Background—
Sarcoplasmic reticulum (SR) Ca
2+
leak through ryanodine receptor type 2 (RyR2) dysfunction is of major pathophysiological relevance in human heart failure (HF); however, mechanisms underlying progressive RyR2 dysregulation from cardiac hypertrophy to HF are still controversial.
Methods and Results—
We investigated healthy control myocardium (n=5) and myocardium from patients with compensated hypertrophy (n=25) and HF (n=32). In hypertrophy, Ca
2+
/calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) both phosphorylated RyR2 at levels that were not different from healthy myocardium. Accordingly, inhibitors of these kinases reduced the SR Ca
2+
leak. In HF, however, the SR Ca
2+
leak was nearly doubled compared with hypertrophy, which led to reduced systolic Ca
2+
transients, a depletion of SR Ca
2+
storage and elevated diastolic Ca
2+
levels. This was accompanied by a significantly increased CaMKII-dependent phosphorylation of RyR2. In contrast, PKA-dependent RyR2 phosphorylation was not increased in HF and was independent of previous β-blocker treatment. In HF, CaMKII inhibition but not inhibition of PKA yielded a reduction of the SR Ca
2+
leak. Moreover, PKA inhibition further reduced SR Ca
2+
load and systolic Ca
2+
transients.
Conclusions—
In human hypertrophy, both CaMKII and PKA functionally regulate RyR2 and may induce SR Ca
2+
leak. In the transition from hypertrophy to HF, the diastolic Ca
2+
leak increases and disturbed Ca
2+
cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2 phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.
To facilitate early diagnosis it is important to recognize that pre-pubertal MS presents with a specific pattern of symptoms that is maintained over the first two disease years.
Thymic neuroendocrine tumors (TNET) are rare primary epithelial neoplasms of the thymus. This study aimed to determine clinically relevant parameters for their classification and for therapeutic decisions. We performed a comprehensive histological, clinical, and genetic study of 73 TNET cases (13 thymic typical carcinoids [TTC], 40 thymic atypical carcinoids [TAC], and 20 high-grade neuroendocrine carcinomas [HGNEC] of the thymus), contributed by multiple institutions. The mean number of chromosomal imbalances per tumor was 0.8 in TTC (31% aberrant cases) versus 1.1 in TAC (44% aberrant cases) versus 4.7 in HGNEC (75% aberrant cases). Gains of 8q24 (MYC gene locus) were the most frequent alteration and one of the overlapping features between carcinoids and HGNEC. The 5-year survival rates for TTC, TAC, and HGNEC were 100, 60, and 30%. The 10-year survival rates for TTC and TAC were 50 and 30% (P = 0.002). Predictive mitotic cut-off values for TTC versus TAC were 2.5 per 10 high-power fields (HPF; indicating a higher death rate, P = 0.062) and 15 per 10 HPF (indicating higher risk of recurrence, P = 0.036) for separating HGNEC from TAC. We conclude that the current histopathologic classifications of TNET reflect tumor biology and provide important information for therapeutic management.
Whereas treatment for spasticity and depression is common in our cohort, sexual dysfunction, dysphagia, cognitive dysfunction, and fatigue are treated to a far lesser extent. The need for psychological support, physical, and occupational therapy has to be recognized as neuropsychological symptoms have a great impact on retirement at an early stage. Overall symptomatic treatment rates for the most common symptoms have increased over the last years ( p < 0.001).
We provide first evidence of differential regulation of NaV1.8 and NaV1.5 in the failing human myocardium and their contribution to arrhythmogenesis due to generation of INaL. We propose inhibition of NaV1.8 thus constitutes a promising novel approach for selective anti-arrhythmic therapy in HF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.