Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy.

AIM: Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. METHODS AND RESULTS: We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. CONTROLS: Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. CONCLUSIONS: Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies.

Mesenchymal cystic hamartoma presenting with pneumothorax: case report and review of the literature.

Mesenchymal cystic hamartoma (MCH) of the lung is a rare disease, with an indolent course in the majority of cases. It can be single or multifocal and it is composed of primitive mesenchymal cells admixed with cystic spaces. Only few cases have been reported in the literature, with variable clinical presentation. We describe the case of a huge MCH, presenting with spontaneous pneumothorax in a 65-year-old man. Further, we provide a brief overview of the literature and discuss the differential diagnosis with other entities, and the possible diagnostic pitfalls.

Dirofilaria repens Infection Mimicking Lung Melanoma Metastasis.

We describe a rare case of Dirofilaria repens infection presenting as peripheral lung nodules and mimicking a metastatic focus from a previously diagnosed cutaneous melanoma. To avoid invasive investigations before arriving at the correct diagnosis, dirofilariasis should be included as a part of the diagnostic process in subjects with lung nodules who live in (or have traveled to) endemic regions.

Chloroquine supplementation increases the cytotoxic effect of curcumin against Her2/neu overexpressing breast cancer cells in vitro and in vivo in nude mice while counteracts it in immune competent mice.

Autophagy is usually a pro-survival mechanism in cancer cells, especially in the course of chemotherapy, thus autophagy inhibition may enhance the chemotherapy-mediated anti-cancer effect. However, since autophagy is strongly involved in the immunogenicity of cell death by promoting ATP release, its inhibition may reduce the immune response against tumors, negatively influencing the overall outcome of chemotherapy. In this study, we evaluated the in vitro and in vivo anti-cancer effect of curcumin (CUR) against Her2/neu overexpressing breast cancer cells (TUBO) in the presence or in the absence of the autophagy inhibitor chloroquine (CQ). We found that TUBO cell death induced by CUR was increased in vitro by CQ and slightly in vivo in nude mice. Conversely, CQ counteracted the Cur cytotoxic effect in immune competent mice, as demonstrated by the lack of in vivo tumor regression and the reduction of overall mice survival as compared with CUR-treated mice. Immunohistochemistry analysis revealed the presence of a remarkable FoxP3 T cell infiltrate within the tumors in CUR/CQ treated mice and a reduction of T cytotoxic cells, as compared with single CUR treatment. These findings suggest that autophagy is important to elicit anti-tumor immune response and that autophagy inhibition by CQ reduces such response also by recruiting T regulatory (Treg) cells in the tumor microenvironment that may be pro-tumorigenic and might counteract CUR-mediated anti-cancer effects.

Prolyl-isomerase Pin1 controls Notch3 protein expression and regulates T-ALL progression.

Deregulated Notch signaling is associated with T-cell Acute Lymphoblastic Leukemia (T-ALL) development and progression. Increasing evidence reveals that Notch pathway has an important role in the invasion ability of tumor cells, including leukemia, although the underlying molecular mechanisms remain mostly unclear. Here, we show that Notch3 is a novel target protein of the prolyl-isomerase Pin1, which is able to regulate Notch3 protein processing and to stabilize the cleaved product, leading to the increased expression of the intracellular domain (N3IC), finally enhancing Notch3-dependent invasiveness properties. We demonstrate that the combined inhibition of Notch3 and Pin1 in the Notch3-overexpressing human leukemic TALL-1 cells reduces their high invasive potential, by decreasing the expression of the matrix metalloprotease MMP9. Consistently, Pin1 depletion in a mouse model of Notch3-induced T-ALL, by reducing N3IC expression and signaling, impairs the expansion/invasiveness of CD4(+)CD8(+) DP cells in peripheral lymphoid and non-lymphoid organs. Notably, in in silico gene expression analysis of human T-ALL samples we observed a significant correlation between Pin1 and Notch3 expression levels, which may further suggest a key role of the newly identified Notch3-Pin1 axis in T-ALL aggressiveness and progression. Thus, combined suppression of Pin1 and Notch3 proteins may be exploited as an additional target therapy for T-ALL.

Leptin induces direct vasodilation through distinct endothelial mechanisms.

In this study, we reveal that leptin evokes an acute hypotensive effect in 6-hydroxydopamine sympathectomized rats (response to maximal leptin dose, mean blood pressure: from 92 +/- 4 to 78 +/- 2 mmHg, P < 0.01). This hemodynamic effect is related to a direct action of the hormone on vascular tone, since in aortic and mesenteric rings increasing doses of leptin evoke a dose-dependent vasorelaxation (aorta: from 3 +/- 1 to 36 +/- 3, n = 15; mesenteric: from 6 +/- 1 to 30 +/- 5, n = 10), which is impaired by endothelial denudation. In particular, leptin-evoked vasorelaxation is impaired by nitric oxide synthase inhibition in aorta (delta% of maximal response: from 36 +/- 3 to 3 +/- 1, P < 0.01) and by endothelium-derived hyperpolarizing factor (EDHF) inhibition in mesenteric arteries (delta% of maximal response: from 30 +/- 5 to 7 +/- 2, P < 0.01), suggesting that vasorelaxation evoked by leptin is heterogeneous and related to the vascular bed. Finally, the inhibition of nitric oxide synthase by NG-nitro-L-arginine-methyl ester does not modify blood pressure response to leptin, suggesting a predominant role of the EDHF mechanism in the hypotensive effect of leptin.

Frequency of development of acute global left ventricular dysfunction in human immunodeficiency virus infection.

OBJECTIVES: This study evaluated prospectively the frequency, clinical outcome and pathologic findings of acute global left ventricular dysfunction in human immunodeficiency virus (HIV) infection during the various stages of the disease. BACKGROUND: Acute global left ventricular dysfunction in the course of HIV infection is still a poorly defined clinical entity, and little is known about the outcome after the acute onset. METHODS: Between January 1988 and June 1992, 136 HIV-positive (HIV+) patients without clinical, electrocardiographic or echocardiographic evidence of cardiovascular dysfunction on admission were prospectively studied with serial echocardiograms. Patients were assigned to three groups: 1) anti-HIV+ asymptomatic (17 patients, 12.5%); 2) acquired immunodeficiency syndrome (AIDS)-related complex (26 patients, 19.1%); 3) AIDS (93 patients, 68.4%). RESULTS: During a mean follow-up period of 415 +/- 220 days, seven patients, all in the AIDS subgroup, developed clinical and echocardiographic findings of acute global left ventricular dysfunction; of these, six (85%) died of congestive heart failure. Mean survival time from symptom onset was 41 +/- 13 days. Necropsy findings in five patients revealed acute lymphocytic myocarditis in three, cryptococcal myocarditis in one and interstitial edema and fibrosis in one. In only one patient was left ventricular dysfunction reversible with treatment. CONCLUSIONS: Although infrequent, acute global left ventricular dysfunction is not rare in the course of HIV infection. It seems to occur exclusively during the AIDS stage. Acute global left ventricular dysfunction is often fatal but may be reversible and is mainly associated with the pathologic findings of acute myocarditis.

Maternally inherited cardiomyopathy: clinical and molecular characterization of a large kindred harboring the A4300G point mutation in mitochondrial deoxyribonucleic acid.

OBJECTIVES: The purpose of this study was to describe the clinical and molecular features of a large family with maternally inherited cardiomyopathy (MICM). BACKGROUND: Recently, several mitochondrial deoxyribonucleic acid (mtDNA) point mutations have been associated with MICM. However, the distinctive clinical and morphologic features of MICM are not fully appreciated. This is partially due to the small size of the reported pedigrees, often lacking detailed clinical and laboratory information. METHODS: Clinical and genetic analysis of the family was carried out. RESULTS: Echocardiography showed mostly symmetrical hypertrophic cardiomyopathy in 10 family members. The illness had an unfavorable course. Progressive heart failure occurred in three subjects, who eventually died; one individual underwent heart transplantation. Electrocardiographic or echocardiographic signs of cardiac hypertrophy in the absence of significant clinical complaints were observed in five subjects. Neurologic examination was normal. The mutation was detected in blood from all available subjects. Abundance of mutated molecules ranged between 13% and 100% of total mtDNA genomes. The severity of the disease could not be foreseen by the proportion of mutation in blood. CONCLUSIONS: This report contributes a better description of the clinical aspects of MICM and provides important clues to distinguish it from hypertrophic cardiomyopathy. We suggest that mtDNA mutations, particularly in the transfer ribonucleic acid for isoleucin, should be systematically searched in patients with MICM. The identification of an underlying maternally inherited mitochondrial DNA defect in familial cases of cardiomyopathy may considerably influence the management and genetic counseling of affected patients.

Clinical course of cardiomyopathy in HIV-infected patients with or without encephalopathy related to the myocardial expression of tumour necrosis factor-alpha and nitric oxide synthase.

OBJECTIVE: To define whether the development of encephalopathy influences the clinical course of HIV-associated cardiomyopathy (HIV-DCM) in relation to the myocardial expression of tumour necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS). DESIGN: Prospective study. SETTING: University hospitals and AIDS centres. METHODS: 115 HIV-infected patients with echocardiographic diagnosis of HIV-associated cardiomyopathy (34 with encephalopathy and 81 without encephalopathy) were followed for a mean of 24 +/- 3.2 months. All patients underwent endomyocardial biopsy for determination of myocardial immunostaining intensity of TNF-alpha and iNOS. Cerebrospinal fluid (CSF) from patients with encephalopathy was examined for the presence of viruses. Patients underwent clinical examination every 3 months and echocardiographic examination every 6 months. The intensity of TNF-alpha and iNOS immunostaining was also evaluated on postmortem cerebral tissue of patients who died of congestive heart failure (CHF). RESULTS: A greater impairment of echocardiographic parameters was observed in patients with HIV-associated cardiomyopathy after development of encephalopathy. These parameters tended to worsen progressively during the follow-up period and were inversely correlated with HIV-1 viral load, CD4 cell count, mini mental status score and the intensity of myocardial and cerebral TNF-alpha and iNOS staining. CSF specimens were available in 29 patients with encephalopathy. HIV-1 sequences were detected in CSF of all these patients with cytomegalovirus sequences in two. The mortality rate for CHF was greater among patients with encephalopathy (73% versus 12%). CONCLUSIONS: The development of encephalopathy has an adverse effect on the clinical course of HIV-associated cardiomyopathy. In the relationship between cardiomyopathy and encephalopathy, the activation of iNOS by TNF-alpha may have a significant pathogenetic role in HIV disease.

Ontogenetic pattern of thyroid hormone receptor expression in the human testis.

We studied the spatiotemporal distribution of thyroid hormone nuclear receptors (TRs) alpha1 and alpha2 and beta messenger RNA (mRNA) levels in normal human testicular tissue during development and in adulthood. Nonpathological specimens from five aborted fetuses (17 and 23 weeks of gestation, three and two cases, respectively) and from four patients undergoing orchiectomy (18 months old and 38-, 42-, and 52-yr-old, respectively) were analyzed by Northern blot, semiquantitative RT-PCR amplification using DNA sequences or specifically designed primers for the TR isoforms, and in situ hybridization. By using PCR amplification, we found that TRalpha1 and TRalpha2 are both expressed at different levels in fetal and adult testis. At all ages TRalpha2 is found at higher levels. Northern analysis showed hybridization signals corresponding to the expression of TRalpha2 and TRalpha in a ratio that increased from 2.6 at 17 weeks of gestation to 12.0 in adulthood. In fact, the expression of TRalpha1 dramatically decreased throughout development, being faintly detectable in the adult testis. Expression of TRbeta was not detected at any age studied. This finding was further confirmed by PCR, which did not amplify TRbeta either in fetal or in adult testis mRNAs. In situ hybridization studies showed the absence of TRbeta and that TRalpha1 and TRalpha2 colocalized in Sertoli cells of prepubertal testis, whereas germ and interstitial cells appeared devoid of TR mRNA signals. From these results it can be concluded that the human testis exclusively expresses TRalpha, which is localized in Sertoli cells, TRbeta being always undetectable. Fetal and prepubertal ages represent the period of maximal expression of TRalpha1 and TRalpha2. The alpha2/alpha1 ratio rises dramatically after development. These results confirm a critical window for the action of thyroid hormone in human testis, in the period of maximal expression of T3 binding isoform TRalpha1, and may account for the macroorchidism without virilization occurring when hyposecretion of thyroid hormones occurs before puberty.

Increased expression of thyroid hormone receptor isoforms in end-stage human congestive heart failure.

Thyroid hormone plays an important role on myocardial development and function. The local effects of thyroid hormone are mediated by the receptor isoforms ultimately driving the expression of cardiac-specific genes. Although overt and subclinical thyroid dysfunction causes well-known changes in the cardiovascular system, little is known about local thyroid hormone action in normal and failing human myocardium. With a newly developed multiplex competitive RT-PCR method, we evaluated the expression of thyroid hormone receptor (TR) isoforms alpha-1, alpha-2, and beta-1 in normal human hearts and in end-stage congestive heart failure. A statistically significant difference in the expression of all three TR isoforms was observed among samples from normal subjects, ischemic heart disease (IHD), and dilated cardiomyopathy (DCM). In DCM, compared with normal, the studied TR isoforms were significantly increased. In IHD, the increased expression was found significant only for alpha-1 and alpha-2 isoforms. No differences were observed between the pathologic groups. In conclusion, a coordinated increment in the expression of the TR isoforms was observed in both DCM and IHD by multiplex competitive RT-PCR. The observed changes could represent a compensatory mechanism to myocardial failure or to locally altered thyroid hormone action.

Mitochondrial myopathy, parkinsonism, and multiple mtDNA deletions in a Sephardic Jewish family.

The authors describe a family of Sephardic Jews with progressive external ophthalmoparesis, skeletal muscle weakness, and parkinsonism. Autosomal recessive inheritance was suggested by many consanguineous marriages, although a dominant disorder could not be excluded. No linkage to known progressive external ophthalmoparesis locus was found. The presence of cytochrome c oxidase-negative ragged-red fibers, biochemically reduced respiratory chain complexes, and multiple mitochondrial DNA deletions in muscle biopsies from four patients suggested a new mitochondrial disorder of intergenomic communication.

Pathologic evidence of extensive left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (also known as arrhythmogenic right ventricular dysplasia) is characterized by adipose or fibroadipose tissue replacement of the right ventricular myocardium, whereas the left ventricle is substantively spared. Two cases of the disease with evidence of extensive left ventricular involvement at pathologic examination are described. Hearts from two patients who died suddenly showed full-thickness right ventricular fatty infiltration associated with extensive left ventricular involvement (greater than 50% of myocardial thickness). These findings might explain the reported clinical features of left ventricle dysfunction in a subset of patients with arrhythmogenic right ventricular cardiomyopathy. In view of the biventricular involvement of the disease, it should simply be termed "arrhythmogenic cardiomyopathy."

The pattern of desmin filaments in myocardial disarray.

"Myofiber disarray" defines a nonparallel arrangement of cardiac myocytes. The presence of a sufficient quantity of myocardial fibers showing this change is considered to be a specific histological feature of hypertrophic cardiomyopathy (HCM). However, small zones of myofiber disarray are found in both cardiac hypertrophy and other pathological conditions. Recently, we demonstrated an altered pattern of desmin intermediate filaments in disarrayed myofibers from specimens of HCM. To test the hypothesis that desmin alterations might be specific for cardiomyopathy, we performed an immunohistochemical study on myocardial surgical samples from 11 patients with HCM and from 12 patients with tetralogy of Fallot (toF) on 14 endomyocardial biopsy specimens (EMBs) from transplant recipients with myofiber disarray surrounding areas of scarring (previous biopsy site) and on specimens of four autoptic hearts with severe acquired left ventricular hypertrophy. Disarrayed myofibers from all specimens of HCM showed the following abnormalities in the pattern of desmin intermediate filament distribution: (1) decrease or loss of labeling of intercalated discs and Z bands, (2) longitudinal arrangement of desmin intermediate filaments, and (3) intense, granular staining of several myocytes. This spectrum of desmin alterations was never observed in disarrayed myofibers in specimens of toF or acquired myocardial hypertrophy or in EMBs. Altered distribution of desmin intermediate filaments seems to be specific to myofiber disarray in HCM and it may play a role in the altered myocyte arrangement in HCM.

Arrhythmogenic right ventricular cardiomyopathy: clinicopathologic correlation based on a revised definition of pathologic patterns.

Different morphologic features of arrhythmogenic right ventricular cardiomyopathy (ARVC) have been described. However, it is still unclear whether they correspond to distinct forms of the same disease. A pathologic study was performed on a series of ARVC (15 from heart transplant and 12 from autopsy) from 2 Italian referral university hospitals. Based on both myocellular features and the nature of myocardial replacement, hearts were divided into 2 groups: infiltrative, with a lacelike pattern of transmural fatty infiltration and strands of normal residual cardiomyocytes (n = 11); and cardiomyopathic, with massive myocardial replacement by fibro fatty tissue and cardiomyopathic changes (such as hypertrophy and myofibril loss) of residual cardiomyocytes (n = 16). Hearts from the infiltrative group were mostly obtained at autopsy of patients who died suddenly. Fatty substitution was limited almost exclusively to the right ventricle. Mitral valve dysplasia (prolapse or cleft) was frequently present. Hearts from the cardiomyopathic group came mainly from heart transplants for congestive heart failure. Fibro fatty replacement was more extensive, usually biventricular. Active myocarditis and features suggestive of myocardial transdifferentiation were also observed. Despite these differences in clinical outcome and morphologic features, patients from the 2 groups showed similar mean age, sex distribution, occurrence of threatening ventricular arrhythmias, and prevalence of family history of sudden death, arrhythmias, or cardiomyopathy. Infiltrative and cardiomyopathic patterns represent different clinical and pathologic subsets of ARVC. Myocellular features are an important clue in the distinction between the two entities. The differentiation between the 2 patterns is feasible on endomyocardial biopsy and could give important prognostic information.

Endomyocardial biopsy findings in patients with ventricular arrhythmias of unknown origin.

To evaluate possible occult myocardial disease in patients with ventricular arrhythmias of unknown origin, over 11 years right ventricular endomyocardial biopsies (EMB) were performed on 80 consecutive such patients (29 Females, 51 Males; median age 42 years). Seventy-one (89%) had ventricular tachycardia or fibrillation, 7 (9%) had complex ventricular arrhythmias, and 2 (3%) had premature ventricular beats. None showed clinical evidence of congestive heart failure or significant coronary artery or valvular disease. Endomyocardial biopsies revealed pathologic changes in 70 out of 80 patients (88%). Of the 70 affected, 39 (56%) had nonspecific changes consistent with cardiomyopathy (e.g., myofiber hypertrophy, interstitial and perivascular fibrosis, and vascular sclerosis); 6 (9%) had active myocarditis (Myo); 7 (10%) had borderline Myo; 7 (10%) had small vessel disease; 6 (9%) had changes consistent with arrhythmogenic cardiomyopathy; 2 (3%) had amyloidosis; 2 (3%) had microfibrillar cardiomyopathy, and one (1.0%) showed intravascular organizing thrombus. Thus, EMB reveals a variety of abnormalities in the majority of patients presenting with ventricular arrhythmias without clinical evidence of structural heart disease.

Hypersensitivity myocarditis: Findings in native and transplanted hearts.

Seven explanted hearts from a total of 288 heart transplants performed at UCLA Medical Center had histologic evidence of hypersensitivity myocarditis (prevalence = 2.4%). Three patients had a clinical history of drug allergy, and two had a clinically documented drug reaction prior to transplant. Three patients had peripheral eosinophilia prior to transplant. Five patients with hypersensitivity myocarditis had dilated cardiomyopathy, one had congenital abnormalities, and one had ischemic heart disease. In the period up to 3 weeks posttransplant, four patients had episodes of acute rejection (ISHLT grade 2 to 4) with eosinophils histologically. Results suggest that hypersensitivity myocarditis may have an increasing prevalence in the native heart before transplant and in the newly transplanted heart.

Dilated cardiomyopathy in a zidovudine-treated AIDS patient.

The pathogenesis of dilated cardiomyopathy in acquired immunodeficiency syndrome (AIDS) is poorly understood. We report a case of an HIV-positive, 45-year-old homosexual male treated with high-dose azidothymidine (AZT, 1,200 mg/day) for two years prior to development of AIDS. He subsequently manifested symptoms of congestive heart failure with left ventricle dilation and a 20% ejection fraction. An endomyocardial biopsy showed no active myocarditis, but intramyocytic vacuoles were found. Transmission electron microscopy revealed mitochondrial cristae with distortion and myofibrillar loss. The clinical consideration was dilated cardiomyopathy in AIDS. His AIDS worsened and he died in October 1991. Autopsy revealed a 100-ml pericardial effusion, cardiomegaly, and biventricular dilation. Vacuolar changes in cardiac myocytes were present. Pathologic findings support a diagnosis of AZT-induced cardiotoxicity. Potential mechanisms are discussed.

Working formulation nomenclature of heart transplant pathology: A retrospective evaluation of 1037 endomyocardial biopsies.

Working Formulation (WF) was recently introduced by the International Society for Heart Transplantation to grade acute cellular rejection, as well as additional lesions observed in endomyocardial biopsies (EMBs). The aim of this study was to evaluate the actual advantages of this grading system in terms of feasibility and predictive value. To this purpose, we reclassified 1037 EMBs performed in our heart transplantation units according to the WF. Our results show that multifocal mild rejection (grade IA), when worsening, tends to progress to multifocal moderate (3A), whereas diffuse mild (1B) generally worsens to diffuse moderate (3B), thus following the same focal or diffuse pattern. Unifocal moderate rejection (grade 2) has a peculiar behavior, in that it almost always resolves, though in our units it is treated the same way as is grade 113. Finally, we found a significant relationship between Quilty B effect and chronic rejection. In conclusion, this retrospective study shows that WF is effective in using both qualitative and quantitative criteria and, particularly, in separating focal and diffuse forms of rejection and devoting a distinct grade to unifocal moderate rejection.

Pathologic evidence of arrhythmogenic cardiomyopathy and myocarditis in two siblings.

This report describes the case of two siblings who underwent heart transplantation with a clinical diagnosis of mildly dilated cardiomyopathy. Pathological examination of the hearts revealed arrhythmogenic (right ventricular) cardiomyopathy, adipose type, associated with biventricular myocarditis in both the recipients' hearts. Family history revealed the occurrence of dilated cardiomyopathy and myocarditis in their father and his sister. To our knowledge, this is the first pathological demonstration of arrhythmogenic cardiomyopathy and myocarditis in siblings. We think this report substantiates a genetic ground for the relationship between these two heart conditions.