A New Hyaluronic Emulgel of Hesperetin for Topical Application-An In Vitro Evaluation

The present study aimed to formulate and characterize a hesperetin formulation to achieve adequate deposition and retention of hesperetin in the epidermis as a target for some cosmetic/dermatological actions. To derive the final emulgel, various formulations incorporating different proportions of Polysorbate 80 and hyaluronic acid underwent testing through a Box-Behnken experimental design. Nine formulations were created until the targeted emulgel properties were achieved. This systematic approach, following the principles of a design of experiment (DoE) methodology, adheres to a quality-by-design (QbD) paradigm, ensuring a robust and purposeful formulation and highlighting the commitment to a quality-driven design approach. The emulsions were developed using the phase inversion method, optimizing the emulgel with the incorporation of hyaluronic acid. Physically stable optimized emulgels were evaluated for their globule size, surface charge, viscosity, pH, electrical conductivity, and hesperetin content. These assays, along with the temperature swing test, were used to select the optimal formulation. It was characterized by a droplet size, d[4,3], of 4.02 μm, a Z-potential of -27.8 mV, an O/W sign, a pH of 5.2, and a creamy texture and proved to be stable for at least 2 months at room temperature. Additionally, in vitro release kinetics from the selected emulgel exhibited a sustained release profile of hesperetin. Skin assays revealed adequate retention of hesperetin in the human epidermis with minimum permeation. Altogether, these results corroborate the promising future of the proposed emulgel in cosmetic or dermatological use on healthy or diseased skin.

Intranasal Drug Administration in Alzheimer-Type Dementia: Towards Clinical Applications

Alzheimer-type dementia (ATD) treatments face limitations in crossing the blood-brain barrier and systemic adverse effects. Intranasal administration offers a direct route to the brain via the nasal cavity's olfactory and trigeminal pathways. However, nasal physiology can hinder drug absorption and limit bioavailability. Therefore, the physicochemical characteristics of formulations must be optimized by means of technological strategies. Among the strategies that have been explored, lipid-based nanosystems, particularly nanostructured lipid carriers, are promising in preclinical investigations with minimal toxicity and therapeutic efficacy due to their ability to overcome challenges associated with other nanocarriers. We review the studies of nanostructured lipid carriers for intranasal administration in the treatment of ATD. Currently, no drugs for intranasal administration in ATD have marketing approval, with only three candidates, insulin, rivastigmine and APH-1105, being clinically investigated. Further studies with different candidates will eventually confirm the potential of the intranasal route of administration in the treatment of ATD.

Blockade of the trans-sulfuration pathway in acute pancreatitis due to nitration of cystathionine β-synthase

Acute pancreatitis is an inflammatory process of the pancreatic gland that may lead to dysregulation of the trans-sulfuration pathway. The aims of this work were firstly to study the methionine cycle as well as the trans-sulfuration pathway using metabolomic and proteomic approaches identifying the causes of this dysregulation in an experimental model of acute pancreatitis; and secondly to reveal the effects of S-adenosylmethionine administration on these pathways. Acute pancreatitis was induced by cerulein in mice, and a group of animals received S-adenosylmethionine treatment. Cerulein-induced acute pancreatitis rapidly caused marked depletion of methionine, S-adenosylmethionine, 5′-methylthioadenosine, cystathionine, cysteine, and glutathione levels in pancreas, but S-adenosylhomocysteine and homocysteine remained unchanged. Protein steady-state levels of S-adenosylhomocysteine-hydrolase and cystathionine gamma-lyase diminished but methylthioadenosine phosphorylase levels increased in pancreas with acute pancreatitis. Although cystathionine β-synthase protein levels did not change with acute pancreatitis, Nos2 mRNA and protein levels were markedly up-regulated and caused tyrosine nitration of cystathionine β-synthase in pancreas. S-adenosylmethionine administration enhanced Nos2 mRNA expression and cystathionine β-synthase nitration and triggered homocysteine accumulation in acute pancreatitis. Furthermore, S-adenosylmethionine administration promoted enrichment of the euchromatin marker H3K4me3 in the promoters of Tnf-α, Il-6, and Nos2 and enhanced the mRNA up-regulation of these genes. Accordingly, S-adenosylmethionine administration increased inflammatory infiltrate and edema in pancreas with acute pancreatitis. In conclusion, tyrosine-nitration of cystathionine β-synthase blockades the trans-sulfuration pathway in acute pancreatitis promoting homocysteine accumulation upon S-adenosylmethionine treatment.

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Acute pancreatitis induces nitration of cystathionine β-synthase (CBS).

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CBS nitration blockades the trans-sulfuration pathway in acute pancreatitis.

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SAM treatment enhances CBS nitration leading to homocysteine accumulation in pancreatitis.

p38α deficiency restrains liver regeneration after partial hepatectomy triggering oxidative stress and liver injury

p38α MAPK negatively regulates the G₁/S and G₂/M cell cycle transitions. However, liver-specific p38α deficiency impairs cytokinesis and reduces hepatocyte proliferation during cirrhosis and aging in mice. In this work, we have studied how p38α down-regulation affects hepatocyte proliferation after partial hepatectomy, focusing on mitotic progression, cytokinesis and oxidative stress. We found that p38α deficiency triggered up-regulation of cyclins A1, B1, B2, and D1 under basal conditions and after hepatectomy. Moreover, p38α-deficient hepatocytes showed enhanced binucleation and increased levels of phospho-histone H3 but impaired phosphorylation of MNK1 after hepatectomy. The recovery of liver mass was transiently delayed in mice with p38α-deficient hepatocytes vs wild type mice. We also found that p38α deficiency caused glutathione oxidation in the liver, increased plasma aminotransferases and lactate dehydrogenase activities, and decreased plasma protein levels after hepatectomy. Interestingly, p38α silencing in isolated hepatocytes markedly decreased phospho-MNK1 levels, and silencing of either p38α or Mnk1 enhanced binucleation of hepatocytes in culture. In conclusion, p38α deficiency impairs mitotic progression in hepatocytes and restrains the recovery of liver mass after partial hepatectomy. Our results also indicate that p38α regulates cytokinesis by activating MNK1 and redox modulation.

Age-dependent regulation of antioxidant genes by p38α MAPK in the liver

p38α is a redox sensitive MAPK activated by pro-inflammatory cytokines and environmental, genotoxic and endoplasmic reticulum stresses. The aim of this work was to assess whether p38α controls the antioxidant defense in the liver, and if so, to elucidate the mechanism(s) involved and the age-related changes. For this purpose, we used liver-specific p38α-deficient mice at two different ages: young-mice (4 months-old) and old-mice (24 months-old). The liver of young p38α knock-out mice exhibited a decrease in GSH levels and an increase in GSSG/GSH ratio and malondialdehyde levels. However, old mice deficient in p38α had higher hepatic GSH levels and lower GSSG/GSH ratio than young p38α knock-out mice. Liver-specific p38α deficiency triggered a dramatic down-regulation of the mRNAs of the key antioxidant enzymes glutamate cysteine ligase, superoxide dismutase 1, superoxide dismutase 2, and catalase in young mice, which seems mediated by the lack of p65 recruitment to their promoters. Nrf-2 nuclear levels did not change significantly in the liver of young mice upon p38α deficiency, but nuclear levels of phospho-p65 and PGC-1α decreased in these mice. p38α-dependent activation of NF-κB seems to occur through classical IκB Kinase and via ribosomal S6 kinase1 and AKT in young mice. However, unexpectedly the long-term deficiency in p38α triggers a compensatory up-regulation of antioxidant enzymes via NF-κB activation and recruitment of p65 to their promoters. In conclusion, p38α MAPK maintains the expression of antioxidant genes in liver of young animals via NF-κΒ under basal conditions, whereas its long-term deficiency triggers compensatory up-regulation of antioxidant enzymes through NF-κΒ.

Redox signaling in the gastrointestinal tract

Redox signaling regulates physiological self-renewal, proliferation, migration and differentiation in gastrointestinal epithelium by modulating Wnt/β-catenin and Notch signaling pathways mainly through NADPH oxidases (NOXs). In the intestine, intracellular and extracellular thiol redox status modulates the proliferative potential of epithelial cells. Furthermore, commensal bacteria contribute to intestine epithelial homeostasis through NOX1- and dual oxidase 2-derived reactive oxygen species (ROS). The loss of redox homeostasis is involved in the pathogenesis and development of a wide diversity of gastrointestinal disorders, such as Barrett's esophagus, esophageal adenocarcinoma, peptic ulcer, gastric cancer, ischemic intestinal injury, celiac disease, inflammatory bowel disease and colorectal cancer. The overproduction of superoxide anion together with inactivation of superoxide dismutase are involved in the pathogenesis of Barrett's esophagus and its transformation to adenocarcinoma. In Helicobacter pylori-induced peptic ulcer, oxidative stress derived from the leukocyte infiltrate and NOX1 aggravates mucosal damage, especially in HspB+ strains that downregulate Nrf2. In celiac disease, oxidative stress mediates most of the cytotoxic effects induced by gluten peptides and increases transglutaminase levels, whereas nitrosative stress contributes to the impairment of tight junctions. Progression of inflammatory bowel disease relies on the balance between pro-inflammatory redox-sensitive pathways, such as NLRP3 inflammasome and NF-κB, and the adaptive up-regulation of Mn superoxide dismutase and glutathione peroxidase 2. In colorectal cancer, redox signaling exhibits two Janus faces: On the one hand, NOX1 up-regulation and derived hydrogen peroxide enhance Wnt/β-catenin and Notch proliferating pathways; on the other hand, ROS may disrupt tumor progression through different pro-apoptotic mechanisms. In conclusion, redox signaling plays a critical role in the physiology and pathophysiology of gastrointestinal tract.

p38α regulates actin cytoskeleton and cytokinesis in hepatocytes during development and aging

Background

Hepatocyte poliploidization is an age-dependent process, being cytokinesis failure the main mechanism of polyploid hepatocyte formation. Our aim was to study the role of p38α MAPK in the regulation of actin cytoskeleton and cytokinesis in hepatocytes during development and aging.

Methods

Wild type and p38α liver-specific knock out mice at different ages (after weaning, adults and old) were used.

Results

We show that p38α MAPK deficiency induces actin disassembly upon aging and also cytokinesis failure leading to enhanced binucleation. Although the steady state levels of cyclin D1 in wild type and p38α knock out old livers remained unaffected, cyclin B1- a marker for G2/M transition- was significantly overexpressed in p38α knock out mice. Our findings suggest that hepatocytes do enter into S phase but they do not complete cell division upon p38α deficiency leading to cytokinesis failure and binucleation. Moreover, old liver-specific p38α MAPK knock out mice exhibited reduced F-actin polymerization and a dramatic loss of actin cytoskeleton. This was associated with abnormal hyperactivation of RhoA and Cdc42 GTPases. Long-term p38α deficiency drives to inactivation of HSP27, which seems to account for the impairment in actin cytoskeleton as Hsp27-silencing decreased the number and length of actin filaments in isolated hepatocytes.

Conclusions

p38α MAPK is essential for actin dynamics with age in hepatocytes.

Oxidative stress triggers cytokinesis failure in hepatocytes upon isolation

Primary hepatocytes are highly differentiated cells and proliferatively quiescent. However, the stress produced during liver digestion seems to activate cell cycle entry by proliferative/dedifferentiation programs that still remain unclear. The aim of this work was to assess whether the oxidative stress associated with hepatocyte isolation affects cell cycle and particularly cytokinesis, the final step of mitosis. Hepatocytes were isolated from C57BL/6 mice by collagenase perfusion in the absence and presence of N-acetyl cysteine (NAC). Polyploidy, cell cycle, and reactive oxygen species (ROS) were studied by flow cytometry (DNA, phospho-histone 3, and CellROX(®) Deep Red) and Western blotting (cyclins B1 and D1, and proliferating cell nuclear antigen). mRNA expression of cyclins A1, B1, B2, D1, and F by reverse transcription (RT)-PCR was also assessed. Glutathione levels were measured by mass spectrometry. Here we show that hepatocyte isolation enhanced cell cycle entry, increased hepatocyte binucleation, and caused marked glutathione oxidation. Addition of 5 mM NAC to the hepatocyte isolation media prevented glutathione depletion, partially blocked ROS production and cell cycle entry of hepatocytes, and avoided the blockade of mitosis progression, abrogating defective cytokinesis and diminishing the formation of binucleated hepatocytes during isolation. Therefore, addition of NAC to the isolation media decreased the generation of polyploid hepatocytes confirming that oxidative stress occurs during hepatocyte isolation and it is responsible, at least in part, for cytokinesis failure and hepatocyte binucleation.

Long term p38-a deficiency up-regulates antioxidant enzymes through compensatory NF-?B activation

p38a MAPK may function as a mediator of reactive oxygen species signaling and thus p38a is considered a sensor of oxidative stress. In liver-specific p38a knock-out (KO) adult mice we previously found glutathione depletion and down-regulation of antioxidant enzymes. Our aim was to assess the influence of long-term p38a deficiency on oxidative stress and on the regulation of antioxidant enzymes in liver of old mice. To this end, wild type or liver-specific KO mice after weaning, at 4-6 months of age, or at 24 months of age were used. Reduced glutathione (GSH) and oxidized glutathione levels were determined by mass spectrometry, gene expression of antioxidant enzymes was determined by RT-PCR, and induction of NRF-2 and PGC-1a as well as activation of NF-?B were assessed by western blotting. We report that GSH levels decreased upon aging only in liver of wild-type mice, but not in p38a KO mice. The mRNA expression of glutathione peroxidase, Cu-Zn superoxide dismutase, Mn-superoxide dismutase, and glutamate cysteine ligase was up-regulated in adult wild-type in comparison with mice after weaning, but their gene expression was down-regulated in old wild-type mice. Although the mRNA expression of glutathione peroxidase, Cu-Zn superoxide dismutase, Mn-superoxide dismutase, and glutamate cysteine ligase was down-regulated in adult KO mice vs KO mice after weaning, their gene expression was up-regulated in old KO mice. This up-regulation was not associated with nuclear translocation of NRF-2, which decreased upon aging in KO mice, nor with up-regulation of PGC-1a. However, phosphorylation of p65 was markedly increased in old KO mice as an index of NF-?B activation. In conclusion, long term deficiency of p38a in the liver causes compensatory activation of NF?B that is likely to be responsible for the up-regulation of antioxidant enzymes upon aging, independently of Nrf-2 and PGC-1a.

p38α deficiency and oxidative stress cause cytokinesis failure in hepatocytes

Cytokinesis is the last step in mitosis and it implies re-organization of the actin cytoskeleton. Its failure is one of the major mechanisms of polyploidy and binucleation in mammals. Our aims were 1) to assess the role of redox-sensitive p38α MAPK in cytokinesis by studying the liver of wild type mice or liver-specific p38α knock-out mice; 2) to assess the role of oxidative stress associated with hepatocyte isolation on cytokinesis. When p38α was down-regulated in hepatocytes, MK2 phosphorylation on threonine 334 was completely abrogated. Activation of MNK-1, required for abscission of the intercellular bridge, was diminished. Key proteins of the RhoA pathway (phospho-PRK2, nuclear phosphorylated cofilin, and cytosolic p27) were assessed confirming the impairment of this pathway. The absence of p38α in aging liver also led to a decrease in HSP27 phosphorylation, which is required for actin polymerization. Indeed, a severe impairment in the F-actin filamentous structure was found in the liver of old mice upon p38α deficiency. Consequently, long-term p38α MAPK down-regulation markedly affects the RhoA pathway and actin cytoskeleton dynamics inducing actin disassembly and cytokinesis failure upon aging. On the other hand, hepatocyte isolation caused marked glutathione depletion, increased generation of reactive oxygen species, and activated cell cycle entry. Addition of N-acetyl cysteine to isolation media prevented glutathione depletion, restrained the cell cycle entry, and abrogated defective cytokinesis and the formation of binucleated hepatocytes during isolation. Our results show that hepatocytes do enter into S phase but they do not complete cell division with age upon p38α deficiency or upon oxidative stress associated with isolation leading in both cases to cytokinesis failure and binucleation.

p38 MAPK: a dual role in hepatocyte proliferation through reactive oxygen species

p38 MAPKs are important mediators of signal transduction that respond to a wide range of extracellular stressors such as UV radiation, osmotic shock, hypoxia, pro-inflammatory cytokines, and oxidative stress. The most abundant family member is p38α, which helps to couple cell proliferation and growth in response to certain damaging stimuli. In fact, increased proliferation and impaired differentiation are hallmarks of p38α-deficient cells. It has been reported that reactive oxygen species (ROS) play a critical role in cytokine-induced p38α activation. Under physiological conditions, p38α can function as a mediator of ROS signaling and either activate or suppress cell cycle progression depending on the activation stimulus. The interplay between cell proliferation, p38 MAPK activation, and ROS production plays an important role in hepatocytes. In fact, low levels of ROS seem to be needed to activate several signaling pathways in response to hepatectomy and to orchestrate liver regeneration. p38 MAPK works as a sensor of oxidative stress and cells that have developed mechanisms to uncouple p38 MAPK activation from oxidative stress are more likely to become tumorigenic. So far, p38α influences the redox balance, determining cell survival, terminal differentiation, proliferation, and senescence. Further studies would be necessary in order to clarify the precise role of p38 MAPK signaling as a redox therapeutical target.

Neural differentiation from human embryonic stem cells as a tool to study early brain development and the neuroteratogenic effects of ethanol

The in vitro generation of neural cells from human embryonic stem cells is a powerful tool to acquire better knowledge of the cellular and molecular events involved in early human neural and brain development under physiological and pathological conditions. Prenatal alcohol exposure can induce important anomalies in the developing brain, the embryogenesis being an important critical period for the craniofacial defects and mental disabilities associated with fetal alcohol syndrome. Here, we report the generation of neural progenitors (NPs) from human embryonic stem cells. Neuroepithelial progenitors display the morphological and functional characteristics of their embryonic counterparts and the proper timing of neurons and glia cells generation. Immunocytochemical and real time (RT)-polymerase chain reaction analyses reveal that cells appeared as clusters during neuroepithelial cell proliferation and that the genes associated with the neuroectodermal (Pax-6) and the endodermic (α-fetoprotein) lineages decreased in parallel to the upregulation of the genes of NPs (nestin and Tuj1), followed by their differentiation into neurons (MAP-2+, GABA+), oligodendrocytes [galactocerebroside (GalC+)], and astrocytes (GFAP+). We further demonstrate, for the first time, that human NPs express the endocannabinoid receptors (CB1 and CB2) and the enzymes involved in endocannabinoids synthesis (NAPE-PLD) and degradation (FAAH). Using this in vitro culture, we demonstrate that ethanol exposure impairs NPs survival, affects the differentiation of NPs into neurons and astrocytes, disrupts the actin cytoskeleton, and affects the expression of different genes associated with neural differentiation. The results provide new insights into the effects of ethanol on human embryogenesis and neuroprogenitors and offer an opportunity to delineate potential therapeutic strategies to restore early ethanol-induced brain damage.

Maximum longitudinal relaxation velocity of the left ventricle: its clinical value and relationship with NT-proBNP plasma levels in heart failure

BACKGROUND

M-mode recordings of the mitral annulus to measure the maximum ascending velocity during early diastole as an expression of maximum longitudinal relaxation velocity of the left ventricle (RVm) can be used as an index of left ventricular (LV) diastolic function. The purpose of this study was to determine the relationship of RVm with LV functional parameters in patients with heart failure, with N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels, and with their functional classification.

METHODS AND RESULTS

RVm was recorded in 97 patients by M-mode echocardiography. Patients were classified according to the New York Heart Association (NYHA) and the concentration of NT-proBNP was determined. Patients with ejection fraction (EF)>40 showed a significant correlation between RVm and mitral annulus motion (MAM), mitral flow propagation velocity, E/A, age, deceleration time (DT), and NT-proBNP. In patients with EF<or=40, RVm correlated significantly with MAM, EF, and NT-proBNP. RVm values were higher in NYHA class I compared to II and III, P<0.0001.

CONCLUSIONS

RVm correlates better with functional parameters in patients with EF>40, though its relationship with NT-proBNP both in patients with EF>or<or=40 is to be highlighted. Correlation between RVm and NT-proBNP is influenced by age, EF, and E/A, whereas in patients with EF>40 it is influenced only by age. RVm values showed a significant decrease in NYHA class II and III.

Hepatogenic differentiation of human mesenchymal stem cells from adipose tissue in comparison with bone marrow mesenchymal stem cells

AIM: To investigate and compare the hepatogenic transdifferentiation of adipose tissue-derived stem cells (ADSC) and bone marrow-derived mesenchymal stem cells (BMSC) in vitro. Transdifferentiation of BMSC into hepatic cells in vivo has been described. Adipose tissue represents an accessible source of ADSC, with similar characteristics to BMSC.

METHODS: BMSCs were obtained from patients undergoing total hip arthroplasty and ADSC from human adipose tissue obtained from lipectomy. Cells were grown in medium containing 15% human serum. Cultures were serum deprived for 2 d before cultivating under similar pro-hepatogenic conditions to those of liver development using a 2-step protocol with sequential addition of growth factors, cytokines and hormones. Hepatic differentiation was RT-PCR-assessed and liver-marker genes were immunohistochemically analysed.

RESULTS: BMSC and ADSC exhibited a fibroblastic morphology that changed to a polygonal shape when cells differentiated. Expression of stem cell marker Thy1 decreased in differentiated ADSC and BMSC. However, the expression of the hepatic markers, albumin and CYPs increased to a similar extent in differentiated BMSC and ADSC. Hepatic gene activation could be attributed to increased liver-enriched transcription factors (C/EBPβ and HNF4α), as demonstrated by adenoviral expression vectors.

CONCLUSION: Mesenchymal stem cells can be induced to hepatogenic transdifferentiation in vitro. ADSCs have a similar hepatogenic differentiation potential to BMSC, but a longer culture period and higher proliferation capacity. Therefore, adipose tissue may be an ideal source of large amounts of autologous stem cells, and may become an alternative for hepatocyte regeneration, liver cell transplantation or preclinical drug testing.

Human mesenchymal stem cells from adipose tissue: Differentiation into hepatic lineage

Adipose tissue represents an accessible source of mesenchymal stem cells (ADSCs), with similar characteristics to bone marrow-derived stem cells. The aim of this work was to investigate the transdifferentiation of ADSCs into hepatic lineage cells in vitro. ADSCs were obtained from human adipose tissue from lipectomy. Cells were grown in medium containing 15% AB human serum. Cultures were serum deprived for two days and exposed to a two-step protocol with two different media using growth factors and cytokines. Hepatic differentiation was assessed by RT-PCR of liver-marker genes. ADSCs exhibited a fibroblastic morphology that changed to a cuboidal shape when cells differentiated. Expression of liver genes increased when using one of the two studied media consisting of DMEM supplemented with HGF, bFGF and nicotinamide for 14 days. The results indicate that, under certain specific inducing conditions, ADSCs can be induced to differentiate into hepatic lineage in vitro. Adipose tissue may be an ideal source of high amounts of autologous stem cells.

Remodelado miocárdico y activación inmunitaria en pacientes con insuficiencia cardiaca

INTRODUCTION AND OBJECTIVES

Immune response-mediated regulation of myocardial collagen remains poorly understood. Our objective was to investigate the relationship between ventricular remodeling and immunologic activation in patients with heart failure (HF) by comparing dilated and ischemic cardiomyopathy.

METHODS

We studied 94 patients with HF and dilated cardiomyopathy (n=46) or ischemic cardiomyopathy (n=48). We recorded left ventricular (LV) volumes, E/A ratio, and ejection fraction. Plasma concentrations of tumor necrosis factor alpha (TNFalpha), soluble TNFa receptor I (sTNF-RI), sTNF-RII, interleukin-6 (IL-6) and IL-10 were measured. The serum procollagen type-III amino-terminal propeptide (PIIINP) level was also obtained.

RESULTS

Ventricular volumes were greater in the dilated cardiomyopathy than in the ischemic cardiomyopathy group (P< .05). However, sTNF-RI, sTNF-RII and PIIINP levels were higher in the ischemic group (P< .05). In this group, there were significant correlations between ventricular volumes and IL-10 and sTNF-RII levels. There was also a significant correlation between PIIINP and sTNF-RII levels (r=0.30; P< .05). In the dilated cardiomyopathy group, there was a significant correlation between ventricular volumes and IL-10 level, and between PIIINP level and IL-6 (r=0.32; P< .05) and sTNF-RII levels (r=0.32; P< .05). Multiple linear regression analysis, which included cytokine levels, age, sex and ventricular function, showed that the sTNF-RII level was an independent predictor of the PIIINP level (adjusted r(2)=0.16; P< .0001) and of ventricular volumes (LV end-systolic volume index, adjusted r(2)=0.034; P< .05; and LV end-diastolic volume index, adjusted r(2)=.048; P< .05) in both groups.

CONCLUSIONS

In HF, there is an interaction between proinflammatory cytokines and the extracellular matrix. Immunologic implications vary according to disease etiology. The elevation in proinflammatory cytokine and PIIINP levels is greater in patients with ischemic cardiomyopathy. Multiple regression analysis showed that the sTNF-RII level was an independent predictor of ventricular remodeling.

Fuentes alternativas de hepatocitos para la terapia celular

There is an urgent need to search for alternatives to whole organ transplantation. Several methods have been proposed. Among these strategies, cell transplantation is currently one of the most promising. To achieve this aim, in addition to highly differentiated adult hepatocytes, the use of stem cells is considered a highly attractive therapeutic method for the treatment of liver disease and for temporary support of hepatic function until a liver becomes available for organ transplantation. This strategy is based on the ability of stem cells to differentiate into different cellular types according to their environment. Therefore, stem cells could be an unlimited source of hepatic cells for transplantation and gene therapy. Bone marrow is considered the most promising source of adult stem cells, partly due to the versatility of the cells obtained in repairing damaged tissues of several lineages. Several different types of stem cells have been described in bone marrow: hematopoietic, mesenchymal, side population and multipotent adult stem cells. Bone marrow cells have been hypothesized as a third recruitment source in liver regeneration in addition to hepatocytes and endogenous liver stem cells. Consequently, attempts have been made to differentiate them into hepatic lineage for their subsequent use in hepatic cell therapy. The present article reviews the progress made in this field or research.

Soluble TNF-alpha and interleukin-6 receptors in the urine of heart failure patients. Their clinical value and relationship with plasma levels

BACKGROUND

Proinflammatory cytokines are important mediators in heart failure (HF). Recently, urinary levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) have been determined.

AIMS

The purpose of this study was to measure the urinary levels of TNF-alpha and IL-6 receptors, sTNF-RI, sTNF-RII, sIL-6R, and the relationship with plasma levels and NYHA classes in HF.

METHODS

Plasma and urine were collected from 114 HF patients and sTNF-RI, sTNF-RII and sIL-6R (ng/ml) were analyzed.

RESULTS

For the whole population, plasma levels of sTNF-RI were 2.1+/-0.1, of sTNF-RII were 5.0+/-0.3 and of sIL-6R were 49.8+/-2.5. Urinary levels were: sTNF-RI, 2.8+/-0.5, r=0.5, p<0.001; sTNF-RII, 12.6+/-2.1, r=0.4, p<0.001; and sIL-6R, 4.2+/-0.4, NS. In NYHA III subjects, we found sTNF-RI, r=0.6, p<0.01, sTNF-RII, r=0.5, p<0.05, and sILR-6, r=0.5, p<0.05. Both plasma TNF receptors and urinary levels of sTNF-RII were higher in patients in a more severe NYHA class (p<0.05).

CONCLUSIONS

Urine is a good environment to study sTNF-RI and sTNF-RII, and this fact has diagnostic and prognostic implications. Plasma and urinary levels of TNF receptors showed a fair correlation, which was increased in higher NYHA classes. Plasma and urinary levels of sIL6R showed a good correlation in NYHA III. The TNF receptor levels in urine increased in patients with more severe HF.

Left ventricular cavity area reflects N-terminal pro-brain natriuretic peptide plasma levels in heart failure☆

AIMS

N-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in the diagnosis of heart failure (HF). LV two-dimensional cavity area from end-diastole (LVEDA) and end-systole (LVESA), and LV fractional area change (LVFAC) reflect changes in LV morphology and function without using geometric assumptions. In a multicenter study, we correlated LVEDA, LVESA and LVFAC with NT-proBNP, comparing patients with dilated and ischemic cardiomyopathy.

METHODS AND RESULTS

We studied 106 HF patients. In the dilated group, NT-proBNP correlated with LVEDAI (r=0.6), LVESAI (r=0.7) and LVFAC (r=-0.6), all significant at p<0.001. In patients with ischemic cardiomyopathy we found LVESAI (r=0.3, p<0.05) and LVFAC (r=-0.4, p<0.01). After adjustment for age and BMI, LVFAC and LVESAI were associated in a multiple linear regression analysis with peptide levels (adjusted r(2)=0.5, p<0.001).

CONCLUSIONS

In this study we found a good correlation of NT-proBNP with LV cavity areas and LVFAC. Multiple regression analysis showed that when adjusted for age and BMI, LVFAC and LVESAI are independent predictors of NT-proBNP levels in both dilated and ischemic etiologies. Patients with dilated cardiomyopathy showed better results than those with ischemic cardiomyopathy. We think LV areas are a useful and reproducible parameter, do not need geometric assumptions and reflect NT-proBNP plasma levels.

Obese subjects with heart failure have lower N-terminal pro-brain natriuretic peptide plasma levels irrespective of aetiology

N-terminal pro-brain natriuretic peptide (NT-proBNP) may be useful in the diagnosis of heart failure and ventricular dysfunction. Obesity is an independent cardiovascular risk factor. The purpose of this study was to measure NT-proBNP plasma levels in obese and non-obese subjects with heart failure and to compare levels in subjects with ischaemic and dilated aetiology. In this study, obese subjects had 63% lower NT-proBNP plasma levels than non-obese subjects (p < 0.01). In multivariate analysis, BMI was inversely associated with NT-proBNP plasma levels (p < 0.05) and a 17% decrease in natriuretic peptide levels was attributed to obesity (p < 0.036). When we analyzed data according to the aetiology of heart failure, we found that both groups (ischaemic and dilated) had a 65% decrease in NT-proBNP plasma levels in obese subjects compared to non-obese subjects.

[Plasma concentration of big endothelin-1 and its relation with plasma NT-proBNP and ventricular function in heart failure patients]

INTRODUCTION AND OBJECTIVES

Elevated plasma concentrations of big endothelin-1 (big ET-1) are related with severity and prognosis in patients with heart failure, and N-terminal pro-brain natriuretic peptide (NT-proBNP) is a marker of ventricular remodeling. The purpose of this study was to investigate the relationship between plasma levels of big ET-1 and NT-proBNP, and between the former and ventricular function.

PATIENTS AND METHOD

We studied 103 patients with heart failure (75 men, mean age 63 [13] years). Each participant completed a questionnaire and underwent Doppler echocardiographic study to measure ejection fraction (EF), mitral flow propagation velocity (Vp) and atrioventricular plane displacement (AVPD). Blood samples were also taken to determine plasma levels of big ET-1, aldosterone and NT-proBNP.

RESULTS

For the whole population big ET-1 concentration was 1.03 [0.75] fmol/m, NT-proBNP 619 (307-1328) pg/mL, aldosterone 168 [102] pg/mL, EF 37 [10], Vp 37 [11] cm/s, and AVPD 8.0 [1.7] mm. Plasma big ET-1 correlated positively with plasma NT-proBNP (r=0.50, P<.0001). However, a negative correlation was found between big ET-1 and EF (r=-0.30, P<.01), Vp, (r=-0.30, P<.01) and AVPD (r=-0.21, P<.05). When ET-1 levels were divided into quartiles and the corresponding NT-proBNP, EF, Vp and AVPD values were compared, we found significant differences (ANOVA P<.0001, P<.01, P<.05 and P<.05, respectively).

CONCLUSIONS

Plasma levels of big ET-1 correlated positively with NT-proBNP levels and inversely with EF, Vp and AVPD. These findings help clarify the relationships between ventricular function and the neurohormonal activation involved in heart failure, and may aid the search for therapeutic interventions.

Ventricular hypertrophy increases NT-proBNP in subjects with and without hypertension

BACKGROUND

It has been published that hypertension (HT) must be taken into account when using NT-proBNP, but left ventricular (LV) hypertrophy without HT could be a cause of NT-proBNP elevation. In a population study we compared NT-proBNP in subjects with hypertrophy, with and without diagnosis of HT.

METHODS

We studied 215 subjects from a random sample of 432 people who had declared to suffer from dyspnea. These 432 subjects were referred to their hospital where blood samples were taken, an echo-Doppler study was performed and a specific questionnaire was completed. We got a positive answer from 215, and 52 (24%) have LV hypertrophy.

RESULTS

When we compared NT-proBNP in non-hypertrophic population, 148 +/- 286 pg/ml, with NT-proBNP in LV hypertrophic population, 202 +/- 209 pg/ml, we found P < 0.001. In the hypertrophic group, when we compared NT-proBNP (199 +/- 201 pg/ml) in normotensive subjects (LV mass index 170 +/- 70 g/m2, Vp 50 +/- 18 cm/s, LVEF 62 +/- 8) with NT-proBNP (205 +/- 220 pg/ml) in subjects with diagnosis of HT (LV mass index 169 +/- 37 g/m2, Vp 55 +/- 20 cm/s, LVEF 64 +/- 10), we found NS.

CONCLUSIONS

This population study shows that NT-proBNP is elevated in patients with LV hypertrophy with or without HT. In LV hypertrophy the presence of HT does not influence the peptide levels significantly.

[NT-proBNP levels and hypertension. Their importance in the diagnosis of heart failure]

INTRODUCTION

N-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in the diagnosis of heart failure. We compared NT-proBNP levels in patients with and without a diagnosis of arterial hypertension.

PATIENTS AND METHOD

Participants were recruited from a random sample of 999 inhabitants from the Community of Valencia (eastern Spain). Of these patients, 432 said they suffered from dyspnea and were referred to their hospital (10 hospitals involved), where blood samples were taken, an echo-Doppler study was performed, and the patients completed a questionnaire. Of the 432 participants with dyspnea, 215 gave informed consent for their inclusion in the study, and 202 completed the study. Hypertension was diagnosed in 72 participants and 130 were normotensive.

RESULTS

For the whole population, NT-proBNP, expressed as the median and range, was 88 (0-2586) pg/mL. When we compared hypertensive with normotensive participants, we found higher NT-proBNP levels in the former group: median 123, range 0-2184 pg/mL, versus median 77, range 0-2586 pg/mL (P<.01). When we excluded subjects with systolic left ventricular dysfunction, we found higher levels in participants with hypertension: 119 (0-2184 pg/mL) vs 72 (0-997 pg/mL) (P<.01). When we also excluded subjects with diastolic dysfunction, we found (median 85, range 0-430 pg/mL) and (median 66, range 0-997 pg/mL), respectively (p = NS).

CONCLUSION

In a population study of subjects with dyspnea, hypertensive patients have higher NT-proBNP levels than subjects with normal blood pressure. This difference disappeared when patients with diastolic dysfunction were excluded from the analysis. Hypertension can thus be a confounding factor that potentially decreases the specificity of NT-proBNP levels for the diagnosis of heart failure. These findings should be taken into account when conducting clinical and epidemiological studies in which patients with both heart failure and hypertension are included.

[Quinolones and Streptococcus pneumoniae. Mechanisms of action and resistance]

Streptococcus pneumoniae is considered the most frequent bacterial cause of community-acquired pneumonia, and is involved in a significant number of cases of acute exacerbations of chronic bronchitis, acute otitis, sinusitis, meningitis and other infectious diseases. Fluoroquinolones have been extensively investigated in recent years in the search for new agents that has been prompted by the emergence of resistance in this microorganism. Furthermore, the study of resistance from a molecular biology standpoint has helped in elucidating almost all the biochemical mechanisms of resistance and the routes of dissemination of genetic information between bacteria. This short review is focused on the mechanism of action of quinolones and on the mechanisms responsible for resistance of S. pneumoniae to them, given their clinical and epidemiological relevance. S. pneumoniae is a case apart because bactericidal activity against this microorganism can be produced through gyrase, topoisomerase IV or both, depending on the quinolone structure, which shows that structure has an influence on the success of treatment. Knowledge of the resistance prototype is therefore important so that the appropriate antibiotic therapy can be recommended when indicated.

Activity-bioavailability balance in oral drug development for a selected group of 6-fluoroquinolones

A nomogram is proposed to select the best candidate in drug development studies with quinolones and is intended to substitute other possible models. The nomogram is referred to as an activity-bioavailability balance (ABB) because it includes the following two criteria: ABB = [(1/gm MIC drug candidate)/ (1/gm MIC ciprofloxacin)].[(F(calc) drug candidate)/( F(calc) ciproflaxacin)]. The in vitro activity of a group of 4'N-alkyl-ciprofloxacin derivatives was determined together with that of ciprofloxacin, initially against some reference strains and subsequently against 159 clinical isolates of eight selected species. The inverse of the geometric mean of the lowest concentration of drug at which the original inoculum was reduced to no more than two colonies (1/gm MIC), as an antimicrobial activity parameter, and the absolute oral bioavailability index (F(calc)), as predicted from in situ intestinal absorption rate constants, were used for calculation of the ABB values, which ranged from 0.1 to 17 for the species and compounds tested. Ciprofloxacin was the best candidate only against Escherichia coli, whereas 4'N-methyl- and/or 4'N-ethyl-ciprofloxacin showed better or much better ABB values than the model drug, and can be selected as potential drug candidates against the remaining clinical strains. The procedure described could be a useful technique for further drug development studies.

[Mechanisms of bacterial resistance to quinolones]

In order to produce their cytotoxic effect, quinolones must enter the cell through the bacterial membrane to reach their target, DNA-gyrase or topoisomerase IV, and induce cell death. The mechanisms of resistance to fluoroquinolones include: those mediated by gene mutations codifying for DNA gyrase and topoisomerase IV and leading to QRDR; those characterized by changes in the permeability of the outer membrane which decrease intracellular penetration of the drug; and those caused by active endogenous carriers responsible for drug efflux. These resistance mechanisms can occur alone or in combination; in fact, it is believed that high resistance levels to quinolones in vivo are associated with simultaneous mechanisms. This article reviews such resistance mechanisms and establishes, when possible, their relation to the structure of quinolones.