Association Between Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to-Lymphocyte Ratio (PLR) With Diabetic Retinopathy in Type 2 Diabetic Patients.

Diabetic retinopathy (DR) is one of the main causes of blindness worldwide, but an effective screening is challenging due to limited available retina specialists. Finding novel biomarkers could help clinical decision in prioritizing ophthalmological consultation in patients at risk of developing severe DR. This study aims to investigate the association between neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and the presence and severity of DR in patients with T2DM. A retrospective study was performed on 90 patients with T2DM admitted in the Ophthalmology Clinic, Emergency University Hospital Bucharest in Bucharest, Romania, between March 2022 and March 2023, for routine cataract surgery. The cases were divided into three groups according to the severity of DR: no DR (noDR), non-proliferative diabetic retinopathy (NPDR), and proliferative DR (PDR) groups. NLR values raised significantly in the PDR group, no DR group (p = 0.003), and NPDR group (p = 0.026), while PLR values did not differ statistically significant among the groups (p = 0.059). No difference in terms of age, sex, HbA1C, and comorbidities were observed. In the multivariate analysis, the NLR (OR = 2.01, [1.29; 3.14], p = 0.0019) and diabetic nephropathy (OR = 3.84, [1.23; 11.98], p = 0.0203) were associated with higher rates of PDR. NLR may be a promising tool in the risk stratification of T2DM patients with DR.

Cardiovascular Disease as a Consequence or a Cause of Cancer: Potential Role of Extracellular Vesicles.

Both cardiovascular disease and cancer continue to be causes of morbidity and mortality all over the world. Preventing and treating heart disease in patients undergoing cancer treatment remain an important and ongoing challenge for improving the lives of cancer patients, but also for their survival. Despite ongoing efforts to improve patient survival, minimal advances have been made in the early detection of cardiovascular disease in patients suffering from cancer. Understanding the communication between cancer and cardiovascular disease can be based on a deeper knowledge of the molecular mechanisms that define the profile of the bilateral network and establish disease-specific biomarkers and therapeutic targets. The role of exosomes, microvesicles, and apoptotic bodies, together defined as extracellular vesicles (EVs), in cross talk between cardiovascular disease and cancer is in an incipient form of research. Here, we will discuss the preclinical evidence on the bilateral connection between cancer and cardiovascular disease (especially early cardiac changes) through some specific mediators such as EVs. Investigating EV-based biomarkers and therapies may uncover the responsible mechanisms, detect the early stages of cardiovascular damage and elucidate novel therapeutic approaches. The ultimate goal is to reduce the burden of cardiovascular diseases by improving the standard of care in oncological patients treated with anticancer drugs or radiotherapy.

Microvesicles and Microvesicle-Associated microRNAs Reflect Glioblastoma Regression: Microvesicle-Associated miR-625-5p Has Biomarker Potential.

Glioblastoma (GB) is the most aggressive and recurrent form of brain cancer in adults. We hypothesized that the identification of biomarkers such as certain microRNAs (miRNAs) and the circulating microvesicles (MVs) that transport them could be key to establishing GB progression, recurrence and therapeutic response. For this purpose, circulating MVs were isolated from the plasma of GB patients (before and after surgery) and of healthy subjects and characterized by flow cytometry. OpenArray profiling and the individual quantification of selected miRNAs in plasma and MVs was performed, followed by target genes' prediction and in silico survival analysis. It was found that MVs' parameters (number, EGFRvIII and EpCAM) decreased after the surgical resection of GB tumors, but the inter-patient variability was high. The expression of miR-106b-5p, miR-486-3p, miR-766-3p and miR-30d-5p in GB patients' MVs was restored to control-like levels after surgery: miR-106b-5p, miR-486-3p and miR-766-3p were upregulated, while miR-30d-5p levels were downregulated after surgical resection. MiR-625-5p was only identified in MVs isolated from GB patients before surgery and was not detected in plasma. Target prediction and pathway analysis showed that the selected miRNAs regulate genes involved in cancer pathways, including glioma. In conclusion, miR-625-5p shows potential as a biomarker for GB regression or recurrence, but further in-depth studies are needed.

The Multifaceted Role of Extracellular Vesicles in Glioblastoma: microRNA Nanocarriers for Disease Progression and Gene Therapy.

Glioblastoma (GB) is the most aggressive form of brain cancer in adults, characterized by poor survival rates and lack of effective therapies. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression post-transcriptionally through specific pairing with target messenger RNAs (mRNAs). Extracellular vesicles (EVs), a heterogeneous group of cell-derived vesicles, transport miRNAs, mRNAs and intracellular proteins, and have been shown to promote horizontal malignancy into adjacent tissue, as well as resistance to conventional therapies. Furthermore, GB-derived EVs have distinct miRNA contents and are able to penetrate the blood-brain barrier. Numerous studies have attempted to identify EV-associated miRNA biomarkers in serum/plasma and cerebrospinal fluid, but their collective findings fail to identify reliable biomarkers that can be applied in clinical settings. However, EVs carrying specific miRNAs or miRNA inhibitors have great potential as therapeutic nanotools in GB, and several studies have investigated this possibility on in vitro and in vivo models. In this review, we discuss the role of EVs and their miRNA content in GB progression and resistance to therapy, with emphasis on their potential as diagnostic, prognostic and disease monitoring biomarkers and as nanocarriers for gene therapy.

Extracellular Vesicles: Versatile Nanomediators, Potential Biomarkers and Therapeutic Agents in Atherosclerosis and COVID-19-Related Thrombosis.

Cells convey information among one another. One instrument employed to transmit data and constituents to specific (target) cells is extracellular vesicles (EVs). They originate from a variety of cells (endothelial, immune cells, platelets, mesenchymal stromal cells, etc.), and consequently, their surface characteristics and cargo vary according to the paternal cell. The cargo could be DNA, mRNA, microRNA, receptors, metabolites, cytoplasmic proteins, or pathological molecules, as a function of which EVs exert different effects upon endocytosis in recipient cells. Recently, EVs have become important participants in a variety of pathologies, including atherogenesis and coronavirus disease 2019 (COVID-19)-associated thrombosis. Herein, we summarize recent advances and some of our own results on the role of EVs in atherosclerotic cardiovascular diseases, and discuss their potential to function as signaling mediators, biomarkers and therapeutic agents. Since COVID-19 patients have a high rate of thrombotic events, a special section of the review is dedicated to the mechanism of thrombosis and the possible therapeutic potential of EVs in COVID-19-related thrombosis. Yet, EV mechanisms and their role in the transfer of information between cells in normal and pathological conditions remain to be explored.

Extracellular Vesicles from Adipose Tissue Stem Cells in Diabetes and Associated Cardiovascular Disease; Pathobiological Impact and Therapeutic Potential.

Adipose tissue-derived stem cells (ADSCs) are pluripotent mesenchymal stem cells found in relatively high percentages in the adipose tissue and able to self-renew and differentiate into many different types of cells. "Extracellular vesicles (EVs), small membrane vesicular structures released during cell activation, senescence, or apoptosis, act as mediators for long distance communication between cells, transferring their specific bioactive molecules into host target cells". There is a general consensus on how to define and isolate ADSCs, however, multiple separation and characterization protocols are being used in the present which complicate the results' integration in a single theory on ADSCs' and their derived factors' way of action. Metabolic syndrome and type 2 diabetes mellitus (T2DM) are mainly caused by abnormal adipose tissue size, distribution and metabolism and so ADSCs and their secretory factors such as EVs are currently investigated as therapeutics in these diseases. Moreover, due to their relatively easy isolation and propagation in culture and their differentiation ability, ADSCs are being employed in preclinical studies of implantable devices or prosthetics. This review aims to provide a comprehensive summary of the current knowledge on EVs secreted from ADSCs both as diagnostic biomarkers and therapeutics in diabetes and associated cardiovascular disease, the molecular mechanisms involved, as well as on the use of ADSC differentiation potential in cardiovascular tissue repair and prostheses.

Integrins α4ß1 and αVß3 are Reduced in Endothelial Progenitor Cells from Diabetic Dyslipidemic Mice and May Represent New Targets for Therapy in Aortic Valve Disease.

Diabetes reduces the number and induces dysfunction in circulating endothelial progenitor cells (EPCs) by mechanisms that are still uncovered. This study aims to evaluate the number, viability, phenotype, and function of EPCs in dyslipidemic mice with early diabetes mellitus and EPC infiltration in the aortic valve in order to identify possible therapeutic targets in diabetes-associated cardiovascular disease. A streptozotocin-induced diabetic apolipoprotein E knock-out (ApoE-/-) mouse model was used to identify the early and progressive changes, at 4 or 7 days on atherogenic diet after the last streptozotocin or citrate buffer injection. Blood and aortic valves from diabetic or nondiabetic ApoE-/- animals were collected.EPCs were identified as CD34 and vascular endothelial growth factor receptor 2 positive monocytes, and the expression levels of α4ß1, αVß3, αVß5, ß1, αLß2, α5 integrins, and C-X-C chemokine receptor type 4 chemokine receptor on EPC surface were assessed by flow cytometry. The number of CD34 positive cells in the aortic valve, previously found to be recruited progenitor cells, was measured by fluorescence microscopy. Our results show that aortic valves from mice fed 7 days with atherogenic diet presented a significantly higher number of CD34 positive cells compared with mice fed only 4 days with the same diet, and diabetes reversed this finding. We also show a reduction of circulatory EPC numbers in diabetic mice caused by cell senescence and lower mobilization. Dyslipidemia induced EPC death through apoptosis regardless of the presence of diabetes, as shown by the higher percent of propidium iodide positive cells and higher cleaved caspase-3 levels. EPCs from diabetic mice expressed α4ß1 and αVß3 integrins at a lower level, while the rest of the integrins tested were unaffected by diabetes or diet. In conclusion, reduced EPC number and expression of α4ß1 and αVß3 integrins on EPCs at 4 and 7 days after diabetes induction in atherosclerosis-prone mice have resulted in lower recruitment of EPCs in the aortic valve.

Sera of Obese Type 2 Diabetic Patients Undergoing Metabolic Surgery Instead of Conventional Treatment Exert Beneficial Effects on Beta Cell Survival and Function: Results of a Randomized Clinical Study.

BACKGROUND: Pancreatic beta cells are highly sensitive to oxidative and endoplasmic reticulum (ER) stress, commonly occurring in type 2 diabetes (T2D) and obesity. OBJECTIVE: We aimed at investigating cellular responses of human beta cells exposed to sera from obese T2D patients treated differently, namely by conventional therapy or laparoscopic sleeve gastrectomy (LSG). METHODS: Serum samples from obese T2D men randomized to conventional treatment or LSG were taken at baseline and 6 months later. After exposing 1.1B4 cells to study patients' sera, the following were assessed: cellular viability and proliferation (by MTT and xCELLigence assays), reactive oxygen species (ROS) production (with DCFH-DA), and expression of ER stress markers, oxidative- or autophagy-related proteins and insulin (by real-time PCR and Western blot). RESULTS: At 6-month follow-up, patients undergoing LSG achieved an adequate glycemic control, whereas conventionally treated patients did not. As compared to 1.1B4 cells incubated with baseline sera (control), cells exposed to sera from LSG-treated participants exhibited (i) increased viability and proliferation (p < 0.05); (ii) diminished levels of ROS and p53 (p < 0.05); (iii) enhanced protein expression of autophagy-related SIRT1 and p62/SQSTM1 (p < 0.05); (iv) significantly decreased transcript levels of ER stress markers (p < 0.05); and (v) augmented insulin expression (p < 0.05). Conversely, the 6-month conventional therapy appeared not to impact on circulating redox status. Moreover, 1.1B4 cells exposed to sera from conventionally treated patients experienced mild ER stress. CONCLUSION: Circulating factors in patients with improved diabetes after metabolic surgery exerted favorable effects on beta cell function and survival.

Role of MicroRNA in Endothelial Dysfunction and Hypertension.

PURPOSE OF REVIEW: Hypertension is either a cause or a consequence of the endothelial dysfunction and a major risk factor for cardiovascular disease (CVD). In vitro and in vivo studies established that microRNAs (miRNAs) are decisive for endothelial cell gene expression and function in various pathological conditions associated with CVD. This review provides an overview of the miRNA role in controlling the key connections between endothelial dysfunction and hypertension. RECENT FINDINGS: Herein we summarize the present understanding of mechanisms underlying hypertension and its associated endothelial dysfunction as well as the miRNA role in endothelial cells with accent on the modulation of renin-angiotensin-aldosterone-system, nitric oxide, oxidative stress and on the control of vascular inflammation and angiogenesis in relation to endothelial dysfunction in hypertension. In particular, latest insights in the identification of endothelial-specific microRNAs and their targets are added to the understanding of miRNA significance in hypertension. This comprehensive knowledge of the role of miRNAs in endothelial dysfunction and hypertension and of molecular mechanisms proposed for miRNA actions may offer novel diagnostic biomarkers and therapeutic targets for controlling hypertension-associated endothelial dysfunction and other cardiovascular complications.

Effects of transplanted circulating endothelial progenitor cells and platelet microparticles in atherosclerosis development.

BACKGROUND INFORMATION: Atherosclerosis is an inflammatory disease, in which risk factors such as hyperlipidemia and hypertension affect the arterial endothelium, resulting in dysfunction, cell damage or both. The number of circulating endothelial progenitor cells and microparticles provides invaluable outcome prediction for atherosclerosis disease. However, evidence for the therapeutic potential of endothelial progenitor cells and microparticles in atherosclerosis development is limited. Our study was designed to investigate the possible protective role of a cell therapy-based approach, using endothelial progenitor cells and the dual behaviour of circulating platelet microparticles, on atherosclerosis development in hypertensive-hypercholesterolemic hamster model. Consequently, control hamsters received four intravenous inoculations of: (1) 1×10(5) endothelial progenitor cells of healthy origins in one dose per month, during four months of diet-induced atherosclerosis, and after hypertensive-hypercholesterolemic diet for further four months; (2) in a second set of experiments, 1×10(5) endothelial progenitor cells of healthy origins or/and 1×10(5) platelet microparticles of atherosclerotic origins were inoculated every other month during hypertensive-hypercholesterolemic diet. RESULTS: Endothelial progenitor cell treatment had the following effects: (1) re-established plasmatic parameters: cholesterol and triglyceride concentrations, blood pressure, heart rate, cytokine and chemokine profiles, platelet microparticle pro-thrombotic activity and endothelial progenitor cell paracrine activity reflected by cytokine/chemokine detection; (2) reduced lipid, macrophage and microparticle accumulation in liver; (3) reduced atherosclerosis development, revealed by decreased lipid, macrophage and microparticle content of arterial wall; (4) induced the recruitment and incorporation of endothelial progenitor cells into liver and arterial wall; (5) improved arterial dysfunction by increasing contraction and relaxation; (6) reduced the protein expression of specific pro-inflammatory molecules in liver and arterial wall. Platelet microparticle transplantation aggravated the above-mentioned biomarkers and atherosclerosis process, which were partially reverted with co-inoculation of platelet microparticles and endothelial progenitor cells. CONCLUSIONS: With this study, we demonstrate in a hypertensive-hypercholesterolemic hamster model, that the endothelial progenitor cell-based therapy suppresses the development of atherosclerosis and reduces hepatic lipid and macrophage accumulation with the consequent alleviation of dyslipidaemia and hypertension. SIGNIFICANCE: Our results support the notion that increasing the number of circulating endothelial progenitor cells by different ways could be a promising therapeutic tool for atherosclerosis.

Midkine proteins in cardio-vascular disease. Where do we come from and where are we heading to?

Midkine is a recently identified new growth factor/cytokine with pleiotropic functions in the human organism. First discovered in the late eighties, midkines have now become the subject of numerous studies in cardiovascular, neurologic, renal diseases and also various types of cancers. We summarize here the most important functions of midkine in cardiovascular diseases, emphasizing its role in inflammation and its antiapoptotic and proangiogenetic effects. Midkine has multiple roles in the organism, with the specific feature of being either beneficial or harmful depending on which tissue it acts on. Even though midkine has been shown to have cardiac protective effects against acute ischemia/reperfusion injury and to inhibit cardiac remodeling, it also promotes intimal hyperplasia and vascular stenosis. As such, different therapeutic strategies are currently being evaluated, consisting of administering either midkine proteins or midkine inhibitors depending on the desired outcome. More data is gathering to suggest that these novel therapies could become an adjunctive to standard cardiovascular therapy. Nonetheless, much is still to be learned about midkine. The encouraging results up till now require further studying in order to fully understand the complete profile of its mechanism of action and the clinical safety and efficacy of novel therapeutic opportunities offered by midkine molecular targeting.

Interaction of platelets with endothelial progenitor cells in the experimental atherosclerosis: Role of transplanted endothelial progenitor cells and platelet microparticles.

BACKGROUND INFORMATION: Recent studies suggest that endothelial progenitor cells (EPCs) and platelets have an important role in repair following vascular injury. Although evidence suggest that platelets are essential in EPC attracting, homing and differentiation to the injury site; however, the platelet effects on EPC function in atherosclerosis have received less attention. In this context, we followed the consequences of circulating EPCs and platelet microparticles (PMPs) administration on platelet-EPC interaction in atherosclerosis and the involved mechanisms. The experiments were performed on Golden Syrian hamsters divided in five equal groups: control (C), hypertensive-hypercholesterolemic (HH), HH treated with EPCs (HH-EPCs) or PMPs (HH-PMPs) and HH treated with EPCs and PMPs (HH-EPCs-PMPs). RESULTS: Compared with C group, EPCs isolated from HH and HH-PMPs groups presented a reduction of endothelial nitric oxide synthase and vascular endothelial growth factor expressions and an increase in thrombospondin-1 expression and inflammatory molecule secretion: interleukin 8 (IL)-8, myeloperoxidase (MPO) and plasminogen activator inhibitor-1 (PAI-1). EPC administration had beneficial effects, the obtained results being similar with those from the C group, while the combination with PMPs did not improve the EPC influences. Static coincubation of EPCs from HH and HH-PMPs with analogous platelets resulted in an increased EPC adhesion/migration, and IL-8, monocyte chemotactic protein-1, regulated on activation, normal T expressed and secreted, MPO and PAI-1 release, explained by the platelet hyperaggregability induced by pronounced distribution of vasodilator-stimulated phosphoprotein and filamentous actin, and the secretion of proinflammatory factors: IL-1ß, -6, -8, CD40 ligand. EPC therapy alone revealed an impaired platelet-EPC interaction directly correlated with the reduction of inflammatory markers and platelet aggregability. Moreover, in a dynamic flow system, EPCs and platelets from HH and HH-PMPs exhibited weakened interplay abilities, while EPC transplantation reinforces them. CONCLUSIONS: The present study demonstrates that HH animals revealed functional impairment of EPCs and platelets, which correlate with their reduced contribution to re-endothelialisation at the injury site, although in vitro exposure to immobilised platelets promotes their adhesion and migration. EPC administration alone recovers EPC/platelet functions and consolidates their interaction under dynamic flow conditions. These findings disclose new advances in understanding the platelet-EPC interaction and its role in the vascular repair.

Extracellular vesicles participate in the transport of cytokines and angiogenic factors in diabetic patients with ocular complications.

INTRODUCTION: Extracellular vesicles (EVs), including circulating microvesicles (MVs) or mi- croparticles (MPs) and exosomes, derived from cells or platelets are present in the peripheral blood and are important elements involved in the activation of the coagulation system, transport of macromolecules and intercellular communication. In patients with vascular complications (including diabetes), the number of EVs is significantly increased during the acute phase of the disease. However, less is known about EVs release in the chronic state of diabetes. OBJECTIVES: To analyse the profile of inflammatory cytokines and angiogenic factors in EVs in diabetic patients with ocular and vascular complications. PATIENTS AND METHODS: The study included patients with diabetes and varying degrees of ocular complications including retinopathy (n = 48) and the control group (n = 13). EV-enriched and EV-depleted fractions were obtained from platelet-poor plasma by means of the centrifugation method (16 000 g, for 90 min). In screening, the profile of cytokines with pro-angiogenic effects was preliminary assessed using the protein microarray technology for controlled diabetic patients - CD, uncontrolled diabetic patients - UD and for the control group. In all patients, concentrations of cytokines: RANTES (Regulated on Activation, Normal T-cell Expressed and secreted) and Ang-2 (angiopoietin-2) were assayed using the ELISA method. Common blood and biochemical tests were performed. RESULTS: In patients with diabetes, analysis of supernatant revealed significantly increased concentrations of basic fibroblast growth factor (bFGF) and soluble receptor for vascular endothelial growth factor 2 (V-EGFR2) when compared to the control group: 49 (10.5-122) vs. 24 (2-72.5) SD (p = 0.03) and 260 (195.5-351) vs. 360 (256-461.5) SD (p = 0.01). In UD patients, concentrations of RANTES, angiostatin, tumor necrosis factor-α (TNF), and tissue inhibitors of metalloproteinase 1 and 2 (TIMP1 and TIMP2) were relatively higher in the EV-enriched fraction when compared to the EV-depleted fraction. Post hoc analysis revealed significant differences between UC patients and the control group in RANTES (16.73 (14.41-18.93) vs. 14.62 (12.37-15.28) mg/ml; p = 0.0235) and Ang-2 (2.76 (2.23-4.64) ng/ml vs. 1.74 (1.54-1.93); p = 0.0316) concentrations. These analyses did not reveal any significant differences in RANTES and Ang-2 concentrations between CD patients and the control group. CONCLUSIONS: The profiles of cytokines and angiogenic factors in EVs are significantly increased in patients with diabetes. Also, the formation of specific cytokines related to EVs is strongly influenced by disease duration and successful treatment. EVs seem to be the conveyors of upregulated cytokines and angiogenic agents in diabetic patients.

Irbesartan administration therapeutically influences circulating endothelial progenitor cell and microparticle mobilization by involvement of pro-inflammatory cytokines.

Circulating microparticles (MPs) and endothelial progenitor cells (EPCs) correlate with endothelial dysfunction and contribute to the pathogenesis of atherosclerosis. In this context, we explored whether the angiotensin II type I receptor antagonist, irbesartan, exerts a pharmacological control in the atherosclerotic process by the improvement of EPC mobilization and inhibitory effects on MP release and VEGF and SDF-1α levels in the hypertensive-hypercholesterolemic (HH) hamster model. The HH hamsters were treated with irbesartan (50mg/kg b.w/day administered by gavage) for 4 month (HHI). We analyzed MP/EPC infiltration in vascular wall before and after irbesartan administration as well as the endothelial function and expression of VEGF/SDF-1α in plasma and tissue and of molecular pathways activated by them. The results showed that treatment with irbesartan significantly increased EPC infiltration and decreased MP infiltration. The mechanisms underlying this response include the reduction/increase of a number of specific membrane receptors exposed by MPs (TF, P-Selectin, E-Selectin, PSGL-1, Rantes), respectively, by EPCs (ß2-Integrins, α4ß1-integrin), the augmentation of endothelium-mediated vasodilation and the reduction of protein expression of VEGF/SDF-1α followed by: (1) the diminishment of pro-inflammatory endothelial cytokines: VEGFR1, VEGFR2, CXCR4, Tie2, PIGF with role in EPC homing to sites of damaged endothelium; and (2) the increase of protein expression of COX-2, PGI2 synthase molecules with role in the improvement of arterial wall vasodilatation. In conclusion, the study underlines that irbesartan administration therapeutically improves/reduces EPC, respectively, MP mobilization and this action may be of salutary relevance contributing to its beneficial cardiovascular effects.

Activation profile of dorsal root ganglia Iba-1 (+) macrophages varies with the type of lesion in rats.

The interactions between neurons, immune and immune-like glial cells can initiate the abnormal processes that underlie neuropathic pain. In the peripheral nervous system the resident macrophages may play an important role. In this study we investigated in experimental adult Sprague-Dawley rats how Iba-1 (ionized calcium binding adaptor molecule 1) (+) resident macrophages in the dorsal root ganglion (DRG) are activated after a spinal nerve ligation (SNL) or streptozotocin (STZ)-induced diabetes. The activation profile was defined by comparing the responses of resident macrophages against microglia in the spinal cord as they share a common origin. After SNL, the Iba-1 (+) macrophages in L5 DRG reached their activation peak 5 days later, clustered as satellite cells around large A-neurons, expressed the MHC-II marker, but did not show p-p38 and p-ERK1/2 activation and did not secrete IL-18. After STZ-induced diabetes, the Iba-1 (+) macrophages reached their activation peak 1 week later in L4 and L5 DRG, remained scattered between neurons, expressed the MHC-II marker only in L5 DRG, did not show p-p38 and p-ERK1/2 activation and did not secrete any of the investigated cytokines/chemokines. These responses suggest that depending on the type of lesion DRG Iba-1 (+) resident macrophages have different activation mechanisms, which are dissimilar to those in microglia.

Circulating endothelial progenitor cell and platelet microparticle impact on platelet activation in hypertension associated with hypercholesterolemia.

AIM: The purpose of this project was to evaluate the influence of circulating endothelial progenitor cells (EPCs) and platelet microparticles (PMPs) on blood platelet function in experimental hypertension associated with hypercholesterolemia. METHODS: Golden Syrian hamsters were divided in six groups: (i) control, C; (ii) hypertensive-hypercholesterolemic, HH; (iii) 'prevention', HHin-EPCs, HH animals fed a HH diet and treated with EPCs; (iv) 'regression', HHfin-EPCs, HH treated with EPCs after HH feeding; (v) HH treated with PMPs, HH-PMPs, and (vi) HH treated with EPCs and PMPs, HH-EPCs-PMPs. RESULTS: Compared to HH group, the platelets from HHin-EPCs and HHfin-EPCs groups showed a reduction of: (i) activation, reflected by decreased integrin 3ß, FAK, PI3K, src protein expression; (ii) secreted molecules as: SDF-1, MCP-1, RANTES, VEGF, PF4, PDGF and (iii) expression of pro-inflammatory molecules as: SDF-1, MCP-1, RANTES, IL-6, IL-1ß; TFPI secretion was increased. Compared to HH group, platelets of HH-PMPs group showed increased activation, molecules release and proteins expression. Compared to HH-PMPs group the combination EPCs with PMPs treatment induced a decrease of all investigated platelet molecules, however not comparable with that recorded when EPC individual treatment was applied. CONCLUSION: EPCs have the ability to reduce platelet activation and to modulate their pro-inflammatory and anti-thrombogenic properties in hypertension associated with hypercholesterolemia. Although, PMPs have several beneficial effects in combination with EPCs, these did not improve the EPC effects. These findings reveal a new biological role of circulating EPCs in platelet function regulation, and may contribute to understand their cross talk, and the mechanisms of atherosclerosis.

Platelet reactivity in chronic venous insufficiency.

BACKGROUND: Chronic venous insufficiency (CVI) is a common medical problem that may result in significant morbidity and mortality. Platelets are key players in haemostasis and thrombosis, but their role in the development of venous thrombosis is more controversial. AIM: The purpose of this study was to investigate platelet properties in CVI and their interaction with the venular endothelium. METHODS: Human peripheral venules were explanted during leg surgery of patients with CVI and of healthy subjects (C); concurrently, the platelets were isolated from blood samples collected. The techniques used were: fluorescence and electron microscopy and Western-blotting. RESULTS: Compared with the C group, the platelets of patients with CVI are activated, as demonstrated by: (i) cellular modifications, such as alteration of the discoidal shape by the development of extended cytoplasmic filopodia and changes of the cells normal ultrastructure, (ii) biochemical modifications, such as the enhanced protein levels of FAK, p85 PI3K, Akt and src, accounting for activation of alphaIIbbeta3 outside-in signaling, and (iii) apparent higher adhesion to the venular endothelium. We demonstrate in addition, that CVI is accompanied by severe modifications of the ultrastructure of the cells within the venular wall. CONCLUSIONS: In CVI, platelets circulate in an activated state and may contribute to the altered dysfunctional response of the venous wall and to the development of this pathology.

The promise of EPC-based therapies on vascular dysfunction in diabetes.

Diabetes mellitus is one of the most common metabolic diseases in the world and the vascular dysfunction represents a challenging clinical problem. In diabetes, endothelial cells (ECs), lining the inner wall of blood vessels, do not function properly and contribute to impaired vascular function. Circulating endothelial progenitor cells (EPCs), the precursor of mature EC, actively participate in endothelial repair, by moving to the vascular injury site to form mature EC and new blood vessels. Knowing that the therapeutic interventions can improve only a part of EC dysfunction in diabetes, this review addresses recent findings on the use of EPCs for cell therapy. The strategies proposed in review are based on in vivo and in vitro studies and, thus, their physiological relevance is confirmed. EPC therapy shows great promise for the prevention and cure of diabetes-induced vascular dysfunction.

Integration properties of Wharton's jelly-derived novel mesenchymal stem cells into ventricular slices of murine hearts.

Wharton's jelly (WJ) is a rich source of multiple-lineage differentiating cells, recently proposed for cell replacement therapy. However, their ability to integrate into the cardiac tissue has not been elucidated, yet. We employed in vitro cardiac transplantation models to investigate the capacity of a novel population of human WJ-derived mesenchymal stem cells (nMSCs) to integrate into both living and ischemic cardiac tissue. NMSCs were characterized for the expression of stem/progenitor cell genes and proteins, as well as for multi-lineage differentiation potential. To assess their integration properties, nMSCs were cocultured with either living or ischemic embryonic murine ventricular slices. Immunohistochemical analyses were performed on cryosections of cocultured preparations to allow human cells tracking within the cocultures. Results showed that nMSCs shared MSC and endothelial colony-forming cell characteristics at gene, protein, and functional levels. NMSCs were markedly chemoattracted towards the ventricular slices, integrating robustly into the depth of both living and ischemic cardiac tissue. In conclusion, the functional ability of WJ-derived cells to populate the cardiac tissue could be validated in vitro. The transplantation models described could be further used to depict the mechanisms of WJ-derived cells integration into the cardiac tissue, contributing to optimization of reliable cell therapies for cardiac repair.

Enoxaparin reduces adrenergic contraction of resistance arterioles in aging and in aging associated with diabetes via engagement of MAP kinase pathway.

The arterial endothelial dysfunction in aging and diabetes remains a clinical problem. We questioned the effect of the low-molecular-weight heparin, enoxaparin, on arterioles contractility in aging and in aging associated with diabetes, and investigated the involvement of the mitogen-activated protein (MAP) kinases pathway in the enoxaparin-mediated effect. The experiments were performed on the isolated resistance arteries of young (4 months old), aged (16 months old), and aged-diabetic hamsters (16 months old and 5 months since streptozotocin injection). The techniques used were myography, molecular biology, and immunoblotting. The results showed that 60 µg/ml enoxaparin has favorable effects on the arteriole reactivity in aged and aged-diabetic conditions, reducing the contractile response to 10-10 mol/l noradrenaline. The diminishment of contractility is exerted via MAP kinase pathway, and involves reduction of c-fos gene expression and of transcription factor AP-1 protein expression. These results suggest that enoxaparin preserves the arterial endothelial function in a mechanism independent of its anticoagulant activity. Understanding the signal transduction mechanisms involved in the altered contractility of vascular wall could provide useful information on the development of specific MAP kinase inhibitors with therapeutic benefits and reduced side effects.