Proteomic and transcriptomic profiling of brainstem, cerebellum and olfactory tissues in early- and late-phase COVID-19

Neurological symptoms, including cognitive impairment and fatigue, can occur in both the acute infection phase of coronavirus disease 2019 (COVID-19) and at later stages, yet the mechanisms that contribute to this remain unclear. Here we profiled single-nucleus transcriptomes and proteomes of brainstem tissue from deceased individuals at various stages of COVID-19. We detected an inflammatory type I interferon response in acute COVID-19 cases, which resolves in the late disease phase. Integrating single-nucleus RNA sequencing and spatial transcriptomics, we could localize two patterns of reaction to severe systemic inflammation, one neuronal with a direct focus on cranial nerve nuclei and a separate diffuse pattern affecting the whole brainstem. The latter reflects a bystander effect of the respiratory infection that spreads throughout the vascular unit and alters the transcriptional state of mainly oligodendrocytes, microglia and astrocytes, while alterations of the brainstem nuclei could reflect the connection of the immune system and the central nervous system via, for example, the vagus nerve. Our results indicate that even without persistence of severe acute respiratory syndrome coronavirus 2 in the central nervous system, local immune reactions are prevailing, potentially causing functional disturbances that contribute to neurological complications of COVID-19.

The neurobiology of SARS-CoV-2 infection

Worldwide, over 694 million people have been infected with SARS-CoV-2, with an estimated 55-60% of those infected developing COVID-19. Since the beginning of the pandemic in December 2019, different variants of concern have appeared and continue to occur. With the emergence of different variants, an increasing rate of vaccination and previous infections, the acute neurological symptomatology of COVID-19 changed. Moreover, 10-45% of individuals with a history of SARS-CoV-2 infection experience symptoms even 3 months after disease onset, a condition that has been defined as 'post-COVID-19' by the World Health Organization and that occurs independently of the virus variant. The pathomechanisms of COVID-19-related neurological complaints have become clearer during the past 3 years. To date, there is no overt - that is, truly convincing - evidence for SARS-CoV-2 particles in the brain. In this Review, we put special emphasis on discussing the  methodological difficulties of viral detection in CNS tissue and discuss immune-based (systemic and central) effects contributing to COVID-19-related CNS affection. We sequentially review the reported changes to CNS cells in COVID-19, starting with the blood-brain barrier and blood-cerebrospinal fluid barrier - as systemic factors from the periphery appear to primarily influence barriers and conduits - before we describe changes in brain parenchymal cells, including microglia, astrocytes, neurons and oligodendrocytes as well as cerebral lymphocytes. These findings are critical to understanding CNS affection in acute COVID-19 and post-COVID-19 in order to translate these findings into treatment options, which are still very limited.

Three dimensional computed tomography texture analysis of pulmonary lesions: Does radiomics allow differentiation between carcinoma, neuroendocrine tumor and organizing pneumonia?

PURPOSE

To investigate whether CT texture analysis allows differentiation between adenocarcinomas, squamous cell carcinomas, carcinoids, small cell lung cancers and organizing pneumonia and between carcinomas and neuroendocrine tumors.

METHOD

This retrospective study included patients 133 patients (30 patients with organizing pneumonia, 30 patients with adenocarcinoma, 30 patients with squamous cell carcinoma, 23 patients with small cell lung cancer, 20 patients with carcinoid), who underwent CT-guided biopsy of the lung and had a corresponding histopathologic diagnosis. Pulmonary lesions were segmented in consensus by two radiologists with and without a threshold of -50HU in three dimensions. Groupwise comparisons were performed to assess for differences between all five above-listed entities and between carcinomas and neuroendocrine tumors.

RESULTS

Pairwise comparisons of the five entities revealed 53 statistically significant texture features when using no HU-threshold and 6 statistically significant features with a threshold of -50HU. The largest AUC (0.818 [95%CI 0.706-0.930]) was found for the feature wavelet-HHH_glszm_SmallAreaEmphasis for discrimination of carcinoid from the other entities when using no HU-threshold. In differentiating neuroendocrine tumors from carcinomas, 173 parameters proved statistically significant when using no HU threshold versus 52 parameters when using a -50HU-threshold. The largest AUC (0.810 [95%CI 0.728-0,893]) was found for the parameter original_glcm_Correlation for discrimination of neuroendocrine tumors from carcinomas when using no HU-threshold.

CONCLUSIONS

CT texture analysis revealed features that differed significantly between malignant pulmonary lesions and organizing pneumonia and between carcinomas and neuroendocrine tumors of the lung. Applying a HU-threshold for segmentation substantially influenced the results of texture analysis.

Organ Donation in Croatia: The Importance of a National Champion, a Comprehensive Plan, and International Collaborations

The Republic of Croatia is a global leader in organ donation and transplantation despite having fewer resources and more modest healthcare expenditures than other countries in the European Union. The results of an extensive literature review were combined with expert input in an iterative multi-step data collection and evaluation process designed to assess trends in Croatian organ donation and transplantation and identify key elements, policy changes, and drivers of the system that have contributed to its success. Multiple sources of evidence were used in this study, including primary documents, national and international transplantation reports, and insights from critical informants and content experts. The results highlight several key organizational reforms that have substantially improved the performance of the Croatian transplant program. Our findings emphasize the importance of strong central governance led by an empowered national clinical leader acting under the direct auspices of the Ministry of Health and a comprehensive and progressive national plan. The Croatian transplant system is notable for its integrated approach and efficient manner of managing scarce health resources. Collectively, the results suggest that Croatia has become nearly self-sufficient due to its systematic implementation of the guiding principles for organ donation and transplantation.

A Conceptual Framework for Evaluating National Organ Donation and Transplantation Programs

Conceptual frameworks are valuable resources that can be used to guide the planning, evaluation, and development of healthcare services. However, there are currently no comprehensive frameworks focused on organ donation and transplantation that identify the critical factors underlying a successful national program. To address this knowledge gap, we developed a conceptual framework that takes into account all major domains of influence, including political and societal aspects as well as clinical implementation. The framework was initially constructed based on a targeted review of the relevant medical literature. Feedback provided by a panel of international experts was incorporated into the framework via an iterative process. The final framework features 16 essential domains that are critical for initiating and maintaining a successful program and improving the health of patients with organ failure. Of particular note, these domains are subject to three overarching health system principles: responsiveness, efficiency, and equity. This framework represents a first attempt to develop a whole-system view of the various factors that contribute to the success of a national program. These findings provide a useful tool that can be adapted to any jurisdiction and used to plan, evaluate, and improve organ donation and transplantation programs.

Lessons From the Portuguese Solid Organ Donation and Transplantation System: Achieving Success Despite Challenging Conditions

Over the past two decades, Portugal has become one of the world leaders in organ donation and transplantation despite significant financial constraints. This study highlights how Portugal achieved success in organ donation and transplantation and discusses how this information might be used by other countries that are seeking to reform their national programs. To accomplish this goal, we performed a narrative review of relevant academic and grey literature and revised our results after consultation with two national experts. Our findings were then synthesized according to a conceptual framework for organ donation and transplantation programs. Our results revealed several key strategies used by the Portuguese organ donation and transplantation program, including collaboration with Spain and other European nations, a focus on tertiary prevention, and sustained financial commitment. This report also explores how cooperative efforts were facilitated by geographical, governmental, and cultural proximity to Spain, a world leader in organ donation and transplantation. In conclusion, our review of the Portuguese experience provides insight into the development of organ donation and transplantation systems. However, other countries seeking to reform their national transplant systems will need to adapt these policies and practices to align with their unique cultures and contexts.

Solid Organ Donation and Transplantation in the United Kingdom: Good Governance is Key to Success

The United Kingdom (UK) supports a highly successful organ donation and transplantation program. While the UK originally had one of the lowest organ donation rates in Europe, sustained reforms have resulted in steady improvement. Of note, the UK nearly doubled its rate of deceased donations between 2008 and 2018. In this report, we present a case study of the UK organ donation and transplantation program as an example of a complete system with sound and inclusive governing structures that are strongly integrated with critical programs focused on training and research. This study was based on an initial targeted review of the literature led by a UK expert that included guidelines, national reports, and academic papers. Feedback solicited from other European experts was incorporated into our findings via an iterative process. Overall, the study highlights the stepwise evolution of the UK program that ultimately became successful largely due to ongoing collaborative efforts carried out at all levels. Centralized coordination of all aspects of the program remains a key driver of improved rates of organ donation and transplantation. The designation and empowerment of expert clinical leadership have helped to maintain focus and promote ongoing quality improvement.

How to Structure a Successful Organ Donation and Transplantation System in Eight (Not So Easy) Steps: An Italian Case Study

Valuable information can be obtained from a systematic evaluation of a successful national transplant program. This paper provides an overview of Italy's solid organ transplantation program which is coordinated by the National Transplant Network (Rete Nazionale Trapianti) and The National Transplant Center (Centro Nazionale Trapianti). The analysis is based on a system-level conceptual framework and identifies components of the Italian system that have contributed to improving rates of organ donation and transplantation. A narrative literature review was conducted and the findings were validated iteratively with input from subject matter experts. The results were organized into eight critical steps, including 1) generating legal definitions of living and deceased donation, 2) taking steps to ensure that altruistic donation and transplantation become part of the national culture and a point of pride, 3) seeking out existing examples of successful programs, 4) creating a situation in which it is easy to become a donor, 5) learning from mistakes, 6) working to diminish risk factors that lead to the need for organ donation, 7) increasing the rate of donations and transplantations via innovative strategies and policies, and 8) planning for a system that supports growth.

The National Organ Donation and Transplantation Program in Greece: Gap Analysis and Recommendations for Change

Greece has fallen far behind many comparable European countries in the field of organ donation and transplantation and has made little progress over the past decade. Despite efforts to improve its organ donation and transplantation program, systemic problems persist. In 2019, the Onassis Foundation commissioned a report to be prepared by the London School of Economics and Political Science that focused on the state of the Greek organ donation and transplantation program and proposed recommendations for its improvement. In this paper, we present our analysis of the Greek organ donation and transplantation program together with an overview of our specific recommendations. The analysis of the Greek program was undertaken in an iterative manner using a conceptual framework of best practices developed specifically for this project. Our findings were further developed via an iterative process with information provided by key Greek stakeholders and comparisons with case studies that featured successful donation and transplantation programs in Croatia, Italy, Portugal, Spain, and the United Kingdom. Because of their overall complexity, we used a systems-level approach to generate comprehensive and far-reaching recommendations to address the difficulties currently experienced by the Greek organ donation and transplantation program.

Ten Lessons From the Spanish Model of Organ Donation and Transplantation

The organ donation and transplantation program in Spain has long been considered the gold standard worldwide. An in-depth understanding of the Spanish program may promote the development and reform of transplant programs in other countries. Here, we present a narrative literature review of the Spanish organ donation and transplantation program supplemented by expert feedback and presented according to a conceptual framework of best practices in the field. Core features of the Spanish program include its three-tiered governing structure, close and collaborative relationships with the media, dedicated professional roles, a comprehensive reimbursement strategy, and intensive tailored training programs for all personnel. Several more sophisticated measures have also been implemented, including those focused on advanced donation after circulatory death (DCD) and expanded criteria for organ donation. The overall program is driven by a culture of research, innovation, and continuous commitment and complemented by successful strategies in prevention of end-stage liver and renal disease. Countries seeking ways to reform their current transplant systems might adopt core features and may ultimately aspire to include the aforementioned sophisticated measures. Countries intent on reforming their transplant system should also introduce programs that support living donation, an area of the Spanish program with potential for further improvement.

The brain reacting to COVID-19: analysis of the cerebrospinal fluid proteome, RNA and inflammation

Patients with COVID-19 can have a variety of neurological symptoms, but the active involvement of central nervous system (CNS) in COVID-19 remains unclear. While routine cerebrospinal fluid (CSF) analyses in patients with neurological manifestations of COVID-19 generally show no or only mild inflammation, more detailed data on inflammatory mediators in the CSF of patients with COVID-19 are scarce. We studied the inflammatory response in paired CSF and serum samples of patients with COVID-19 (n = 38). Patients with herpes simplex virus encephalitis (HSVE, n = 10) and patients with non-inflammatory, non-neurodegenerative neurological diseases (n = 28) served as controls. We used proteomics, enzyme-linked immunoassays, and semiquantitative cytokine arrays to characterize inflammatory proteins. Autoantibody screening was performed with cell-based assays and native tissue staining. RNA sequencing of long-non-coding RNA and circular RNA was done to study the transcriptome. Proteomics on single protein level and subsequent pathway analysis showed similar yet strongly attenuated inflammatory changes in the CSF of COVID-19 patients compared to HSVE patients with, e.g., downregulation of the apolipoproteins and extracellular matrix proteins. Protein upregulation of the complement system, the serpin proteins pathways, and other proteins including glycoproteins alpha-2 and alpha-1 acid. Importantly, calculation of interleukin-6, interleukin-16, and CXCL10 CSF/serum indices suggest that these inflammatory mediators reach the CSF from the systemic circulation, rather than being produced within the CNS. Antibody screening revealed no pathological levels of known neuronal autoantibodies. When stratifying COVID-19 patients into those with and without bacterial superinfection as indicated by elevated procalcitonin levels, inflammatory markers were significantly (p < 0.01) higher in those with bacterial superinfection. RNA sequencing in the CSF revealed 101 linear RNAs comprising messenger RNAs, and two circRNAs being significantly differentially expressed in COVID-19 than in non-neuroinflammatory controls and neurodegenerative patients. Our findings may explain the absence of signs of intrathecal inflammation upon routine CSF testing despite the presence of SARS-CoV2 infection-associated neurological symptoms. The relevance of blood-derived mediators of inflammation in the CSF for neurological COVID-19 and post-COVID-19 symptoms deserves further investigation.

Hypertrophic Pachymeningitis with Persistent Intrathecal Inflammation Secondary to Neurosarcoidosis Treated with Intraventricular Chemotherapy: A Case Report

Hypertrophic pachymeningitis (HP) is a rare immune-mediated disease characterized by thickening of the dura mater with consecutive cranial neuropathy. While HP is usually treated with systemic immunotherapies, response to therapy is variable and may be limited by insufficient drug concentrations in the brain. We report on a 57-year-old patient with HP manifesting with vision and hearing loss who had sustained clinical progression despite various systemic immunotherapies. Intraventricular chemotherapy with methotrexate, cytarabine, and dexamethasone was initiated. We present clinical, imaging and cerebrospinal fluid (CSF) findings, including cytokine levels before and after intraventricular treatment: rapid decrease of cell count, lactate and profibrotic cytokine levels in the CSF following intraventricular chemotherapy was paralleled by a mild reduction of dura thickness in MRI. The already severely impaired visual acuity and hearing loss did not progress further. Treatment was complicated by exacerbation of previously subtle psychiatric symptoms. Follow-up was terminated after 6 months as the patient suffered from a fatal ischemic stroke. Autopsy revealed neurosarcoidosis as the underlying cause of HP. This case report suggests that intrathecal chemotherapy can reduce the inflammatory milieu in the CNS and should be considered for treatment-refractory HP before irreversible damage of cranial nerves has occurred.

Intracranial hemorrhage in COVID-19 patients during extracorporeal membrane oxygenation for acute respiratory failure: a nationwide register study report

Background

In severe cases, SARS-CoV-2 infection leads to acute respiratory distress syndrome (ARDS), often treated by extracorporeal membrane oxygenation (ECMO). During ECMO therapy, anticoagulation is crucial to prevent device-associated thrombosis and device failure, however, it is associated with bleeding complications. In COVID-19, additional pathologies, such as endotheliitis, may further increase the risk of bleeding complications. To assess the frequency of bleeding events, we analyzed data from the German COVID-19 autopsy registry (DeRegCOVID).

Methods

The electronic registry uses a web-based electronic case report form. In November 2021, the registry included N = 1129 confirmed COVID-19 autopsy cases, with data on 63 ECMO autopsy cases and 1066 non-ECMO autopsy cases, contributed from 29 German sites.

Findings

The registry data showed that ECMO was used in younger male patients and bleeding events occurred much more frequently in ECMO cases compared to non-ECMO cases (56% and 9%, respectively). Similarly, intracranial bleeding (ICB) was documented in 21% of ECMO cases and 3% of non-ECMO cases and was classified as the immediate or underlying cause of death in 78% of ECMO cases and 37% of non-ECMO cases. In ECMO cases, the three most common immediate causes of death were multi-organ failure, ARDS and ICB, and in non-ECMO cases ARDS, multi-organ failure and pulmonary bacterial ± fungal superinfection, ordered by descending frequency.

Interpretation

Our study suggests the potential value of autopsies and a joint interdisciplinary multicenter (national) approach in addressing fatal complications in COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03945-x.

Effect of transcutaneous electrical nerve stimulation (TENS) on knee pain and physical function in patients with symptomatic knee osteoarthritis: the ETRELKA randomized clinical trial

OBJECTIVE

To determine the effectiveness of TENS at relieving pain and improving physical function as compared to placebo TENS, and to determine its safety, in patients with knee osteoarthritis.

METHODS

Multi-centre, parallel, 1:1 randomized, double-blind, placebo-controlled clinical trial conducted in six outpatient clinics in Switzerland. We included 220 participants with knee osteoarthritis recruited between October 15, 2012, and October 15, 2014. Patients were randomized to 3 weeks of treatment with TENS (n = 108) or placebo TENS (n = 112). Our pre-specified primary endpoint was knee pain at the end of 3-weeks treatment assessed with the WOMAC pain subscale. Secondary outcome measures included WOMAC physical function subscale and safety outcomes.

RESULTS

There was no difference between TENS and placebo TENS in WOMAC pain at the end of treatment (mean difference -0.06; 95%CI -0.41 to 0.29; P = 0.74), nor throughout the trial duration (P = 0.98). Subgroup analyses did not indicate an interaction between patient/treatment characteristics and treatment effect on WOMAC pain at the end of treatment (P-interaction ≥0.22). The occurrence of adverse events was similar across groups, with 10.4% and 10.6% of patients reporting events in the TENS and placebo TENS groups, respectively (P = 0.95). No relevant differences were observed in secondary outcomes.

CONCLUSIONS

TENS does not improve knee osteoarthritis pain when compared to placebo TENS. Therapists should consider other potentially more effective treatment modalities to decrease knee osteoarthritis pain and facilitate strengthening and aerobic exercise. Our findings are conclusive and further trials comparing TENS and placebo TENS in this patient population are not necessary.

First report from the German COVID-19 autopsy registry

Background

Autopsies are an important tool in medicine, dissecting disease pathophysiology and causes of death. In COVID-19, autopsies revealed e.g., the effects on pulmonary (micro)vasculature or the nervous system, systemic viral spread, or the interplay with the immune system. To facilitate multicentre autopsy-based studies and provide a central hub supporting autopsy centres, researchers, and data analyses and reporting, in April 2020 the German COVID-19 Autopsy Registry (DeRegCOVID) was launched.

Methods

The electronic registry uses a web-based electronic case report form. Participation is voluntary and biomaterial remains at the respective site (decentralized biobanking). As of October 2021, the registry included N=1129 autopsy cases, with 69271 single data points including information on 18674 available biospecimens gathered from 29 German sites.

Findings

In the N=1095 eligible records, the male-to-female ratio was 1·8:1, with peaks at 65-69 and 80-84 years in males and >85 years in females. The analysis of the chain of events directly leading to death revealed COVID-19 as the underlying cause of death in 86% of the autopsy cases, whereas in 14% COVID-19 was a concomitant disease. The most common immediate cause of death was diffuse alveolar damage, followed by multi-organ failure. The registry supports several scientific projects, public outreach and provides reports to the federal health authorities, leading to legislative adaptation of the German Infection Protection Act, facilitating the performance of autopsies during pandemics.

Interpretation

A national autopsy registry can provide multicentre quantitative information on COVID-19 deaths on a national level, supporting medical research, political decision-making and public discussion.

Funding

German Federal Ministries of Education and Research and Health.

Hintergrund: Obduktionen sind ein wichtiges Instrument in der Medizin, um die Pathophysiologie von Krankheiten und Todesursachen zu untersuchen. Im Rahmen von COVID-19 wurden durch Obduktionen z.B. die Auswirkungen auf die pulmonale Mikrovaskulatur, das Nervensystem, die systemische Virusausbreitung, und das Zusammenspiel mit dem Immunsystem untersucht. Um multizentrische, auf Obduktionen basierende Studien zu erleichtern und eine zentrale Anlaufstelle zu schaffen, die Obduktionszentren, Forscher sowie Datenanalysen und -berichte unterstützt, wurde im April 2020 das deutsche COVID-19-Autopsieregister (DeRegCOVID) ins Leben gerufen.

Methoden: Das elektronische Register verwendet ein webbasiertes elektronisches Fallberichtsformular. Die Teilnahme ist freiwillig und das Biomaterial verbleibt am jeweiligen Standort (dezentrales Biobanking). Im Oktober 2021 umfasste das Register N=1129 Obduktionsfälle mit 69271 einzelnen Datenpunkten, die Informationen über 18674 verfügbare Bioproben enthielten, die von 29 deutschen Standorten gesammelt wurden.

Ergebnisse: In den N=1095 ausgewerteten Datensätzen betrug das Verhältnis von Männern zu Frauen 1,8:1 mit Spitzenwerten bei 65-69 und 80-84 Jahren bei Männern und >85 Jahren bei Frauen. Die Analyse der Sequenz der unmittelbar zum Tod führenden Ereignisse ergab, dass in 86 % der Obduktionsfälle COVID-19 die zugrunde liegende Todesursache war, während in 14 % der Fälle COVID-19 eine Begleiterkrankung war. Die häufigste unmittelbare Todesursache war der diffuse Alveolarschaden, gefolgt von Multiorganversagen. Das Register unterstützt mehrere wissenschaftliche Projekte, die Öffentlichkeitsarbeit und liefert Berichte an die Bundesgesundheitsbehörden, was zu einer Anpassung des deutschen Infektionsschutzgesetzes führte und die Durchführung von Obduktionen in Pandemien erleichtert.

Interpretation: Ein nationales Obduktionsregister kann multizentrische quantitative Informationen über COVID-19-Todesfälle auf nationaler Ebene liefern und damit die medizinische Forschung, die politische Entscheidungsfindung und die öffentliche Diskussion unterstützen.

Finanzierung: Bundesministerien für Bildung und Forschung und für Gesundheit.

[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

Impact of the COVID-19 pandemic on the intensity of health services use in general practice

Background

The COVID-19 pandemic affects non-COVID-19-related health services use due to shutdown measures and fears of potential coronavirus infection or fears of overwhelmed health systems. We aimed to explore the impact of the shutdown in spring 2020 on the intensity of health services use (consultation counts, chronic disease measurement counts) in Swiss general practice.

Methods

Based on electronic medical records from 278 general practitioners in Switzerland, we built two patient cohorts: (1) Jan-Jun 2019 (173,523 patients); (2) Jan-Jun 2020 (179,086 patients). We used linear regression analysis to model weekly consultation counts, as well as weekly blood pressure (BP) and glycated hemoglobin (HbA1c) measurement counts, per 100 patients. We calculated expected values in absence of a shutdown and compared them to actual observed values in 2020. The analyses were repeated for selected at-risk groups (patients with hypertension, diabetes, or cardiovascular disease) and different age groups (&lt;60 years, 60-80 years, and &gt;80 years).

Results

During the shutdown period (calendar weeks 13-19 in 2020), weekly consultation counts were lower than non-shutdown models predicted. Consultation rates reduced by 17.2% for the total population, 16.5% for patients with hypertension, 17.5% for patients with diabetes, and 17.6% for patients with cardiovascular disease. Between different age groups, consultation counts reduced by 15.7% for patients aged &lt;60 years, 20.4% for patients aged 60-80 years, and 14.5% for patients aged &gt;80 years. Weekly BP counts reduced by 35.3% in the total population and by 35.0% for patients with hypertension. Weekly HbA1c counts reduced by 33.2% in the total population and by 29.8% for patients with diabetes. P-values were &lt;0.001 for all reported estimates.

Conclusions

We found a significant decrease in the intensity of health services use in Swiss general practice during the shutdown in spring 2020.

Key messages

We demonstrate that the intensity of health services use in general practice decreased during the first Swiss shutdown in spring 2020, overall and among patients with chronic conditions. It is crucial that health systems remain able to meet the non-COVID-19-related health care needs of patients during shutdowns, especially for patients with chronic conditions who require regular care.

Continuity of care during the COVID-19 pandemic: Qualitative results from a mixed-methods study

Background

Decreases in health service use were observed globally during the COVID-19 pandemic. In the quantitative part of this mixed-methods study, we documented similar trends in Switzerland, with a retrospective cohort study showing a 15-20% decrease in general practitioner (GP) consultations/chronic disease monitoring in spring 2020. These changes need to be understood, particularly for individuals at risk of COVID-19 complications, as many have conditions requiring regular monitoring.

Methods

With a mixed-methods design, we examine continuity of care for at-risk groups (people: ≥65-years-old, with cancer, diabetes, respiratory disease, etc.) between Mar-2020 and Apr-2021. Following quantitative analyses, we qualitatively studied changes in GP/patient practices thru semi-structured interviews with 23 GPs and 36 at-risk patients. We here focus on thematically analyzed qualitative results.

Results

Qualitative data helped explain observed reductions in consultations/monitoring: 1) some patients were discouraged to seek care by official recommendations and/or GPs during the first semi-shutdown; 2) some patients perceived GP offices as closed/overburdened; 3) some patients feared contracting coronavirus; 4) some patients sought alternatives to traditional primary care consultations (e.g., tele-consultations, consulting pharmacists/other professionals, self-reliance). Many patients did not feel that there was discontinuity of their cares. GPs commonly described feeling like an underutilized resource during the pandemic and explained how they could have been mobilized for population needs.

Conclusions

During the first wave, there was a mismatch between 1) GPs' reported availability/preparedness to adequately care for at-risk patients, and 2) some GPs discouraging at-risk patients to come for consultations, at-risk patients' perceptions that their care was not “urgent” in a pandemic setting, and patient perceptions that GPs were otherwise unavailable/overburdened.

Key messages

Qualitative data offer explanations for health service use reductions during the COVID-19 pandemic.

Results provide potential paths forward and highlight GP views of being an underutilized resource.

Association Between SARS-CoV-2 Infection and Immune-Mediated Myopathy in Patients Who Have Died

Importance

Myalgia, increased levels of creatine kinase, and persistent muscle weakness have been reported in patients with COVID-19.

Objective

To study skeletal muscle and myocardial inflammation in patients with COVID-19 who had died.

Design, Setting, and Participants

This case-control autopsy series was conducted in a university hospital as a multidisciplinary postmortem investigation. Patients with COVID-19 or other critical illnesses who had died between March 2020 and February 2021 and on whom an autopsy was performed were included. Individuals for whom informed consent to autopsy was available and the postmortem interval was less than 6 days were randomly selected. Individuals who were infected with SARS-CoV-2 per polymerase chain reaction test results and had clinical features suggestive of COVID-19 were compared with individuals with negative SARS-CoV-2 polymerase chain reaction test results and an absence of clinical features suggestive of COVID-19.

Main Outcomes and Measures

Inflammation of skeletal muscle tissue was assessed by quantification of immune cell infiltrates, expression of major histocompatibility complex (MHC) class I and class II antigens on the sarcolemma, and a blinded evaluation on a visual analog scale ranging from absence of pathology to the most pronounced pathology. Inflammation of cardiac muscles was assessed by quantification of immune cell infiltrates.

Results

Forty-three patients with COVID-19 (median [interquartile range] age, 72 [16] years; 31 men [72%]) and 11 patients with diseases other than COVID-19 (median [interquartile range] age, 71 [5] years; 7 men [64%]) were included. Skeletal muscle samples from the patients who died with COVID-19 showed a higher overall pathology score (mean [SD], 3.4 [1.8] vs 1.5 [1.0]; 95% CI, 0-3; P < .001) and a higher inflammation score (mean [SD], 3.5 [2.1] vs 1.0 [0.6]; 95% CI, 0-4; P < .001). Relevant expression of MHC class I antigens on the sarcolemma was present in 23 of 42 specimens from patients with COVID-19 (55%) and upregulation of MHC class II antigens in 7 of 42 specimens from patients with COVID-19 (17%), but neither were found in any of the controls. Increased numbers of natural killer cells (median [interquartile range], 8 [8] vs 3 [4] cells per 10 high-power fields; 95% CI, 1-10 cells per 10 high-power fields; P < .001) were found. Skeletal muscles showed more inflammatory features than cardiac muscles, and inflammation was most pronounced in patients with COVID-19 with chronic courses. In some muscle specimens, SARS-CoV-2 RNA was detected by reverse transcription-polymerase chain reaction, but no evidence for a direct viral infection of myofibers was found by immunohistochemistry and electron microscopy.

Conclusions and Relevance

In this case-control study of patients who had died with and without COVID-19, most individuals with severe COVID-19 showed signs of myositis ranging from mild to severe. Inflammation of skeletal muscles was associated with the duration of illness and was more pronounced than cardiac inflammation. Detection of viral load was low or negative in most skeletal and cardiac muscles and probably attributable to circulating viral RNA rather than genuine infection of myocytes. This suggests that SARS-CoV-2 may be associated with a postinfectious, immune-mediated myopathy.

COVID-19: Autopsy findings in six patients between 26 and 46 years of age

Objectives

Studies on coronavirus disease 2019 (COVID-19) usually focus on middle-aged and older adults. However, younger patients may present with severe COVID-19 with potentially fatal outcomes. For optimized, more specialized therapeutic regimens in this particular patient group, a better understanding of the underlying pathomechanisms is of utmost importance.

Methods

Our study investigated relevant, pre-existing medical conditions, clinical histories, and autopsy findings, together with SARS-CoV-2-RNA, determined by qPCR, and laboratory data in six COVID-19 decedents aged 50 years or younger, who were autopsied at the Charité University Hospital.

Results

From a total of 76 COVID-19 patients who underwent an autopsy at our institution, six (7.9%) were 50 years old or younger. Most of these younger COVID-19 decedents presented with pre-existing medical conditions prior to SARS-CoV-2 infection. These included overweight and obesity, arterial hypertension, asthma, and obstructive sleep apnea, as well as graft-versus-host disease following cancer and bone marrow transplantation. Furthermore, clinical histories and autopsy results revealed a disproportionally high prevalence of thromboembolism and ischemic organ damage in this patient cohort. Histopathology and laboratory results indicated coagulopathies, signs of immune dysregulation, and liver damage.

Conclusions

In conclusion, pre-existing health conditions may increase the risk of severe and fatal COVID-19 in younger patients, who may be especially prone to developing thromboembolic complications, immune dysregulation, and liver damage.

Life course socioeconomic conditions, multimorbidity and polypharmacy in older adults

Many older adults have multiple chronic conditions (multimorbidity). With multimorbidity often comes the concurrent intake of multiple medications (polypharmacy). Our aims were to assess if childhood socioeconomic conditions (CSC) are associated with multimorbidity and polypharmacy in older adults, and how these associations change when adjusting for adulthood socioeconomic conditions (ASC).

We used data from the European longitudinal Survey of Health, Ageing, and Retirement (SHARE), which follows individuals aged 50 years and over in 27 countries since 2004. We analysed data from 35,229 individuals with multimorbidity (mean age: women=64.1, men=65.4) and 20,757 individuals with polypharmacy (mean age: women=69.2, men=70.2). Multimorbidity was defined as 2 or more self-reported chronic conditions and polypharmacy as the intake of 5 or more medications. Confounder-adjusted multilevel logistic regression models were used to analyse associations of CSC (5 categories: most disadvantaged-most advantaged) and ASC with multimorbidity and polypharmacy. All analyses were adjusted for country, age, weight, alcohol consumption, smoking status and physical exercise. In addition, we adjusted the polypharmacy model with the number of chronic conditions, mental health, activities of daily living and living situation. We stratified the analyses by sex.

34% of women had multimorbidity and 26% received polypharmacy. In men, these percentages were 34% and 28%. All categories of CSC (except for disadvantaged CSC in men) were associated with multimorbidity. In both sexes, a higher advantage was associated with lower odds of multimorbidity. In women, advantaged and most advantaged CSC were associated with lower odds of polypharmacy (OR = 0.53, 95% CI 0.31-0.89; OR = 0.48, 95% CI 0.24-0.94). In men, CSC were not associated with polypharmacy. ASC attenuated the association of CSC with multimorbidity among women, but CSC remained associated. In men, CSC were attenuated after adjusting for ASC.

Key messages

Lower childhood socioeconomic conditions increase the odds of having multiple chronic conditions in older adults. In women, the odds of polypharmacy are marginally linked with CSC. Less disadvantaged socioeconomic conditions in adulthood may allow for compensating a more disadvantaged start in life, particularly in men.

Are general practitioners willing to deprescribe in oldest-old patients with polypharmacy?

Key messages

Despite international differences, most GPs report they would deprescribe in older multimorbid patients with polypharmacy. The results will facilitate the development of interventions supporting general practitioners to deprescribe.

[Ultrasonographic findings for selected gastrointestinal tract diseases]

OBJECTIVE

In addition to general and specific examinations, ultrasonographic and endoscopic examinations of the gastrointestinal tract may be necessary. This study aimed to determine possible relationships between the ultrasonographic and histopathological findings in the following diseases of the gastrointestinal tract: IBD (inflammatory bowel disease), FRD (food-responsive diarrhoea), ulcer and infection with GHLO (gastric Helicobacter-like organisms).

MATERIAL AND METHODS

The data of 41 dogs and 19 cats were analysed. The inclusion criterion was the presence of acute or chronic gastrointestinal symptoms in patients that had also undergone the standard diagnostic tests to rule out extragastrointestinal diseases. The patients underwent ultrasonographic and endoscopic examinations of the gastrointestinal tract, and a histopathological examination of the tissue samples from the endoscopy was performed. Patients with intestinal foreign bodies, neoplasms of the gastrointestinal tract or inconclu- sive histopathological results were excluded.

RESULTS

In a total of 41 dogs, 16 were diagnosed with IBD, 14 with FRD, 5 with ulceration and six with an infection with GHLO. Of the 19 cats, 12 had a diagnosis of IBD, 2 of FRD, 2 with ulceration and 3 with an infection with GHLO. In 26 dogs and 4 cats of the evaluated patients, the ultrasonographic examination did not show pathological changes, even though the patients had clinical symptoms and significant histopathological findings. However, in 14 dogs and 4 cats of the included patients, one or more pathological changes of the extragastrointestinal organs were found. In particular, cats with a diagnosis of IBD often presented lymphadenopathies (4 cats) or thickening of the zona muscularis (six cats). There were no specific ultrasonographic findings confirming an FRD or an infection with GHLO. Only 5 dogs and 1 cat without a primary diagnosis of infection with GHLO were positive for colonization with GHLO. The presence of ulcers was ultrasonographically indicated as areas showing a loss of wall layering with accumulation of gas.

CONCLUSION AND CLINICAL RELEVANCE

Changes can be found during ultrasonographic examinations of patients with IBD and ulcer. However, the absence of findings in ultrasonographic examinations does not necessarily rule out serious gastrointestinal diseases. The histopathological examination still plays an important part in diagnosing the evaluated diseases.

[Automatic feeding systems for horses in group housing systems with regard to animal welfare. Part 2: Comparison of different automatic feeding systems]

OBJECTIVE

Comparison with regard to animal welfare of different automatic feeding systems for hay and concentrate in group housing systems for horses using parameters of ethology and physiology.

MATERIAL AND METHODS

Parameters of research comprised: duration of stay, frequency of visit, threatening behaviour with and without risk of injury, and avoiding behaviour as well as heart rate and injuries of the integument. 452 horses were observed at the feeding area of 32 run-out-sheds. Every group of horses was continuously observed following the pie chart system for 24 hours.

RESULTS

The "walk-through" station significantly reduced the number of conflicts in the feeding area, whereas those systems which are appropriate for the feeding horses (feeding station with access barrier and without stimulation device by electric shock) led to a higher frequency of visits and a longer duration of stay resulting in more threatening gestures. However, the number of negative interactions in the feeding area of the feeding systems can all together be classified as relatively insignificant. The heart rate was within the physiological range (45.1 ± 12.42 beats/min) in the waiting area, but increased by approximately 20 beats/min on average within the feeding station. Some horses showed a very high heart rate (≥ 100 beats/min) while entering the feeding station, possibly stress-related. There were no injuries of the integument associated with the feeding systems. The most important factor of the observation criteria was the individual group housing system with its different dimensions, conception and management.

CONCLUSION

"Walk-through" stations are better than "walk-back" stations with regard to animal welfare. Likewise, automatic feeding stations with a current-carrying stimulation device are not supportive of good welfare. The other differences between the constructions of feeding stations of present systems are probably of less importance, particularly as it was shown that the stable (management, stable area, conception) had a significant influence on the surveyed parameters. Investigations to obtain information on the cause for the sporadic occurrence of very high heart rate values should be undertaken.

Tiergerechtheit von Futterabrufstationen in der Gruppenhaltung von Pferden

Ziel: Uberprufung der Tiergerechtheit von in der Bauweise unterschiedlichen Futterabrufstationen fur Pferde in Gruppenhaltung anhand ethologischer und physiologischer Parameter. Material und Methoden: In 32 Offenlaufstallen (452 Pferde) mit computergesteuerten Abrufstationen fur Kraftfutter und Heu erfolgten kontinuierliche Direktbeobachtungen fur je einen 24-Stunden-Tag (Tortenstuckverfahren). Erfasst wurden: Aufenthaltsdauer, Besuchshaufigkeit, Droh- und Meideverhalten im Futterungsbereich, Blockaden sowie Herzfrequenz und Integumentverletzungen. Ergebnisse: Eine Durchlaufstation reduzierte die Zahl der Auseinandersetzungen im Futterungsbereich signifikant. Ansonsten erhohten die fur das fressende Pferd tiergerechten Varianten (Fressstand mit Eingangssperre, ohne Austreibehilfe) Besuchshaufigkeit und Aufenthaltsdauer und steigerten somit auch die Anzahl an Drohgesten je Tier und Tag. Insgesamt betrachtet kann jedoch die Anzahl an sozionegativen Interaktionen im Futterungsbereich der Abrufstationen als relativ gering eingestuft werden. Die Herzfrequenz lag im Warteareal bei den meisten Pferden im physiologischen Bereich (45,1 ± 12,42 Schlage/min), erhohte sich jedoch in der Abrufstation um ca. 20 Schlage/min. Einige Tiere zeigten moglicherweise stressbedingt kurzfristig auffallend hohe Werte (≥ 100 Schlage/ min). Integumentverletzungen im Zusammenhang mit dem Futterungssystem traten nicht auf. Der wichtigste Einflussfaktor auf die Untersuchungskriterien war der Betrieb (Flache, Konzeption, Management). Schlussfolgerung: Durchlaufstationen sind pferdegerechter als Rucklaufstationen. Nicht tiergerecht sind Stationen mit stromfuhrender Austreibehilfe. Weitere bauliche Unterschiede der derzeitigen Futterabrufstationen durften eher von untergeordneter Bedeutung sein, vor allem da Flachengebot und Konzeption der Offenstallanlage sowie das Management die uberpruften Kriterien zur Tiergerechtheit masgeblich beeinflussen. Untersuchungen zur Abklarung der Ursache fur die vereinzelt aufgetretenen sehr hohen Herzfrequenzwerte sollten durchgefuhrt werden.

AZGP1 is a tumor suppressor in pancreatic cancer inducing mesenchymal-to-epithelial transdifferentiation by inhibiting TGF-β-mediated ERK signaling

Epithelial-to-mesenchymal transdifferentiation (EMT) mediated by transforming growth factor-β (TGF-β) signaling leads to aggressive cancer progression. In this study, we identified zinc-α2-glycoprotein (AZGP1, ZAG) as a tumor suppressor in pancreatic ductal adenocarcinoma whose expression is lost due to histone deacetylation. In vitro, ZAG silencing strikingly increased invasiveness of pancreatic cancer cells accompanied by the induction of a mesenchymal phenotype. Expression analysis of a set of EMT markers showed an increase in the expression of mesenchymal markers (vimentin (VIM) and integrin-α5) and a concomitant reduction in the expression of epithelial markers (cadherin 1 (CDH1), desmoplakin and keratin-19). Blockade of endogenous TGF-β signaling inhibited these morphological changes and the downregulation of CDH1, as elicited by ZAG silencing. In a ZAG-negative cell line, human recombinant ZAG (rZAG) specifically inhibited exogenous TGF-β-mediated tumor cell invasion and VIM expression. Furthermore, rZAG blocked TGF-β-mediated ERK2 phosphorylation. PCR array analysis revealed that ZAG-induced epithelial transdifferentiation was accompanied by a series of concerted cellular events including a shift in the energy metabolism and prosurvival signals. Thus, epigenetically regulated ZAG is a novel tumor suppressor essential for maintaining an epithelial phenotype.

Tiergerechtheit von Futterabrufstationen in der Gruppenhaltung von Pferden

Gegenstand und Ziel: Überprüfung der Tiergerechtheit von Abrufstationen für Kraftfutter und Heu in der Gruppenhaltung von Pferden anhand ethologischer und physiologischer Parameter im Vergleich zu konventionellen Fressständen. Material und Methoden: Die Verhaltensbeobachtungen fanden in 11 bzw. 10 Offenlaufställen mit Abrufstationen bzw. Fressständen statt. 270 Pferde wurden individuell unterschieden. Untersuchungsparameter waren: Drohverhalten mit und ohne Verletzungsrisiko, Meideverhalten, Verdrängung aus dem Fressstand sowie Herzfrequenz und Integumentverletzungen. In jedem Betrieb erfolgten kontinuierliche Direktbeobachtungen für je einen 24-Stunden-Tag (Tortenstückverfahren). Ergebnisse: Im Wartebereich der Abrufautomaten traten signifikant mehr Drohgesten ohne bzw. mit Verletzungsgefahr je Pferd und Tag (8,6 bzw. 3,0) auf als im Wartebereich der Fressstände (3,4 bzw. 0,9). Demgegenüber konnten die Pferde in Abrufstationen (1,4 Drohgesten je Pferd und Tag) ungestörter fressen als in Fressständen (3,2 Drohgesten je Pferd und Tag). Insgesamt betrachtet ergab sich jedoch bei beiden Fütterungssystemen eine geringe Anzahl an sozionegativen Interaktionen im Bereich der Futtereinrichtungen. Die Herzfrequenz lag im Warteareal im Durchschnitt im physiologischen Bereich (44,59 ±11,73 Schläge/min). Integumentverletzungen im Zusammenhang mit dem Fütterungssystem traten nicht auf. Der wichtigste Einflussfaktor auf die Untersuchungskriterien war der Betrieb (Fläche, Konzeption, Management). Schlussfolgerung: Unter dem Aspekt der Tiergerechtheit hinsichtlich des Stress- und Verletzungsrisikos durch soziale Interaktionen eignen sich bei ordnungsgemäßer Gruppenhaltung mit fachgerechtem Management sowohl Fressstände als auch Abrufstationen für Pferde im Offenlaufstall.

The FGFR4 Y367C mutant is a dominant oncogene in MDA-MB453 breast cancer cells

Mutational analysis of oncogenes is critical for our understanding of cancer development. Oncogenome screening has identified a fibroblast growth factor receptor 4 (FGFR4) Y367C mutation in the human breast cancer cell line MDA-MB453. Here, we investigate the consequence of this missense mutation in cancer cells. We show that MDA-MB453 cells harbouring the mutation are insensitive to FGFR4-specific ligand stimulation or inhibition with an antagonistic antibody. Furthermore, the FGFR4 mutant elicits constitutive phosphorylation leading to an activation of the mitogen-activated protein kinase cascade as shown by an enhanced Erk1/2 phosphorylation. Cloning and ectopic expression of the FGFR4 Y367C mutant in HEK293 cells revealed high pErk levels and enhanced cell proliferation. Based on these findings, we propose that FGFR4 may be a driver of tumour growth, particularly when highly expressed or stabilized and constitutively activated through genetic alterations. As such, FGFR4 presents an option for further mutational screening in tumours and is an attractive cancer target with the therapeutic potential.

Two-dimensional dynamics of metal nanoparticles on the surface of thin polymer films studied with coherent X rays

X-ray photon-correlation spectroscopy is used to measure the dynamic structure factor f(q,tau) of gold particles moving on the surface of thin polymer films. Above the glass transition of the polymer the peculiar form f(q,tau) approximately exp[-(Gamma tau)(alpha)] is found with 0.7 < alpha < 1.5, depending on sample age and temperature. The relaxation rates Gamma scale linearly with q, excluding a simple Brownian diffusive motion. This type of behavior, already observed in aging bulk soft matter systems, is explained by a power law distribution of particle velocities due to ballistic motion.

FGFR4 Arg388 allele is associated with resistance to adjuvant therapy in primary breast cancer

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Background: Bange et al. recently found that a single-nucleotide polymorphism (SNP) at codon 388 of fibroblast growth factor receptor 4 (FGFR4) gene, causing a transmembrane domain missense mutation (Gly388Arg), is associated with outcome in node-positive breast cancer. Methods: This study addresses clinical relevance of this SNP, FGFR4 genotype, phenotype, and HER2 regarding patient outcome and influence of adjuvant systemic therapy in a substantial primary breast cancer collective (n=372; 1987–2002), median follow-up 94.5 months. Treatment was administered according to consensus recommendations at the time: 73 patients (all N0) received no adjuvant systemic therapy; 114 received adjuvant chemotherapy (87% CMF-based), 164 tamoxifen, 10 combined chemo-endocrine therapy, 11 unknown. 128 (36%) patients experienced disease recurrence, 104 (81%) distant relapses; 140 (38%) died. PCR-RFLP-analysis of germ-line polymorphism was performed in uninvolved lymph nodes; FGFR4 and HER2 expression were assessed immunohistochemically in tumor tissue arrays. Primary endpoint was DFS, since it best reflects impact of adjuvant systemic therapy. Results: In 51% of patients, homo- or heterozygous Arg388 allele was present. No correlation existed between FGFR4 genotype and expression or HER2 status. In N0 patients, FGFR4 genotype was not correlated with disease outcome. In N+ patients, however, FGFR4 Arg388 was significantly associated with poor DFS (p=0.02) and OS (p=0.04). Notably, this association seems to be attributable to relatively poor therapy response in Arg388 carriers, reflected in their significantly shorter DFS (p=0.02) and OS (p=0.045) among patients receiving adjuvant systemic therapy. It is also seen as a significant interaction term in a multivariate proportional hazards model with Arg388 carriers having only about half as much benefit from adjuvant systemic therapy as wild-type carriers. Conclusions: Our results show that the previously found association of FGFR4 Arg388 genotype with breast cancer progression is strongest in patients with adjuvant systemic therapy, particularly chemotherapy, and thus may reflect therapy resistance.

No significant financial relationships to disclose.

FGFR4 Arg388 allele correlates with tumour thickness and FGFR4 protein expression with survival of melanoma patients

A single nucleotide polymorphism in the gene for FGFR4 (−Arg388) has been associated with progression in various types of human cancer. Although fibroblast growth factors (FGFs) belong to the most important growth factors in melanoma, expression of FGF receptor subtype 4 has not been investigated yet. In this study, the protein expression of this receptor was analysed in 137 melanoma tissues of different progression stages by immunohistochemistry. FGFR4 protein was expressed in 45% of the specimens and correlated with pTNM tumour stages (UICC, P=0.023 and AJCC, P=0.046), presence of microulceration (P=0.009), tumour vascularity (P=0.001), metastases (P=0.025), number of primary tumours (P=0.022), overall survival (P=0.047) and disease-free survival (P=0.024). Furthermore, FGFR4 Arg388 polymorphism was analysed in 185 melanoma patients by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The Arg388 allele was detected in 45% of the melanoma patients and was significantly associated with tumour thickness (by Clark's level of invasion (P=0.004) and by Breslow in mm (P=0.02)) and the tumour subtype nodular melanoma (P=0.002). However, there was no correlation of the FGFR4 Arg388 allele with overall and disease-free survival. In conclusion, the Arg388 genotype and the protein expression of FGFR4 may be potential markers for progression of melanoma.

The epidermal growth factor receptor family as a central element for cellular signal transduction and diversification

Homeostasis of multicellular organisms is critically dependent on the correct interpretation of the plethora of signals which cells are exposed to during their lifespan. Various soluble factors regulate the activation state of cellular receptors which are coupled to a complex signal transduction network that ultimately generates signals defining the required biological response. The epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases represents both key regulators of normal cellular development as well as critical players in a variety of pathophysiological phenomena. The aim of this review is to give a broad overview of signal transduction networks that are controlled by the EGFR superfamily of receptors in health and disease and its application for target-selective therapeutic intervention. Since the EGFR and HER2 were recently identified as critical players in the transduction of signals by a variety of cell surface receptors, such as G-protein-coupled receptors and integrins, our special focus is the mechanisms and significance of the interconnectivity between heterologous signalling systems.