AntimiR-21 Prevents Myocardial Dysfunction in a Pig Model of Ischemia/Reperfusion Injury.

BACKGROUND: miR-21 is a central regulator of cardiac fibrosis, and its inhibition in small-animal models has been shown to be an effective antifibrotic strategy in various organs, including the heart. Effective delivery of therapeutic antisense micro-ribonucleic acid (antimiR) molecules to the myocardium in larger organisms is challenging, though, and remains to be established for models of chronic heart failure. OBJECTIVES: The aims of this study were to test the applicability and therapeutic efficacy of local, catheter-based delivery of antimiR-21 in a pig model of heart failure and determine its effect on the cardiac transcriptomic signature and cellular composition. METHODS: Pigs underwent transient percutaneous occlusion of the left coronary artery and were followed up for 33 days. AntimiR-21 (10 mg) was applied by intracoronary infusion at days 5 and 19 after the injury. Cardiac function was assessed in vivo, followed by histological analyses and deep ribonucleic acid sequencing (RNA-seq) of the myocardium and genetic deconvolution analysis. RESULTS: AntimiR-21 effectively suppressed the remodeling-associated increase of miR-21. At 33 days after ischemia/reperfusion injury, LNA-21-treated hearts exhibited reduced cardiac fibrosis and hypertrophy and improved cardiac function. Deep RNA-seq revealed a significant derepression of the miR-21 targetome in antimiR-21-treated myocardium and a suppression of the inflammatory response and mitogen-activated protein kinase signaling. A genetic deconvolution approach built on deep RNA-seq and single-cell RNA-seq data identified reductions in macrophage and fibroblast numbers as the key cell types affected by antimiR-21 treatment. CONCLUSIONS: This study provides the first evidence for the feasibility and therapeutic efficacy of miR-21 inhibition in a large animal model of heart failure.

Caplacizumab for relapsing thrombotic thrombocytopenic purpura.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is an ultra-rare disorder in childhood and belongs to the microangiopathic hemolytic anemias (MAHA) and the thrombotic microangiopathies (TMA). In the acquired form, autoantibodies against ADAMTS13 inhibit cleaving of von Willebrand factor (vWF) multimers, thereby promoting their interaction with thrombocytes, causing TMA and MAHA. A recently introduced nanobody, caplacizumab, inhibits the binding of platelets to vWF. CASE-DIAGNOSIS/TREATMENT: During a first episode, a 10-year-old girl was admitted for TTP. Plasma exchange (PE) and immunosuppressive therapy with corticosteroids and mycophenolate mofetil were initiated. The course was complicated by catheter-associated septicemia and a very slow hematological and clinical recovery. Platelet count became normal at day 40 after admission and treatment initiation. Three years later, the child presented again with TTP. During this second episode, caplacizumab was introduced together with PE and immunosuppressive therapy within 4 days after admission. With this regimen, platelet count normalized within 3 days of treatment, and PE treatment could be stopped after a total of 14 days. The child could be discharged and caplacizumab was continued on an outpatient basis until day 30 after initiation. Adverse events during the use of caplacizumab were not encountered. CONCLUSIONS: Caplacizumab treatment was safe and effective in a child with relapsing, autoantibody-mediated TTP. With respect to this potentially life-threatening condition, the add-on use of caplacizumab represents a novel option to reduce morbidity and mortality and improve quality of life in children and adolescents with TTP.

Diabetes Mellitus-Induced Microvascular Destabilization in the Myocardium.

BACKGROUND: Diabetes mellitus causes microcirculatory rarefaction and may impair the responsiveness of ischemic myocardium to proangiogenic factors. OBJECTIVES: This study sought to determine whether microvascular destabilization affects organ function and therapeutic neovascularization in diabetes mellitus. METHODS: The authors obtained myocardial samples from patients with end-stage heart failure at time of transplant, with or without diabetes mellitus. Diabetic (db) and wild-type (wt) pigs were used to analyze myocardial vascularization and function. Chronic ischemia was induced percutaneously (day 0) in the circumflex artery. At day 28, recombinant adeno-associated virus (rAAV) (5 × 1012 viral particles encoding vascular endothelial growth factor-A [VEGF-A] or thymosin beta 4 [Tß4]) was applied regionally. CD31+ capillaries per high power field (c/hpf) and NG2+ pericyte coverage were analyzed. Global myocardial function (ejection fraction [EF] and left ventricular end-diastolic pressure) was assessed at days 28 and 56. RESULTS: Diabetic human myocardial explants revealed capillary rarefaction and pericyte loss compared to nondiabetic explants. Hyperglycemia in db pigs, even without ischemia, induced capillary rarefaction in the myocardium (163 ± 14 c/hpf in db vs. 234 ± 8 c/hpf in wt hearts; p < 0.005), concomitant with a distinct loss of EF (44.9% vs. 53.4% in nondiabetic controls; p < 0.05). Capillary density further decreased in chronic ischemic hearts, as did EF (both p < 0.05). Treatment with rAAV.Tß4 enhanced capillary density and maturation in db hearts less efficiently than in wt hearts, similar to collateral growth. rAAV.VEGF-A, though stimulating angiogenesis, induced neither pericyte recruitment nor collateral growth. As a result, rAAV.Tß4 but not rAAV.VEGF-A improved EF in db hearts (34.5 ± 1.4%), but less so than in wt hearts (44.8 ± 1.5%). CONCLUSIONS: Diabetes mellitus destabilized microvascular vessels of the heart, affecting the amplitude of therapeutic neovascularization via rAAV.Tß4 in a translational large animal model of hibernating myocardium.

Antagonism of V1b receptors promotes maternal motivation to retrieve pups in the MPOA and impairs pup-directed behavior during maternal defense in the mpBNST of lactating rats.

Recent studies using V1b receptor (V1bR) knockout mice or central pharmacological manipulations in lactating rats highlighted the influence of this receptor for maternal behavior. However, its role in specific brain sites known to be important for maternal behavior has not been investigated to date. In the present study, we reveal that V1bR mRNA (qPCR) and protein levels (Western blot) within either the medial preoptic area (MPOA) or the medial-posterior part of the bed nucleus of the stria terminalis (mpBNST) did not differ between virgin and lactating rats. Furthermore, we characterized the effects of V1bR blockade via bilateral injections of the receptor subtype-specific antagonist SSR149415 within the MPOA or the mpBNST on maternal behavior (maternal care under non-stress and stress conditions, maternal motivation to retrieve pups in a novel environment, maternal aggression) and anxiety-related behavior in lactating rats. Blocking V1bR within the MPOA increased pup retrieval, whereas within the mpBNST it decreased pup-directed behavior, specifically licking/grooming the pups, during the maternal defense test. In addition, immediately after termination of the maternal defense test, V1bR antagonism in both brain regions reduced nursing, particularly arched back nursing. Anxiety-related behavior was not affected by V1bR antagonism in either brain region. In conclusion our data indicate that V1bR antagonism significantly modulates different aspects of maternal behavior in a brain region-dependent manner.