Daniel Lindhorst

Publications of Daniel Lindhorst

• Increase in periosteal angiogenesis through heat shock conditioning.

  Authors: Majeed Rana, Constantin von See, Martin Rücker, Paul Schumann, Harald Essig, Horst Kokemüller, Daniel Lindhorst, Nils-Claudius Gellrich

  Head & face medicine. 11/2011; 7:22.

  It is widely known that stress conditioning can protect microcirculation and induce the release of vasoactive factors for a period of several hours. Little, however, is known about the long-termIt is widely known that stress conditioning can protect microcirculation and induce the release of vasoactive factors for a period of several hours. Little, however, is known about the long-term effects of stress conditioning on microcirculation, especially on the microcirculation of the periosteum of the calvaria. For this reason, we used intravital fluorescence microscopy to investigate the effects of heat shock priming on the microcirculation of the periosteum over a period of several days. Fifty-two Lewis rats were randomized into eight groups. Six groups underwent heat shock priming of the periosteum of the calvaria at 42.5°C, two of them (n = 8) for 15 minutes, two (n = 8) for 25 minutes and two (n = 8) for 35 minutes. After 24 hours, a periosteal chamber was implanted into the heads of the animals of one of each of the two groups mentioned above. Microcirculation and inflammatory responses were studied repeatedly over a period of 14 days using intravital fluorescence microscopy. The expression of heat shock protein (HSP) 70 was examined by immunohistochemistry in three further groups 24 hours after a 15-minute (n = 5), a 25-minute (n = 5) or a 35-minute (n = 5) heat shock treatment. Two groups that did not undergo priming were used as controls. One control group (n = 8) was investigated by intravital microscopy and the other (n = 5) by immunohistochemistry. During the entire observation period of 14 days, the periosteal chambers revealed physiological microcirculation of the periosteum of the calvaria without perfusion failures. A significant (p < 0.05) and continuous increase in functional capillary density was noted from day 5 to day 14 after 25-minute heat shock priming. Whereas a 15-minute exposure did not lead to an increase in functional capillary density, 35-minute priming caused a significant but reversible perfusion failure in capillaries. Non-perfused capillaries in the 35-minute treatment group were reperfused by day 10. Immunohistochemistry demonstrated an increase in cytoprotective HSP70 expression in the periosteum after a 15-minute and a 35-minute heat shock pretreatment when compared with the control group. The level of HSP70 expression that was measured in the periosteum after 25 minutes of treatment was significantly higher than the levels observed after 15 or 35 minutes of heat shock exposure. A few days after heat shock priming over an appropriate period of time, a continuous increase in functional capillary density is seen in the periosteum of the calvaria. This increase in perfusion appears to be the result of the induction of angiogenesis.

• Virtual 3D tumor marking-exact intraoperative coordinate mapping improve post-operative radiotherapy.

  Authors: Harald Essig, Majeed Rana, Andreas Meyer, André M Eckardt, Horst Kokemueller, Constantin von See, Daniel Lindhorst, Frank Tavassol, Martin Ruecker, Nils-Claudius Gellrich

  Radiation oncology (London, England). 11/2011; 6:159.

  The quality of the interdisciplinary interface in oncological treatment between surgery, pathology and radiotherapy is mainly dependent on reliable anatomical three-dimensional (3D) allocation ofThe quality of the interdisciplinary interface in oncological treatment between surgery, pathology and radiotherapy is mainly dependent on reliable anatomical three-dimensional (3D) allocation of specimen and their context sensitive interpretation which defines further treatment protocols. Computer-assisted preoperative planning (CAPP) allows for outlining macroscopical tumor size and margins. A new technique facilitates the 3D virtual marking and mapping of frozen sections and resection margins or important surgical intraoperative information. These data could be stored in DICOM format (Digital Imaging and Communication in Medicine) in terms of augmented reality and transferred to communicate patient's specific tumor information (invasion to vessels and nerves, non-resectable tumor) to oncologists, radiotherapists and pathologists.

• A novel approach for studying microcirculation in bone defects by intravital fluorescence microscopy.

  Authors: Frank Tavassol, Andreas Kampmann, Paul Schumann, Daniel Lindhorst, Horst Kokemüller, Harald Essig, Jan-Helge Meemken, Martin Rücker, Nils-Claudius Gellrich

  Tissue engineering. Part C, Methods. 07/2011; 17(12):1151-9.

  Angiogenic and inflammatory responses to biodegradable scaffolds were previously studied using the dorsal skinfold chamber for testing different scaffold materials. In this model, the angiogenicAngiogenic and inflammatory responses to biodegradable scaffolds were previously studied using the dorsal skinfold chamber for testing different scaffold materials. In this model, the angiogenic response originates from the soft tissue of the skin. Herein, we introduce a new model that allows the study of developing microcirculation of bone defects for testing tissue-engineered constructs. A bone defect was prepared in the femur of Balb/c mice by inserting a pin for intramedullary fixation, and a custom-made observation window fixed over the defect allowed constant observation. This study included three different groups: empty defect (control), defect filled with porous poly(L-lactide-co-glycolide), and beta-tricalcium-phosphate scaffolds. Starting from 6 days after surgery, angiogenesis, neovascularization, leukocyte-endothelial cell interaction, and microvascular permeability were analyzed over 22 days by using intravital fluorescence microscopy. The empty defects showed no signs of angiogenesis during the observation period, but a distinct increase of capillary density was detected in the scaffold-containing defects. Surprisingly, the histological sections of the scaffold-treated defects showed new bone formation 22 days after implantation. We present a new bone chamber model for intravital long-term study of scaffold materials suitable for bone reconstruction in mice by using fluorescence microscopy.

• Comparably accelerated vascularization by preincorporation of aortic fragments and mesenchymal stem cells in implanted tissue engineering constructs.

  Authors: Paul Schumann, Constantin von See, Andreas Kampmann, Daniel Lindhorst, Frank Tavassol, Horst Kokemüller, Kai-Hendrik Bormann, Nils-Claudius Gellrich, Martin Rücker

  Journal of biomedical materials research. Part A. 04/2011; 97(4):383-94.

  The demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineeringThe demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineering constructs is a limited vascularization. In an attempt to accelerate the vascularization of tissue engineering constructs we compared the usage of bone marrow mesenchymal stem cells (bmMSCs) and fragments derived from the aorta in vivo. Tissue engineering constructs composed of PLGA scaffolds containing Matrigel (n = 8), aortic fragments embedded in Matrigel (n = 8), bmMSCs embedded in Matrigel (n = 8), and aortic fragments embedded in Matrigel combined with bmMSCs (n = 8) were implanted into dorsal skinfold chambers of balb/c mice and analyzed repetitively over 14 days. In all groups a weak inflammatory response was transiently apparent. Vascularization was significantly (p = 0.05) accelerated in bmMSC and aortic fragments containing constructs compared with Matrigel alone, demonstrated by a distinctly increased microvascular density throughout the whole experiment. The combination of bmMSCs and aortic fragments showed no additional effect compared with bmMSCs and aortic fragments alone. The accelerated vascularization and microvascular density of tissue engineering constructs triggered by bmMSCs and aortic fragments is comparable. Thus aortic fragments provide a new promising source for clinical relevant tissue engineering constructs.

• Prolongated survival of osteoblast-like cells on biodegradable scaffolds by heat shock preconditioning.

  Authors: Frank Tavassol, Andreas Kampmann, Daniel Lindhorst, Paul Schumann, Horst Kokemüller, Kai-Hendrik Bormann, Nils-Claudius Gellrich, Martin Rücker

  Tissue engineering. Part A. 03/2011; 17(15-16):1935-43.

  The implantation of tissue-engineered constructs leads to hypoxic and physical stress to the seeded cells until they were reached by a functional microvascular system. Preconditioning of cells withThe implantation of tissue-engineered constructs leads to hypoxic and physical stress to the seeded cells until they were reached by a functional microvascular system. Preconditioning of cells with heat shock induced heat shock proteins, which can support the cells to survive a subsequent episode of stress that would otherwise be lethal. Preconditioning of tissue-engineered constructs resulted in significantly higher number of surviving osteoblast-like cells (OLC). At the 6th and 10th day, angiogenic response was found comparative to poly(L-lactide-co-glycolide) (PLGA) scaffolds vitalized with either unconditioned or preconditioned OLC. However, they were significantly enhanced compared with the nonvitalized collagen-labeled PLGA scaffolds. This study demonstrates that vitalization of PLGA scaffolds with OLC accelerates the angiogenic response induced by the surrounding host tissue. In addition, heat shock preconditioning significantly enhances the survival rate of the OLC that are seeded on these scaffolds. Thus, vitalization of substitutes with adequately pretreated OLC may promise biologically adequate osseous restorations.

• The Hannover experience: surgical treatment of tongue cancer--a clinical retrospective evaluation over a 30 years period.

  Authors: Horst Kokemueller, Majeed Rana, Jennifer Rublack, Andre Eckardt, Frank Tavassol, Paul Schumann, Daniel Lindhorst, Martin Ruecker, Nils-Claudius Gellrich

  Head & neck oncology. 01/2011; 3:27.

  In this retrospective study, we present a clinical review of our experience with tongue cancer in order to obtain valid criteria for therapeutic decision-making. Between 1980 and 2009, a total of 341In this retrospective study, we present a clinical review of our experience with tongue cancer in order to obtain valid criteria for therapeutic decision-making. Between 1980 and 2009, a total of 341 patients with squamous cell carcinoma of the tongue were treated at our Department. The average follow-up was 5.2 years. 309 patients received surgical treatment, which was combined in nearly 10% with neoadjuvant and in nearly 20% with postoperative radio(chemo)therapy. 32 patients were excluded from surgery and received primary radiation. Local and regional failure occurred in 23.9% and 20.4%, leading to a total failure rate of 37.2% after an average duration of 1,6 years. N-Status, extracapsular spread and clear margins were identified as the dominant factors for survival, which was calculated with 54.5% after 5 years. We recommend categorical bilateral neck dissection in order to reliably remove occult lymph node metastases. Adjuvant treatment modalities should be applied more frequently in controlled clinical trials and should generally be implemented in cases with unclear margins and lymphatic spread. This study provides new treatment strategies for primary tumour disease and for tumour recurrence.

• Effects of VEGF loading on scaffold-confined vascularization.

  Authors: Daniel Lindhorst, Frank Tavassol, Constantin von See, Paul Schumann, Matthias W Laschke, Yves Harder, Kai-Hendrik Bormann, Harald Essig, Horst Kokemüller, Andreas Kampmann, André Voss, Rolf Mülhaupt, Michael D Menger, Nils-Claudius Gellrich, Martin Rücker

  Journal of biomedical materials research. Part A. 12/2010; 95(3):783-92.

  Adequate vascularization of tissue-engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß-tricalcium-phosphate (ß-TCP) and porous poly(L-lactide-co-glycolide)Adequate vascularization of tissue-engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß-tricalcium-phosphate (ß-TCP) and porous poly(L-lactide-co-glycolide) (PLGA) scaffolds via collagen coating with vascular endothelial growth factor (VEGF) and studied whether the VEGF loading improves scaffold angiogenesis and vascularization. Dorsal skinfold chambers were implanted into 48 balb/c mice, which were assigned to 6 groups (n = 8 each). Uncoated (controls), collagen-coated, and additionally VEGF-loaded PLGA and ß-TCP scaffolds were inserted into the chambers. Angiogenesis, neovascularization, and leukocyte-endothelial cell interaction were analyzed repeatedly during a 14-day observation period using intravital fluorescence microscopy. Furthermore, VEGF release from PLGA und ß-TCP scaffolds was studied by ELISA. Micromorphology was studied from histological specimens. Unloaded ß-TCP scaffolds showed an accelerated and increased angiogenic response when compared with unloaded PLGA scaffolds. In vitro, PLGA released significantly higher amounts of VEGF compared with ß-TCP at the first two days resulting in a rapid drop of the released amount at the following days up to day 7 where the VEGF release was negligible. Nonetheless, in vivo VEGF loading increased neovascularization, especially in ß-TCP scaffolds. This increased vascularization was associated with a temporary leukocytic response with pronounced leukocyte-endothelial cell interaction at days 3 and 6. Histology revealed adequate host tissue response and engraftment of both ß-TCP and PLGA scaffolds. Our study demonstrates that ß-TCP scaffolds offer more suitable conditions for vascularization than PLGA scaffolds, in particular if they are loaded with VEGF.

• Accelerated angiogenic host tissue response to poly(L-lactide-co-glycolide) scaffolds by vitalization with osteoblast-like cells.

  Authors: Frank Tavassol, Paul Schumann, Daniel Lindhorst, Branko Sinikovic, André Voss, Constantin von See, Andreas Kampmann, Kai-Hendrik Bormann, Carlos Carvalho, Rolf Mülhaupt, Yves Harder, Matthias W Laschke, Michael D Menger, Nils-Claudius Gellrich, Martin Rücker

  Tissue engineering. Part A. 02/2010; 16(7):2265-79.

  Bone substitutes should ideally promote rapid vascularization, which could be accelerated if these substitutes were vitalized by autologous cells. Although adequate engraftment of porousBone substitutes should ideally promote rapid vascularization, which could be accelerated if these substitutes were vitalized by autologous cells. Although adequate engraftment of porous poly(L-lactide-co-glycolide) (PLGA) scaffolds has been demonstrated in the past, it has not yet been investigated how vascularization is influenced by vitalization or, more precisely, by seeding PLGA scaffolds with osteoblast-like cells (OLCs). For this reason, we conducted an in vivo study to assess host angiogenic and inflammatory responses after the implantation of PLGA scaffolds vitalized with isogeneic OLCs. OLCs were seeded on collagen-coated PLGA scaffolds that were implanted into dorsal skinfold chambers in BALB/c mice (n = 8). Two further groups of animals received either collagen-coated (n = 8) or uncoated PLGA scaffolds (n = 8). Animals that received chambers without implants served as controls (n = 8). Angiogenesis, neovascularization, and leukocyte-endothelial cell interaction were analyzed for 14 days using intravital fluorescence microscopy. PLGA scaffolds with and without OLCs showed a temporary increase in leukocyte recruitment. At day 3 after implantation, a marked angiogenic host tissue response was observed in close vicinity of all scaffolds studied. At days 6 and 10, the angiogenic response was significantly higher (p < 0.05) in PLGA scaffolds vitalized with OLCs than in uncoated or collagen-coated PLGA scaffolds. The majority of OLCs, however, died within 14 days after implantation. Our study demonstrates that PLGA scaffold vitalization with OLCs accelerates the angiogenic response in the surrounding host tissue. Bone substitutes created by tissue engineering may thus be superior to nonvitalized substitutes although the seeded cells do not survive for long periods.

• Different curcuminoids inhibit T-lymphocyte proliferation independently of their radical scavenging activities.

  Authors: Michael Deters, Heiko Knochenwefel, Daniel Lindhorst, Therese Koal, Hartmut H Meyer, Wolfram Hänsel, Klaus Resch, Volkhard Kaever

  Pharmaceutical research. 08/2008; 25(8):1822-7.

  PURPOSE: We investigated the inhibitory effects of curcumin, curcumin derivatives and degradation products on OKT3-induced human peripheral blood mononuclear cell (PBMC) proliferation and the role ofPURPOSE: We investigated the inhibitory effects of curcumin, curcumin derivatives and degradation products on OKT3-induced human peripheral blood mononuclear cell (PBMC) proliferation and the role of their radical scavenging activity. METHODS: OKT3-induced human PBMC proliferation was determined by measuring (3)H-thymidine incorporation. Radical scavenging activity was evaluated by using an in vitro DPPH assay. RESULTS: OKT3-induced PBMC proliferation was inhibited by curcumin, isocurcumin, bisdesmethoxy-, diacetyl-, tetrahydro-, hexahydro-, and octahydrocurcumin as well as by vanillin, ferulic acid, and dihydroferulic acid with IC(50)-values of 2.8, 2.8, 6.4, 1.0, 25, 38, 82, 729, 457, and >1,000 muM, respectively. The investigated substances with the strongest effect on radical scavenging were tetrahydro-, hexahydro-, and octahydrocurcumin with IC(50) values of 10.0, 11.7, and 12.3 muM, respectively. IC(50)-values of dihydroferulic acid, ferulic acid, and curcumin were 19.5, 37, and 40 muM. The substances with the lowest radical scavenging activities were vanillin, isocurcumin, diacetylcurcumin, and bisdesmethoxycurcumin with IC(50) values higher than 100 muM each. CONCLUSIONS: Curcuminoid-induced inhibition of OKT3-induced PBMC proliferation depends on the number of carbon atoms and double bonds of the 1,6-heptadiene-3,5-dione structure as well as on the phenolic ring substitutes of the curcuminoids but is not correlated to their respective radical scavenging activity.

• Consequences of seeded cell type on vascularization of tissue engineering constructs in vivo

  Authors: Paul Schumann, Frank Tavassol, Daniel Lindhorst, Constantin Stuehmer, Kai-Hendrik Bormann, Andreas Kampmann, Rolf Mülhaupt, Matthias W. Laschke, Michael D. Menger, Nils-Claudius Gellrich, Martin Rücker

  Microvascular Research.

  Implantation of tissue engineering constructs is a promising technique to reconstruct injured tissue. However, after implantation the nutrition of the constructs is predominantly restricted toImplantation of tissue engineering constructs is a promising technique to reconstruct injured tissue. However, after implantation the nutrition of the constructs is predominantly restricted to vascularization. Since cells possess distinct angiogenic potency, we herein assessed whether scaffold vitalization with different cell types improves scaffold vascularization. 32 male balb/c mice received a dorsal skinfold chamber. Angiogenesis, microhemodynamics, leukocyte–endothelial cell interaction and microvascular permeability induced in the host tissue after implantation of either collagen coated poly (l-lactide-co-glycolide) (PLGA) scaffolds (group 4), additionally seeded with osteoblast-like cells (OLCs, group 1), bone marrow mesenchymal stem cells (bmMSCs, group 2) or a combination of OLCs and bmMSCs (group 3) were analyzed repetitively over 14 days using intravital fluorescence microscopy. Apart from a weak inflammatory response in all groups, vascularization was found distinctly accelerated in vitalized scaffolds, indicated by a significantly increased microvascular density (day 6, group 1: 202 ± 15 cm/cm2, group 2: 202 ± 12 cm/cm2, group 3: 194 ± 8 cm/cm2), when compared with controls (group 4: 72 ± 5 cm/cm2). This acceleration was independent from the seeded cell type. Immunohistochemistry revealed in vivo VEGF expression in close vicinity to the seeded OLCs and bmMSCs. Therefore, the observed lack of cell type confined differences in the vascularization process suggests that the accelerated vascularization of vitalized scaffolds is VEGF-related rather than dependent on the potential of bmMSCs to differentiate into specific vascular cells.