AAP

The Research Unit Analytical Pathology (AAP) builds on clinical pathology and expands it by the inclusion and development of the very latest methods for tissue analysis. Analytical Pathology opens up new directions for reverse translational research, molecular imaging pathology, digital pathology, and machine learning and pathology-related omics data.

The Research Unit Analytical Pathology (AAP) carries out scientific development, as a complement to research units with a clinical and fundamental orientation of translational research on diseases that occur in tissue.

About our Research

Our research includes two areas of research activity. One is the process of applying discoveries generated during research in the laboratory, and in preclinical studies, to the development of trials and studies in humans. The second area concerns research aimed at enhancing the adoption of best practices in the community.

Heterogeneous distribution of four metabolites in cancer tissue

Understanding tumor heterogeneity presents one of the most important tasks in cancer research towards improving both diagnosis and treatment of patients. Heterogeneity of tumors contributes to treatment failure and disease recurrence, whereas the interaction between tumor cells and the associated stroma poses novel therapeutic opportunities. Intratumoral heterogeneity refers to the fact that cells within a tumor mass can be highly diverse due to an evolving process in cancer development driven by the stepwise accumulation of molecular changes and clonal selection, while intertumoral heterogeneity describes molecular alterations in several (metastatic) tumors present within or between patients. In malignant cells alteration in molecular features and clonal selection constantly takes place and provides either a selective advantage in function such as proliferation and survival, proceed neutral without any effects, or has negative cell damaging effects. Thereby, the fitness of a neoplastic cell is affected by the interactions with itself and other cells in its microenvironment competing with one another for the available resources. Tumor heterogeneity has mainly been described at a genetic, chromosomal, or transcriptional level. The approaches used to analyze tumor heterogeneity are mostly targeted either focusing on the distribution of a single molecule in tissues such as proteins by using immunohistochemistry, or provide detailed molecular insight in tumor subpopulations by the targeted selection of tumor subpopulations. However, selection of representative tumor areas leads only to an average picture which describes the most dominant clone and therefore underestimates the extent and pattern of clonal heterogeneity. MALDI MSI has demonstrated its suitability to study tumor heterogeneity in its native microenvironment.

In situ metabolite MALDI imaging offers enormous clinical potential by enabling the imaging of a largely previously intractable class of biomolecules. Combined with known metabolic pathways, this approach provides a means to image the activities of the pathways in tissues. The endocrine system is a collection of glands that secrete hormones directly into the circulatory system. The MALDI imaging based endocrinology project fills the heuristic gap to visualize the distributions of hormones, metabolites and drugs within tissues. Recently, tissue metabolomic studies have been initiated on adrenal tissues, which have revealed a refined functional structure beyond classical histological anatomy in human adrenal glands (Sun et al. Endocrinology, 2018 PubMed). Future developments will extend the so far existing clinicopathologic application areas by imaging the activities of pathways in tissues, imaging of hormones (steroids, catecholamines), drugs and their metabolites in the cortex and medulla of the adrenal glands and other endocrine organs of tissue from patients and animal models. The aims of these projects are to advance the understanding of the mechanism of endocrine diseases and to improve diagnosis, prognostic and therapeutic decision making.

How β-cell lose their ability to provide insulin in the progress of type 2 diabetes.

In the field of diabetes research we focus on the morphological and molecular background of the disease in the endocrine pancreas, insulin resistance in peripheral organs and complications which are caused by type 2 diabetes to generate a deeper understanding of the disease which can be used as a new basis for interventional strategies. High-resolution mass spectrometry imaging (MALDI imaging) is used for investigating unsolved questions in diabetes research. The technology makes it possible to examine the distribution of metabolic products (cell metabolites) and many other molecular classes directly in tissue sections without the need of tissue homogenization and thus enables the generation of very high quality and complex data. In the field of diabetes research we focus on the morphological and molecular background of the disease in the endocrine pancreas, insulin resistance in peripheral organs and complications which are caused by type 2 diabetes to generate a deeper understanding of the disease which can be used as a new basis for interventional strategies. High-resolution mass spectrometry imaging (MALDI imaging) is used for investigating unsolved questions in diabetes research.

Prof. Dr. med. Axel Karl Walch

Head

Ulrike Buchholz

MTLA

Claudia-Mareike Pflüger

MTLA

Dipl.-Ing. Andreas Voss

Engineer, Technical Management

Dr. Na Sun

Senior scientist

Sükriye Koccayir

Service Assistant

Qian Wang

PhD student

Chaoyang Zhang

PhD Student

Xu Yin

Dr. med. vet. Monica Tost

Recent Publications

Correction: GIP receptor agonism improves dyslipidemia and atherosclerosis independently of body weight loss in preclinical mouse model for cardio-metabolic disease.

Following publication of the original article [1], the author noticed the errors in Fig. 2 and in Results section. The bar graph is mistakenly duplicated in “percentage of plaque area of the aortic valves” of Fig. 2E. The corrected figure is given below: Acyl-GIP ameliorates dyslipidemia and atherosclerotic plaque formation in LDLR-/- male mice. Plasma (A) triglycerides, (B) cholesterol and (C) lipoprotein fractions as well as (D and E) the percentage of plaque area in aortic arches and valves and along the descending aorta of male LDLR-/- mice treated daily with either vehicle or acyl-GIP via subcutaneous injections for 28 days. n = 7. Blood lipids were determined from sac plasma at the end of the study. Data represent means ± SEM. *P < 0.05, **P < 0.01, *** P < 0.001, determined by unpaired two-sided t-test In Result section under the heading “GIPR-agonist acyl-GIP ameliorates dyslipidemia and atherosclerotic plaque formation in male LDLR-/- mice independently of weight loss”, the last sentence should read “Most importantly, acyl-GIP treatment was accompanied by reduced atherosclerotic plaque formation within the aortic valve and a trend to decrease fat streaks along the descending aorta (Fig. 2E)“ instead of “Most importantly, acyl-GIP treatment was accompanied by reduced atherosclerotic plaque formation within the aortic valve (Fig. 2G–H) and decreased fat streaks along the descending aorta (Fig. 2I)”.

2024 Scientific Article in Scientific Reports

Juhász, B.* ; Horváth, K.* ; Kuti, D.* ; Shen, J. ; Feuchtinger, A. ; Zhang, C.-Y. ; Bata-Vidács, I.* ; ... ; Witting, M. ; Walch, A.K. ; Sun, N. ; Kovács, K.J.*

Dipeptide metabolite, glutamyl-glutamate mediates microbe-host interaction to boost spermatogenesis.

The decrease in sperm count and infertility is a global issue that remains unresolved. By screening environmental bacterial isolates, we have found that a novel lactic acid bacterium, Lactiplantibacillus plantarum SNI3, increased testis size, testosterone levels, sperm count, sexual activity and fertility in mice that have consumed the bacteria for four weeks. The abundance of L. plantarum in the colon microbiome was positively associated with sperm count. Fecal microbiota transplantation (FMT) from L. plantarum SNI3-dosed mice improved testicular functions in microbiome-attenuated recipient animals. To identify mediators that confer pro-reproductive effects on the host, untargeted in situ mass spectrometry metabolomics was performed on testis samples of L. plantarum SNI3-treated and control mice. Enrichment pathway analysis revealed several perturbed metabolic pathways in the testis of treated mice. Within the testis, a dipeptide, glutamyl-glutamate (GluGlu) was the most upregulated metabolite following L. plantarum SNI3 administration. To validate the pro-reproductive feature of GluGlu, systemic and local injections of the dipeptide have been performed. γ-GluGlu increased sperm count but had no effect on testosterone. These findings highlight the role of γ-GluGlu in mediating spermatogenetic effects of L. plantarum on the male mouse host and -following relevant human clinical trials- may provide future tools for treating certain forms of male infertility.

2024 Scientific Article in Metabolism: clinical and experimental

Sun, N. ; Krauss, T.* ; Seeliger, C.* ; Kunzke, T. ; Stöckl, B. ; Feuchtinger, A. ; Zhang, C.-Y. ; Voss, A. ; Heisz, S.* ; ... ; Walch, A.K.

Inter-organ cross-talk in human cancer cachexia revealed by spatial metabolomics.

BACKGROUND: Cancer cachexia (CCx) presents a multifaceted challenge characterized by negative protein and energy balance and systemic inflammatory response activation. While previous CCx studies predominantly focused on mouse models or human body fluids, there's an unmet need to elucidate the molecular inter-organ cross-talk underlying the pathophysiology of human CCx. METHODS: Spatial metabolomics were conducted on liver, skeletal muscle, subcutaneous and visceral adipose tissue, and serum from cachectic and control cancer patients. Organ-wise comparisons were performed using component, pathway enrichment and correlation network analyses. Inter-organ correlations in CCx altered pathways were assessed using Circos. Machine learning on tissues and serum established classifiers as potential diagnostic biomarkers for CCx. RESULTS: Distinct metabolic pathway alteration was detected in CCx, with adipose tissues and liver displaying the most significant (P ≤ 0.05) metabolic disturbances. CCx patients exhibited increased metabolic activity in visceral and subcutaneous adipose tissues and liver, contrasting with decreased activity in muscle and serum compared to control patients. Carbohydrate, lipid, amino acid, and vitamin metabolism emerged as highly interacting pathways across different organ systems in CCx. Muscle tissue showed decreased (P ≤ 0.001) energy charge in CCx patients, while liver and adipose tissues displayed increased energy charge (P ≤ 0.001). We stratified CCx patients by severity and metabolic changes, finding that visceral adipose tissue is most affected, especially in cases of severe cachexia. Morphometric analysis showed smaller (P ≤ 0.05) adipocyte size in visceral adipose tissue, indicating catabolic processes. We developed tissue-based classifiers for cancer cachexia specific to individual organs, facilitating the transfer of patient serum as minimally invasive diagnostic markers of CCx in the constitution of the organs. CONCLUSIONS: These findings support the concept of CCx as a multi-organ syndrome with diverse metabolic alterations, providing insights into the pathophysiology and organ cross-talk of human CCx. This study pioneers spatial metabolomics for CCx, demonstrating the feasibility of distinguishing cachexia status at the organ level using serum.

2024 Scientific Article in npj Precision Oncology

Danko, B. ; Hess J. ; Unger, K. ; Samaga, D. ; Walz, C.* ; Walch, A.K. ; Sun, N. ; Baumeister, P. ; Zeng, P.Y.F.* ; Walter, F. ; Marschner, S. ; Späth, R. ; Gires, O. ; Herkommer, T. ; Dazeh, R. ; Matos, T. ; Kreutzer, L. ; Matschke, J.B.* ; ... ; Pflugradt, U. ; Ganswindt, U. ; Belka, C. ; Zitzelsberger, H. ; Lauber, K. ; Selmansberger, M.

Metabolic pathway-based subtypes associate glycan biosynthesis and treatment response in head and neck cancer.

Head and Neck Squamous Cell Carcinoma (HNSCC) is a heterogeneous malignancy that remains a significant challenge in clinical management due to frequent treatment failures and pronounced therapy resistance. While metabolic dysregulation appears to be a critical factor in this scenario, comprehensive analyses of the metabolic HNSCC landscape and its impact on clinical outcomes are lacking. This study utilized transcriptomic data from four independent clinical cohorts to investigate metabolic heterogeneity in HNSCC and define metabolic pathway-based subtypes (MPS). In HPV-negative HNSCCs, MPS1 and MPS2 were identified, while MPS3 was enriched in HPV-positive cases. MPS classification was associated with clinical outcome post adjuvant radio(chemo)therapy, with MPS1 consistently exhibiting the highest risk of therapeutic failure. MPS1 was uniquely characterized by upregulation of glycan (particularly chondroitin/dermatan sulfate) metabolism genes. Immunohistochemistry and pilot mass spectrometry imaging analyses confirmed this at metabolite level. The histological context and single-cell RNA sequencing data identified the malignant cells as key contributors. Globally, MPS1 was distinguished by a unique transcriptomic landscape associated with increased disease aggressiveness, featuring motifs related to epithelial-mesenchymal transition, immune signaling, cancer stemness, tumor microenvironment assembly, and oncogenic signaling. This translated into a distinct histological appearance marked by extensive extracellular matrix remodeling, abundant spindle-shaped cancer-associated fibroblasts, and intimately intertwined populations of malignant and stromal cells. Proof-of-concept data from orthotopic xenotransplants replicated the MPS phenotypes on the histological and transcriptome levels. In summary, this study introduces a metabolic pathway-based classification of HNSCC, pinpointing glycan metabolism-enriched MPS1 as the most challenging subgroup that necessitates alternative therapeutic strategies.

2024 Review in Heliyon

Yuan, X.Q.* ; Zhou, N.* ; Song, S.J.* ; Xie, Y.X.* ; ... ; Zhang, C.-Y. ; Peng, L.*

Decoding the genomic enigma: Approaches to studying extrachromosomal circular DNA.

Extrachromosomal circular DNA (eccDNA), a pervasive yet enigmatic component of the eukaryotic genome, exists autonomously from its chromosomal counterparts. Ubiquitous in eukaryotes, eccDNA plays a critical role in the orchestration of cellular processes and the etiology of diseases, particularly cancers. However, the full scope of its influence on health and disease remains elusive, presenting a rich vein of research yet to be mined. Unraveling the complexities of eccDNA necessitates a distillation of methodologies — from biogenesis to functional analysis — a landscape we overview in this study with precision and clarity. Here, we systematically outline cutting-edge methodologies from high-throughput sequencing and bioinformatics to experimental validations, showcasing the intricate world of eccDNAs. We combed through a treasure trove of auxiliary research resources and analytical tools. Moreover, we chart a course for future inquiry, illuminating the horizon with potential groundbreaking strategies for designing eccDNA research projects and pioneering new methodological frontiers.

CRC/Transregio 205 „The Adrenal: Central Relay in Health and Disease“

Project S01 “Analytical Platforms”, 2nd funding period

Previous Funding by Deutsche Forschungsgemeinschaft

dfg_logo_schriftzug_blau_foerderung_en — Deutsche Forschungsgemeinschaft Logo mit englischem Untertitel; DFG;

SFB 824 "Imaging for the Selection, Monitoring and Individualization of Cancer Therapy", 3^rd funding period

Project C04: "Molecular and metabolic imaging and targeting of tumor heterogeneity in pancreatic cancer"

SFB 824 "Imaging for the Selection, Monitoring and Individualization of Cancer Therapy"

Central Projekt Z02: "Zentralbereich für Histopathologie, Immunhistochemie und analytische Pathologie"), 2^nd funding period

Major Instrumentation Initiatives: „Improving the Clinical Application Areas of Imaging Mass Spectrometry for Selection, Monitoring and Individualization of Cancer Therapies"

Research grant: „Exploring the potential of MALDI imaging mass spectrometry for personalized biomarker analysis in triple-negative breast cancer patients"

SFB 824 "Imaging for the Selection, Monitoring and Individualization of Cancer Therapy"

Central Projekt Z02: "Zentralbereich für Histopathologie, Immunhistochemie und analytische Pathologie"), 1^st funding period

Previous Funding by Bundesministerium für Bildung und Forschung