seems to be desirable. Therefore, to improve the future of academic medicine, significant structural changes are needed to enable projectable career paths (e. g., tenure track, assistant professorship, young medical professionals model) for mid-level academic staff.

[How important is an academic career in medicine today? A survey of medical students in Germany: results of study arm XIII of the KARiMED study]

OBJECTIVE

Academic careers still play a significant role in medicine. Although the doctorate remains interesting for many students, there are no data available from medical students, for example, with regard to the interest of a habilitation. In parallel, a good work-life/family balance is a key career element for young medical professionals. The aim was to obtain an up-to-date opinion on the academic career of medical students.

METHODOLOGY

Using an online survey, medical students of all semesters in Germany were questioned on the topics of academic career, mentoring, and work-life balance from October 2017 to December 2018. For this purpose, the medical students were invited by e-mail to participate and answer an anonymized online questionnaire.

RESULTS

A total of 1,775 participants from all 38 German medical faculties (68.3% female; age 23.3 ± 4.0 years) were included. Almost half of the participants could envision working in a branch office after graduation. While a professional career appeared important to a clear majority (70.8%), leisure time was rated as even more important (84.3%), and work-life balance clearly prioritized personal life (41.2%) over career (9.6%). Acquiring a title was rated as important to one's career by 53.6%. However, while the acquisition of a doctorate was still an option for 88.0% of the respondents, the situation is significantly different for academic titles following a successful habilitation. Although the significance of a habilitation is rated as high to very high (66.1%), the titles of assistant professor ("yes": 13.0%), associate professor (6.0%) or university professor (7.0%) are much less likely to be considered by medical students and are therefore rated as "maybe" and "no". Nevertheless, almost 60% wished for better information and advice in their future field of work.

CONCLUSION

Careers in medicine are undergoing a transformation where better compatibility of leisure/family and work is no longer the sole focus. On the contrary, work-life blending is sought, as a connection between work and life. Changes are therefore necessary for professional and especially academic careers in order to make working in science and research attractive again.

Free Flaps for Skin and Soft Tissue Reconstruction in the Elderly Patient: Indication or Contraindication

BACKGROUND

Increased lifespan and the improvement of medical treatment have given rise to research in reconstructive procedures in elderly patients. Higher postoperative complication rates, longer rehabilitation, and surgical difficulties remain a problem in the elderly. We asked whether a free flap in elderly patients is an indication or a contraindication and performed a retrospective, monocentric study.

METHODS

Patients were divided into two groups (YOUNG 0-59 years; OLD > 60 years). The endpoint was the survival of flaps and their dependence on patient- and surgery-specific parameters using multivariate analysis.

RESULTS

A total of 110 patients (OLD n = 59) underwent 129 flaps. The chance of flap loss increased as soon as two flaps were performed in one surgery. Anterior lateral thigh flaps had the highest chance for flap survival. Compared with the lower extremity, the head/neck/trunk group had a significantly increased chance of flap loss. There was a significant increase in the odds of flap loss in linear relation to the administration of erythrocyte concentrates.

CONCLUSION

The results confirm that free flap surgery can be indicated as a safe method for the elderly. Perioperative parameters such as two flaps in one surgery and transfusion regimens must be considered as risk factors for flap loss.

Skin wound healing: of players, patterns and processes

Wound healing of the skin is a very complex biological activity. For a better understanding, an attempt is made to describe and subdivide the different players (cell types and signaling molecules), patterns (different regeneration or repair mechanisms) and processes (division of the overall process into categories, phases and steps). However, this is always based on different points of view. On the one hand, the temporality of the phases, and on the other hand, the dominant activity in each step can play a role. In addition, classifications according to wound theory and wound treatment are possible. This article aims to shed more light on the various classifications of skin wound healing and presents the underlying paradigms starting from simple approaches and ending with more detailed concepts.

Digitalization in Medicine: Are German Medical Students Well Prepared for the Future?

The German healthcare system is facing a major transformation towards digitalized medicine. The aim was to find out the attitude and the degree of preparation of upcoming medical professionals for digital medicine. By means of an online survey, medical students from 38 German faculties were asked about different topics concerning digitalization. Most students (70.0%) indicated that they had not had any university courses on digital topics. Thus, only 22.2% feel prepared for the technical reality of digitalized medicine. Most fear losing patient contact because of digitalized medicine and assume that the medical profession will not be endangered by digitalization. Security systems, data protection, infrastructure and inadequate training are cited as the top problems of digitalization in medicine. Medical students have major concerns about incorrect decisions and the consecutive medicolegal aspects of using digital support as part their treatment plans. Digitalization in medicine is progressing faster than it can currently be implemented in the practical work. The generations involved have different understandings of technology, and there is a lack of curricular training in medical schools. There must be a significant improvement in training in digital medical skills so that the current and future healthcare professionals are better prepared for digitalized medicine.

Improving Vascularization of Biomaterials for Skin and Bone Regeneration by Surface Modification: A Narrative Review on Experimental Research

Artificial tissue substitutes are of great interest for the reconstruction of destroyed and non-functional skin or bone tissue due to its scarcity. Biomaterials used as scaffolds for tissue regeneration are non-vascularized synthetic tissues and often based on polymers, which need ingrowth of new blood vessels to ensure nutrition and metabolism. This review summarizes previous approaches and highlights advances in vascularization strategies after implantation of surface-modified biomaterials for skin and bone tissue regeneration. The efficient integration of biomaterial, bioactive coating with endogenous degradable matrix proteins, physiochemical modifications, or surface geometry changes represents promising approaches. The results show that the induction of angiogenesis in the implant site as well as the vascularization of biomaterials can be influenced by specific surface modifications. The neovascularization of a biomaterial can be supported by the application of pro-angiogenic substances as well as by biomimetic surface coatings and physical or chemical surface activations. Furthermore, it was confirmed that the geometric properties of the three-dimensional biomaterial matrix play a central role, as they guide or even enable the ingrowth of blood vessels into a biomaterial.

[Balancing Family and Career in Medicine: Greatly Desired but Given Little Consideration Results of the Study Arm VI of the KARiMED Study]

AIM OF THE STUDY

Family life and professional practice are both highly important for young physicians. Accordingly, a good balancing of both areas of life is necessary. Despite political framework conditions and legal requirements that have been in place for years, implementation of measures to achieve this seems to be difficult, especially in medicine, and is associated with great reservations and problems on the part of those involved.

METHODS

By means of an online survey, the medical mid-level staff from university and peripheral hospitals was questioned on topics related to family, children and professional biographical as well as career-relevant topics and subsequently analyzed on a gender-specific basis.

RESULTS

Of the study participants, 65.1% were married and already had children or expressed a desire to have children (86.0%). Most were employed full-time (80.8%). The majority of part-time employees were female (87.4%). For 34.6%, there was a career break of 18.5±21.3 months, 87.8% of which were taken due to pregnancy or children. Female physicians generally took significantly more parental leave than male physicians (6-12 months: females 62.2%; males 22.4%; 12 months or more: females 25.2%; males 6.6%). Family planning received little support from superiors (21.2% much to very much support) and 45.6% reported having experienced problems with their return to work or career advancement. Almost 60% of the participants did not have any specific working time models in their own hospital for employees with children who need to be cared for.

CONCLUSION

In order to implement a work-life balance for physicians, changes are first and foremost necessary on the part of the institutions. In addition, the respective superiors must rethink in order to enable a parallelization of these two areas of their employees' lives. However, young physicians must also rethink their view of this issue. Demanding changes in labor law while continuing traditional family constellations at home does not seem to do address this issue adequately.

Facilitation of adhesion and spreading of endothelial cells on silicone oxide-coated dacron material by microwave-excited low-pressure plasma

Objectives

Autologous transplants are still the means of choice for bypass surgery. In addition to good tolerability, there is a reduced thrombogenicity and fewer neointima hyperplasia compared to artificial materials. However, since viable transplants are limited, attempts are being made to improve existing artificial vascular prosthesis material. Next to the reduction of thrombogenicity, a rapid endothelialization of the vascular graft should reduce intimal hyperplasia and thus prevent stenoses. The effect of newly developed silicon oxide coatings on the growth of endothelial cells was therefore the goal of this work in a cell culture study.

Methods

A woven, uncoated polyethylene terephthalate (PET) vessel prosthesis was used. The coating process was carried out in a low-pressure plasma reactor in a multi-step process. After preparation of the vacuum chamber hexamethyldisiloxane (HDMSO) with oxygen was evaporated using argon plasma. By this an approx. 1 nm thin adhesion promoter layer was separated from plasma and HMDSO. The silicone oxide barrier layer was applied to the PET vessel samples. The carbon content of the layer could be selectively altered by changing the HMDSO oxygen flow ratio, resulting in coatings of 100 nm, 500 nm, and 1,000 nm. In addition, two different oxygen-to-HMDSO ratios were used. To achieve a carbon coating as low as possible, the ratio was set to 200:1. A carbon-rich layer was obtained with the 1:1 setting. The various coatings were then examined for their surface texture by scanning electron microscopy (SEM) as well as by cell culture experiments for cell viability and growth using EA.hy 926 cells.

Results

SEM showed no changes in the surface morphology; however a layer thickness of 1,000 nm showed peeled off coating areas. Alamar blue assays showed a significantly higher metabolic activity (p=0.026) for the coating 500 nm, ratio 200:1 compared to untreated control samples and a significantly lower metabolic activity (p=0.037) of the coating 500 nm, ratio 1:1 compared to the coating 500 nm, ratio 200:1. This underlines the apparent tendency of the 1:1 coating to inhibit the metabolic activity of the cells, while the 200:1 coating increases the activity. Fluorescence microscopy after calcein acetoxymethyl ester (AM) staining showed no significant difference between the different coatings and the uncoated PET material. However, a tendency of the increased surface growth on the coating 500 nm, ratio 200:1, is shown. The coatings with the ratio 1:1 tend to be less densely covered.

Conclusions

The results of this work indicate a great potential in the silicon coating of vascular prosthesis material. The plasma coating can be carried out easy and gently. Cell culture experiments demonstrated a tendency towards better growth of the cells on the 200:1 ratio coating and a poorer growth on the carbon-rich coating 1:1 compared to the uncoated material. The coating with silicon oxide with a thickness of 500 nm and an oxygen-HMDSO ratio of 200:1, a particularly low-carbon layer, appears to be a coating, which should therefore be further investigated for its effects on thrombogenicity and intimal hyperplasia.

[The medical habilitation at German universities: a comparison of the regulations over 23 years]

BACKGROUND

Due to the further decrease in the number of habilitations in medicine since 2010, the general requirements for habilitation could have increased during the same period.

OBJECTIVE

The requirements for a medical habilitation at German universities in a comparison of 23 years are re-evaluated.

MATERIAL AND METHODS

An analysis of habilitation regulations for 12 target parameters and evaluation of these by a scoring system (range 0-34 points).

RESULTS

Only the criterion of the requirement for a doctorate has remained the same in the 23-year comparison in the evaluation (1998-2021). All results of the other 11 criteria have changed compared to the previous study from 2010. The rating of habilitation achievements has increased from a total score in 1998 of 15.2 ± 5.1 points (95% confidence interval 13.6-16.9 points) to 25.1 ± 3.6 points in 2021 (95% confidence interval 23.9-26.2 points; p < 0.001). The range of assigned scoring values is again more broadly spread in the 11-year comparison with values from 12 to 31 points. A striking new criterion was that 98% of the assessed habilitation regulations now require a didactic continuing education in, however, significantly different requirements from the faculties.

CONCLUSION

The requirements for a medical habilitation continued to significantly increase over the 23-year period with, however, a wider dispersion of scores. The more detailed description can be seen as a direct indication of an improvement in transparency. In contrast, the broader dispersion shows that a uniform assessment standard for Germany has again receded into the distance.

Effects of Extracorporeal Shock Waves on Microcirculation and Angiogenesis in the in vivo Wound Model of the Diver Box

INTRODUCTION

Extracorporeal shock waves (ESWs) have been shown to have a positive effect on skin wound healing; however, little is known on the regeneration of the microcirculation and angiogenesis as well as the different application modes.

METHODS

A total of 40 BALB/c mice were provided with dorsal skin fold chambers and were divided into 3 therapy groups (n = 30) and one control group (n = 10). The 3 therapy groups were treated with shock waves at different pulse rates (500-1,000 pulses/min) and application frequencies (day 0 and day 6 or day 0 only). Photographic documentation and intravital microscopy were carried out on day 1, 2, 4, and 6 after wounding.

RESULTS

Using the newly developed Diver Box, shock waves could be applied in vivo without mechanical tissue damage. Shock wave therapy to skin wounds demonstrated to induce faster wound closure rates in the beginning than controls in groups with higher pulse rates and frequencies of the shock waves. Furthermore, the regeneration of microcirculation and perfusion in the healing skin was significantly improved after the application of, in particular, higher pulse rates as given by increased numbers of perfused capillaries and functional vessel density. The study of inflammation showed, especially in high-pulse ESW groups, higher leukocyte counts, and rolling leukocytes over time until day 6 as a response to the induction of inflammatory reaction after ESW application. Angiogenesis showed a marked increase in positive areas as given by sprouts, coils, and recruitments in all ESW groups, especially between days 4 and 6.

CONCLUSION

The major findings of this trial demonstrate that ESW therapy to skin wounds is effective and safe. This is demonstrated by the initially faster wound closure rate, but later the same wound closure rate in the treatment groups than in controls. Furthermore, during the regeneration of microcirculation and perfusion in the healing skin, a significant improvement was observed after the application of, in particular, higher ESW pulse rates, suggesting an ESW-related increase in nutrient and oxygen supply in the wound tissue.

Experimental Models to Study Skin Wound Healing with a Focus on Angiogenesis

A large number of models are now available for the investigation of skin wound healing. These can be used to study the processes that take place in a phase-specific manner under both physiological and pathological conditions. Most models focus on wound closure, which is a crucial parameter for wound healing. However, vascular supply plays an equally important role and corresponding models for selective or parallel investigation of microcirculation regeneration and angiogenesis are also described. In this review article, we therefore focus on the different levels of investigation of skin wound healing (in vivo to in virtuo) and the investigation of angiogenesis and its parameters.

Optimierung der chirurgischen Behandlung Brandverletzter: Auszüge aus der fachübergreifenden S2k-Leitlinie „Behandlung thermischer Verletzungen des Erwachsenen“

Hintergrund Trotz Brandschutzmaßnahmen und Aufklärung erleiden ca. 0,5 Millionen Menschen pro Jahr in Deutschland Verbrennungen. Im Jahr 2018 mussten fast 2000 Schwerstbrandverletzte in deutschen Verbrennungszentren behandelt werden. Brandverletzungen stellen eine schwerwiegende Erkrankung mit hoher Mortalität und langfristigen Folgen für den Patienten dar.

Methodik und Ergebnisse Ziel dieses Übersichtsartikels ist es, eine Zusammenfassung der derzeit gültigen Leitlinie zur Behandlung von Verbrennungen im Erwachsenenalter (https://www.awmf.org/leitlinien/detail/ll/044–001.html) zu präsentieren, wobei der Fokus auf folgenden Aspekten liegt: 1. der Akutbehandlung der Brandwunde am Unfallort, 2. der Entscheidungsfindung zur Verlegung in ein Brandverletztenzentrum, 3. der chirurgischen Wundversorgung mit Debridement und Hauttransplantation und 4. der Nachsorge. Die S2k-Leitlinie basiert auf aktueller Literatur und dem Konsens von 11 an der Behandlung Brandverletzter beteiligter Fachgesellschaften.

Zusammenfassung Dieser Übersichtsartikel enthält gewichtete Empfehlungen zur Behandlung von Brandwunden erwachsener Patienten in Deutschland. Der Artikel soll Ärzten und medizinischem Personal in der Akutsituation vor Ort und in der Klinik die Entscheidung über die notwendige Behandlung erleichtern. Hiermit soll die Behandlungsqualität für Patienten verbessert werden.

[Change of perception of aged male attractiveness by conventional or male facelift: 3D simulation study of a new facelift concept for men]

BACKGROUND

 Facelift is now the fourth most common aesthetic procedure in men. Facial ageing is very different in men and women. Therefore, individual techniques are used since a uniform concept for the surgical facelift in men does not exist. This study aims to evaluate a gender-specific facelift concept especially developed for men.

MATERIAL AND METHODS

 Women and men (n = 10 each) were subjected to a three-dimensional face scan and a subsequent simulation of a V-shaped lift vector (standard lift) and a new facelift concept especially for men in a double T shape (male lift). In an online survey with 262 participants, the simulated as well as the unchanged images were presented and the attributes masculinity, femininity, attractiveness and youthfulness were queried. Statistical models were used to identify attributes of lifting as well as other factors and differences between the simulations.

RESULTS

 Facelift changes are generally associated with a significant improvement in the attributes of youthfulness and attractiveness compared with unchanged control faces. As expected, a male lift leads to masculinisation, while a standard lift leads to feminisation, regardless of the sex of the subjects. The male lift led to higher values for the attribute attractiveness in male subjects, as did the standard lift in female subjects. The standard lift developed for women is indeed more suitable for women and is associated with a significantly higher probability for the attribute youthfulness, whereas this is not the case in the newly introduced male lift concept.

CONCLUSION

 The new facelift concept for male patients is significantly associated with masculinity and attractiveness, while the standard lift suitable for women is associated with significantly higher evaluations of femininity and youthfulness. The results of the SIMALIFT study are the first evidence of the need for a more differentiated, gender-specific approach to facelifting.

Panta Rhei: Neovascularization, Angiogenesis and Nutritive Perfusion in Wound Healing

BACKGROUND

In response to tissue damage, angiogenesis is an extremely dynamic process that is finely regulated by signals from cells, the surrounding extracellular matrix (ECM), and derived mediators. As the only process, angiogenesis remains of decisive importance in the context of the entire wound healing process and is subject to constant change. The dissolution of the endothelial basement membrane, the migration of endothelial cells, and the development of new capillary vessels during wound healing depend not only on the cells and cytokines present, but also on the production and organization of ECM components in the immediate wound.

SUMMARY

Angiogenesis in wound healing can be divided into two main phases. During the pro-angiogenic phase at the beginning of wound healing, excessive neo-formation of blood vessels, some of which are poorly differentiated, occurs, which restore blood flow and thus nutritive perfusion as quickly as possible. This is followed by an anti-angiogenic phase in which the initially established vascular network undergoes a maturing process, which, however, is accompanied by a significant reduction in the number of vessels. Key Messages: Although many mechanisms and specific cell functions in wound healing have already been described, many underlying pathophysiological processes remain unknown. Because angiogenesis and its maturation is a very fast but also very long-lasting process, the understanding of the underlying mechanisms is of crucial importance. This article will give an overview of the current understanding and controversy in this sub-step of wound healing.

In-vivo monitoring of infection via implantable microsensors: a pilot study

The most common complication after implantation of foreign material is infection, leading to implant failure and severe patient discomfort. Smoldering-infections proceed inapparently and might not get verified by radiological diagnostics. Early identification of this type of infection might significantly reduce the rate of complications. Therefore, we manufactured a microsensor strip in a hybrid of thin-film and laminate technology in a wafer-level process. It comprises electrochemical, amperometric microsensors for glucose, oxygen and lactate as well as an integrated reference electrode. Microsensors have been implanted in the mouse dorsal skin fold chamber, which got inoculated with a human-pathogen bacterial strain. A selective signal could be measured for all parameters and time points. The infection led to measurable changes of the wound environment as given by a decrease of the oxygen- as well as the glucose-concentration while the lactate concentration increased markedly over time. The given results in this study are the first hints on a promising new tool and should therefore be interpreted as a proof of the principle to show the functionality of the microsensors in an in vivo setting. These microsensors could be used to monitor smoldering infections of implantable foreign materials reducing foreign implant associated complications.

A Novel Technique for the Standardized Application of Shock Waves in Experimental Research: The Diver Box

The Diver Box is designed to prevent impedance differences, energy loss or damage to neighboring structures caused by the use of shock waves with application gels. The Diver Box is an acrylic glass container filled with tempered water and includes a coupling membrane to prevent the impedance jump from air to water and to avoid the continuous propagation of shock waves into the tissue, maintaining wave dynamics. Different modes of extracorporeal shock waves can be applied to a mouse skin wound without energy loss and protected from harmful phase-reversed waves. Macroscopic changes were seen in only 5% to 12% of tested specimens. Hazardous phase reversal, back reflection and mechanical tissue damage can be avoided by use of the Diver Box, ensuring standardized extracorporeal shock wave application.

Trendy Tattoos-Maybe a Serious Health Risk?

BACKGROUND

The literature reports many cases of cutaneous malignancy in the setting of skin tattoos. In this study, we review the reported incidence of and risk factors for tattoo-associated skin cancer.

METHODS

A PubMed literature review was performed for all cases of tattoo-associated skin cancer, including squamous cell carcinoma, basal cell carcinoma, malignant melanoma, keratoacanthoma, and other rare skin malignancies (source: PubMed/until June 2017).

RESULTS

The authors identified 51 publications and 63 total cases of tattoo-associated skin cancer. We also report on a single new case of tattoo-associated skin cancer observed at one of our co-authors' institutions. Among these 64 total cases, 58% were associated with black and blue inks and 34% were associated with red ink.

CONCLUSIONS

Overall, while the strength of association remains unclear, the literature reports many cases of tattoo-associated skin cancer. Among these cases, black, blue, and red inks were particularly worrisome for their carcinogenic potential.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Antithrombin is as effective as heparin and hirudin to prevent formation of microvascular thrombosis in a murine model

A recently published post-hoc analysis of a trial using high-dose antithrombin (AT) in septic patients (KyberSept) revealed significant reduction of lethality when no concomitant heparin was administered, whereas patients with the combination of heparin and AT did not benefit in terms of survival. Therefore, it seems feasible to study the capability of AT in prevention of microvascular thrombus formation to avoid concomitant application of heparin and AT. Using fluorescence microscopy and a light/dyeinjury mouse ear model, the kinetics of thrombus formation were analyzed quantitatively in vivo upon single iv bolus of saline (control), heparin (100 IU/kg), hirudin (1 mg/kg) or AT (25, 50, 100 or 250 IU/kg) (N=7 animals per group each). In controls, light/dye-injury induced complete thrombotic occlusion in all arterioles and venules studied. Heparin and hirudin prevented thrombotic vessel occlusion in 62% and 43% of arterioles and 11% and 28% of venules. AT-250 was found to be more effective than heparin and hirudin, because thrombus formation was completely banned in all arterioles and venules. AT-100 and AT-50 were also capable of significantly blocking thrombus formation in both arterioles and venules. In blood vessels, which finally clogged, the time for development of complete vessel occlusion was delayed after heparin, hirudin and AT-25, but in particular after AT-50 and AT-100. In conclusion, AT-mediated antithrombotic activity has been characterized in a model of phototoxicity-induced microvascular thrombosis formation, demonstrating thatAT delays and prevents thrombus formation in arterioles and venules at least comparably effective as heparin and hirudin.

Oxytocin effects on experimental skin wound healing

OBJECTIVE

Oxytocin (OXY) has significant effects on mammalian behavior. Next to its role in lactation and social interactions, it is described to support better wound healing as well. However, direct OXY effects on wound healing and the regeneration of the microvascular network are still not clarified. We therefore examined the effects of OXY and an OXY receptor antagonist [atosiban (ATO)] on skin wound healing, focusing on epithelialization and neovascularization.

METHODS

Skin wound healing has been assessed using intravital fluorescence microscopy in a model of full dermal thickness wounds in the dorsal skin fold chamber of hairless mice. Animals received repetitive low or high doses of OXY or ATO. Morphological and cellular characterization of skin tissue repair was performed by histology and in vitro cell assays.

RESULTS

The assessment of skin tissue repair using this therapy regimen showed that OXY and ATO had no major influence on epithelialization, neovascularization, wound cellularity, or inflammation. Moreover, OXY and ATO did neither stimulate nor deteriorate keratinocyte or fibroblast migration and proliferation.

CONCLUSION

In summary, this study is the first to demonstrate that OXY application does not impair skin wound healing or cell behavior. However, until now, the used transmitter system seems not to be clarified in detail, and it might be proposed that it is associated with the stress response of the organism to various stimuli.

[The scaphoid fracture : Between pseudoarthrosis and possible anatomical variance]

The diagnosis of a scaphoid fracture, especially in the differentiation of a fresh fracture, the nonunion or a possible anatomical norm variant, can be difficult. We report on two patients who presented with stress-related, radiocarpal pain in our department. In both cases, radiological abnormalities were observed in the scaphoideal area, with a scaphoideum bipartitum on both sides, as well as an approximately 25-year-old scaphoid pseudarthrosis.

Localized eosinophilic fasciitis (Shulman's disease) as a differential diagnosis of nerve compression syndrome

A 46-year-old man presented with clinical signs of nerve compression syndrome of his right ulnar nerve as confirmed by nerve conduction studies. Unexpectedly, clinical examination and magnetic resonance imaging (MRI) revealed a subcutaneous tumor of 5×2 cm above the ulnar groove. Surgical exploration and histopathology of biopsies demonstrated the nerve distended and entrapped into an eosinophilic, inflammatory tissue. This rare condition is consistent with localized eosinophilic fasciitis, with no systemic manifestations. There are reports of isolated forearm versions of the disease. However, none occurred with the entrapment of a peripheral nerve appearing as a peripheral nerve tumor, yet. Consequentially, the presented patient would not have benefitted from further surgical neurolysis or tumor debulking, as eosinophilic fasciitis is an inflammatory and systemic disease. The patient’s symptoms decreased spontaneously after 4 weeks of postsurgical treatment, including nonsteroidal anti-inflammatory drugs (NSAIDs). Altogether, this case proved the necessity to regard even rare diseases as a potential cause of entrapment of peripheral nerves. This should lead surgeons to critical, differential diagnostic thinking and suggest that systemic diseases may be encountered during surgery due to their capability to mimic peripheral nerve tumors.

Skin Wound Healing: An Update on the Current Knowledge and Concepts

BACKGROUND

The integrity of healthy skin plays a crucial role in maintaining physiological homeostasis of the human body. The skin is the largest organ system of the body. As such, it plays pivotal roles in the protection against mechanical forces and infections, fluid imbalance, and thermal dysregulation. At the same time, it allows for flexibility to enable joint function in some areas of the body and more rigid fixation to hinder shifting of the palm or foot sole. Many instances lead to inadequate wound healing which necessitates medical intervention. Chronic conditions such as diabetes mellitus or peripheral vascular disease can lead to impaired wound healing. Acute trauma such as degloving or large-scale thermal injuries are followed by a loss of skin organ function rendering the organism vulnerable to infections, thermal dysregulation, and fluid loss.

METHODS

For this update article, we have reviewed the actual literature on skin wound healing purposes focusing on the main phases of wound healing, i.e., inflammation, proliferation, epithelialization, angiogenesis, remodeling, and scarring.

RESULTS

The reader will get briefed on new insights and up-to-date concepts in skin wound healing. The macrophage as a key player in the inflammatory phase will be highlighted. During the epithelialization process, we will present the different concepts of how the wound will get closed, e.g., leapfrogging, lamellipodial crawling, shuffling, and the stem cell niche. The neovascularization represents an essential component in wound healing due to its fundamental impact from the very beginning after skin injury until the end of the wound remodeling. Here, the distinct pattern of the neovascularization process and the special new functions of the pericyte will be underscored. At the end, this update will present 3 topics of high interest in skin wound healing issues, dealing with scarring, tissue engineering, and plasma application.

CONCLUSION

Although wound healing mechanisms and specific cell functions in wound repair have been delineated in part, many underlying pathophysiological processes are still unknown. The purpose of the following update on skin wound healing is to focus on the different phases and to brief the reader on the current knowledge and new insights. Skin wound healing is a complex process, which is dependent on many cell types and mediators interacting in a highly sophisticated temporal sequence. Although some interactions during the healing process are crucial, redundancy is high and other cells or mediators can adopt functions or signaling without major complications.

Immediate Dose-Response Effect of High-Energy Versus Low-Energy Extracorporeal Shock Wave Therapy on Cutaneous Microcirculation

Elucidation of the precise mechanisms and therapeutic options of extracorporeal shock wave therapy (ESWT) is only at the beginning. Although immediate real-time effects of ESWT on cutaneous hemodynamics have recently been described, the dose response to different ESWT energies in cutaneous microcirculation has never been examined. Thirty-nine Sprague-Dawley rats were randomly assigned to three groups that received either focused high-energy shock waves (group A: total of 1000 impulses, 10 J) to the lower leg of the hind limb, focused low-energy shock waves (group B: total of 300 impulses, 1 J) or placebo shock wave treatment (group C: 0 impulses, 0 J) using a multimodality shock wave delivery system (Duolith SD-1 T-Top, Storz Medical, Tägerwilen, Switzerland). Immediate microcirculatory effects were assessed with the O2C (oxygen to see) system (LEA Medizintechnik, Giessen, Germany) before and for 20 min after application of ESWT. Cutaneous tissue oxygen saturation increased significantly higher after high-energy ESWT than after low-energy and placebo ESWT (A: 29.4% vs. B: 17.3% vs. C: 3.3%; p = 0.003). Capillary blood velocity was significantly higher after high-energy ESWT and lower after low-energy ESWT versus placebo ESWT (group A: 17.8% vs. group B: -22.1% vs. group C: -5.0%, p = 0.045). Post-capillary venous filling pressure was significantly enhanced in the high-energy ESWT group in contrast to the low-energy ESWT and placebo groups (group A: 25% vs. group B: 2% vs. group C: -4%, p = 0.001). Both high-energy and low-energy ESWT affect cutaneous hemodynamics in a standard rat model. High-energy ESWT significantly increases parameters of cutaneous microcirculation immediately after application, resulting in higher tissue oxygen saturation, venous filling pressure and blood velocity, which suggests higher tissue perfusion with enhanced oxygen saturation, in contrast to low-energy as well as placebo ESWT. Low-energy ESWT also increased tissue oxygen saturation, albeit to a lower extent, and decreases both blood velocity and venous filling pressure. Low-energy ESWT reduced tissue perfusion, but improved oxygen saturation immediately after the application.

[Assessment of the significance and the requirements of medical postdoctoral lecture qualifications in Germany by the assessment committees]

OBJECTIVE

The postdoctoral medical lecture qualification (Habilitation) represents the highest academic qualification in Germany, which is successfully completed by approximately 850 candidates in medicine and health sciences per year. However, there is only a limited number of respective academic positions available. In addition, structures in education and society have changed over the last years, challenging the importance of this specific German qualification. The aim of this study was to elicit the opinions of members of German habilitation committees concerning the requirements, processes and the overall importance of the postdoctoral medical lecture qualification. Furthermore we wanted to evaluate potential needs for reforms.

METHODS

The online survey was conducted asking for biographic parameters, subjective ratings and potential needs for reforms concerning the postdoctoral medical lecture qualification (PLQ).

RESULTS

The PLQ was rated high in significance by 71.3 % of the committee members. According to the medical understanding of the Humboldt triad (research, teaching, patient care), research (94.3 %) and teaching (89.7 %) have been rated as the most important requirements for a PLQ. Asked for the motivation to undertake a PLQ, 91.0 % of the members gave the joy of doing research, 78.2 % the joy of teaching and 65.5 % better career prospects perspectives as their reason. The recognition of a Ph.D. degree as being equivalent to a German PQL was clearly rejected by the survey respondents (58.6 %: no equivalence). The majority is against the abolition of the German PLQ. However, there is a definite desire for reform, preferably concerning internal obstacles such as the dependence on full professors, more transparency in the PLQ process, but also the demand for a federal standard PLQ regulation.

CONCLUSION

From the committee members' point of view the German PLQ has still a role to play and, despite controversy, is still regarded as a timely qualification. However, there is clear-cut evidence for local, national and international reforms in order to create equality of opportunity for the candidates and to open up suitable career options.

[The medical dissertation in Germany : A quantitative analysis of promotion regulations in medical faculties]

BACKGROUND

The medical dissertation represents an independently processed scientific project. In the field of medicine this has for many years displayed the basis for controversial discussions. The aim of the study presented here was to evaluate the prerequisites of all current promotion regulations in German medical faculties in order to develop a comparability on the basis of a scoring system.

METHOD

An independent analysis of all promotion regulations from German medical faculties for the year 2014 was carried out according to 12 primary outcome measures and a scoring system.

RESULTS

The average total score of promotion regulations at 37 German medical faculties was 57.2 points (SD ±9.5) out of a possible 100 scoring points. The highest scores with 72-85 points were achieved by 3 faculties and 5 achieved scores of only 42-45 points. The range of the different criteria tested was broad. While the written thesis, the review process, the examination requirements as well as the grading of the thesis were defined in all regulations, the introduction into good clinical practice, knowledge of methodology as well as a check for plagiarism only seem to play minor roles.

CONCLUSION

The promotion regulations at German medical faculties show a great variation using the scoring system presented here for the first time. Standardized federal promotion regulations might help to establish a structured transparency as well as a national equality of opportunity.

[Evaluation of Cutaneous Microcirculation at the Dorsum of the Hand within Different Age Groups - Implications for Wound Healing in Hand Surgery?]

BACKGROUND

Cutaneous microcirculation has shown to play a key role in wound healing. Although healing disorders are still one of the most common complications in hand surgery, there still exists a lack of scientific research on possible age-related changes in cutaneous microcirculation at the dorsum of hand.

HYPOTHESIS

Cutaneous microcirculation at the dorsum of the hand differs significantly between different age groups.

METHODS

53 healthy subjects were divided into 2 groups by age (Group A:<40 years, n=31 vs. Group B≥40 years, n=22). All subjects underwent measurement of the microcirculation at the dorsum of the hand with combined laser-Doppler and photo spectrometry.

RESULTS

Cutaneous oxygen saturation was significantly higher in Group A than in Group B (A: 64.7±9.9% vs. B: 58.3±12.6%; p=0,044). In contrast, blood flow velocity was significantly higher in Group B (A: 43±19.6 AU vs. B: 56.7±21.1 AU; p=0.019).

CONCLUSION

The hypothesis of this study was confirmed. This is the first study to show significant differences of cutaneous microcirculation at the dorsum of the hand within different age groups. Further clinical trials are needed in order to examine if delayed wound healing can be correlated to impaired cutaneous microcirculation at the dorsum of the hand.

Analysis of the influence of antithrombin on microvascular thrombosis: anti-inflammation is crucial for anticoagulation

Purpose

Microvascular thrombosis during septic conditions is of essential clinical relevance, but the pathomechanisms are not yet completely understood. The purpose of this study was to study the distinguished differentiation of the interactions of inflammation and coagulation using antithrombin (AT), a mediator of anticoagulation and anti-inflammation.

Methods

Using a thrombosis model in a cremaster muscle preparation of male C57Bl/6J mice (n = 83), we quantitatively assessed microvascular thrombus formation by using intravital fluorescence microscopy. Experimental groups consisted of animals treated with AT or with tryptophan⁴⁹-blocked AT (TrypAT), which exerts only anticoagulant but no anti-inflammatory effects. To further see whether endothelial glycosaminoglycan (GAG) binding with consecutive prostacyclin (PGI₂) release is mandatory for the anticoagulant process of AT, animals were administered heparin or indomethacin either alone or in combination with AT.

Results

The antithrombotic capacity of AT significantly differs in the experimental groups in which anti-inflammation was antagonized. This is given by the significantly prolonged occlusion times (p < 0.05) and higher patency rates in case of application of AT alone; while all other groups in which the anti-inflammatory action of AT was blocked by TrypAT, heparin or indomethacin revealed thrombus kinetics comparable to controls.

Conclusions

The anti-inflammatory influence of AT is essentially linked to its anticoagulant effect in the microvascular system. Those specifications of the active profile of AT characterize the intimate interactions of the anticoagulant and anti-inflammatory pathways. This might be of relevance for AT as a therapeutic agent in critically diseased patients and the clinical understanding of microvascular thrombosis.

Coating of an anti-Fas antibody on silicone: first in vivo results

BACKGROUND

Although the etiology of capsular contracture after breast augmentation has not yet been definitively clarified, the literature contains numerous reports placing the blame on a foreign body reaction. We have developed a procedure for covalently activating a silicone surface with an anti-Fas antibody, which might suppress the foreign body reaction on the silicone surface.

OBJECTIVES

The authors evaluate whether surrounding tissue might be influenced by anti-Fas antibody coating on silicone disks in comparison to untreated silicone disks in an in vivo model.

METHODS

During this study, 4-mm anti-Fas-coated silicone disks were implanted subcutaneously in the paravertebral region of mice (C57/BL6). Silicone disks passing the activation coating process without anti-Fas antibody incubation were defined as the control group. Twelve weeks after implantation, the disks were removed and the surrounding tissue examined.

RESULTS

The tissue surrounding the silicone disks in the experimental group showed significantly increased levels of collagen type 3, elevated levels of matrix metalloproteinase 9, markedly decreased levels of transforming growth factor β2, and a reduced CD68 expression in the pericapsular tissue.

CONCLUSIONS

The first in vivo data reveal that the tissue surrounding a silicone surface can be influenced by the vectored binding of an anti-Fas antibody.

Acute effects of local cold therapy in superficial burns on pain, in vivo microcirculation, edema formation and histomorphology

BACKGROUND

Local cold therapy for burns is generally recommended to relief pain and limit tissue damage, however, there is limited data of its physiological benefit. This study aimed to evaluate pathophysiological effects of cold therapy in superficial burn on microcirculation, edema formation, and histomorphology.

METHODS

In 12 volunteers (8f, 4m; aged 30.4±14.1 years) circumscribed superficial burn was induced on both hand back and either left untreated as control (control-group) or treated by local-cold-application (cold-treatment-group). Prior to burn (t0), immediately (t1), 15 min (t2), and 30 min (t3) following cold therapy, following parameter was evaluated using intravital-microscopy; epidermal-thickness (ET), granular-cell-size (GCS), individual-blood-cell-flow (IBCF), and functional-capillary-density (FCD).

RESULTS

Both ET and GCS increased significantly more in control-group and slightly in cold-treatment-group in t1, while turns to insignificant t2 onwards. IBCF and FCD raised up in control-group compared to dramatically decrease in cold-treatment-group in t1. In t2 both parameter remains in control-group and increased in cold-treatment-group. Comparison of both groups for IBCF and FCD indicates significant difference in t1 and t2, however, insignificant in t0 and t3.

CONCLUSIONS

Microcirculation, edema formation, and histomorphology of superficial burn has been significantly influenced through immediate cold therapy, however, this alterations are transient and turns to ineffective after 30 min.

Capsular contracture by silicone breast implants: possible causes, biocompatibility, and prophylactic strategies

The most common implanted material in the human body consists of silicone. Breast augmentation and breast reconstruction using silicone-based implants are procedures frequently performed by reconstructive and aesthetic surgeons. A main complication of this procedure continues to be the development of capsular contracture (CC), displaying the result of a fibrotic foreign body reaction after the implantation of silicone. For many years, experimental and clinical trials have attempted to analyze the problem of its etiology, treatment, and prophylaxis. Different theories of CC formation are known; however, the reason why different individuals develop CC in days or a month, or only after years, is unknown. Therefore, we hypothesize that CC formation, might primarily be induced by immunological mechanisms along with other reasons. This article attempts to review CC formation, with special attention paid to immunological and inflammatory reasons, as well as actual prophylactic strategies. In this context, the word “biocompatibility” has been frequently used to describe the overall biological innocuousness of silicone in the respective studies, although without clear-cut definitions of this important feature. We have therefore developed a new five-point scale with distinct key points of biocompatibility. Hence, this article might provide the basis for ongoing discussion in this field to reduce single-publication definitions as well as increase the understanding of biocompatibility.

The anti-thrombotic effect of hydrogen sulfide is partly mediated by an upregulation of nitric oxide synthases

INTRODUCTION

Hydrogen sulfide (H2S) known as a gasotransmitter is increasingly recognized for its anti-adhesive, anti-inflammatory and vasoactive properties. Due to these properties, we analysed anti-thrombotic effects of H2S and the participation of the nitric oxide synthase (NOS)-pathway.

MATERIALS AND METHODS

In individual venules of the ear of hairless SKH1-hr mice, thrombus formation was induced using a phototoxic light/dye-injury model and intravital fluorescence microscopy. Animals were treated intravenously with the H2S donor Na2S or NaCl as control. In a second setting, the NOS inhibitor L-NAME was applied intraperitoneally as a bolus 12h prior to Na2S treatment and thrombus induction. Blood and ear tissue were sampled after microscopy for assessment of plasma concentrations of soluble (s)P-selectin, sE-selectin, sVCAM-1 and sICAM-1 and expression of endothelial (e)NOS and inducible (i)NOS, respectively.

RESULTS

When mice were treated with Na2S, venular thrombus formation was significantly delayed versus that in animals of the NaCl-treated control group. While plasma levels of pro-thrombotic adhesion molecules were not affected by Na2S, immunohistochemistry of the vessel walls showed a significant up-regulation of eNOS and iNOS expression within the Na2S-treated group. The delay of thrombus formation in the Na2S-group was partly but significantly reverted by application of L-NAME.

CONCLUSIONS

The anti-thrombotic efficacy of H2S involves the NOS-pathway and may be of preventive and therapeutic value for clinical disorders with increased risk of thrombotic events.

[Primary treatment of tendon injuries of the hand]

Tendon injuries of the hand are common and their treatment is surgically challenging. Precise knowledge of the anatomy of the extensor and flexor tendons in the hand is necessary to be able to perform a detailed clinical examination and to estimate adequately the extent of injury. Depending on the injury pattern, various conservative and surgical treatment options must be considered. Concerning the overall concept of the supply of tendon injuries of the hand, follow-up treatment is crucial to achieve an optimal functional outcome. It should be noted, however, that the results are influenced by the following: extent of the injury, mechanism, exact anatomical location, associated injuries, and finally the participation of the patient in the follow-up treatment.

Tissue engineered skin substitutes created by laser-assisted bioprinting form skin-like structures in the dorsal skin fold chamber in mice

Tissue engineering plays an important role in the production of skin equivalents for the therapy of chronic and especially burn wounds. Actually, there exists no (cellularized) skin equivalent which might be able to satisfactorily mimic native skin. Here, we utilized a laser-assisted bioprinting (LaBP) technique to create a fully cellularized skin substitute. The unique feature of LaBP is the possibility to position different cell types in an exact three-dimensional (3D) spatial pattern. For the creation of the skin substitutes, we positioned fibroblasts and keratinocytes on top of a stabilizing matrix (Matriderm®). These skin constructs were subsequently tested in vivo, employing the dorsal skin fold chamber in nude mice. The transplants were placed into full-thickness skin wounds and were fully connected to the surrounding tissue when explanted after 11 days. The printed keratinocytes formed a multi-layered epidermis with beginning differentiation and stratum corneum. Proliferation of the keratinocytes was mainly detected in the suprabasal layers. In vitro controls, which were cultivated at the air-liquid-interface, also exhibited proliferative cells, but they were rather located in the whole epidermis. E-cadherin as a hint for adherens junctions and therefore tissue formation could be found in the epidermis in vivo as well as in vitro. In both conditions, the printed fibroblasts partly stayed on top of the underlying Matriderm® where they produced collagen, while part of them migrated into the Matriderm®. In the mice, some blood vessels could be found to grow from the wound bed and the wound edges in direction of the printed cells. In conclusion, we could show the successful 3D printing of a cell construct via LaBP and the subsequent tissue formation in vivo. These findings represent the prerequisite for the creation of a complex tissue like skin, consisting of different cell types in an intricate 3D pattern.

Quantitative evaluation of the requirements for the promotion as associate professor at German medical faculties

Background: First quantitative evaluation of the requirements for the promotion as associate professor (AP) at German Medical Faculties

Material and methods: Analysis of the AP-regulations of German Medical Faculties according to a validated scoring system, which has been adapted to this study.

Results: The overall scoring for the AP-requirements at 35 German Medical Faculties was 13.5±0.6 of 20 possible scoring points (95% confidence interval 12.2-14.7). More than 88% of the AP-regulations demand sufficient performance in teaching and research with adequate scientific publication. Furthermore, 83% of the faculties expect an expert review of the candidate´s performance. Conference presentations required as an assistant professor as well as the reduction of the minimum time as an assistant professor do only play minor roles.

Conclusion: The requirements for assistant professors to get nominated as an associate professor at German Medical Faculties are high with an only small range. In detail, however, it can be seen that there still exists large heterogeneity, which hinders equal opportunities and career possibilities. These data might be used for the ongoing objective discussion.

[Preoperative perfusion analysis before total ankle arthroplasty]

PURPOSE

Soft tissue management is of paramount importance in ankle surgery. As such, full thickness necrosis of the soft tissue envelope represents a severe complication following total ankle joint arthroplasty (TAA) potentially leading to implant exposure, infection and thus, substantially compromised patient outcomes. One of the main factors leading to soft tissue complications is an undetermined arterial perfusion of the lower leg or ankle joint. We report on clinical cases suffering soft tissue complications following TAA with the respective plastic surgical therapy regimen and present a simple algorithm for preoperative perfusion evaluation.

METHODS

The medical records of 30 consecutive primary TAA patients were retrospectively reviewed after observing a higher than expected rate of severe soft tissue defects which have been referred to our plastic surgery department.

RESULTS

3 patients (10%, all females, age 63 ± 5 years; BMI 27 ± 3 kg/m2) presented with a soft tissue defect leading to angiography revealing one case of severe arterial obstruction. Wound closure could be reached in one case by conservative therapy consisting of regular dressing changes. In the further patients definite soft tissue reconstruction could only be performed by surgical intervention. One could be covered by split-thickness skin grafting and one by a microsurgical transplantation of a free latissimus dorsi flap. On the basis of these complications we established an easy algorithm for the preoperative evaluation of the arterial perfusion in the ankle region. First, (I) the pulses of the dorsal foot artery and posterior tibial artery should be examined. In the case of not palpable pulses (II) the ankle-brachial index should be performed. Values of <0.9 or >1.2 recommend (III) to perform angiography. In the case of stenosis or complete obstruction (IV) the arterial blood flow should be reconstituted by interventional radiological stenting or vascular surgical procedures.

CONCLUSION

The identification of the arterial perfusion status of patients undergoing TAA using a straightforward clinical algorithm might overcome TAA-related soft tissue complications and improve patient-related outcome measures.

Targeted delivery of human VEGF gene via complexes of magnetic nanoparticle-adenoviral vectors enhanced cardiac regeneration

This study assessed the concept of whether delivery of magnetic nanobeads (MNBs)/adenoviral vectors (Ad)–encoded hVEGF gene (Ad_hVEGF) could regenerate ischaemically damaged hearts in a rat acute myocardial infarction model under the control of an external magnetic field. Adenoviral vectors were conjugated to MNBs with the Sulfo-NHS-LC-Biotin linker. In vitro transduction efficacy of MNBs/Ad–encoded luciferase gene (Ad_luc) was compared with Ad_luc alone in human umbilical vein endothelial cells (HUVECs) under magnetic field stimulation. In vivo, in a rat acute myocardial infarction (AMI) model, MNBs/Ad_hVEGF complexes were injected intravenously and an epicardial magnet was employed to attract the circulating MNBs/Ad_hVEGF complexes. In vitro, compared with Ad_luc alone, MNBs/Ad_luc complexes had a 50-fold higher transduction efficiency under the magnetic field. In vivo, epicardial magnet effectively attracted MNBs/Ad_hVEGF complexes and resulted in strong therapeutic gene expression in the ischemic zone of the infarcted heart. When compared to other MI-treated groups, the MI-M⁺/Ad_hVEGF group significantly improved left ventricular function (p<0.05) assessed by pressure-volume loops after 4 weeks. Also the MI-M⁺/Ad_hVEGF group exhibited higher capillary and arteriole density and lower collagen deposition than other MI-treated groups (p<0.05). Magnetic targeting enhances transduction efficiency and improves heart function. This novel method to improve gene therapy outcomes in AMI treatment offers the potential into clinical applications.

Wound repair and regeneration

The skin is the biggest organ of the human being and has many functions. Therefore, the healing of a skin wound displays an extraordinary mechanism of cascading cellular functions which is unique in nature. As healing and regeneration processes take place in all parts of the human body, this review focuses on the healing processes of the skin and highlights the classical wound healing phases. While regeneration describes the specific substitution of the tissue, i.e. the superficial epidermis, mucosa or fetal skin, skin repair displays an unspecific form of healing in which the wound heals by fibrosis and scar formation. The first stage of acute wound healing is dedicated to hemostasis and the formation of a provisional wound matrix, which occurs immediately after injury and is completed after some hours. Furthermore, this phase initiates the inflammatory process. The inflammatory phase of the wound healing cascade gets activated during the coagulation phase and can roughly be divided into an early phase with neutrophil recruitment and a late phase with the appearance and transformation of monocytes. In the phase of proliferation the main focus of the healing process lies in the recovering of the wound surface, the formation of granulation tissue and the restoration of the vascular network. Therefore, next to the immigration of local fibroblasts along the fibrin network and the beginning of reepithelialization from the wound edges, neovascularization and angiogenesis get activated by capillary sprouting. The formation of granulation tissue stops through apoptosis of the cells, characterizing a mature wound as avascular as well as acellular. During the maturation of the wound the components of the extracellular matrix undergo certain changes. The physiological endpoint of mammalian wound repair displays the formation of a scar, which is directly linked to the extent of the inflammatory process throughout wound healing.

Diabetes and peripheral arterial occlusive disease impair the cutaneous tissue oxygenation in dorsal hand microcirculation of elderly adults: implications for hand rejuvenation

BACKGROUND

In spite of potential implications for anti-aging therapy regarding the selection of the most suitable therapeutical method and potential perinterventional complications, cutaneous microcirculation of the aging hand in healthy individuals as well as in those with diabetes mellitus or peripheral arterial occlusive disease (PAOD) has never been evaluated.

HYPOTHESIS

Functional microcirculation of the dorsal hand differs between healthy individuals and individuals with diabetes or PAOD at the same age.

MATERIALS AND METHODS

Prospective controlled cohort study. One hundred ten individuals were allocated to group A (healthy individuals, n = 37), group B (diabetes mellitus, n = 36), and group C (PAOD, n = 37). Microcirculatory data were obtained using combined laser-Doppler and photospectrometry.

RESULTS

Cutaneous oxygen saturation at the dorsal hand of healthy individuals was 11.1% higher than of those with diabetes mellitus (p = .04) and 18.8% higher than of those with PAOD (p = .001). Cutaneous capillary blood flow in participants with PAOD was 20% higher than in healthy individuals (p = .047).

CONCLUSION

This is the first study demonstrating that capillary microcirculation of the dorsal hand differs between healthy individuals and those with diabetes or PAOD of the same age. Further studies should explore whether ameliorating cutaneous tissue oxygen saturation could emerge as a viable antiaging strategy for elderly hands.

The mouse dorsal skin fold chamber as a means for the analysis of tissue engineered skin

The therapy of extensive and deep burn wounds is still a challenging task for reconstructive plastic surgery. The outcome is generally not satisfactory, neither from the functional nor from the aesthetic aspect. Several available skin substitutes are used but there is need for optimization of new skin substitutes which have to be tested in vitro as well as in vivo. Here, we show that the dorsal skin fold chamber preparation of mice is well suited for the testing of skin substitutes in vivo. Dermal skin constructs consisting of matriderm(®) covered with a collagen type I gel were inserted into full thickness skin wounds in the skin fold chambers. The skin substitutes integrated well into the adjacent skin and got epithelialized from the wound edges within 11 days. The epithelialization by keratinocytes is the prerequisite that also cell-free dermal substitutes might be used in the case of the lack of sufficient areas to gain split thickness skin grafts. Further advantage of the chambers is the lack of wound contraction, which is common but undesired in rodent wound healing. Furthermore, this model allows a sophisticated histological as well as immunohistochemical analysis. As such, we conclude that this model is well suited for the analysis of tissue engineered skin constructs. Besides epithelialization the mode and extend of neovascularization and contraction of artificial grafts may be studied under standardized conditions.

The nonhematopoietic effects of erythropoietin in skin regeneration and repair: from basic research to clinical use

Erythropoietin (EPO) is the main regulator of red blood cell production but there exists also a variety of nonhematopoietic properties. More recent data show that EPO is also associated with the protection of tissues suffering from ischemia and reperfusion injury as well as with improved regeneration in various organ systems, in particular the skin. This review highlights the mechanisms of EPO in the different stages of wound healing and the reparative processes in the skin emphasizing pathophysiological mechanisms and potential clinical applications. There is clear evidence that EPO effectively influences all wound-healing phases in a dose-dependent manner. This includes inflammation, tissue, and blood vessel formation as well as the remodeling of the wound. The molecular mechanism is predominantly based on an increased expression of the endothelial and inducible nitric oxide (NO) synthase with a consecutive rapid supply of NO as well as an increased content of vascular endothelial growth factor (VEGF) in the wound. The improved understanding of the functions and regulatory mechanisms of EPO in the context of wound-healing problems and ischemia/reperfusion injury, especially during flap surgery, may lead to new considerations of this growth hormone for its regular clinical application in patients.

Laser printing of skin cells and human stem cells

Laser printing based on laser-induced forward transfer (LIFT) is a new biofabrication technique for the arrangement of biological materials or living cells in well-defined patterns. In the current study, skin cell lines (fibroblasts/keratinocytes) and human mesenchymal stem cells (hMSC) were chosen for laser printing experiments due to their high potential in regeneration of human skin and new application possibilities of stem cell therapy. To evaluate the influence of LIFT on the cells, their survival rate, their proliferation and apoptotic activity, and the DNA damages and modifications of their cell surface markers were assessed and statistically evaluated over several days. The cells survived the transfer procedure with a rate of 98%  +/- 1% standard error of the mean (skin cells) and 90%  +/- 10% (hMSC), respectively. All used cell types maintain their ability to proliferate after LIFT. Further, skin cells and hMSC did not show an increase of apoptosis or DNA fragmentation. In addition, the hMSC keep their phenotype as proven by fluorescence activated cell sorting (FACS) analysis. This study demonstrates LIFT as a suitable technique for unharmed computer-controlled positioning of different cell types and a promising tool for future applications in the ex vivo generation of tissue replacements.

Cell origin of human mesenchymal stem cells determines a different healing performance in cardiac regeneration

The possible different therapeutic efficacy of human mesenchymal stem cells (hMSC) derived from umbilical cord blood (CB), adipose tissue (AT) or bone marrow (BM) for the treatment of myocardial infarction (MI) remains unexplored. This study was to assess the regenerative potential of hMSC from different origins and to evaluate the role of CD105 in cardiac regeneration. Male SCID mice underwent LAD-ligation and received the respective cell type (400.000/per animal) intramyocardially. Six weeks post infarction, cardiac catheterization showed significant preservation of left ventricular functions in BM and CD105(+)-CB treated groups compared to CB and nontreated MI group (MI-C). Cell survival analyzed by quantitative real time PCR for human GAPDH and capillary density measured by immunostaining showed consistent results. Furthermore, cardiac remodeling can be significantly attenuated by BM-hMSC compared to MI-C. Under hypoxic conditions in vitro, remarkably increased extracellular acidification and apoptosis has been detected from CB-hMSC compared to BM and CD105 purified CB-derived hMSC. Our findings suggests that hMSC originating from different sources showed a different healing performance in cardiac regeneration and CD105(+) hMSC exhibited a favorable survival pattern in infarcted hearts, which translates into a more robust preservation of cardiac function.

[Stem cells from fatty tissue : A new resource for regenerative medicine?]

While stem cells derived from the bone marrow are well-known in clinical medicine, fatty tissue as a source of mesenchymal stem cells is still the subject of recent research. However, adipose-derived stem cells (ASC) are not only harvested less invasively, i.e. via minimally invasive liposuction, but also yield higher numbers of multipotent stem cells.Due to cell-cell interactions and also because of the very favorable secretion profile of growth factors and cytokines ASCs displayed an extraordinary regenerative potential in recent preclinical and clinical applications and achieved a significantly better healing in ischemic muscle, heart, and brain insults and in impaired wound healing. ASCs enhanced regeneration in skeletal tissues such as cartilage or bone. They also revealed immunomodulatory effects and improved the clinical status in immunological diseases.In conclusion ASCs are comparable to bone marrow-derived stem cells concerning possible applications in clinical medicine.

Intracardiac injection of matrigel induces stem cell recruitment and improves cardiac functions in a rat myocardial infarction model

Matrigel promotes angiogenesis in the myocardium from ischemic injury and prevents remodelling of the left ventricle. We assessed the therapeutic efficacy of intracardiac matrigel injection and matrigel-mediated stem cell homing in a rat myocardial infarction (MI) model. Following MI, matrigel (250 μl) or phosphate-buffered solution (PBS) was delivered by intracardiac injection. Compared to the MI control group (MI-PBS), matrigel significantly improved left ventricular function (n= 11, P < 0.05) assessed by pressure–volume loops after 4 weeks. There is no significant difference in infarct size between MI-matrigel (MI-M; 21.48 ± 1.49%, n= 10) and MI-PBS hearts (20.98 ± 1.25%, n= 10). The infarct wall thickness of left ventricle is significantly higher (P < 0.01) in MI-M (0.72 ± 0.02 mm, n= 10) compared with MI-PBS (0.62 ± 0.02 mm, n= 10). MI-M hearts exhibited higher capillary density (border 130.8 ± 4.7 versus 115.4 ± 6.0, P < 0.05; vessels per high-power field [HPF; 400×], n= 6) than MI-PBS hearts. c-Kit⁺ stem cells (38.3 ± 5.3 versus 25.7 ± 1.5 c-Kit⁺ cells per HPF [630×], n= 5, P < 0.05) and CD34⁺ cells (13.0 ± 1.51 versus 5.6 ± 0.68 CD34⁺ cells per HPF [630×], n= 5, P < 0.01) were significantly more numerous in MI-M than in MI-PBS in the infarcted hearts (n= 5, P < 0.05). Intracardiac matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34⁺ and c-Kit⁺ stem cells.