Our research
The research focus of Prof. Hinkel and her team is the elucidation of molecular signaling pathways in cardiovascular diseases in order to develop potential new therapeutic approaches. To this end, the working group deals with a broad spectrum of cardiac diseases such as acute and chronic cardiac ischemia, ischemic or genetic cardiomyopathies, cardiac hypertrophy as well as the impact of cardiovascular risk factors on their pathogenesis and progression. Our research is mainly conducted in large animal models.
One novel way of positively influencing the pathological signaling pathways in the aforementioned diseases next to pharmacological treatments is gene modification. Herein, we have a particular focus on targeting non-coding RNAs as well as the utilization of viral particles, the so-called adeno-associated viral vectors (AAVs), to deliver potential nucleic acid therapies. Due to their envelope proteins, these viruses exhibit tissue tropism and can therefore be used for tissue-specific application. By using various transgenic animal models, it is also possible to investigate this in the context of cardiovascular risk factors, such as diabetes mellitus, hyperlipidemia or aging, thereby improving translation into clinical application. Importantly, whenever possible, these animal experiments are supplemented, deepened or replaced by innovative in vitro studies on human primary, stem cells and or cell line.
Diseases of the heart muscles
Cardiomyopathies
Cardiomyopathies comprise various structural diseases of the heart muscle. Despite their different origins, these changes manifest themselves in common pathophysiological pathways, characterized by myocardial hypertrophy, dilatation of the ventricle, increased fibrosis and loss of myocardial pumping function. Currently available pharmacological therapies increase the survival time of patients with the disease, but cannot stop the pathophysiological changes in the heart, such as hypertrophy or fibrosis of the myocardium and the associated remodeling. Targeted molecular therapy has recently become possible by inhibiting specific micro-RNAs (miRs), which are highly elevated upton certain cardiovascular diseases in the affected cell types and/or tissues, by means of antagomiRs (antimiRs). We have investigated this therapeutic strategy in pigs as preclinical large animal models.
Ischemic cardiomyopathy
In a first study, regional inhibition of a specific miR, miR-21, in the affected working myocardium reduced fibrosis development and the associated loss of function in the ischemic cardiomyopathy model. MiR-21 is a key regulator of cardiac fibrosis, and its inhibition has already been shown to be an effective anti-fibrotic strategy in various organs, including the heart, in small animal models. In the pre-clinical study in pigs, we demonstrated that intracoronary infusion of antimiR-21 is feasible and therapeutically effective. The catheter-based regional application of antimiR-21 could represent a novel therapeutic option to prevent the development of heart failure after myocardial infarction.
Hypertrophic cardiomyopathies
Another entity of cardiomyopathy is cardiac hypertrophy. Pathologic cardiac hypertrophy is a consequence of diseases that increase afterload, such as untreated hypertension and aortic stenosis. It is characterized by negative remodeling, capillary rarefaction and fibrosis, which often lead to heart failure. In a translational study in pigs, we first established a model for cardiac hypertrophy by stent implantation in the aorta.
While control animals developed cardiomyocyte growth with increased afterload, which led to massive hypertrophy, this effect was significantly attenuated by the intracoronary application of inhibition of m-132 (antimiR-132). In addition, interstitial fibrosis and negative remodeling were significantly reduced, resulting in a marked improvement in function.
In addition to other results from the cooperation partners from the MHH Hannover (Prof. Thomas Thum), this knowledge contributed to clinical translation and testing in the form of clinical studies, which are currently underway.
Genetic cardiomyopathies
In addition to disease-related changes in heart structure and function, there are also congenital genetic changes that cause heart muscle weakness. These can be treated using traditional gene therapy, in which the faulty protein is replaced with a correct one. However, this approach is limited by the size of the protein to be replaced. Novel therapeutic approaches therefore aim to directly correct the faulty sequence of the protein produced (in vivo genome editing). Our research group is pursuing approaches in which adeno-associated viral vectors transport recombinases (enzymes) into the affected cells, which are able to repair the gene sequences.
Diabetic cardiomyopathy
Diabetes mellitus is a common and serious metabolic disease that affected 422 million people worldwide in 2014, with the incidence increasing in industrialized countries in particular. The search is on for new treatment options to treat diabetes itself and the various secondary symptoms of diabetes mellitus. Diabetes mellitus affects many organ systems, including blood vessels. As the most common secondary disease, diabetes mellitus affects the cardiovascular system. Particularly the function of the coronary arteries and, hence the blood flow to the heart. Heart attacks and the resulting heart failure are the most common causes of death in diabetics. Unfortunately, for reasons still unknown, cardiovascular mortality in diabetics is barely affected by modern antidiabetic treatments, including insulin. Therefore, there is a great need for better understanding and treatments of diabetic cardiomyopathy.
Current research projects on diabetic cardiomyopathy are predominantly based on animal models, which, in addition to obvious advantages such as genetics that can be traced over generations and the directly measurable influence of nutritional regimens, also have limitations that should not be underestimated. For example, many studies are based on transgenic rodent models, which are only partially symptomatically comparable with humans due to their genetically modified backgrounds. Moreover, they are also under debated discussion with regard to their clinical relevance for translation of biomedical therapeutic approaches. We have therefore set up a range of models (cell culture, ex-vivo studies and animal models (mouse and pig)) in order to have a rather comprehensive understanding of the pathophysiological changes in diabetes and to enable the development and testing of new therapeutic approaches.
In our studies on pigs with a genetic diabetes mellitus caused by a mutated insulin, we were able to show that hyperglycemia itself leads to pathophysiological changes in the heart (e.g. capillarization, fibrosis) at a very early stage and thus to a deterioration in cardiac function.
Gene therapy with a pro-angiogenic factor using an adeno-associated viral vector coding for Thymosin ß4 showeds a significant growth of micro- and macro- vessels in diabetic animals in a model of chronic myocardial ischemia, associated with a reduction in fibrosis, as well as improvement in cardiac function, however not to the same level as in non-diabetic animals.
Ischemia / reperfusion
Ischemia / reperfusion: Acute myocardial infarction
The standard treatment for occluded coronary arteries is rapid recanalization of the affected vessels, known as revascularization. This method is time-sensitive and the proportion of salvaged tissue decreases the longer the vascular occlusion lasts. However, the reopening of the occluded vessel also results in damage, known as reperfusion damage. This is caused by the rapid influx of oxygen-rich blood into the ischaemic heart tissue and is characterized by increased cell death, migration of inflammatory cells and reduced contractile performance in this area. This damage is partially reversible and therefore very suitable for new therapeutic strategies. Optimized pharmacological and interventional therapy has contributed significantly to improved survival of patients with myocardial ischemia, but adverse remodeling still occurs, particularly in patients with large myocardial infarction, which can lead to heart failure in one third of patients with acute myocardial infarction.
Ischemia / reperfusion: microRNAs
Therapeutic approaches
MicroRNAs (miRs) are small, ~18-22 nucleotide long, non-coding RNAs that are processed intracellularly by the RNases Drosha and Dicer. By binding to complementary sequences on their specific messenger RNAs(mRNAs), miRs can prevent translation or induce mRNA degradation and thus regulate a variety of target genes post-transcriptionally. MiRs play a central role in developmental biology, in the maintenance of tissue homeostasis and especially under pathophysiological conditions. Several studies have shown that molecular interventions with miR antisense molecules (antimiRs) can be used to specifically target dysregulated miRs in animal models of different diseases.
Review: Gene therapy for ischemic heart disease.
Inhibition of miR-92a using a locked-nucleic acid antisense (LNA)-modified antagonist showed a significant improvement in ischemia-reperfusion injury. In addition to the reduction in infarct size, this treatment showed an improvement in microcirculation and a reduction in local inflammation, all of which are central processes involved in ischemia-reperfusion injury.
Chronic ischemia
The gradual occlusion of coronary arteries can result in a reversible loss of cardiomyocyte function (hibernating myocardium). This hibernating myocardium appears to be amenable to therapeutic neovascularization, as it can be reactivated by adequate perfusion. However, in our view, therapeutic neovascularization not only requires the growth of new blood vessels, i. e. angiogenesis, but also the maturation of these newly formed vessels. Two novel factors, thymosin ß4 and MRTF-A, are able to recruit significantly more pericytes, which support the maturation of these new vessels. We were able to demonstrate the essential role of vascular maturation in the rabbit hind limb ischemia model. Whether this concept could be a therapeutic option in patients with ischemic cardiomyopathy was investigated in further studies in a pre-clinical porcine model of the hibernating myocardium.
In this model, both thymosin ß4 and MRTF-A were able to increase perfusion in the myocardium in addition to angio- and arteriogenesis. This increased perfusion was able to significantly improve global and regional myocardial function. In summary, thymosin ß4 in cooperation with MRTF-A increases both angiogenesis via CCN-1 and vascular maturation via CCN-2 and thus enables an improvement of perfusion and function in the ischemic muscles.
Cardiovascular aging
The heart ages
Particularly in view of the fact that the global population of people over 60 is expected to almost double to more than 2 billion by 2050 (World Health Organization), it is essential to ensure healthy aging as well as therapeutic measures for age-related diseases. All countries worldwide are increasingly faced with the challenge of preparing their health and social systems for this demographic shift and its associated consequences. In this context, the aging process represents a significant risk factor for the development of a wide range of diseases. In particular, aging is accompanied by profound changes in the cardiovascular system: at the cellular level, changes in mitochondria, the energy power plants of the cell, accumulation of free oxygen radicals, and increasing inflammatory processes accompanied by a limited repair capacity of the cells become apparent during the course of life. At the organ level, hypertrophy of the heart tissue and increased accumulation of connective tissue both in the heart (so-called myocardial fibrosis) and in the large vessels can be found, as well as the development of arteriosclerotic plaques and deterioration of cardiac function. These mechanisms, in complex interactions also with other organs, lead to the clinically visible pictures of hypertension, coronary heart disease, myocardial infarction and heart failure. Therefore, a significant increase in cardiovascular diseases can be expected, especially from the fifth decade of life. Research into and elucidation of these mechanisms and underlying causes, as well as their treatment and prevention, are essential to adequately counter the predicted massive increase in cardiovascular diseases, especially in the elderly population.

In biomedical research, various animal models are available to address research questions in cardiology. In particular, rodent species and pigs are currently used to study molecular and functional mechanisms of cardiac pathologies, to test new surgical methods and therapeutic options, or to identify potential biomarkers for cardiovascular diseases. Although a lot of essential information can be obtained in these animals, various inte-specific differences and their genetic distances to humans in some systems limit the translation of obtained knowledge to humans.
Here, the use of non-human primate species opens up new possibilities: particularly short-lived species such as the common marmoset (Callithrix jacchus, 300-500g, average age 12 years). These New-World primates show the first natural signs of aging such as cartilage defects, hearing loss and nerve cell degeneration already at the age of a few years. In addition, it is known from colony studies that they can develop obesity and diabetes, which makes them comparable to humans.

As part of the research focus "Cardiovascular Aging", our department is investigating and characterizing the common marmoset as a potential animal model for age-associated cardiovascular changes. Molecular biological investigations are used in an interdisciplinary project funded by the German Center for Cardiovascular Research e.V. (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) together with functional cardiac catheterizations and non-invasive imaging techniques to collect physiological data for the species common marmoset. In cooperation with internal and external colleagues, additional organs will also be examined for signs of aging. In a second step, biomarkers and possible human-relevant therapeutic targets for the occurring changes will be identified before these can be tested in the future using disease models.
External cooperations
- Universitätsmedizin Göttingen : Priv-Doz. Dr. rer. nat. Laura ZelarayanInstitut für Pharmakologie und Toxikologie
- Max-Planck-Institut für Neurobiologie des Verhaltens – caesar: Dr. Silke HaverkampComputational Neuroethology
- Max-Planck-Institut für Multidisziplinäre Naturwissenschaften: Prof. Frauke AlvesArbeitsgruppe Translationale Molekulare Bildgebung
- Universitätsmedizin Göttingen: Prof. Jochen StaigerInstitut für Neuroanatomie
Translational Cardiac Optics Research
Translational Cardiac Optics Research
The “translational Cardiac Optics Research” group focuses on the investigation of cardiovascular
events with the long-term goal of developing new translational approaches. The translational aspect is
not only based on the fact that basic research results can be transferred to the preclinical phase, but
also on visualizing the different developmental courses of cardiac processes in various laboratory models
for knowledge deepening and making the causes of the different manifestations more understandable.
In addition to electrophysiological and molecular biological techniques, we also rely on newly developed
electrotechnical sensor and light technology, as well as biomedical imaging techniques on the microand
macroscopic scales. With the help of these measurement techniques, we are able to obtain an
all-round view of the heart, which enables us to better understand systemic relationships and optimize
preclinical processes.
Arrhythmia Classification & Characterization
Optogenetic Arrhythmia Termination & LED-Array
Cardiac diseases are omnipresent and pose ever new challenges to cardiovascular research. In
particular, the mechanisms and tissue alterations underlying these diseases are often difficult
to investigate in their three-dimensional complexity. All-optical measurement techniques are
currently very popular when it comes to describing the physiological functions of the heart.
Per definitionem, the term all-optical physiology stands for the usage of optical properties
and accordingly devices, which allows non-contact multidimensional and multicellular physiological
observations. But how could this specifically benefit cardiac physiology? Especially for all kinds of
electro-sensitive questions, optical approaches can be of great advantage and
due to the steady development of technology, more and more optics can be used not only
in vitro but also in ex vivo or in vivo experiments. Here, we focus on new optophysiological
methods with respect to their translational research direction and with these we can address
a variety of scientific questions, from measurable characterization to the manipulation of
physiological processes in optogenetically modified hearts.
Always the same?
Influence of gender and tissue remodeling in aging heart populations
Ventricular tachyarrhythmia represent a serious challenge in cardiac rhythm research, especially
against the background of gerontological tissue remodelling and its potential influence
on arrhythmia termination protocols. Standard electrotherapies somehow thwart the investigation
of underlying changes in excitation patterns by producing electrical artefacts and
therefore could be hiding critical termination mechanisms. Photosensitive excitation control
in cardiac tissue applying structured illumination, however, can be used to overcome these
artefacts and to deepen our understanding of rhythm changes before, during and after
arrhythmia termination.
Cardiac differences between the individual laboratory animal models
In cooperation with the University of Veterinary Medicine Hannover, we are conducting a project
on imaging in the optically cleared heart. Here, heart preparations from various laboratory animal
models are made quasi-transparent by means of the so-called optical clearing procedure; only
the blood vessel structures are then visible due to staining. The data obtained using camera
technology is statistically analyzed with regard to the comparative parameters of the different
species and processed in the form of a public database. This can be used to decide on a specific
and the best possible animal model in advance of an experimental study, which, in addition to
experimental improvement, can also have a positive effect on reducing the number of laboratory
animals (3R principle - Refinement & Reduction).
Cardiovascular inflammation
Cardiovascular inflammation
Leukocyte are not only important as first innate defense against pathogens but they also play a fundamental role in the progression of cardiovascular diseases.
Our aim is to characterize the interconnection between leukocyte and endothelial cells in order to modulate inflammatory responses as therapeutic approach in cardiovascular associated pathology such as diabetes. To achieve this goal, we investigate the role of microRNAs and exosomes in different in vivo and in vitro assays.
Active collaboration with:
Priv-Doz Laura Zelarayan - Institute of Pharmacology and Toxicology
Prof Ferdinand Le Noble - Karlsruher Institut für Technologie
Replacement and supplementary methods
Replacement and supplementary methods
The 3R principle
Animal experiments are indispensable in biomedical research, only with the help of experimental animals can complex processes and interactions in the living organism be detected and understood. A large number of scientific findings can be attributed to results from animal experiments. In this respect, animal experiment-based research creates an important basis for biomedical progress in Germany.
All scientists working in animal experiments are aware of the great responsibility they carry for the welfare of the experimental animals. Although animal experiments are essential in research, there is consensus that this should be kept to a necessary minimum. A guideline is the ethical principle of "3R": Replace, Reduce and Refine. The three terms were coined by two British researchers, zoologist William Russell and microbiologist Rex Burch, and published in 1959 in their book "The Principles of Humane Experimental Technique". The principles of action described therein are intended to limit the number of experiments and reduce the suffering of the animals used to an indispensable level. Consistent implementation of the 3R principle in all areas of animal research is the prerequisite for animal experiments to be approved by the responsible statutory authorities.
The following principles are used in the planning and implementation of animal experiments in the sense of 3R:
Replacement, Reduction, Refinement
Replacement:
If possible, animal testing will be replaced by alternative methods. It is always checked whether it is sufficient to answer the scientific question, by using simple organisms such as bacteria or invertebrates or to use cell/tissue cultures, computer models or other substitute methods.
Reduction:
The number of laboratory animals is reduced to a necessary minimum. A clever design of the experiment and statistical and methodical optimizations contribute to this. Suitable animal models are carefully selected based on experience. By centralizing the results from animal experiments and good coordination between scientists, it is prevented that similar experiments are made several times.
Refinement:
The animals must be kept in an appropriate manner, so with enough space and in an environment that promotes their well-being. The constant improvement of examination methods, such as anesthesia, anesthetics and special animal training, reduces stress and suffering as much as possible. Also, a good and sound training of the experimenters leads to an improvement of the experiments and gives benefit to the experimental animals by refining theirs surrounding as well as the procedure they have to undergo. In addition to the established LAS course for non-human primates at the DPZ, in which the Department of experimental animal science is significantly involved, the newly established Skills Lab gives the opportunity to learn and refined a number of interventions and applications first on the model before they are used in the experiment.