Multiscale Analysis of Extracellular Matrix Remodeling in the Failing Heart

RATIONALE

Cardiac ECM (extracellular matrix) comprises a dynamic molecular network providing structural support to heart tissue function. Understanding the impact of ECM remodeling on cardiac cells during heart failure (HF) is essential to prevent adverse ventricular remodeling and restore organ functionality in affected patients.

OBJECTIVES

We aimed to (1) identify consistent modifications to cardiac ECM structure and mechanics that contribute to HF and (2) determine the underlying molecular mechanisms.

METHODS AND RESULTS

We first performed decellularization of human and murine ECM (decellularized ECM) and then analyzed the pathological changes occurring in decellularized ECM during HF by atomic force microscopy, 2-photon microscopy, high-resolution 3-dimensional image analysis, and computational fluid dynamics simulation. We then performed molecular and functional assays in patient-derived cardiac fibroblasts based on YAP (yes-associated protein)-transcriptional enhanced associate domain (TEAD) mechanosensing activity and collagen contraction assays. The analysis of HF decellularized ECM resulting from ischemic or dilated cardiomyopathy, as well as from mouse infarcted tissue, identified a common pattern of modifications in their 3-dimensional topography. As compared with healthy heart, HF ECM exhibited aligned, flat, and compact fiber bundles, with reduced elasticity and organizational complexity. At the molecular level, RNA sequencing of HF cardiac fibroblasts highlighted the overrepresentation of dysregulated genes involved in ECM organization, or being connected to TGFβ1 (transforming growth factor β1), interleukin-1, TNF-α, and BDNF signaling pathways. Functional tests performed on HF cardiac fibroblasts pointed at mechanosensor YAP as a key player in ECM remodeling in the diseased heart via transcriptional activation of focal adhesion assembly. Finally, in vitro experiments clarified pathological cardiac ECM prevents cell homing, thus providing further hints to identify a possible window of action for cell therapy in cardiac diseases.

CONCLUSIONS

Our multiparametric approach has highlighted repercussions of ECM remodeling on cell homing, cardiac fibroblast activation, and focal adhesion protein expression via hyperactivated YAP signaling during HF.

Identification of a Diagnostic Set of Endomyocardial Biopsy microRNAs for Acute Cellular Rejection Diagnostics in Patients after Heart Transplantation Using Next-Generation Sequencing

Introduction: Acute cellular rejection (ACR) of heart allografts represents the most common reason for graft failure. Endomyocardial biopsies (EMB) are still subject to substantial interobserver variability. Novel biomarkers enabling precise ACR diagnostics may decrease interobserver variability. We aimed to identify a specific subset of microRNAs reflecting the presence of ACR. Patients and Methods: Monocentric retrospective study. A total of 38 patients with the anamnesis of ACR were identified and for each patient three consecutive samples of EMB (with, prior and after ACR) were collected. Sixteen trios were used for next-generation sequencing (exploratory cohort); the resting 22 trios were used for validation with qRT-PCR (validation cohort). Statistical analysis was performed using R software. Results: The analysis of the exploration cohort provided the total of 11 miRNAs that were altered during ACR, the three of which (miR-144, miR-589 and miR-182) were further validated in the validation cohort. Using the levels of all 11 miRNAs and principal component analysis, an ACR score was created with the specificity of 91% and sensitivity of 68% for detecting the presence of ACR in the EMB sample. Conclusion: We identified a set of microRNAs altered in endomyocardial biopsies during ACR and using their relative levels we created a diagnostic score that can be used for ACR diagnosis.

[Heart transplantation and follow-up treatment with AL-amyloidosis in 5 patients]

The prognosis for patients with cardiac impairment due to AL-amyloid deposition and severe cardiac insufficiency is poor, with a survival median in the order of months. The classical treatment of AL-amyloidosis in combination with cardiac insufficiency is very poorly tolerated and the treatment of such patients is associated with considerably higher mortality than among other patients with AL-amyloidosis. If, however, patients with an isolated or another dominating cardiac impairment, without severe damage to other organs and tissues, have a heart transplant performed, their cardiovascular condition will significantly improve as a result, along with their ability to tolerate any kind of treatment for AL-amyloidosis including that using high-dose chemotherapy with a transplant of autologous hematopoietic stem cells. The achievement of complete remission of AL-amyloidosis is a precondition for long-term survival, since when not achieved, amyloid deposition also arises in the transplanted heart. At the Centre for Cardiovascular and Transplantation Surgery, Brno, the first heart transplant due to its impairment by AL-amyloidosis was performed in 2010. By the year 2017 the number of patients with AL-amyloidosis, who had first undergone a heart transplant with subsequent treatment for AL-amyloidosis, increased to 5. The median age at which a heart transplant was performed is 60 (48-65) years. Four patients were men, one was a woman. The median monitoring equals 65 (88-15) months. Complete remission of AL-amyloidosis was achieved in all the patients. There were 5 lines of treatment needed for the first patient to attain it, of that twice high-dose melphalan with autologous stem cell transplantation, for the second patient a second-line treatment, high-dose melphalan and bortezomib-based therapy. No specific therapy was needed for the third patient, as immunosuppressive therapy following the heart transplant containing prednison led to complete remission of AL-amyloidosis. In the fourth case, sustainable complete remission was reached by high-dose melphalan and in the fifth case by one line of bortezomib-based therapy. The aforementioned data illustrate that a heart transplant is the first step which makes the patients with a severe heart failure, not tolerating any efficient therapy of AL-amyloidosis, capable of undergoing intense treatment of AL-amyloidosis. Sometimes one high-dose chemotherapy is sufficient, while at other times multiple treatment lines are needed to reach complete remission of AL-amyloidosis.Key words: AL-amyloidosis - autologous hematopoietic stem cells transplantation - bortezomib - cardiomyopathy - lenalidomide - thalidomide - heart transplantation.

Dirofilaria repens: emergence of autochthonous human infections in the Czech Republic (case reports)

Background

Human dirofilariasis is a zoonotic infection that continues to spread to previously unaffected areas of Europe. In the South Moravian Region of the Czech Republic (CR), imported as well as autochthonous canine infections were recorded in the last decade, and parasite DNA was detected in mosquitoes of Aedes vexans. In the present paper, human Dirofilaria infections are reported from the country for the first time.

Case presentation

The samples from five patients with suspected tissue helminthiases were investigated. In particular cases, nematodes were isolated from various tissues including skin of lower leg, soft tissues of finger, subcutaneous tissue of hypogastrium, lymph node and peritoneum. The diagnosis was based on light microscopic morphology and/or DNA analysis of the worms. In addition, ELISA examination of patients’ sera for anti-filaria IgG antibodies was performed.

Conclusions

In the CR, five cases of human dirofilariasis caused by Dirofilaria repens were recorded during 2010–2014 (species determination for three of them was confirmed besides morphological also by DNA analysis). At least, three of the cases were of autochthonous origin (the patients are Czech citizens residing in South Moravian Region who have never travelled abroad). The findings confirm the natural setting of D. repens in South Moravian Region of the CR. Dirofilariasis should be therefore considered as endemic in this area where it may represent a significant risk factor for public health.

[Recurrence of primary diseases after liver transplantation]

A majority of primary diseases for which orthotopic liver transplantation is carried out may recur in the liver allograft, mostly in adults. As the indication criteria, transplantation surgery and post-transplantation care improve, the patients survival lengthens as well, leading to concurrently increasing incidence as well as an increase in the relevance of recurrent diseases, which are the most significant cause of late liver graft dysfunction. The frequency, clinical consequences and therapeutic options of different disease recurrence vary considerably. Even recently the worst prognosis has been associated with hepatitis C for 100% reinfection, this situation is beginning to change with new oral antiviral drugs, as has already been successfully done with hepatitis B. Among immune-mediated disorders, primary biliary cirrhosis recurrence affects 30 - 50% of transplant patients, albeit with mild consequences. Graft loss and subsequent necessity of retransplantation are observed in almost 10% of patients with primary sclerosing cholangitis recurrence. 30% prevalence rates for autoimmune hepatitis recurrence are reported but the frequency of graft loss has declined considerably due to maintenance of corticosteroid therapy. Excessive relapse of alcohol consumption in patients with liver transplant for alcoholic liver disease leads most commonly to extrahepatic complications. Recurrent non-alcoholic steatohepatitis is rarely connected with graft loss in 5 - 10 years after transplantation. The diagnosis of a recurrent disease following liver transplantation is to a large extent based on histopathological features. In the differential diagnosis, other causes of graft dysfunction must be excluded.