General note: We are proud and happy that the laboratory is attracting many excellent and motivated students. Due to the high number of requests for internships, doctoral thesis projects and Research Track/WissPro  projects we are currently not able to accept any further applications in winter semester 2020/21 and in summer semester 2021.

August 2020


August-24 Congratulation Sarkawt for obtaining the PhD in Health Sciences.


Today, Sarkawt has defended his PhD thesis in the graduate school PhD Health Sciences at the Medical Faculty of the University of Cologne. "An outstanding presentation for an outstanding thesis" as one of the reviewers told. That´s definitively true.



August 2020


Following the adverse outcome pathway from micronucleus to cancer using H2B-eGFP transgenic healthy stem cells.


Hölzel BN, Pfannkuche K, Allner B, Allner HT, Hescheler J, Derichsweiler D, Hollert H, Schiwy A, Brendt J, Schaffeld M, Froschauer A, Stahlschmidt-Allner P.
Arch Toxicol. 2020 Sep;94(9):3265-3280. doi: 10.1007/s00204-020-02821-3. Epub 2020 Jul 22.
In vitro assessment of genotoxicity as an early warning tool for carcinogenicity mainly relies on recording cytogenetic damages (micronuclei, nucleoplasmic bridges) in tumour-derived mammalian cell lines like V79 or CHO. The forecasting power of the corresponding standardised test is based on epidemiological evidence between micronuclei frequencies and cancer incidence. As an alternative to destructive staining of nuclear structures a fish stem cell line transgenic for a fusion protein of histone 2B (H2B) and enhanced green fluorescent protein (eGFP) was established. The cells are derived from koi carp brain (KCB) and distinguish from mammalian culturable cells by non-tumour-driven self-renewal. This technology enables the analysis of genotoxic- and malign downstream effects in situ in a combined approach. In proof-of concept-experiments, we used known carcinogens (4-Nitroquinoline 1-oxide, colchicine, diethylstilbestrol, ethyl methanesulfonate) and observed a significant increase in micronuclei (MNi) frequencies in a dose-dependent manner. The concentration ranges for MNi induction were comparable to human/mammalian cells (i.e. VH-16, CHL and HepG2). Cannabidiol caused the same specific cytogenetic damage pattern as observed in human cells, in particular nucleoplasmic bridges. Metabolic activation of aflatoxin B1 and cyclophosphamide could be demonstrated by pre-incubation of the test compounds using either conventional rat derived S9 mix as well as an in vitro generated biotechnological alternative product ewoS9R. The presented high throughput live H2B-eGFP imaging technology using non-transformed stem cells opens new perspectives in the field of in vitro toxicology. The technology offers experimental access to investigate the effects of carcinogens on cell cycle control, gene expression pattern and motility in the course of malign transformation. The new technology enables the definition of Adverse Outcome Pathways leading to malign cell transformation and contributes to the replacement of animal testing. Summary: Complementation of genotoxicity testing by addressing initiating events leading to malign transformation is suggested. A vertebrate cell model showing "healthy" stemness is recommended, in contrast to malign transformed cells used in toxicology/oncocology.
The study was supported by a BMWi Central Innovation Program for SMEs (ZIM; no. ZF4066801MD5) and BMBF for KMU-Innovative BioChance (PLUG; no. 031A263A)
Read the full article: Link to Journal
This manuscript results from our ongoing collaboration with Gobio GmbH and EWOMIS GmbH.

April 2020

April-28 Congratulation Raja for obtaining your doctorate!


Today my team member Raja Sahito has successfully defended his thesis and obtained the doctor title.


Congratulations Raja and good luck with your next projects!

March 2020




The laboratory is almost down due to the restrictions associated with the spreading of the Corona virus. However, we are still making progress and Daniel has succeeded to derive a seahorse from human stem cells. 


January 2020


Supercritical carbondioxide sterilizer from Novasterilis


New technology has arrived! Thanks to funding by the Marga-and-Walter-Boll Foundation we are now installing a Novasterilis device in our laboratory. The device can be used to sterilize sensitive biological materials with supercritical carbon dioxide. Furthermore, it can decellularize tissues by the same approach but at higher pressures. 

October 2019


Marga-and-Walter-Boll Laboratory for Cardiac Tissue Engineering


The Marga-and-Walter-Boll Foundation has decided to support my group with a new laboratory for cardiac tissue engineering. A room at the Center for Physiology and Pathophysiology is already found and we will soon start with renovations and purchasing the equipment. The Marga and Walter Boll Laboratory for Cardiac Tissue Engineering will allow us to intensify research on human iPS cell-derived cardiomyocytes for cardiac tissue engineering and cell therapy. Thanks a lot for this great opportunity!


August 2019


2nd Cologne Conference on Cardiac Regeneration and Therapy (26./27.9.2019)


Our conference is coming closer and we have finalized the conference program. Registration is open as well.

Please visit the conference page

August 2019

(updated October 2019)


Generation of human induced pluripotent stem cell-derived cardiomyocytes in 2D monolayer and scalable 3D suspension bioreactor cultures with reduced batch-to-batch variations

Sarkawt Hamad, Daniel Derichsweiler, Symeon Papadopolous, Filomain Nguemo, Tomo Saric, Agapios Sachinidis, Jürgen Hescheler, Bastiaan Boukens, Kurt Pfannkuche

Theranostics online date 2019-7-18; doi:10.7150/thno.32058; accepted


To download the PDF version click here


Mai 2019


On March 21st the 7th "Forschungsbörse" took place at the Medical Faculty Cologne. This event is organized by the students and allows research groups of the faculty to present their current work and discuss project opportunities with the students. 

I had a lot of interesting discussions with our highly motivated students that inquire for information on scientific projects and seek to inform themselves on current progress in cardiac tissue engineering and stem cell technologies.


(Foto: Dorothea Hensen, Medizinfoto Köln)

Mai 2019

First Cologne Conference on Cardiac Repair


Save the date: Sept. 26-27, 2019


Organizers: Kurt Pfannkuche and Tomo Saric

Further infos will appear soon on our conference website

Sponsor: Fritz-Thyssen-Foundation, Cologne


Confirmed speakers


  • Gabriele Pfitzer (Universität Köln, Deutschland)
  • Egbert Flory (Paul Ehrlich Institute, Cell Therapy and Tissue Engineering, Langen, Deutschland)
  • Jürgen Hescheler (Universität Köln, Deutschland)
  • Leo Kurian (Zentrum für molekulare Medizin Köln, Deutschland)
  • Christoph Dieterich (Heidelberg, Deutschland)
  • Felix Engel (Erlangen, Deutschland)
  • Hossein Baharvand (Royan Institute, Teheran, Iran)
  • Francisco Fernandez-Aviles (Hospital Gregorio Marañon, Madrid, Spanien)
  • Marcel Halbach (UKK, Cologne)
  • Peter Ertl (TU Wien, Österreich)
  • Wolfram Zimmermann (Göttingen, Deutschland)
  • Joost Sluijter (UMC Utrecht, Niederlande)
  • Marie Jose Goumans (Leiden, Niederlande)
  • Bernd K. Fleischmann (Uni Bonn, Deutschland)
  • Vitaliy Khlebnikov (UMC Utrecht, Niederlande)
  • Felipe Prósper (Hematology and Cell Therapy, Clínica Univ. de Navarra, Pamplona, Spain)


Mai 2019

Leitmarkt NRW: Vaskularisierter, bioartifizieller Herzmuskel aus induziert-pluripotenten Stammzellen


We proudly announce that the project proposal "Vaskularisierter, bioartifizieller Herzmuskel aus induziert-pluripotenten Stammzellen" has been selected by the "Leitmarkt-Agentur" for funding.


In the frame of this project the project consortium will employ a radically novel approach to generate vascularized engineered tissues for therapeutical approaches.


Consortium partners:


LightFab GmbH, Aachen

Miltenyi Biotech GmbH, Bergisch Gladbach

Taros Chemicals GmbH und Co KG, Dortmund

Fraunhofer-Institut für Lasertechnik ILT, Aachen (Dr. Elke Bremus-Koebberling, Dr. Nadine Nottrodt, Dr. Martin Wehner)

Universitätsklinik Köln (AG PD Dr. Kurt Pfannkuche)

Universität zu Köln, Institut für physikalische Chemie (AG Prof. Annette Schmidt)


Follow this link to see a list with all granted projects: Pressemitteilung

Mai 2019

"In vitro grown micro-tissues for cardiac cell replacement therapy in vivo"


Raja Ghazanfar Ali Sahito, Xiaowu Sheng, Martina Maass, Nelly Mikhael,l Sarkawt Hamad, Carlos O. Heras-Bautista, Daniel Derichsweiler, Dimitry Spitkovsky, Frank Suhr, Markus Khalil, Konrad Brockmeier, Marcel Halbach, Tomo Saric, Jürgen Hescheler, Benjamin Krausgrill, Kurt Pfannkuche


Background/Aims: Different approaches have been considered to improve heart reconstructive medicine and direct delivery of pluripotent stem cell-derived cardiomyocytes (PSC-CMs) appears to be highly promising in this context. However, low cell persistence post-transplantation remains a bottleneck hindering the approach. Here, we present a novel strategy to overcome the low engraftment of PSC-CMs during the early post-transplantation phase into the myocardium of both healthy and cryoinjured syngeneic mice. 

Methods: Adult murine bone marrow mesenchymal stem cells (MSCs) and PSC-CMs were co-cultured on thermo-responsive polymers and later detached through temperature reduction, resulting in the protease-free generation of cell clusters (micro-tissues) composed of both cells types. Micro-tissues were transplanted into healthy and cryo-injured murine hearts. Short term cell retention was quantified by real-time-PCR. Longitudinal cell tracking was performed by bioluminescence imaging for four weeks. Transplanted cells were further detected by immunofluorescence staining of tissue sections. 

Results: We demonstrated that in vitro grown micro-tissues consisting of PSC-CMs and MSCs can increase cardiomyocyte retention by >10-fold one day post-transplantation, but could not fully rescue a further cell loss between day 1 and day 2. Neutrophil infiltration into the transplanted area was detected in healthy hearts and could be attributed to the cellular implantation rather than tissue damage exerted by the transplantation cannula. Injected PSC-CMs were tracked and successfully detected for up to four weeks by bioluminescence imaging. 

Conclusion: This approach demonstrated that in vitro grown micro-tissues might contribute to the development of cardiac cell replacement therapies.


Read the full text:


Fig. 5. Histological observation of transplanted micro-tissues. Micro-tissues of low-dose MSC/iPS-CM were transplanted into cryoinjured cardiac tissue. Trichrome staining revealed fibrotic areas of myocardial damage after one week (A) and two weeks (E). Transplanted cells were stained with antibodies against luciferase (green) and nuclei were co-stained by Hoechst dye (blue). Tissue autofluorescence (red) was recorded to visualize the endogenous cardiac tissue. Panel A/B and C/D show results for two individual animals one week after cryoinjury and cell transplantation. Panel E/F show engrafted cells from one animal two weeks after cell transplantation. Panel G/H display magnified regions from the section shown in F.

Mai 2019

CCCR: First Cologne Conference on Cardiac Repair: 26./27. September 2019


Together with Tomo Saric at the Institute of Neurophysiology, Cologne we are organizing the first Cologne Conference on Cardiac Repair. The Event will take place on the 26st and 27th Sept. 2019 at the Center of Physiology, Cologne. We gratefully aknowledge support of the Fritz-Thyssen-Foundation to organize the meeting. I am comming back with more detailed information on topics, invited and confirmed speakers soon. This will be a great chance for networking, I am happy to be part of it!


March 2019

“Cardiomyocytes facing fibrotic conditions re-express extracellular matrix transcripts”


Carlos O.Heras Bautista*,  Nelly Mikhael*, Jennifer Lam, Vaibhav Shinde, Alisa Katsen-Globa, Sabine Dieluweit, 

Marek Molcanyi, Vladimir Uvarov, Peter Jütten, Raja G.A. Sahito, Francisco Mederos Henry, Alexander Piechot, 

Konrad Brockmeier, Jürgen Hescheler, Agapios Sachinidis, Kurt Pfannkuche

*both authors contributed equally


Pathophysiological conditions, such as myocardial infarction and mechanical overload affect the mammalian heart integrity, leading to a stiffened fibrotic tissue. With respect to the pathophysiology of cardiac fibrosis but also in the limelight of upcoming approaches of cardiac cell therapy it is of interest to decipher the interaction of cardiomyocytes with fibrotic matrix. Therefore, we designed a hydrogel-based model to engineer fibrotic tissue in vitro as an approach to predict the behavior of cardiomyocytes facing increased matrix rigidity. Here, we generated pure induced pluripotent stem cell-derived cardiomyocytes and cultured them on engineered polyacrylamide hydrogels matching the elasticities of healthy as well as fibrotic cardiac tissue. Only in cardiomyocytes cultured on matrices with fibrotic-like elasticity, transcriptional profiling revealed a substantial up-regulation of a whole panel of cardiac fibrosis-associated transcripts, including collagen I and III, decorin, lumican, and periostin. In addition, matrix metalloproteinases and their inhibitors, known to be essential in cardiac remodeling, were found to be elevated as well as insulin-like growth factor 2. Control experiments with primary cardiac fibroblasts were analyzed and did not show comparable behavior. In conclusion, we do not only present a snapshot on the transcriptomic fingerprint alterations in cardiomyocytes under pathological conditions but also provide a new reproducible approach to study the effects of fibrotic environments to various cell types.



Read the full text:

February 2019

Mobility Grant for MSc. Sarkawt Hamad


Congratulations to Sarkawt for winning a mobility grant (IPaK: Promoting international students at the University of Cologne) supported by the DAAD and selected by the medical faculty, Cologne. The grant will allow Sarkawt to stay for 2 months in the laboratory of Dr. Carolina Galvez-Monton located at Badalona, Spain. The aim of this visit is to initate first experiments of cardiac cell replacement therapy using human induced pluripotent stem cell derived cardiomyocytes in a large animal model.

February 2019

Novel project granted by the Elisabeth and Rudolf Hirsch-Foundation


We have just received the good news that the Elisabeth and Rudolf Hirsch Foundation gives support to the team thereby allowing us to conduct initial experiment of cardiac cell replacement therapy in a porcine model. This project is handled mainly by Daniel Derichsweiler and Msc. Sarkawt Hamad in the laboratory with support by Karina Neumann. Cell production technologies are established and experimental permissions were granted.

January 2019

Collaboration News Gobio GmbH


Our group has supported the SME Gobio GmbH (Aarbergen, Germany) in the develop of a stem cell-based cell assays for toxicity measurements. The collaborative work was funded by the German Federal Ministry for Economic Affairs and Energy within a "ZIM project" and has now resulted in the application of patents in Europe and US

("Indicator stem cell line/living organism (non human) and a method for detection of the genotoxic potential of aquatic samples or aqueous solutions of test compounds.")

December 2018

Networking Event Badalona - Spain


In preparation for the upcoming projects in the field of cardiac cell replacement therapy we have visited the IGTP Institute in Badalona, Spain to meet our collaboration partners Dr. Carolina Galvez-Monton and Prof. Bas Boukens (Amsterdam) for a brain storming. The novel facility at IGTP provides the best possible environment for our research with state of the art facilities and instrumentation.

October 2018

Networking Event Tandojam - Cologne Initiative


In the follow up of our first online course in cell culture technologies for students at our partner University SAU in Tandojam, PK  vicechancelor Prof. Memon is guest in Cologne to report on the ongoing initiative to establish a new institute for stem cell research. The building is now ready to use and we are planning the next steps.





July 2018

Novel project granted by the German Research Foundation (DFG)

Our team has now received a novel grant to optimize the early retention of transplanted stem cell-derived cardiomyocytes in a rodent model of cardiac infarction. In the frame of the project our successful strategy of micro-tissue transplantation will be further developed to enhance the efficiency of the approach. Magnetic targeting is among the strategies that appear attractive to boost the cell transplantation success.

June 2018

Generation of human induced pluripotent stem cell derived cardiomyocytes (HiPS-CMs) optimized

Sarkawt and Daniel from my team have made a hell of effort to optimize the differentiation of HiPS-CMs for reproducible generation of cardiac differentiation, high differentiation efficiencies of up to 95%, high yields of maximally 100 million cardiomyocytes per 100 ml suspension culture and controlled costs. Alltogether, we are now moving forward to plan preclinical studies in the porcine model together with Dr. Gálvez Montón in Badalona, Spain. Pall Corporation has just offered support for the bioreactor technology - hope to getting started soon.

June 2018

Tandojam Laboratory of Regenerative Medicine

Our team supports the SAU to rise a own stem cell laboratory at Tandojam, Pakistan. This collaboration has arisen from a project ("KAZE" project) funded by the BMBF in the frame of scientific collaborations with partners in Pakistan in 2014. Raja is busy in networking and keeping everybody in the consortium busy. The Vice-chancellor of SAU Prof. Mujeeb-u-ddin Sahrai has visited Cologne on several occasions to keep the business rolling.  Efforts have already payed-off and the Pakistan Ministry has just granted about 3.5 Mio. Euro to raise a stem cell laboratory at SAU. We are involved in the planning and help the SAU to get started in the field of stem cell technology. The online lecture series in April will be followed by further and more specific training measures in the future.

April 2018

Online course on basic stem cell culturing techniques at Sindh Agricultural University (SAU)

Together with our colleagues at the Institute of Neurophysiology Cologne we have prepared an online course for cell culturing technologies for students at the SAU in Tandojam, Pakistan. The lecture was attended by nearly 50 persons from student to principal investigator level. We are planning further activities in the future to intensify our collaboration with the SAU in the field of Stem Cell Research. Many thanks to the Vice Chancellor Prof. Mujeeb-u-ddin Sahrai for his great support of the project.