Christian Weinand

Publications

• 1.29

  Impact points

  Failure of Secondary Wound Closure After Sternal Wound Infection Following Failed Initial Operative Treatment: Causes and Treatment.

  Truong Q V Phan, Panagiotis Theodorou, Christian Depner, Rolf Lefering, Walter Perbix, Gerald Spilker, Christian Weinand

  Annals of plastic surgery. 01/2012;

  BACKGROUND: Patients transferred to Plastic Surgery Departments for sternum osteomyelitis have a high morbidity of about 3%. Despite several known options for sternal wound coverage and salvage operations, wound dehiscence or wound necrosis can occur, increasing patient morbidity. PATIENTS AND METHO... [more] BACKGROUND: Patients transferred to Plastic Surgery Departments for sternum osteomyelitis have a high morbidity of about 3%. Despite several known options for sternal wound coverage and salvage operations, wound dehiscence or wound necrosis can occur, increasing patient morbidity. PATIENTS AND METHODS: One hundred thirty-five patients admitted between January 2007 and December 2010 were evaluated in a retrospective study for wound dehiscence after salvage wound coverage at our institution. Various flaps were applied, such as pectoralis major myocutaneous pedicled flaps, pectoralis major muscle pedicled flaps, latissimus dorsi pedicled flaps, greater omental flaps, and vertical rectus abdominis muscle and transverse rectus abdominis muscle flaps. Inclusion criteria were sternal wound infection, bacterial wound infection, previous wound debridement outside our institution, vacuum-assisted closure device wound treatment at our institution, and secondary flap closure of the sternal defect at our institution. A multivariate regression analysis was performed. RESULTS: One hundred thirty patients met the inclusion criteria. In all patients, bacterial wound colonization was shown. Forty patients showed wound dehiscence after closure at our institution. Reasons for wound dehiscence were attributed to wound size, >4 different species of bacteria colonizing the wound, gram-negative bacteria, Candida albicans, intensive care unit stay, and female gender. Interestingly, wound dehiscence was not significant correlated to obesity, smoking, atherosclerosis, renal insufficiency or type of closure influenced significantly, or necrosis. CONCLUSIONS: Female patients after coronary artery bypass grafting (CABG), with large sternal wounds infected with gram-negative bacteria and candida, have an 85% risk of wound dehiscence after flap coverage for sternal wound infection.
• 1.24

  Impact points

  Combined latissimus dorsi and serratus anterior flaps for pelvic reconstruction.

  Truong Q V Phan, Gerald Spilker, Panagiotis Theodorou, Andreas Gossmann, Michael Heiss, Christian Weinand

  Microsurgery. 07/2011; 31(7):529-34.

  In recurrent pressure sores, adjacent tissue has already been consumed by multiple surgeries. Additional problems are several co-morbidities of patients. Especially, severe atherosclerosis would be a contraindication for using free flaps. However, microsurgical techniques allow circumventing these l... [more] In recurrent pressure sores, adjacent tissue has already been consumed by multiple surgeries. Additional problems are several co-morbidities of patients. Especially, severe atherosclerosis would be a contraindication for using free flaps. However, microsurgical techniques allow circumventing these limitations and preparing even severely atherosclerotic vessels. We performed a total of eight sacral pressure sore coverage in our standardized fashion, using the free combined latissimus dorsi and serratus anterior free flaps. All patients had severe atherosclerosis and needed large soft tissue coverage of the sacral defects. Five patients presented after bowel resection, three with recurrent sacral pressure sores. The average follow-up was 12 months. Postoperatively, all patients were allowed to be prone on the operated area. One minor wound dehiscence was sutured in local anesthesia. CT imaging analysis of the pelvis showed complete void space coverage. The combined latissimus dorsi and serratus anterior flaps are a valuable tool for pelvic reconstruction in our hands. In addition, severe atherosclerosis should not be considered an obstacle to microsurgery and the use of free flaps.
• 1.29

  Impact points

  Suicide by burning: epidemiological and clinical profiles.

  Panagiotis Theodorou, Vu T Q Phan, Christian Weinand, Marc Maegele, Christoph A Maurer, Walter Perbix, Sebastian Leitsch, Rolf Lefering, Gerald Spilker

  Annals of plastic surgery. 02/2011; 66(4):339-43.

  Self-immolation constitutes a rare form of suicide in developed countries, though it accounts for unique injury characteristics in the burn intensive care unit. The aim of this study was to present the epidemiological and clinical features of patients burned during a suicidal attempt seen in a North... [more] Self-immolation constitutes a rare form of suicide in developed countries, though it accounts for unique injury characteristics in the burn intensive care unit. The aim of this study was to present the epidemiological and clinical features of patients burned during a suicidal attempt seen in a North Rhine-Westphalia burn intensive care unit (BICU). To address this aim, we undertook a 21-year retrospective study involving patients with thermal injuries admitted to the largest burn unit in Germany. A total of 125 suicide-related burn victims were identified in the study period (9.4%). Comparing the self-immolation group with the rest burn patient cohort, suicide victims were more likely to be single and to act under the influence of alcohol. The suicidal group had a larger extent of burns, higher incidence of inhalation injury, required more surgical procedures, catecholamines, blood transfusions, and a longer BICU stay. Their clinical course was complicated by prolonged intubation period, higher rate of multiple drug-resistant bacteria acquisition and sepsis, leading to a higher mortality rate. Although the proportion of self-immolation victims among all burned patients is not high, the markedly higher severity of their burns and their poorer quality of outcomes makes them an important clinical subgroup for further study.
• 4.14

  Impact points

  Factors of osteogenesis influencing various human stem cells on third-generation gelatin/β-tricalcium phosphate scaffold material.

  Christian Weinand, Afshin Nabili, Mohammed Khumar, Joey R Dunn, Jessica Ramella-Roman, James C Jeng, Marion H Jordan, Yasuhiko Tabata

  Rejuvenation research. 01/2011; 14(2):185-94.

  Human bone marrow-derived stem cells (hBMSCs) and adipose-derived stem cells (hASCs) have been used to regenerate bone. Both sources are claimed to have comparable osteogenic potential, but few comparative studies are available. Third-generation biomaterials have been developed to reduce steps in re... [more] Human bone marrow-derived stem cells (hBMSCs) and adipose-derived stem cells (hASCs) have been used to regenerate bone. Both sources are claimed to have comparable osteogenic potential, but few comparative studies are available. Third-generation biomaterials have been developed to reduce steps in regenerating tissues. For osteogenesis gelatin/β-tricalcium phosphate (β-TCP) scaffolds with incorporated controlled-release bone morphogenetic protein-2 (BMP-2) as third-generation biomaterials were recently developed. So far, few studies on protein-induced osteogenesis versus chemical-induced osteogenesis have been performed. This study evaluates the osteogenic potential of hBMSCs versus hASCs derived on gelatin/β-TCP scaffolds in vitro under four different conditions. Gelatin/β-TCP scaffolds with and without incorporated controlled-release BMP-2 were seeded with hBMSCs or hASCs under oscillating fluid conditions in osteogenic (OS) medium or growth medium (GM). All were evaluated radiologically (computed tomography [CT] scan), histologically, biomechanically, and for gene expression at 1, 2, 4, and 6 weeks. The highest radiological densities were seen in specimens at 6 weeks with controlled-release BMP-2, close to native bone. HBMSCs, hASCs, OS, and GM conditions resulted in similar bone formation with gelatin/β-TCP scaffolds and incorporated controlled-release BMP-2. This was confirmed histologically by Toluidine Blue and van Kossa staining and biomechanically. Gene expression studies of these specimens showed the presence of preosteoblasts, transitory osteoblasts, and secretory osteoblasts. Specimens comprised of gelatin/β-TCP scaffolds without incorporated controlled release BMP-2 in OS medium showed lesser bone formation. hASCs and hBMSCs have similar osteogenic potential. hASCs are an attractive alternative to hBMSCs for bone regeneration using third-generation gelatin/β-TCP scaffolds with incorporated controlled-release BMP-2.

• Thoracic Radionecrosis Following Repeated Cardiac Catheterization

  Banic Borut, Meier Bernhard, Banic Andrej, Weinand Christian

  Radiology Research and Practice. 01/2011;

• What's behind the mask? A look at blood flow changes with prolonged facial pressure and expression using laser Doppler imaging.

  Van-Buendia LB, Allely RR, Lassiter R, Weinand C, Jordan MH, Jeng JC.

  Journal of Burn Care and Research. 01/2010; 31:441-7.

  Clinically, the initial blanching in burn scar seen on transparent plastic face mask application seems to diminish with time and movement requiring mask alteration. To date, studies quantifying perfusion with prolonged mask use do not exist. This study used laser Doppler imaging (LDI) to assess perf... [more] Clinically, the initial blanching in burn scar seen on transparent plastic face mask application seems to diminish with time and movement requiring mask alteration. To date, studies quantifying perfusion with prolonged mask use do not exist. This study used laser Doppler imaging (LDI) to assess perfusion through the transparent face mask and movement in subjects with and without burn over time. Five subjects fitted with transparent face masks were scanned with the LDI on four occasions. The four subjects without burn were scanned in the following manner: 1) no mask, 2) mask on while at rest, 3) mask on with alternating intervals of sustained facial expression and rest, and 4) after mask removal. Images were acquired every 3 minutes throughout the 85-minute study period. The subject with burn underwent a shortened scanning protocol to increase comfort. Each face was divided into five regions of interest for analysis. Compared with baseline, mask application decreased perfusion significantly in all subjects (P < .0001). Perfusion did not change during the rest period. There were no significant differences with changing facial expression in any of the regions of interest. On mask removal, all regions of the face demonstrated a hyperemic effect with the chin (P = .05) and each cheek (P < .0001) reaching statistical significance. Perfusion levels did not return to baseline in the chin and cheeks after 30 minutes of mask removal. Perfusions remain constantly low while wearing the face mask, despite changing facial expressions. Changing facial expressions with the mask on did not alter perfusion. Hyperemic response occurs on removal of the mask. This study exposed methodology and statistical issues worth considering when conducting future research with the face, pressure therapy, and with LDI technology.
• 2.19

  Impact points

  Conditions affecting cell seeding onto three-dimensional scaffolds for cellular-based biodegradable implants.

  Christian Weinand, Jian-Wei Xu, Giuseppe M Peretti, Lawrence J Bonassar, Thomas J Gill

  Journal of biomedical materials research. Part B, Applied biomaterials. 05/2009;

  Seeding cells efficiently and uniformly onto three-dimensional scaffolds is a key element for engineering tissues, particularly when only a low-number of cells is available for tissue repair and regeneration. The aim of this study was to evaluate three seeding techniques on two biocompatible scaffol... [more] Seeding cells efficiently and uniformly onto three-dimensional scaffolds is a key element for engineering tissues, particularly when only a low-number of cells is available for tissue repair and regeneration. The aim of this study was to evaluate three seeding techniques on two biocompatible scaffolds in vitro using chondrocytes as follows: (1) static; (2) modified centrifugal cell immobilization (CCI); and (3) dynamic oscillating motion. Five milliliters of media containing 5, 10, or 25 million articular, auricular, or costal chondrocytes were used to seed porous PLGA scaffolds and sections of devitalized cartilage. The dynamic oscillating technique resulted in up to 150% higher cellular load at 7 days than CCI seeding. Cell distribution was more homogeneous throughout the scaffold under dynamic conditions versus more sporadic and dispersed cell concentrations on the scaffolds when using either the static or the modified CCI technique. Cell load and distribution, when using a low numbers of chondrocytes at one and two million cells per milliliter, was comparable to that using the much higher number, especially under dynamic seeding conditions. The seeded scaffolds were used as implants to achieve cellular bonding between two devitalized meniscus discs. The constructs were implanted subcutaneously in nude mice for 12 weeks and analyzed histologically. Implants seeded with auricular chondrocytes showed qualitative more integration into native meniscus tissue than articular and costal cell implants. We conclude the dynamic oscillating seeding technique is an efficient technique for seeding low-cell numbers onto scaffolds resulting in consistent and uniform cell distribution throughout porous PLGA scaffolds. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009.
• 4.64

  Impact points

  Towards regenerating a human thumb in situ.

  Christian Weinand, Rajiv Gupta, Eli Weinberg, Ijad Madisch, Craig Neville, Jesse B Jupiter, Joseph Vacanti

  Tissue engineering. Part A. 03/2009;

  Regenerative technology promises to alleviate the problem of limited donor supply for bone or organ transplants. Most expensive and time consuming is cell expansion in laboratories. We propose a method of magnetically enriched osteoprogenitor stem cells, dispersed in self-assembling hydrogels and ap... [more] Regenerative technology promises to alleviate the problem of limited donor supply for bone or organ transplants. Most expensive and time consuming is cell expansion in laboratories. We propose a method of magnetically enriched osteoprogenitor stem cells, dispersed in self-assembling hydrogels and applied onto new ultra-high resolution, jet-based 3D printing of living human bone in a single-step for in-situ bone regeneration. Human mesenchymal stem-cells (hBMSCs) were enriched with CD 117+ osteoprogenitor cells, dispersed in different collagen I, RAD 16I hydrogels mixes and applied onto 3-dimensional printed (3DP) beta-TCP/PLGA scaffolds, printed from ultra-high-resolution volumetric CT (VCT) images of a human thumb. Constructs were directly implanted subcutaneously into nude mice for 6 weeks. In-vivo radiographic VCT scanning and histological evaluations were performed at 1, 2, 4 and 6 weeks, expression of bone-specific genes and biomechanical compression-testing at 6 weeks endpoint. Time dependant accumulation of bone-like extracellular matrix was most evident in CD 117+ hBMSCs using collagen I/RAD 16I hydrogel mix. This was shown histologically by Toluidine blue, von Kossa and alkaline-phosphatase staining, paralleled by increased radiological densities within implants approximating that of human bone, and confirmed by high expression of bone-specific osteonectin and biomechanical stiffness at 6 weeks. Human origin of newly formed tissue was established by expression of human GAPDH using RT-PCR. Statistical analysis confirmed high correlations between biomechanical stiffness, radiological densities and bone-markers. Bone tissue can be successfully regenerated in-situ using a single-step procedure with constructs comprised of RAD 16I /collagen I hydrogel, CD 117+ enriched hBMSCs and porous beta-TCP/PLGA scaffolds.
• 2.30

  Impact points

  Using ordinal logistic regression to evaluate the performance of laser-Doppler predictions of burn-healing time.

  Rose Baker, Christian Weinand, James Jeng, Henk Hoeksema, Stan Monstrey, Sarah Pape, Robert Spence, David Wilson

  BMC medical research methodology. 03/2009; 9(1):11.

  ABSTRACT: BACKGROUND: Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of th... [more] ABSTRACT: BACKGROUND: Laser-Doppler imaging (LDI) of cutaneous blood flow is beginning to be used by burn surgeons to predict the healing time of burn wounds; predicted healing time is used to determine wound treatment as either dressings or surgery. In this paper, we do a statistical analysis of the performance of the technique, using data from a study carried out by five burn centers: LDI once between days 2 to 5 post burn, and healing assessed at 14 days and 21 days post burn. Random-effects ordinal logistic regression and other models such as the continuation ratio model were used. RESULTS: Overall performance is that diagnoses are over 90% correct. Related questions addressed were what was the best blood flow summary statistic and whether, given the blood flow measurements, demographic and observational variables had any additional predictive power (age, sex, race, % total body surface area burned (%TBSA), site and cause of burn, day of LDI scan, burn center). It was found that mean laser-Doppler flux over a wound area was the best statistic, and that, given the same mean flux, women recover slightly more slowly than men. Further, the likely degradation in predictive performance on moving to a patient group with larger %TBSA than those in the data sample was studied, and shown to be small. Statistical methods were also used to study the false-color palette, which enables the laser-Doppler imager to be used by clinicians as a decision-support tool. Here the conclusion is that an optimum three-color palette can be chosen 'automatically', but the optimum choice of a 5-color palette cannot be made solely by optimizing the percentage of correct diagnoses. CONCLUSIONS: Modeling healing time is a complex statistical problem, with random effects due to multiple burn areas per individual, and censoring caused by patients missing hospital visits. This analysis applies state-of-the art statistical methods such as the bootstrap and permutation tests to a medical problem of topical interest. New medical findings are that age and %TBSA are not important predictors whereas gender does influence recovery time, even when blood flow is controlled for.
• 1.62

  Impact points

  The Vacuum-Assisted Closure (VAC) Device for Hastened Attachment of an Ileo-Epigastric Flap to Third-Degree Burns on Hand and Fingers.

  Christian Weinand, Marion Jordan, James Jeng

  Journal of burn care & research : official publication of the American Burn Association. 02/2009;

  The vacuum-assisted closure (VAC) device has a wide range of clinical applications, including treatment of infected surgical wounds, traumatic wounds, pressure ulcers, wounds with exposed bone and hardware, diabetic foot ulcers, and venous stasis ulcers. Increased release of growth factors has been ... [more] The vacuum-assisted closure (VAC) device has a wide range of clinical applications, including treatment of infected surgical wounds, traumatic wounds, pressure ulcers, wounds with exposed bone and hardware, diabetic foot ulcers, and venous stasis ulcers. Increased release of growth factors has been described, leading to improved vascularization and thereby formation of new tissue has been described. The system is also used in burn surgery for reconstructive purposes. In their case report, a patient suffered from a third-degree burn injury to the dorsum of the hand with exposure of tendons, necessitating the use of a flap reconstruction. The patient was treated with an ileo-epigastric artery-based flap and the VAC system was applied in a created glove-like shape. Hastened attachment of the flap onto the exposed fingers was observed after 2 days. The authors report on the additional use of the VAC system to hasten flap attachment in a patient with a burn injury to the dorsum of the hand.

• Liquid silicone breast cosmesis—pros and cons of a conversely discussed material in a case report of silicone pneumonia in a transsexual male

  Weinand Christian, Murthy Ananth

  European Journal of Plastic Surgery. 01/2009;
• 1.29

  Impact points

  Human shaped thumb bone tissue engineered by hydrogel-beta-tricalciumphosphate/poly-epsilon-caprolactone scaffolds and magnetically sorted stem cells.

  Christian Weinand, Rajiv Gupta, Eli Weinberg, Ijad Madisch, Jesse B Jupiter, Joseph P Vacanti

  Annals of plastic surgery. 08/2007; 59(1):46-52; discussion 52.

  Traumatic amputation of a thumb with bone loss leaves a patient in severe disability. Reconstructive procedures are restricted by limited shape and have the disadvantage of severe donor-site morbidity. To overcome these limitations, we used a tissue engineering approach to create a distal thumb bone... [more] Traumatic amputation of a thumb with bone loss leaves a patient in severe disability. Reconstructive procedures are restricted by limited shape and have the disadvantage of severe donor-site morbidity. To overcome these limitations, we used a tissue engineering approach to create a distal thumb bone phalanx, combining magnetically sorted 133+ human mesenchymal stem cells (hMSCs) suspended in successful tested hydrogels for bone formation and porous 3-dimensionally printed scaffolds (3DP) in the shape of a distal thumb bone phalanx. Collagen I and fibrin glue hydrogels with suspended hMSCs were first histologically evaluated in vitro for bone formation after 6 weeks.Then 3DP scaffolds, made from a mix of osteoinductive and -conductive beta-tricalciumphosphate (beta-TCP) and poly-epsilon-caprolactone (PCL), with hydrogels and suspended hMSCs, were implanted into nude mice subcutaneously for 15 weeks. Histologic evaluation, high-resolution volumetric CT (VCT) scanning, and biomechanical testing confirmed formation of bonelike tissue. Both hydrogels with CD 133+ hMSCs on 3DP scaffolds supported bone formation. Collagen I resulted in radiologically better bone formation. Bone tissue can be successfully tissue engineered with CD 133+ hMSCs, collagen I hydrogels, and porous 3DP beta-TCP/PCL scaffolds.

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• 2.29

  Impact points

  Comparison of hydrogels in the in vivo formation of tissue-engineered bone using mesenchymal stem cells and beta-tricalcium phosphate.

  Christian Weinand, Rajiv Gupta, Albert Y Huang, Eli Weinberg, Ijad Madisch, Rameez A Qudsi, Craig M Neville, Irina Pomerantseva, Joseph P Vacanti

  Tissue engineering. 05/2007; 13(4):757-65.

  Availability of grafts and morbidity at the donor site limit autologous transplantation in patients requiring bone reconstruction. A tissue-engineering approach can overcome these limitations by producing bone-like tissue of custom shape and size from isolated cells. Several hydrogels facilitate ost... [more] Availability of grafts and morbidity at the donor site limit autologous transplantation in patients requiring bone reconstruction. A tissue-engineering approach can overcome these limitations by producing bone-like tissue of custom shape and size from isolated cells. Several hydrogels facilitate osteogenesis on porous scaffolds; however, the relative suitability of various hydrogels has not been rigorously assessed. Fibrin glue, alginate, and collagen I hydrogels were mixed with swine bone marrow-derived differentiated mesenchymal stem cells (MSCs), applied to 3-dimensionally printed porous beta-tricalcium phosphate (beta-TCP) scaffolds and implanted subcutaneously in nude mice. Although noninvasive assessment of osteogenesis in 3 dimensions is desirable for monitoring new bone formation in vivo, correlations with traditional histological and mechanical testing need to be established. High-resolution volumetric computed tomography (VCT) scanning, histological examination, biomechanical compression testing, and osteonectin (ON) expression were performed on excised scaffolds after 1, 2, 4, and 6 weeks of subcutaneous implantation in mice. Statistical correlation analyses were performed between radiological density, stiffness, and ON expression. Use of collagen I as a hydrogel carrier produced superior bone formation at 6 weeks, as demonstrated using VCT scanning with densities similar to native bone and the highest compression values. Continued contribution of the seeded MSCs was demonstrated using swine-specific messenger ribonucleic acid probes. Radiological density values correlated closely with the results of histological and biomechanical testing and ON expression. High-resolution VCT is a promising method for monitoring osteogenesis.

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• 3.61

  Impact points

  An allogenic cell-based implant for meniscal lesions.

  Christian Weinand, Giuseppe M Peretti, Samuel B Adams, Lawrence J Bonassar, Mark A Randolph, Thomas J Gill

  The American journal of sports medicine. 12/2006; 34(11):1779-89.

  BACKGROUND: Meniscal tears in the avascular zones do not heal. Although tissue-engineering approaches using cells seeded onto scaffolds could expand the indication for meniscal repair, harvesting autologous cells could cause additional trauma to the patient. Allogenic cells, however, could provide a... [more] BACKGROUND: Meniscal tears in the avascular zones do not heal. Although tissue-engineering approaches using cells seeded onto scaffolds could expand the indication for meniscal repair, harvesting autologous cells could cause additional trauma to the patient. Allogenic cells, however, could provide an unlimited amount of cells. HYPOTHESIS: Allogenic cells from 2 anatomical sources can repair lesions in the avascular region of the meniscus. STUDY DESIGN: Controlled laboratory study. METHODS: Both autologous and allogenic chondrocytes were seeded onto a Vicryl mesh scaffold and sutured into a bucket-handle lesion created in the medial menisci of 17 swine. Controls consisted of 3 swine knees treated with unseeded implants and controls from a previous experiment in which 4 swine were treated with suture only and 4 with no treatment. Menisci were harvested after 12 weeks and evaluated histologically for new tissue and percentage of interface healing surface; they were also evaluated statistically. RESULTS: The lesions were closed in 15 of 17 menisci. None of the control samples demonstrated healing. Histologic analysis of sequential cuts through the lesion showed formation of new scar-like tissue in all experimental samples. One of 8 menisci was completely healed in the allogenic group and 2 of 9 in the autologous group; the remaining samples were partially healed in both groups. No statistically significant differences in the percentage of healing were observed between the autologous and allogenic cell-based implants. CONCLUSION: Use of autologous and allogenic chondrocytes delivered via a biodegradable mesh enhanced healing of avascular meniscal lesions. CLINICAL RELEVANCE: This study demonstrates the potential of a tissue-engineered cellular repair of the meniscus using autologous and allogenic chondrocytes.
• 1.12

  Impact points

  Healing potential of transplanted allogeneic chondrocytes of three different sources in lesions of the avascular zone of the meniscus: a pilot study.

  Christian Weinand, Giuseppe M Peretti, Samuel B Adams, Mark A Randolph, Estafios Savvidis, Thomas J Gill

  Archives of orthopaedic and trauma surgery. 12/2006; 126(9):599-605.

  Successful treatment of tears to the avascular region of the meniscus remains a challenge. Current repair techniques, such as sutures and anchors, are effective in stabilizing the peripheral, vascularized regions of the meniscus, but are not adequate for promoting healing in the avascular region. Th... [more] Successful treatment of tears to the avascular region of the meniscus remains a challenge. Current repair techniques, such as sutures and anchors, are effective in stabilizing the peripheral, vascularized regions of the meniscus, but are not adequate for promoting healing in the avascular region. The purpose of this study was to demonstrate the healing ability of a tissue-engineered repair technique using allogenic chondrocytes from three different sources for the avascular zone of the meniscus. MATERIAL AND METHODS: Articular, auricular, and costal chondrocytes were harvested from 3-month-old Yorkshire swine. A 1-cm bucket-handle lesion was created in the avascular zone of each three swine. A cell-scaffold construct, composed of a single chondrocyte cell type and Vicryl mesh, was implanted into the lesion and secured with two vertical mattress sutures. Controls consisted of each three sutured unseeded mesh implants, suture only, and untreated lesions. The swine were allowed immediate post-operative full weight bearing. Menisci and controls were harvested after 12 weeks. RESULTS: In all experimental samples, lesion closure was observed. Gross mechanical testing with two Adson forceps demonstrated bonding of the lesion. Histological analysis showed formation of new tissue in all three experimental samples. None of the control samples demonstrated closure and formation of new matrix. CONCLUSION: We present preliminary data that demonstrates the potential of a tissue-engineered, allogenic cellular repair to provide successful healing of lesions in the avascular zone in a large animal model.
• 2.74

  Impact points

  Tissue engineering cartilage with aged articular chondrocytes in vivo.

  John M Mesa, Victor Zaporojan, Christian Weinand, Timothy S Johnson, Lawrence Bonassar, Mark A Randolph, Michael J Yaremchuk, Peter E Butler

  Plastic and reconstructive surgery. 08/2006; 118(1):41-9; discussion 50-3.

  BACKGROUND: Tissue engineering has the potential to repair cartilage structures in middle-aged and elderly patients using their own "aged" cartilage tissue as a source of reparative chondrocytes. However, most studies on tissue-engineered cartilage have used chondrocytes from postfetal or ... [more] BACKGROUND: Tissue engineering has the potential to repair cartilage structures in middle-aged and elderly patients using their own "aged" cartilage tissue as a source of reparative chondrocytes. However, most studies on tissue-engineered cartilage have used chondrocytes from postfetal or very young donors. The authors hypothesized that articular chondrocytes isolated from old animals could produce neocartilage in vivo as well as articular chondrocytes from young donors. METHODS: Articular chondrocytes from 8-year-old sheep (old donors) and 3- to 6-month-old sheep (young donors) were isolated. Cells were mixed in fibrin gel polymer at 40 x 10 cells/ml until polymerization. Cell-polymer constructs were implanted into the subcutaneous tissue of nude mice and harvested at 7 and 12 weeks. RESULTS: Samples and native articular cartilage controls were examined histologically and assessed biochemically for total DNA, glycosaminoglycan, and hydroxyproline content. Histological analysis showed that samples made with chondrocytes from old donors accumulated basophilic extracellular matrix and sulfated glycosaminoglycans around the cells in a manner similar to that seen in samples made with chondrocytes from young donors at 7 and 12 weeks. Biochemical analysis revealed that DNA, glycosaminoglycan, and hydroxyproline content increased in chondrocytes from old donors over time in a pattern similar to that seen with chondrocytes from young donors. CONCLUSIONS: This study demonstrates that chondrocytes from old donors can be rejuvenated and can produce neocartilage just as chondrocytes from young donors do when encapsulated in fibrin gel polymer in vivo. This study suggests that middle-aged and elderly patients could benefit from cartilage tissue-engineering repair using their own "aged" articular cartilage as a source of reparative chondrocytes.
• 4.09

  Impact points

  Hydrogel-beta-TCP scaffolds and stem cells for tissue engineering bone.

  Christian Weinand, Irina Pomerantseva, Craig M Neville, Rajiv Gupta, Eli Weinberg, Ijad Madisch, Frederic Shapiro, Harutsugi Abukawa, Maria J Troulis, Joseph P Vacanti

  Bone. 05/2006; 38(4):555-63.

  Trabecular bone is a material of choice for reconstruction after trauma and tumor resection and for correction of congenital defects. Autologous bone grafts are available in limited shapes and sizes; significant donor site morbidity is another major disadvantage to this approach. To overcome these l... [more] Trabecular bone is a material of choice for reconstruction after trauma and tumor resection and for correction of congenital defects. Autologous bone grafts are available in limited shapes and sizes; significant donor site morbidity is another major disadvantage to this approach. To overcome these limitations, we used a tissue engineering approach to create bone replacements in vitro, combining bone-marrow-derived differentiated mesenchymal stem cells (MSCs) suspended in hydrogels and 3-dimensionally printed (3DP) porous scaffolds made of beta-tricalcium-phosphate (beta-TCP). The scaffolds provided support for the formation of bone tissue in collagen I, fibrin, alginate, and pluronic F127 hydrogels during culturing in oscillating and rotating dynamic conditions. Histological evaluation including toluidine blue, alkaline phosphatase, and von Kossa staining was done at 1, 2, 4, and 6 weeks. Radiographic evaluation and high-resolution volumetric CT (VCT) scanning, expression of bone-specific genes and biomechanical compression testing were performed at 6 weeks. Both culture conditions resulted in similar bone tissue formation. Histologically collagen I and fibrin hydrogels specimens had superior bone tissue, although radiopacities were detected only in collagen I samples. VCT scan revealed density values in all but the Pluronic F127 samples, with Houndsfield unit values comparable to native bone in collagen I and fibrin glue samples. Expression of bone-specific genes was significantly higher in the collagen I samples. Pluronic F127 hydrogel did not support formation of bone tissue. All samples cultured in dynamic oscillating conditions had slightly higher mechanical strength than under rotating conditions. Bone tissue can be successfully formed in vitro using constructs comprised of collagen I hydrogel, MSCs, and porous beta-TCP scaffolds.

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• [Strategy for defect coverage in extensive degloving and crush injuries of 4 fingers]

  C Weinand, K J Prommersberger, P Hahn, R E Giunta, H Krimmer

  03/2001;

• [Strategy for defect coverage in extensive degloving and crush injuries of 4 fingers]

  C Weinand, K J Prommersberger, P Hahn, R E Giunta, H Krimmer

  01/2001;

• [Strategy for defect coverage in extensive degloving and crush injuries of 4 fingers]

  C Weinand, K J Prommersberger, P Hahn, R E Giunta, H Krimmer

  01/2001;