Heart transplantation in amyloidosis: Clinical and imaging manifestations

Objetivo: Describir las características clínicas e imagenológicas de los pacientes con trasplante cardiaco por amiloidosis en una institución de la comunidad. Método: Serie de casos descriptiva de pacientes consecutivos receptores de trasplante cardiaco con amiloidosis en un centro médico. Se incluyeron todos los pacientes con diagnóstico de amiloidosis con compromiso cardiaco receptores de trasplante cardiaco en el periodo de noviembre de 2008a febrero de 2021. Resultados: Se incluyeron 16 pacientes con una edad media de 59.9 años (± 10.2) y el 81.25 % (n = 13) eran de sexo masculino. Según el tipo de amiloidosis, 12 pacientes recibieron el trasplante por amiloidosis por cadenas livianas (AL) y 4 por amiloidosis por transtiretina (ATTR). Las formas más frecuentes de presentación clínica fueron sobrecarga izquierda (50 %) y shock cardiogénico (32 %). La mitad recibieron el trasplante estando en lista de emergencia. La fracción de eyección promedio previa al trasplante fue del 43% (± 16). Presentaron disfunción del ventrículo derecho 14 de los 16 pacientes. El hallazgo más común en la resonancia magnética cardiaca fue el patrón de realce tardío de gadolinio subendocárdico difuso, con anulación del pool sanguíneo. La realización del trasplante cardiaco permitió a la mitad de los pacientes con amiloidosis AL (n = 6) la posibilidad de recibir trasplante de médula ósea en un segundo tiempo. Conclusiones: En la actualidad, el trasplante cardiaco se ha convertido en una opción para pacientes con insuficiencia cardiaca por amiloidosis, tanto AL como ATTR. En los pacientes con amiloidosis AL incluso puede permitir en un segundo tiempo el trasplante de médula ósea.Objective: To describe the clinical and imaging characteristics of heart transplantation patients due to amyloidosis in a community institution. Method: Descriptive case series of consecutive heart transplantation patients with amyloidosis in a medical center. All patients with diagnosis of amyloidosis with cardiac compromise receiving heart transplantation, performed in the period November 2008 to February 2021, were included in the analysis. Results: A total of 16 patients were included. The mean age was 59.9 years (± 10.2). 81.25% (n = 13) were male. According to the type of amyloidosis, 12 patients were transplanted for AL amyloidosis and 4 for ATTR amyloidosis. The most frequent clinical presentations were left overload (50%) and cardiogenic shock (32%). The mean ejection fraction prior to transplantation was 43% (± 16), 14 of the 16 patients had right ventricular dysfunction. The most common finding on cardiac magnetic resonance was the diffuse subendocardial late gadolinium enhancement pattern, with cancellation of the blood pool. The heart transplantation gave 6 patients the chance to receive a bone marrow transplantation afterwards. Conclusions: Heart transplantation has become an option for patients with heart failure due to AL and ATTR amyloidosis. In patients with AL amyloidosis, it might even allow bone marrow transplantation in a second stage.Fil: Decotto, Santiago. Hospital Italiano; ArgentinaFil: Villanueva, Eugenia. Hospital Italiano; ArgentinaFil: Pérez de Arenaza, Diego. Hospital Italiano; ArgentinaFil: Nucifora, Elsa Mercedes. Hospital Italiano; ArgentinaFil: Aguirre, Maria Adela. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Posadas Martinez, Maria Lourdes. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marenchino, Ricardo G.. Hospital Italiano; ArgentinaFil: Belziti, César. Hospital Italiano; Argentin

Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation

Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation. The steroid hormone ecdysone regulates germline development and stem cell niche establishment in the Drosophila ovary by modulating TGF-β signalling and cell adhesion

Spindle positioning in the stem cell niche

Stem cells are the source of differentiated cells that constitute tissues and organs. Two fundamental characteristics of stem cells are their abilities to self‐renew stem cell identity and to produce differentiated cells, the balance of which can be achieved by asymmetric stem cell division. Many stem cells have been shown to reside in a stem cell niche, the home of stem cells that regulates the stem cell behavior. Recent studies have revealed the critical contribution of cytoskeletons in achieving asymmetric stem cell division: mitotic spindles in dividing stem cells are often oriented with respect to the stem cell niche, which is supported by concerted actions of microtubule networks and components at the cell membrane such as adherens junctions, the actin cytoskeleton, and the extracellular matrix. In this article, we review the mechanism of stem cell spindle orientation, with emphasis on its relationship with the stem cell niche, and discuss how it contributes to tissue development and homeostasis. WIREs Dev Biol 2012, 1:215–230. doi: 10.1002/wdev.16 For further resources related to this article, please visit the WIREs website .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90343/1/16_ftp.pd

Rab11 Is Required for Epithelial Cell Viability, Terminal Differentiation, and Suppression of Tumor-Like Growth in the Drosophila Egg Chamber

The Drosophila egg chamber provides an excellent system in which to study the specification and differentiation of epithelial cell fates because all of the steps, starting with the division of the corresponding stem cells, called follicle stem cells, have been well described and occur many times over in a single ovary.Here we investigate the role of the small Rab11 GTPase in follicle stem cells (FSCs) and in their differentiating daughters, which include main body epithelial cells, stalk cells and polar cells. We show that rab11-null FSCs maintain their ability to self renew, even though previous studies have shown that FSC self renewal is dependent on maintenance of E-cadherin-based intercellular junctions, which in many cell types, including Drosophila germline stem cells, requires Rab11. We also show that rab11-null FSCs give rise to normal numbers of cells that enter polar, stalk, and epithelial cell differentiation pathways, but that none of the cells complete their differentiation programs and that the epithelial cells undergo premature programmed cell death. Finally we show, through the induction of rab11-null clones at later points in the differentiation program, that Rab11 suppresses tumor-like growth of epithelial cells. Thus, rab11-null epithelial cells arrest differentiation early, assume an aberrant cell morphology, delaminate from the epithelium, and invade the neighboring germline cyst. These phenotypes are associated with defects in E-cadherin localization and a general loss of cell polarity.While previous studies have revealed tumor suppressor or tumor suppressor-like activity for regulators of endocytosis, our study is the first to identify such activity for regulators of endocytic recycling. Our studies also support the recently emerging view that distinct mechanisms regulate junction stability and plasticity in different tissues

Differential Roles of HOW in Male and Female Drosophila Germline Differentiation

The adult gonads in both male and female Drosophila melanogaster produce gametes that originate from a regenerative pool of germline stem cells (GSCs). The differentiation programme that produces gametes must be co-ordinated with GSC maintenance and proliferation in order to regulate tissue regeneration. The HOW RNA-binding protein has been shown to maintain mitotic progression of male GSCs and their daughters by maintenance of Cyclin B expression as well as suppressing accumulation of the differentiation factor Bam. Loss of HOW function in the male germline results in loss of GSCs due to a delay in G2 and subsequent apoptosis. Here we show that female how mutant GSCs do not have any cell cycle defects although HOW continues to bind bam mRNA and suppress Bam expression. The role of HOW in suppressing germ cell Bam expression appears to be conserved between sexes, leading to different cellular outcomes in how mutants due to the different functions of Bam. In addition the role in maintaining Cyclin B expression has not been conserved so female how GSCs differentiate rather than arrest

Binding between Crossveinless-2 and Chordin Von Willebrand Factor Type C Domains Promotes BMP Signaling by Blocking Chordin Activity

BACKGROUND: Crossveinless-2 (CV2) is an extracellular BMP modulator protein of the Chordin family, which can either enhance or inhibit BMP activity. CV2 binds to BMP2 via subdomain 1 of the first of its five N-terminal von Willebrand factor type C domains (VWC1). Previous studies showed that this BMP binding is required for the anti-, but not for the pro-BMP effect of CV2. More recently, it was shown that CV2 can also bind to the BMP inhibitor Chordin. However, it remained unclear which domains mediate this binding, and whether it accounts for an anti- or pro-BMP effect. PRINCIPAL FINDINGS: Here we report that a composite interface of CV2 consisting of subdomain 2 of VWC1 and of VWC2-4, which are dispensable for BMP binding, binds to the VWC2 domain of Chordin. Functional data obtained in zebrafish embryos indicate that this binding of Chordin is required for CV2's pro-BMP effect, which actually is an anti-Chordin effect and, at least to a large extent, independent of Tolloid-mediated Chordin degradation. We further demonstrate that CV2 mutant versions that per se are incapable of BMP binding can attenuate the Chordin/BMP interaction. CONCLUSIONS: We have physically dissected the anti- and pro-BMP effects of CV2. Its anti-BMP effect is obtained by binding to BMP via subdomain1 of the VWC1 domain, a binding that occurs in competition with Chordin. In contrast, its pro-BMP effect is achieved by direct binding to Chordin via subdomain 2 of VWC1 and VWC2-4. This binding seems to induce conformational changes within the Chordin protein that weaken Chordin's affinity to BMP. We propose that in ternary Chordin-CV2-BMP complexes, both BMP and Chordin are directly associated with CV2, whereas Chordin is pushed away from BMP, ensuring that BMPs can be more easily delivered to their receptors

Gonadal Transcriptome Alterations in Response to Dietary Energy Intake: Sensing the Reproductive Environment

Reproductive capacity and nutritional input are tightly linked and animals' specific responses to alterations in their physical environment and food availability are crucial to ensuring sustainability of that species. We have assessed how alterations in dietary energy intake (both reductions and excess), as well as in food availability, via intermittent fasting (IF), affect the gonadal transcriptome of both male and female rats. Starting at four months of age, male and female rats were subjected to a 20% or 40% caloric restriction (CR) dietary regime, every other day feeding (IF) or a high fat-high glucose (HFG) diet for six months. The transcriptional activity of the gonadal response to these variations in dietary energy intake was assessed at the individual gene level as well as at the parametric functional level. At the individual gene level, the females showed a higher degree of coherency in gonadal gene alterations to CR than the males. The gonadal transcriptional and hormonal response to IF was also significantly different between the male and female rats. The number of genes significantly regulated by IF in male animals was almost 5 times greater than in the females. These IF males also showed the highest testosterone to estrogen ratio in their plasma. Our data show that at the level of gonadal gene responses, the male rats on the IF regime adapt to their environment in a manner that is expected to increase the probability of eventual fertilization of females that the males predict are likely to be sub-fertile due to their perception of a food deficient environment

Cytoneme-Mediated Delivery of Hedgehog Regulates the Expression of Bone Morphogenetic Proteins to Maintain Germline Stem Cells in Drosophila

Genetic manipulation of the germline stem cell niche in Drosophila ovaries reveals that support cells ensure the maintenance of stem cells by modulating the spread of Hedgehog within the niche

Histone H3K9 Trimethylase Eggless Controls Germline Stem Cell Maintenance and Differentiation

Epigenetic regulation plays critical roles in the regulation of cell proliferation, fate determination, and survival. It has been shown to control self-renewal and lineage differentiation of embryonic stem cells. However, epigenetic regulation of adult stem cell function remains poorly defined. Drosophila ovarian germline stem cells (GSCs) are a productive adult stem cell system for revealing regulatory mechanisms controlling self-renewal and differentiation. In this study, we show that Eggless (Egg), a H3K9 methyltransferase in Drosophila, is required in GSCs for controlling self-renewal and in escort cells for regulating germ cell differentiation. egg mutant ovaries primarily exhibit germ cell differentiation defects in young females and gradually lose GSCs with time, indicating that Egg regulates both germ cell maintenance and differentiation. Marked mutant egg GSCs lack expression of trimethylated H3K9 (H3k9me3) and are rapidly lost from the niche, but their mutant progeny can still differentiate into 16-cell cysts, indicating that Egg is required intrinsically to control GSC self-renewal but not differentiation. Interestingly, BMP-mediated transcriptional repression of differentiation factor bam in marked egg mutant GSCs remains normal, indicating that Egg is dispensable for BMP signaling in GSCs. Normally, Bam and Bgcn interact with each other to promote GSC differentiation. Interestingly, marked double mutant egg bgcn GSCs are still lost, but their progeny are able to differentiate into 16-cell cysts though bgcn mutant GSCs normally do not differentiate, indicating that Egg intrinsically controls GSC self-renewal through repressing a Bam/Bgcn-independent pathway. Surprisingly, RNAi-mediated egg knockdown in escort cells leads to their gradual loss and a germ cell differentiation defect. The germ cell differentiation defect is at least in part attributed to an increase in BMP signaling in the germ cell differentiation niche. Therefore, this study has revealed the essential roles of histone H3K9 trimethylation in controlling stem cell maintenance and differentiation through distinct mechanisms

Caprin Controls Follicle Stem Cell Fate in the Drosophila Ovary

Adult stem cells must balance self-renewal and differentiation for tissue homeostasis. The Drosophila ovary has provided a wealth of information about the extrinsic niche signals and intrinsic molecular processes required to ensure appropriate germline stem cell renewal and differentiation. The factors controlling behavior of the more recently identified follicle stem cells of the ovary are less well-understood but equally important for fertility. Here we report that translational regulators play a critical role in controlling these cells. Specifically, the translational regulator Caprin (Capr) is required in the follicle stem cell lineage to ensure maintenance of this stem cell population and proper encapsulation of developing germ cells by follicle stem cell progeny. In addition, reduction of one copy of the gene fmr1, encoding the translational regulator Fragile X Mental Retardation Protein, exacerbates the Capr encapsulation phenotype, suggesting Capr and fmr1 are regulating a common process. Caprin was previously characterized in vertebrates as Cytoplasmic Activation/Proliferation-Associated Protein. Significantly, we find that loss of Caprin alters the dynamics of the cell cycle, and we present evidence that misregulation of CycB contributes to the disruption in behavior of follicle stem cell progeny. Our findings support the idea that translational regulators may provide a conserved mechanism for oversight of developmentally critical cell cycles such as those in stem cell populations