Pericyte-specific deletion of ninjurin-1 induces fragile vasa vasorum formation and enhances intimal hyperplasia of injured vasculature

Adventitial abnormalities including enhanced vasa vasorum malformation are associated with development and vulnerability of atherosclerotic plaque. However, the mechanisms of vasa vasorum malformation and its role in vascular remodeling have not been fully clarified. We recently reported that ninjurin-1 (Ninj1) is a crucial adhesion molecule for pericytes to form matured neovessels. The purpose is to examine if Ninj1 regulates adventitial angiogenesis and affects the vascular remodeling of injured vessels using pericyte-specific Ninj1 deletion mouse model. Mouse femoral arteries were injured by insertion of coiled wire. Four weeks after vascular injury, fixed arteries were decolorized. Vascular remodeling, including intimal hyperplasia and adventitial microvessel formation were estimated in a three-dimensional view. Vascular fragility, including blood leakiness was estimated by extravasation of fluorescein isothiocyanate (FITC)-lectin or FITC-dextran from microvessels. Ninj1 expression was increased in pericytes in response to vascular injury. NG2-CreER/Ninj1^loxp mice were treated with tamoxifen (Tam) to induce deletion of Ninj1 in pericyte (Ninj1 KO). Tam-treated NG2-CreER or Tam-nontreated NG2-CreER/Ninj1^loxp mice were used as controls. Intimal hyperplasia was significantly enhanced in Ninj1 KO compared with controls. Vascular leakiness was significantly enhanced in Ninj1 KO. In Ninj1 KO, the number of infiltrated macrophages in adventitia was increased, along with the expression of inflammatory cytokines. In conclusion, deletion of Ninj1 in pericytes induces the immature vasa vasorum formation of injured vasculature and exacerbates adventitial inflammation and intimal hyperplasia. Thus, Ninj1 contributes to the vasa vasorum maturation in response to vascular injury and to reduction of vascular remodeling.NEW & NOTEWORTHY Although abnormalities of adventitial vasa vasorum are associated with vascular remodeling such as atherosclerosis, the mechanisms of vasa vasorum malformation and its role in vascular remodeling have not been fully clarified. The present study provides a line of novel evidence that ninjurin-1 contributes to adventitial microvascular maturation during vascular injury and regulates vascular remodeling.

Antimitochondrial Antibody-associated Myopathy with Slowly Progressive Cardiac Dysfunction

A 45-year-old woman was referred to our hospital for the evaluation of proximal muscle weakness and serum creatine kinase elevation [corrected]. She had atrial fibrillation and left ventricular asynergy. She was diagnosed with myopathy, accompanied by cardiomyopathy of unknown etiology. She was treated with prednisolone. After long-term follow-up and a detailed examination, the patient was diagnosed with antimitochondrial antibody (AMA)-associated myopathy with cardiac involvement. Although the patient received medical treatment, including beta-blockers and prednisolone, her cardiac function deteriorated progressively. Physicians should consider AMA-associated myopathy when diagnosing myopathies of unknown etiology. The presence of cardiac involvement should be proactively investigated in AMA-associated myopathy.

Comparison between unattended automated office blood pressure and conventional office blood pressure under the environment of health checkup among Japanese general population

Unattended automated office blood pressure (AOBP) measurement has been endorsed as the preferred in-office measurement modality in recent Canadian and American clinical practice guidelines. However, the difference between AOBP and conventional office blood pressure (CBP) under the environment of a health checkup remains unclear. We aimed to identify the clinical significance of AOBP as compared to CBP under the environment of a health checkup. There were 491 participants (333 females, mean age of 62.5 years) who were at least 20 years old, including 179 participants who were previously diagnosed with hypertension. Mean AOBPs were 131.8 ± 20.9/76.6 ± 11.7 mm Hg, and CBPs were 135.6 ± 21.6/77.3 ± 11.5 mm Hg. There was a difference of 3.9 mm Hg in systolic blood pressure (SBP) and 0.8 mm Hg in diastolic BP between AOBP and CBP. In all participants, SBP and pulse pressure, as well as the white coat effect (WCE), increased with age. The cutoff value used was 140/90 mm Hg for CBP and 135/85 mm Hg for AOBP, and the prevalence of WCE and masked hypertension effect (MHE) was 12.4% and 14.1%, respectively. Even in a health checkup environment of the general population, there was a difference between the AOBP and CBP, and the WCE was observed more strongly in the elderly with a history of hypertension, suggesting that a combination of AOBP with CBP may be useful in detecting WCE and MHE in all clinical scenarios including health checkups, and help solve the "hypertension paradox" not only in Japan but in all over the world.

Sarcopenia-derived exosomal micro-RNA 16-5p exerts the cardio-repair disturbance via pro-apoptotic mechanism in myocardial infarction of mice

Background

Sarcopenia is a pathophysiological malfunction induced by skeletal muscle atrophy, and several studies reported an association between sarcopenia-induced cardiac cachexia and poor prognosis in heart disease. Since only a few established animal models are recently available, the underlying mechanism of disturbed cardiac repair accompanied with sarcopenia remains poorly understood.

Purpose

We hypothesized that specific microRNAs in sarcopenia-derived exosomes play crucial roles in disturbed cardiac repair with sarcopenia, and these microRNAs directly exacerbate cardiomyocyte injury following cardiac ischemia and reperfusion.

Methods

We developed a novel sarcopenia-induced cardiac repair disturbance mouse model that is induced by tail suspension (TS) 7 days after a 45-min coronary occlusion of cardiac ischemia and reperfusion (I/R). The reduction of the left ventricular ejection fraction (LVEF) after I/R was compared in mice with TS [I/R-TS(+), n=14] and without [I/R-TS(−), n=12] by echocardiography. To investigate the exosomal mechanism of cardiac repair disturbance, a comprehensive analysis of extracted exosomal microRNAs from mice serum was performed in the 2 groups at day 8. Then, we investigated the impact of the identified candidate microRNA in neonatal rat cardiomyocytes (NRVMs). After 4 days in primary culture, candidate microRNA was transfected into NRVMs under hypoxic culture conditions. TUNEL analysis and quantitative PCR analysis of apoptosis-related genes were performed on the NRVMs.

Results

At day 8 after I/R, the LVEF of I/R-TS(+) was not significantly ameliorated compared to that of I/R-TS(−) (ΔLVEF; 1.59±6.92 vs. 8.04±7.71% p=0.034). Four candidate microRNAs obtained from I/R mice serum were identified in the microRNA array analysis. The re-analysis of these candidate micro-RNAs using all I/R mice demonstrated that the level of mir-16-5p in I/R-TS(+) was raised by approximately nine-fold than that in I/R-TS(−) (9.67±13.35 vs. 0.99±1.41, p<0.05). Next, an in vitro experimental model using a microRNA mimic revealed that apoptosis in NRVMs was greatly enhanced by the transfection of a mir-16-5p mimic in hypoxic culture conditions (mir-16-5p vs. control = 5.77±2.84 vs. 1.72±0.55%, p<0.01). Furthermore, by qRT-PCR analysis, the expression of CASP3 and TRP53 were upregulated in NRVMs treated with a mir-16-5p mimic than in control NRVMs.

Conclusion

Myocardial I/R injury in sarcopenia ended in cardiac repair disturbance accompanying with the enhanced expression of exosomal-mir-16-5p. A pro-apoptotic effect of mir-16-5p may exacerbate myocardial I/R injury and thus can be a novel therapeutic target for cardiac repair disturbance in sarcopenia.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science

Anti-signal Recognition Particle Antibody-positive Necrotizing Myopathy with Secondary Cardiomyopathy: The First Myocardial Biopsy- and Multimodal Imaging-proven Case

A 69-year-old Japanese woman was admitted to our hospital with progressive muscle weakness and dysphagia. She was taking pitavastatin for dyslipidemia. Her serum creatine kinase was 6,300 U/L. Pitavastatin was stopped, but her symptoms deteriorated, and cardiac congestion appeared. A muscle biopsy showed necrotizing myopathy (NM), and anti-signal recognition particle (SRP) antibody was positive. ¹⁸F-fluorodeoxyglucose-positron emission tomography showed an abnormal uptake, and magnetic resonance imaging showed abnormal gadolinium enhancement in the left ventricular wall. An endomyocardial biopsy revealed inflammatory cardiomyopathy. Steroid, tacrolimus, and intravenous immunoglobulins were effective against the symptoms. This is the first case of biopsy-proven secondary cardiomyopathy due to anti-SRP-positive NM.

P4144Pericyte-specific deletion of ninjurin1 induces abnormal vasa vasorum formation and persistent inflammation and enhances intimal hyperplasia of injured vasculature

Introduction

Atherosclerosis is fundamental pathological condition inducing severe ischemic diseases such as ischemic heart disease and stroke. New concept has been proposed that adventitial abnormalities including enhanced malformation of adventitial microvessel, vasa vasorum are associated with development and vulnerability of atherosclerotic plaque. However, the role of vasa vasorum malformation in vascular remodelling has not been fully clarified. We recently reported that Ninjurin1 (Ninj1) is critical adhesion molecule to associate pericytes (PCs) with endothelial (EC) tubes to form stabilized mature neovessels. The purpose of this study is to examine if formation of adventitial microvessels affects the vascular remodelling of injured vessels using PCs-specific Ninj1 deletion mouse model.

Methods and results

Deletion of Ninj1 gene in NG2-positive PCs was induced by tamoxifen (Tam)-treated NG2-CreER/Ninj1loxp mice (Ninj1KO, n=9). Tam-treated-NG2-CreER (n=4) or Tam-nontreated NG2-CreER/Ninj1loxp (n=5) mice were used as Control (Ct1 and Ct2 respectively). Femoral arteries were injured by insertion of coiled wire. After 4 weeks of surgery, blood vessels were stained by venous injection of FITC-lectin. Isolated femoral arteries were fixed with paraformaldehyde and decolorized with CUBIC reagent. Wire-mediated vessel injury induced intimal hyperplasia, as assessed by intima/media (I/M) ratio and accordingly grew microvessels in adventitia. Intimal hyperplasia in Ninj1KO were significantly enhanced compared to Controls. Although there was no significant difference in total length of adventitial microvessels among three groups, extravasation of FITC-lectin from adventitial microvessels were significantly enhanced in Ninj1KO. The number of infiltrated macrophages in adventitia were increased in Ninj1KO.

Conclusion

Deletion of Ninj1 in PCs contributes to formation of immature microvessels in adventitia of injured vasculature and to adventitial microbleeding, and subsequently enhances intimal hyperplasia. Ninj1 is an attractive target to normalize microvessels for anti-atherosclerotic therapy.

Capillary-resident EphA7+ pericytes are multipotent cells with anti-ischemic effects through capillary formation

The presence of pericytes (PCs) with multipotency and broad distribution along capillary suggests that microvasculature plays a role not only as a duct for blood fluid transport but also as a stem cell niche that contributes to tissue maintenance and regeneration. The lack of an appropriate marker for multipotent PCs still limits our understanding of their pathophysiological roles. We identified the novel marker EphA7 to detect multipotent PCs using microarray analysis of an immortalized PC library. PCs were isolated from microvessels of mouse subcutaneous adipose tissues, then EphA7⁺ PCs called capillary stem cells (CapSCs) were separated from EphA7⁻ control PCs (ctPCs) using fluorescence‐activated cell sorting system. CapSCs had highly multipotency that enabled them to differentiate into mesenchymal and neuronal lineages compared with ctPCs. CapSCs also differentiated into endothelial cells and PCs to form capillary‐like structures by themselves. Transplantation of CapSCs into ischemic tissues significantly improved blood flow recovery in hind limb ischemia mouse model due to vascular formation compared with that of ctPCs and adipose stromal cells. These data demonstrate that EphA7 identifies a subpopulation of multipotent PCs that have high angiogenesis and regenerative potency and are an attractive target for regenerative therapies.

Pericyte-Specific Ninjurin1 Deletion Attenuates Vessel Maturation and Blood Flow Recovery in Hind Limb Ischemia

Supplemental Digital Content is available in the text.

Objective—

Angiogenesis, entire step from endothelial cells (ECs) sprouts to vascular maturation, is a critical response to ischemia. To form functional mature vessels, interactions between ECs and pericytes are essential. Ninj1 (ninjurin1) is an adhesion molecule that contributes to the pathogenesis of neuroinflammation. We recently demonstrated that Ninj1 is expressed in pericytes during angiogenesis. However, the role of Ninj1 in angiogenesis under pathophysiological ischemic conditions has not yet been elucidated.

Approach and Results—

Ninj1 was detected in microvessels, and its expression was enhanced in ischemic tissues after mouse hindlimb ischemia. Knockdown of Ninj1 was performed by injection of biodegradable microspheres releasing Ninj1-small interfering RNA into muscle tissues. Alternatively, pericyte-specific Ninj1 knockout was induced by tamoxifen treatment of NG2-CreERT/Ninj1-flox mice. Ninj1 knockdown/knockout reduced the formation of blood-circulating functional vessels among total CD31⁺ microvessels within ischemic tissues and subsequently attenuated color Doppler–assessed blood flow recovery. Ninj1 overexpression enhanced expression of Anpt (angiopoietin) 1, whereas Ninj1 knockdown enhanced the endogenous Anpt1 antagonist, Anpt2 expression in pericytes and inhibited the association of pericytes with ECs and subsequent formation of capillary-like structure, that is, EC tube surrounded with pericytes in 3-dimensional gel culture.

Conclusions—

Our data demonstrate that Ninj1 is involved in the formation of functional matured vessels through the association between pericytes and ECs, resulting in blood flow recovery from ischemia. These findings further the current our understanding of vascular maturation and may support the development of therapeutics for ischemic diseases.

Fungal Planet description sheets: 868-950

Novel species of fungi described in this study include those from various countries as follows: Australia, Chaetomella pseudocircinoseta and Coniella pseudodiospyri on Eucalyptus microcorys leaves, Cladophialophora eucalypti, Teratosphaeria dunnii and Vermiculariopsiella dunnii on Eucalyptus dunnii leaves, Cylindrium grande and Hypsotheca eucalyptorum on Eucalyptus grandis leaves, Elsinoe salignae on Eucalyptus saligna leaves, Marasmius lebeliae on litter of regenerating subtropical rainforest, Phialoseptomonium eucalypti (incl. Phialoseptomonium gen. nov.) on Eucalyptus grandis × camaldulensis leaves, Phlogicylindrium pawpawense on Eucalyptus tereticornis leaves, Phyllosticta longicauda as an endophyte from healthy Eustrephus latifolius leaves, Pseudosydowia eucalyptorum on Eucalyptus sp. leaves, Saitozyma wallum on Banksia aemula leaves, Teratosphaeria henryi on Corymbia henryi leaves. Brazil, Aspergillus bezerrae, Backusella azygospora, Mariannaea terricola and Talaromyces pernambucoensis from soil, Calonectria matogrossensis on Eucalyptus urophylla leaves, Calvatia brasiliensis on soil, Carcinomyces nordestinensis on Bromelia antiacantha leaves, Dendryphiella stromaticola on small branches of an unidentified plant, Nigrospora brasiliensis on Nopalea cochenillifera leaves, Penicillium alagoense as a leaf endophyte on a Miconia sp., Podosordaria nigrobrunnea on dung, Spegazzinia bromeliacearum as a leaf endophyte on Tilandsia catimbauensis, Xylobolus brasiliensis on decaying wood. Bulgaria, Kazachstania molopis from the gut of the beetle Molops piceus. Croatia, Mollisia endocrystallina from a fallen decorticated Picea abies tree trunk. Ecuador, Hygrocybe rodomaculata on soil. Hungary, Alfoldia vorosii (incl. Alfoldia gen. nov.) from Juniperus communis roots, Kiskunsagia ubrizsyi (incl. Kiskunsagia gen. nov.) from Fumana procumbens roots. India, Aureobasidium tremulum as laboratory contaminant, Leucosporidium himalayensis and Naganishia indica from windblown dust on glaciers. Italy, Neodevriesia cycadicola on Cycas sp. leaves, Pseudocercospora pseudomyrticola on Myrtus communis leaves, Ramularia pistaciae on Pistacia lentiscus leaves, Neognomoniopsis quercina (incl. Neognomoniopsis gen. nov.) on Quercus ilex leaves. Japan, Diaporthe fructicola on Passiflora edulis × P. edulis f. flavicarpa fruit, Entoloma nipponicum on leaf litter in a mixed Cryptomeria japonica and Acer spp. forest. Macedonia, Astraeus macedonicus on soil. Malaysia, Fusicladium eucalyptigenum on Eucalyptus sp. twigs, Neoacrodontiella eucalypti (incl. Neoacrodontiella gen. nov.) on Eucalyptus urophylla leaves. Mozambique, Meliola gorongosensis on dead Philenoptera violacea leaflets. Nepal, Coniochaeta dendrobiicola from Dendriobium lognicornu roots. New Zealand, Neodevriesia sexualis and Thozetella neonivea on Archontophoenix cunninghamiana leaves. Norway, Calophoma sandfjordenica from a piece of board on a rocky shoreline, Clavaria parvispora on soil, Didymella finnmarkica from a piece of Pinus sylvestris driftwood. Poland, Sugiyamaella trypani from soil. Portugal, Colletotrichum feijoicola from Acca sellowiana. Russia, Crepidotus tobolensis on Populus tremula debris, Entoloma ekaterinae, Entoloma erhardii and Suillus gastroflavus on soil, Nakazawaea ambrosiae from the galleries of Ips typographus under the bark of Picea abies. Slovenia, Pluteus ludwigii on twigs of broadleaved trees. South Africa, Anungitiomyces stellenboschiensis (incl. Anungitiomyces gen. nov.) and Niesslia stellenboschiana on Eucalyptus sp. leaves, Beltraniella pseudoportoricensis on Podocarpus falcatus leaf litter, Corynespora encephalarti on Encephalartos sp. leaves, Cytospora pavettae on Pavetta revoluta leaves, Helminthosporium erythrinicola on Erythrina humeana leaves, Helminthosporium syzygii on a Syzygium sp. bark canker, Libertasomyces aloeticus on Aloe sp. leaves, Penicillium lunae from Musa sp. fruit, Phyllosticta lauridiae on Lauridia tetragona leaves, Pseudotruncatella bolusanthi (incl. Pseudotruncatellaceae fam. nov.) and Dactylella bolusanthi on Bolusanthus speciosus leaves. Spain, Apenidiella foetida on submerged plant debris, Inocybe grammatoides on Quercus ilex subsp. ilex forest humus, Ossicaulis salomii on soil, Phialemonium guarroi from soil. Thailand, Pantospora chromolaenae on Chromolaena odorata leaves. Ukraine, Cadophora helianthi from Helianthus annuus stems. USA, Boletus pseudopinophilus on soil under slash pine, Botryotrichum foricae, Penicillium americanum and Penicillium minnesotense from air. Vietnam, Lycoperdon vietnamense on soil. Morphological and culture characteristics are supported by DNA barcodes.

Conifer-Derived Monoterpenes and Forest Walking

Conifer and broadleaf trees emit volatile organic compounds in the summer. The major components of these emissions are volatile monoterpenes. Using solid phase microextraction fiber as the adsorbant, monoterpenes were successfully detected and identified in forest air samples. Gas chromatography/mass chromatogram of monoterpenes in the atmosphere of a conifer forest and that of serum from subjects who were walking in a forest were found to be similar each other. The amounts of α-pinene in the subjects became several folds higher after forest walking. The results indicate that monoterpenes in the atmosphere of conifer forests are transferred to and accumulate in subjects by inhalation while they are exposed to this type of environment.

Eosinophilic myocarditis without hypereosinophilia accompanied by giant cell infiltration

A 53-year-old woman with a history of allergic disease was admitted to our hospital because of syncope induced by sustained ventricular tachycardia. The clinical course and the laboratory data did not correspond to those of acute myocarditis. Although eosinophils in the peripheral blood count were not increased, the diagnosis of eosinophilic myocarditis was made following a right ventricular endomyocardial biopsy that showed a remarkable infiltration of eosinophils. While giant cells were another histopathological feature of this case, they were considered to be an expression of the disease severity. This is a rare case of eosinophilic myocarditis, without peripheral eosinophilia. <Learning objective: Eosinophils in the peripheral blood usually increase in eosinophilic myocarditis. We describe a case of eosinophilic myocarditis without hypereosinophilia. Even in the absence of hypereosinophilia, endomyocardial biopsy should be performed during the investigation of unexplained myocardial disease.>.

Late Gadolinium Enhancement on Cardiac MRI Correlates with QT Dynamicity Represented by QT/RR Relationship in Patients with Ventricular Arrhythmias

BACKGROUND

The distribution of late gadolinium enhancement (LGE) on the cardiac MRI (CMR) indicates myocardial fibrosis and provides information of possible reentry substrates. QT dynamicity reflecting repolarization abnormalities has gained attention as a potential prognostic predictive factor.

OBJECTIVE

To clarify the correlation between the LGE distribution on CMR and QT dynamicity represented by the QT/RR relationship.

METHODS

CMR and QT/RR analyses using Holter monitoring were performed in 34 patients (24 males, 60 ± 11 years) with ventricular tachycardia (VT) and/or ventricular fibrillation (VF). The LGE on CMR was scored using a 4-point score in 17 left ventricular segments. The sum of the LGE scores was calculated for each patient. The QT/RR slope and daytime/nighttime QT/RR ratio (day/night ratio) were calculated. The correlation between the slope or the day/night QT/RR ratio and late enhancement findings was analyzed.

RESULTS

All patients were divided into 23 LGE positive (LGE(+)) and 11 LGE negative (LGE(-)) patients. The slopes of the QTe/RR and QTa /RR were significantly steeper in the LGE(+) than in LGE(-) patients (0.21 ± 0.03 vs 0.13 ± 0.02; P < 0.001, 0.19 ± 0.03 vs 0.13 ± 0.02; P < 0.001, respectively), and both slopes were significantly correlated with the total LGE scores (r = 0.83, P < 0.001; r = 0.71, P < 0.001, respectively). In the LGE(+) patients, the QTe day/night (1.37 ± 0.38 vs 0.91 ± 0.33; P = 0.002) and QTa day/night ratios (1.33 ± 0.26 vs 1.06 ± 0.30; P = 0.011) were significantly greater than those in the LGE(-) patients.

CONCLUSION

The LGE distribution was closely related to the QT dynamicity, suggesting that a combination of these markers can be a powerful tool for understanding the background pathophysiology.