Increased lipofuscin on endomyocardial biopsy predicts greater cardiac improvement in adolescents and young adults

Reducing lipofuscin accumulation and cardiomyocytic senescence of aging heart by enhancing autophagy

Cardiomyocytes are particularly prone to lipofuscin accumulation. In the aging heart, lipofuscin accumulation is augmented. This study examined distribution of lipofuscin and senescent cardiomyocytes and evaluated improvement of lipofuscin accumulation and cardiomyocytic senescence of the aging heart after treatment with rapamycin. The results of Schmorl staining, Sudan black staining and autofluorescence detection showed that there was more lipofuscin in the myocardium of the ventricles especially in the left ventricle. The conductive tissue contained less lipofuscin than the myocardium. In the aged hearts, lipofuscin accumulation and senescent cardiomyocytes were increased, and the level of autophagy was reduced. In double staining of Sudan black B and senescence-associated β-galactosidase, 10%-20% lipofuscin-loaded cardiomyocytes became senescent. All senescent cardiomyocytes contained lipofuscin deposits. After enhancing autophagy with feed of rapamycin for six months, lipofuscin accumulation and senescence of cardiomyocytes were improved in old rats. Colocalization of autophagic structure and lipofuscin as well as electron micrographs showed that some lipofuscin-loaded lysosomes were sequestrated by autophagic structures. This study suggests that rapamycin-enhanced autopahgy is effective for reducing lipofuscinogenesis and promoting degradation of lipofuscin. Therefore, enhancing autophagy is a novel therapy for alleviating lipofuscin accumulation and myocardial senescence.

A case report on lipofuscin deposition in a graft biopsy two years after kidney transplantation: an insignificant bystander or a pathogenic benefactor?

Background

Lipofuscin deposition is a characteristic manifestation of aging. There is very limited literature in humans and in animals describing these deposits in native kidneys. Overall, it is thought to be non-pathogenic and successful transplants from a donor with lipofuscin deposits have been reported. We present the case of a patient who underwent a kidney transplant and a for-cause biopsy post-transplantation incidentally revealed lipofuscin deposition.

Case presentation

A 48-year old gentleman with a past medical history of diabetes, hypertension, coronary artery disease, and ischemic and then hemorrhagic cardiovascular accident underwent a successful kidney transplant. His donor was an expanded criteria donor with no major past medical history. Post-transplant course was complicated by delayed graft function requiring one dialysis treatment for hyperkalemia. After that he had an uneventful course and achieved a baseline creatinine of 1.2 mg/dL, with no proteinuria. On a routine 19-month follow-up he was noted to have proteinuria and an antibody against the major-histocompatibility-complex class I-related chain A. A graft biopsy revealed acute antibody-mediated rejection and impressive lipofuscin deposition. He was subsequently treated with an antibody-mediated rejection protocol that included high dose steroids, Rituximab, plasmapheresis, and intravenous immunoglobulin, but responded poorly to this regimen. A 6-month follow up biopsy continued to show lipofuscin deposition, with similar microvascular injury scores and 12-months later his creatinine remained stable but his proteinuria worsened. Patient was struggling with recurrent infectious episodes requiring hospitalizations and thus no further diagnostic or therapeutic treatments were pursued.

Conclusions

Lipofuscin deposition has been reported in solid organ transplants but the significance and cause are not well understood. Several physiologic and some pathologic causes to these deposits have been reported including age, diabetes, medications and a genetic syndrome. We propose that immunologic causes such as rejection in the presence of other risk factors could potentiate the oxidative stress leading to excessive lipofuscin deposition in kidney transplants. In the case of our patient, we conclude that these deposits were likely recipient-derived, and postulate that the cumulative burden of inflammation from rejection, and underlying medical conditions led to increased lipofuscin deposition. We speculate them to be an innocent bystander.

Outcomes and predictors of recovery in acute-onset cardiomyopathy: A single-center experience of patients undergoing endomyocardial biopsy for new heart failure

BACKGROUND

About one-third of patients with unexplained acute-onset heart failure (HF) recover left ventricular (LV) function; however, characterization of these patients in the setting of contemporary HF therapies is limited. We aim to describe baseline characteristics and predictors of recovery in patients with acute-onset cardiomyopathy.

METHODS

We previously described 851 patients with unexplained HF undergoing endomyocardial biopsy. In this study, 235 patients with acute-onset HF were further retrospectively examined.

RESULTS

Follow-up LV ejection fraction (LVEF) was available for 138 patients. At 1 year, 48 of 138 (33%) had LVEF recovery (follow-up LVEF ≥50%), and 90 of 138 (65%) had incomplete or lack of recovery. Higher cardiac index (P=.019), smaller LV diastolic diameter (P=.002), and lack of an intraventricular conduction delay (IVCD) (P=.002) were associated with LVEF recovery. IVCD (P=.001) and myocarditis (P=.016) were independent predictors of the composite end point of death, LV assist device placement, and/or transplant at 1 year. Those with an IVCD had a significantly lower 1-year survival than those without (P=.007).

CONCLUSIONS

Patients with a smaller LV end-diastolic diameter, higher cardiac index, and lack of IVCD at presentation for acute-onset HF were more likely to have LVEF recovery. IVCD was a poor prognostic marker in all patients presenting with acute cardiomyopathy.