To study the features of bleeding conditions apparently not associated with vascular, platelet, or clotting dysfunctions.Conditions that may meet these criteria are: Münchausen syndrome factitious or fictitious, suicidal or homicidal bleeding, bleeding due to self-punishment, stigmatization, the battered child syndrome, and psychogenic bleeding.The importance of these variegate conditions is not trivial in clinical practice. Differential diagnosis may be difficult and involve other specialists besides hematologists. Occasionally, invasive procedures are involved.The occurrence of bleeding in patients, without a clotting defect or a systemic disorder and a negative family history for bleeding represents a diagnostic challenge. A careful examination of the physical and psychological status of the patient and an appropriate evaluation of the environment in which bleeding occurs, is always needed.
<b>Objective</b>. In patients with type 2 diabetes (T2D) and critical limb ischemia (CLI), migration of circulating CD34<sup>+</sup> cells predicted cardiovascular mortality at 18 months post-revascularization. This study aimed to provide long-term validation and mechanistic understanding of the biomarker. <p><b>Research Design and Methods</b>. The association between CD34<sup>+</sup> cell migration and cardiovascular mortality was reassessed at 6 years post-revascularization. In a new series of T2D-CLI and control subjects, immuno-sorted bone marrow (BM)-CD34<sup>+</sup> cells were profiled for microRNA expression and assessed for apoptosis and angiogenesis activity. The differentially regulated microRNA-21, and its pro-apoptotic target PDCD4, were titrated to verify their contribution in transferring damaging signals from CD34<sup>+</sup> cells to endothelial cells.</p> <p><b>Results</b>.<b> </b>Multivariable regression analysis confirmed CD34<sup>+</sup> cell migration forecasts long-term cardiovascular mortality. <a>CD34<sup>+</sup> cells from T2D-CLI patients were more apoptotic and less proangiogenic than controls and featured microRNA-21 downregulation, modulation of several long non-coding RNAs acting as microRNA-21 sponges, and upregulation of the microRNA-21 proapoptotic target PDCD4. Silencing miR-21 in control CD34<sup>+</sup> cells phenocopied the T2D-CLI cell behavior. In coculture, T2D-CLI CD34<sup>+</sup> cells imprinted naïve endothelial cells, increasing apoptosis, reducing network formation, and modulating the TUG1 sponge/microRNA-21/PDCD4 axis. Silencing PDCD4 or scavenging ROS protected endothelial cells from the negative influence of T2D-CLI CD34<sup>+</sup> cells</a></p> <p><b>Conclusions</b>.<b> </b>Migration of CD34<sup>+</sup> cells predicts long-term cardiovascular mortality in T2D-CLI patients. An altered paracrine signalling conveys anti-angiogenic and pro-apoptotic features from CD34<sup>+</sup> cells to the endothelium. This damaging interaction may increase the risk for life-threatening complications.</p>
Correction to: The Old and the New in Prekallikrein Deficiency: Historical Context and a Family from Argentina with PK Deficiency due to a New Mutation (Arg541Gln) in Exon 14 Associated with a Common Polymorphysm (Asn124Ser) in Exon 5Semin Thromb Hemost 2014; 40(05): 592-599DOI: 10.1055/s-0034-1384767
Prekallikrein (PK) is one of the clotting factors involved in the contact phase of blood. PK has an important historical role as its deficiency state represents the second instance of a clotting defect without bleeding manifestations, the first one being factor XII deficiency. PK deficiency is a rare clotting disorder. Moreover, only 11 patients have been investigated so far by molecular biology techniques. In this article, we briefly review some of the history around PK and also present some recent data on a newly identified family from Argentina suffering from PK deficiency. Two patients are homozygous whereas other family members are heterozygous. PK activity and antigen are 1% of normal in the homozygotes and around 60 to 70% of normal in the heterozygotes. As expected, all patients are asymptomatic of bleeding or thrombosis presentations. However, the two homozygotes showed essential hypertension. The PK deficiency in this family is due to a new mutation (Arg541Gln) in exon 14. The defect segregates together with a known polymorphism, Asn124Ser, in exon 5. The significance of the presence of hypertension in the two homozygotes is discussed in view of the extra coagulation effects of PK on vasodilation, vessel permeability, and the control of blood pressure. Structure function analysis indicates that the substitution of Arg with Gln probably impedes the transmembrane diffusion of the molecule, which therefore cannot be secreted in the homozygotes. The presence of hypertension in patients with PK deficiency has been previously reported in some but not all patients. Future research activities will probably concentrate on the effect of PK and other contact phase factors on the vascular system.
Introduction: Diabetic neuropathy and distal foot lesions are common complications of type two diabetic patients (T2DM), however the underlying pathophysiology remains uncertain. Mast cells (MCs) provide a possible link with immunity and neuroinflammation. These cells of innate immune system are found near sensory nerves or the endoneurial compartment, where they differentiate and participate in innate host defense reactions. MCs are involved in wound healing, but their role in diabetes is unknown. Aim: To evaluate a possible connection between peripheral bone marrow derived blood MC precursors and diabetic neuropathy without and with ischemic skin lesions. Methods: We enrolled 26 healthy controls (C), 15 T2DM with peripheral sensimotor neuropathy (N) and 14 T2DM with neuropathy, distal ischemia (allux oximetry <30 mm Hg) and foot lesions (N1). Peripheral blood was analysed by flow-cytometry (CD34, CD117, lineage cocktail 1 and FcεRI antibodies). Results: We found a significant decrease of MC precursors (LIN-, CD34+, CD117+, FcεRI+ cells) in N and N1 (0.00and 0.00051% of mononuclear cells vs. 0.0018% in C, p<0.04). MC number directly correlated with total lymphocyte (p<0.005, R =0.474) T-lymphocyte (p<0.005, R =0.396) and CD4+ T-lymphocyte (p<0.0005, R =0.515) numbers. There was an inverse but not significant correlation with monocytes (p=0.073, R =0.197). Conclusions: Our results show a possible involvement of MC precursors in human neuropathy and neuroischemic diabetic foot lesions. Conceivably, MCs could have a protective role in favoring wound healing by interaction with cells such as fibroblasts, endothelial, immune, nervous and epithelial cells and by release mediators and neurotransmitters. The correlation with T-lymphocytes might explain the impaired wound healing in N1, suggesting a direct contact between the two populations at the lesion site. Although not significant, the inverse relation with monocytes could be i up-regulated by the decrease in MC precursors. Disclosure M. Sambataro: None. L. Sambado: None. E. Trevisiol: None. A. Paccagnella: None.
Cholangiocarcinoma (CCA) is characterized by an abundant stromal reaction. Cancer-associated fibroblasts (CAFs) are pivotal in tumor growth and invasiveness and represent a potential therapeutic target. To understand the mechanisms leading to CAF recruitment in CCA, we studied (1) expression of epithelial-mesenchymal transition (EMT) in surgical CCA specimens and CCA cells, (2) lineage tracking of an enhanced green fluorescent protein (EGFP)-expressing human male CCA cell line (EGI-1) after xenotransplantation into severe-combined-immunodeficient mice, (3) expression of platelet-derived growth factors (PDGFs) and their receptors in vivo and in vitro, (4) secretion of PDGFs by CCA cells, (5) the role of PDGF-D in fibroblast recruitment in vitro, and (6) downstream effectors of PDGF-D signaling. CCA cells expressed several EMT biomarkers, but not alpha smooth muscle actin (α-SMA). Xenotransplanted CCA masses were surrounded and infiltrated by α-SMA-expressing CAFs, which were negative for EGFP and the human Y-probe, but positive for the murine Y-probe. CCA cells were strongly immunoreactive for PDGF-A and -D, whereas CAFs expressed PDGF receptor (PDGFR)β. PDGF-D, a PDGFRβ agonist, was exclusively secreted by cultured CCA cells. Fibroblast migration was potently induced by PDGF-D and CCA conditioned medium and was significantly inhibited by PDGFRβ blockade with Imatinib and by silencing PDGF-D expression in CCA cells. In fibroblasts, PDGF-D activated the Rac1 and Cdc42 Rho GTPases and c-Jun N-terminal kinase (JNK). Selective inhibition of Rho GTPases (particularly Rac1) and of JNK strongly reduced PDGF-D-induced fibroblast migration.CCA cells express several mesenchymal markers, but do not transdifferentiate into CAFs. Instead, CCA cells recruit CAFs by secreting PDGF-D, which stimulates fibroblast migration through PDGFRβ and Rho GTPase and JNK activation. Targeting tumor or stroma interactions with inhibitors of the PDGF-D pathway may offer a novel therapeutic approach.
Patients with a low platelet count are prone to bleeding. The occurrence of a thrombotic event in congenital thrombocytopenic patients is rare and puzzling. At least nine patients with Glanzmann thrombasthenia have been reported to have had a thrombotic event, eight venous and one arterial (intracardiac, in the left ventricle). On the contrary, three patients with Bernard-Soulier syndrome have been shown to have had arterial thrombosis (myocardial infarction) but no venous thrombosis. Finally, seven patients with the familiar macrothrombocytopenia due to alterations of the MYH9 gene have been reported to have had thrombosis (five myocardial infractions, one ischemic stroke, one deep vein thrombosis and one portal vein thrombosis). The significance of these findings is discussed with particular emphasis on the discrepancy between venous and arterial thrombosis seen in patients with Glanzmann thrombasthenia and Bernard-Soulier syndrome.
