Disrupting pro-survival and inflammatory pathways with dimethyl fumarate sensitizes chronic lymphocytic leukemia to cell death

Microenvironmental signals strongly influence chronic lymphocytic leukemia (CLL) cells through the activation of distinct membrane receptors, such as B-cell receptors, and inflammatory receptors, such as Toll-like receptors (TLRs). Inflammatory pathways downstream of these receptors lead to NF-κB activation, thus protecting leukemic cells from apoptosis. Dimethyl fumarate (DMF) is an anti-inflammatory and immunoregulatory drug used to treat patients with multiple sclerosis and psoriasis in which it blocks aberrant NF-κB pathways and impacts the NRF2 antioxidant circuit. Our in vitro analysis demonstrated that increasing concentrations of DMF reduce ATP levels and lead to the apoptosis of CLL cells, including cell lines, splenocytes from Eµ-TCL1-transgenic mice, and primary leukemic cells isolated from the peripheral blood of patients. DMF showed a synergistic effect in association with BTK inhibitors in CLL cells. DMF reduced glutathione levels and activated the NRF2 pathway; gene expression analysis suggested that DMF downregulated pathways related to NFKB and inflammation. In primary leukemic cells, DMF disrupted the TLR signaling pathways induced by CpG by reducing the mRNA expression of NFKBIZ, IL6, IL10 and TNFα. Our data suggest that DMF targets a vulnerability of CLL cells linked to their inflammatory pathways, without impacting healthy donor peripheral blood mononuclear cells.

Toll-like receptor 9 signaling in chronic lymphocytic leukemia cell lines

Chronic lymphocytic leukemia (CLL) is a prototypic neoplasia in which malignant cells strongly depend on microenvironmental stimulations in the lymphoid tissues where they accumulate; leukemic cells are exposed to interaction with bystander and accessory cells, as well as inflammatory soluble mediators. Cell lines are frequently used to model the pathobiology of this disease; however, they do not always recapitulate leukemic cell growth and response to stimulation, and no data are available on Toll-like receptors (TLR) signaling in CLL cell lines. To address this gap, we analyzed HG3, MEC2, and PCL12 cell lines, before and after CpG stimulation, by RNA-sequencing followed by bioinformatic analyses and validation experiments. We identified NFKBIZ mRNA and the corresponding IkBz protein as robust markers of TLR9 activation in both MEC2 and PCL12, but not in HG3 cells. Next, we compared our current results with previous results obtained with primary CLL patient samples and were able to conclude that MEC2 is most similar to the patients' cells in terms of global responsiveness to TLR stimulation; in particular, MEC2 better resembles the samples of patients, as it is characterized by high expression levels of IkBz, but with a lower number of genes regulated.

Dimethyl itaconate selectively targets inflammatory and metabolic pathways in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) co-evolves with its own microenvironment where inflammatory stimuli including toll-like receptors (TLR) signaling can protect CLL cells from spontaneous and drug-induced apoptosis by upregulating IκBζ, an atypical co-transcription factor. To dissect IκBζ-centered signaling pathways, we performed a gene expression profile of primary leukemic cells expressing either high or low levels of IκBζ after stimulation, highlighting that IκBζ is not only an inflammatory gene but it may control metabolic rewiring of malignant cells thus pointing to a novel potential opportunity for therapy. We exploited the capacity of the dimethyl itaconate (DI), an anti-inflammatory electrophilic synthetic derivative of the metabolite Itaconate, to target IκBζ. CLL cells, murine leukemic splenocytes, and leukocytes from healthy donors were treated in vitro with DI that abolished metabolic activation and reduced cell viability of leukemic cells only, even in the presence of robust TLR prestimulation. RNA sequencing highlighted that in addition to the expected electrophilic stress signature observed after DI treatment, novel pathways emerged including the downregulation of distinct MHC class II complex genes. In conclusion, DI not only abrogated the proinflammatory effects of TLR stimulation but also targeted a specific metabolic vulnerability in CLL cells.

Dry eye disease treatment: the role of tear substitutes, their future, and an updated classification

OBJECTIVE

The aim of this review is to summarize the results of a consensus meeting held by a group of experts in dry eye disease (DED) to discuss the importance of tear substitutes in the treatment of DED. The meeting focused especially on the main characteristics of lacrimal substitutes, the development of in vitro models to investigate DED pathophysiology and treatment, the importance of conducting rigorous clinical trials, the requirements of the upcoming European Legislation on medical devices, the advances in the formulation of safer preservatives, the peculiarities of treatment in younger subjects, and the importance of an updated terminology for lacrimal substitutes.

MATERIALS AND METHODS

A literature search was conducted using MEDLINE, with different combinations of pertinent keywords, depending on the subject under discussion, such as "dry eye disease"; "tear substitutes"; "in vitro models"; "ocular surface"; "clinical trials"; "European Regulation"; "preservatives" "younger patients". Also, each author included in the discussion selected articles from their personal library. Using a consensus-based method called nominal group technique to reach a conclusion and proposal for a new classification of eye drops used to improve the tear film and ocular surface epithelia, the experts also conducted a round table meeting.

RESULTS

The new terms proposed by the authors are "wetting agents", "multiple-action tear substitutes" or "ocular surface modulators". The new classification is needed to distinguish eye drops used to improve the tear film and ocular surface epithelia, in line with the new definition of DED, which recognizes the loss of ocular homeostasis, and the creation of a vicious circle of chronic inflammation and ocular damage as fundamental aspects of DED pathophysiology.

CONCLUSIONS

Although tear substitutes have been historically used to provide eye lubrication to the ocular surface, recent advances in the pathophysiology of dry eye disease (DED) clarified that treatment should not just focus on tear film quality or quantity, but address the loss of homeostasis of the ocular surface, blocking the vicious circle of chronic inflammation and ocular damage. Given the scant comparative evidence on tear substitutes currently on the market, further studies should focus on developing new agents, considering the advantages provided by in vitro models, importance of conducting rigorous clinical trials, availability of less harmful preservatives and obligations related to the new European legislation on medical devices. Based on the discussion of these topics, a group of experts held a consensus meeting to identify new and more appropriate terms for different tear substitutes. The proposed terms are wetting agents, multiple-action tear substitutes and ocular surface modulators. Regardless of the agent used, it is important to note that tear substitutes represent one of many options for DED treatment, which should not overlook the psychological aspects of the disease and the peculiarities of younger subjects, who seem to have a higher risk for DED, possibly related to digital devices excessive use.

A short term treatment with a Mek1/2 inhibitor promotes myocardial arteriogenesis and perfusion in vivo: focus on cardiac mural cells

Background

Arteriogenesis is crucial for heart recovery after ischaemia, but cellular and molecular mechanisms able to foster this phenomenon are still poorly characterised.

Purpose

To discover novel pro-arteriogenic approaches by exploiting cardiac mural cells endowed with arteriogenic capacity: pericytes (PCs) and vascular smooth muscle cells (VSMCs).

Methods and results

We derived human and murine CD31neg CD34pos cardiac PCs (cPCs) from myocardial samples of adult subjects and confirmed the pericyte phenotype and function in vitro. We discovered that the withdrawal of EGF and bFGF from the culture media induces the differentiation of cPCs into contractile VSMCs. Molecular investigations of pathways associated with the two factors showed that the Mek1/2-Erk1/2 signalling exerts an inhibitory transcriptional control on contractile VSMC genes. Screening of compounds able to interfere with this pathway revealed that PD0325901 – a potent Mek1/2 inhibitor (MeKi) tested in clinical trials for the treatment of cancer – activates the VSMC phenotype in cPCs. We observed a similar effect on coronary artery VSMCs. Next, we interrogated the effect of PD0325901 on cardiac arteriogenesis in vivo. Adult C57BL6/J mice were given the MeKi 10 mg/kg/day or vehicle (DMSO), orally for 14 days (n=11/group). At the endpoint, echocardiographic evaluation of left ventricle (LV) function and dimensions (n=6/group) showed no difference in comparison with the respective baseline in both groups. Effective inhibition of Mek1/2 in the heart of PD-treated mice was confirmed by the reduced immunostaining for the phosphorylated form of Erk1/2. The MeKi cardiotoxicity was ruled out by assessment of cardiomyocytes and vascular cells apoptosis (Tunel) and plasmatic levels of cTn-I. Histological analyses of the hearts (n=5/group) showed an increase in small arterioles (diameter <20μm) density in the LV of PD-mice compared with the DMSO group (16.4 vs 11.7 art/mm2). No change was observed for the capillary density. The drug promoted the maturation of VSMCs within both small and large (>20μm) arterioles, as shown by the higher ratio between the areas of the vascular wall occupied by the mature contractile marker SM myosin heavy chain and the synthetic/early contractile marker alpha-SM actin (αSMA). The PD treatment reduced the fraction of small arterioles covered with a CD34pos layer (53% vs 70% of total arterioles), along with a lower ratio between the areas occupied by adventitial CD34pos cells and αSMApos VSMCs, suggesting a contribution of cPCs to the arteriolar remodelling. Last, the drug improved the LV myocardial perfusion in the PD- vs the DMSO-group (6.8 vs 5.3 ml/min/g of LV tissue, n=6/group).

Conclusions

We show that a short treatment with a Mek1/2 inhibitor stimulates myocardial arteriogenesis and perfusion without either inducing cardiotoxicity or deteriorating heart function. This may be a novel, intriguing approach to promote therapeutic arteriogenesis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation Centre for Vascular Regeneration II

Physician experts in diabetes are natural team leaders for managing diabetic patients with foot complications. A position statement from the Italian diabetic foot study group

Diabetic foot syndrome (DFS) is a complex disease. The best outcomes are reported with the multi-disciplinary team (MDT) approach, where each member works collaboratively according to his/her expertise. However, which health provider should act as the team leader (TL) has not been determined. The TL should be familiar with the management of diabetes, related complications and comorbidities. He/she should be able to diagnose and manage foot infections, including prompt surgical treatment of local lesions, such as abscesses or phlegmons, in an emergent way in the first meeting with the patient. According to the Organization for Economic Co-operation and Development (OECD) reports, Italy is one of countries with a low amputation rate in diabetic patients. Many factors might have contributed to this result, including 1)the special attention directed to diabetes by the public health system, which has defined diabetes as a "protected disease", and accordingly, offers diabetic patients, at no charge, the best specialist care, including specific devices, and 2)the presence of a network of diabetic foot (DF) clinics managed by diabetologists with medical and surgical expertise. The health care providers all share a "patient centred model" of care, for which they use their internal medicine background and skills in podiatric surgery to manage acute or chronic needs in a timely manner. Therefore, according to Italian experiences, which are fully reported in this document, we believe that only a skilled diabetologist/endocrinologist should act as a TL. Courses and university master's degree programmes focused on DF should guarantee specific training for physicians to become a TL.

Does REM sleep behavior disorder change in the progression of Parkinson's disease?

OBJECTIVES/BACKGROUND

Rapid eye movement (REM) Sleep Behavior Disorder (RBD) in Parkinson's disease (PD) may be associated with a malignant phenotype. Despite its prognostic value, little is known about the time course of RBD in PD. In this study, we aimed to ascertain whether or not RBD is a stable feature in PD. In this study, we prospectively evaluated clinical and neurophysiological features of RBD, including REM Sleep Without Atonia (RSWA), in PD patients with RBD at baseline and after three years then assessed whether the changes in measures of RSWA parallel the progression of PD.

PATIENTS/METHODS

In sum, 22 (17M, mean age 64.0 ± 6.9 years) moderate-to-advanced PD patients (mean PD duration at baseline:7.6±4.8 years) with RBD, underwent a video-polysomnography (vPSG) recording and clinical and neuropsychological assessment at baseline and after three years.

RESULTS

At follow-up, the self-assessed frequency of RBD symptoms increased in six patients, decreased in six and remained stable in 10, while RSWA measures significantly increased in all subjects. At follow-up, patients showed worse H&Y stage (p = 0.02), higher dopaminergic doses (p = 0.05) and they performed significantly worse in phonetic and semantic fluency tests (p = 0.02; p = 0.04). Changes in RSWA correlated significantly with the severity in levodopa-induced dyskinesia (r = 0.61,p = 0.05) and motor fluctuation (r = 0.54,p = 0.03) scores, and with the worsening of executive functions (r = 0.78,p = 0.001) and visuo-spatial perception (r = -0.57,p = 0.04).

CONCLUSION

Despite the subjective improvement of RBD symptoms in one-fourth of PD patients, all RSWA measures increased significantly at follow-up, and their changes correlated with the clinical evolution of motor and non-motor symptoms. RBD is a long-lasting feature in PD and RSWA is a marker of the disease's progression.

P4163Long term comparison between homograft vs stented bio-prostheses for pulmonary valve replacement in tetralogy of Fallot patients

Background

Tetralogy of Fallot (TOF) repair results in long term chronic pulmonary regurgitation requiring pulmonary valve replacement (PVR). Homograft and stented bio-prosthesis are currently used for PVR but whether one should be considered superior to another remains unknown.

Aim

To compare echocardiographic and clinical outcomes after PVR with Homograft vs stented bioprosthesis in patients with previous TOF repair.

Methods

137 patients who underwent PVR with stented bioproshesis were compared with 80 patients who received an homograft using Mixed linear model and multivariate Cox regression.

Results

Homograft were associated with a significantly lower transpulmonary gradient postoperatively (P=0.04) and after a mean follow-up 6 years (table). Homograft were associated with a significantly lower risk of reintervention (HR 0.24; 95% CI 0.07–0.85, p=0.026) while long term mortality was comparable between the two groups (P=0.1).

Echocardiographic findings BIO HOMOGRAFT P N 137 80 Preoperatively   TV regurgitation (mean, sd) 1.80 (0.63) 1.94 (0.81) 0.353   TV regurgitation pressure drop (mean,sd) 35.15 (15.49) 45.34 (25.24) 0.009   PV regurgitation (mean,sd) 3.63 (0.52) 3.34 (0.64) 0.004   PV systolic peak gradient (mean, sd) 25.07 (17.05) 30.68 (21.70) 0.138 Early postoperatively   TV regurgitation (mean,sd) 1.52 (0.54) 1.54 (0.55) 0.858   TV regurgitation pressure drop (mean,sd) 30.10 (13.82) 29.13 (13.98) 0.733   PV regurgitation (mean,sd) 1.50 (0.54) 1.64 (0.53) 0.224   PV systolic peak gradient (mean,sd) 24.05 (11.10) 20.16 (14.19) 0.045 Latest follow_up   TV regurgitation (mean,sd) 1.63 (0.61) 1.83 (0.80) 0.195   TV regurgitation pressure drop (mean,sd) 37.46 (18.84) 32.58 (13.47) 0.233   PV regurgitation (mean,sd) 2.06 (0.77) 2.07 (0.94) 0.982   PV systolic peak gradient (mean,sd) 32.22 (18.17) 21.25 (13.47) 0.001 TAPSE: Tricuspid annular plane systolic excursion; TV: tricuspid valve; PV: pulmonary valve.

PV re-intervention

Conclusions

When compared to stented bio-prostheses, homografts were associated better early and late hemodynamic profile and a significantly lower risk of re-intervention. Homograft should be considered the first choice in patients undergoing PVR after TOF repair.

Amino acid and hyaluronic acid mixtures differentially regulate extra cellular matrix genes in cultured human fibroblasts

The aim of this screening study was to evaluate the efficacy of different proprietary mixtures of amino acid and hyaluronic acid (HA) in stimulating the production of extracellular matrix (ECM) components, particularly the neo-synthesis of elastin, and in promoting a more efficient deposition of elastic fibres (elastogenesis), while at the same time maintaining the stimulation of collagen. The study has allowed identification of the optimal ratios between the amino acids (AA) for the production of collagen and elastin. Human primary dermal fibroblasts from a 44-year-old female donor were used as a test system in an experimental design based on the evaluation of the expression of relevant ECM genes using a transcriptomic dynamic approach. The expression of ECM genes was evaluated by RTqPCR from 24 to 120 hours in the presence of the test items. Moreover, the production of ECM proteins was verified by Western blot analysis after a 120 h treatment period. In addition to elastin, collagen IV, a fundamental structural component of the basal lamina responsible for epithelial and connective tissue anchoring, was analysed as potential target for the modulation of ECM protein production by human fibroblast. The first phase of the study demonstrated that alanine and valine are essential to promote production of elastin, of which they are important constituents. The second phase of the study, which was conducted to clarify the interactions between the different clusters of AA, demonstrated that it is necessary to choose a mixture that contains specific amounts of amino acids of both proteins, collagen and elastin, to give a significant response and a significant production of both. This also proves the existence of a ratio between the 2 clusters (AA elastin/AA collagen) that guarantees an adequate and balanced response to gene expression and production by fibroblasts, collagen and elastin. The study has allowed identification of the optimal ratios between the AA for the production of collagen and elastin.

Resident cells of the myocardium: more than spectators in cardiac injury, repair and regeneration

Multiple resident cell types contribute to maintaining the structure and physiological function of the heart over the life course. Cardiomyocyte proliferation supports scar free regeneration in the neonatal heart following injury, but a lower rate of proliferation in the adult necessitates replacement by a collagen scar to maintain ventricular integrity. In this short review we discuss recent studies that have identified novel roles for non-myocyte resident cells and the extracellular matrix in supporting repair, as well as cardiomyocyte and vascular regeneration, following myocardial infarction.

Effects of clonality on the genetic variability of rare, insular species: the case of Ruta microcarpa from the Canary Islands

Many plant species combine sexual and clonal reproduction. Clonal propagation has ecological costs mainly related to inbreeding depression and pollen discounting; at the same time, species able to reproduce clonally have ecological and evolutionary advantages being able to persist when conditions are not favorable for sexual reproduction. The presence of clonality has profound consequences on the genetic structure of populations, especially when it represents the predominant reproductive strategy in a population. Theoretical studies suggest that high rate of clonal propagation should increase the effective number of alleles and heterozygosity in a population, while an opposite effect is expected on genetic differentiation among populations and on genotypic diversity. In this study, we ask how clonal propagation affects the genetic diversity of rare insular species, which are often characterized by low levels of genetic diversity, hence at risk of extinction. We used eight polymorphic microsatellite markers to study the genetic structure of the critically endangered insular endemic Ruta microcarpa. We found that clonality appears to positively affect the genetic diversity of R. microcarpa by increasing allelic diversity, polymorphism, and heterozygosity. Moreover, clonal propagation seems to be a more successful reproductive strategy in small, isolated population subjected to environmental stress. Our results suggest that clonal propagation may benefit rare species. However, the advantage of clonal growth may be only short-lived for prolonged clonal growth could ultimately lead to monoclonal populations. Some degree of sexual reproduction may be needed in a predominantly clonal species to ensure long-term viability.

Biological monitoring of low-level exposure to benzene

INTRODUCTION

Conflicting opinions exist about the reliability of biomarkers of low-level exposure to benzene. We compared the ability of the urinary excretion of trans,trans-muconic acid (t,t-MA), s-phenilmercapturic acid (s-PAMA) and urinary benzene (U-Benz) to detect low level occupational and environmental exposure to benzene.

METHODS

We monitored airborne benzene by personal air sampling, and U-Benz, s-PMAI, t,t-MA and cotinine (U-Cotinine) in spot urine samples, collected at 8 am and 8 pm, in 32 oil refinery workers and 65 subjects, randomly selected among the general population of urban and suburban Cagliari, Italy. Information on personal characteristics, diet and events during the sampling day was acquired through in person interviews.

RESULTS

The median concentration of airborne benzene was 25.2 microg/m3 in oil refinery workers, and 8.5 microg/m3 in the general population subgroup. U-Benz in morning and evening samples was significantly more elevated among oil refinery workers than the general population subgroup (p = 0.012, and p = 7.4 x 10(-7), respectively) and among current smokers compared to non-smokers (p = 5.2 x 10(-8), and p = 5.2 x 10(-5) respectively). Benzene biomarkers and their readings in the two sampling phases were well correlated to each other. The Spearman's correlation coefficient with airborne benzene was significant for U-Benz in the evening sample, while no correlation was seen with t,t-MA and s-PMA readings in either samplings. The two benzene metabolites were frequently below limit of detection (LOD), particularly among the general population study subjects (17-9% and 39%, for t,t-MA and s-PMA respectively). Morning U-Cotinine excretion showed a good correlation with U-Benz in the morning and in the evening sampling (p < 0.001), and with s-PMA in the evening sample (p < 0.001), but not with t,t-MA in either samplings. t,t-MA in the evening sample was the only biomarker showing a moderate inverse correlation with BMI (p < 0.05). The multiple regression analysis adjusting by BMI and number of cigarettes smoked during the day confirmed the results of the univariate analysis.

DISCUSSION

Our results suggest that unmetabolized U-Benz would allow a more reliable biomonitoring of low-level exposure to benzene than s-PMA and t,t-MA.

[Cancer risk among shift workers: a review]

INTRODUCTION

According to IARC, shift work resulting in disruption of circadian rhythm is a probable human carcinogen (Group 2A).

METHODS

We examined the scientific literature on the carcinogenic risk among shift workers for risk assessment purposes.

RESULTS

Clock genes polymorphisms might contribute with suppression of melatonin synthesis, immuno-suppression from sleep deprivation, individual habits associated with shift work, and low vitamin D levels, in increasing risk of breast cancer, prostate cancer and lymphoma among shift workers.

CONCLUSION

Although the epidemiological evidence seems scanty, the hypothesis that shift work-related sleep deprivation would contribute to increasing cancer risk seems based on solid ground.

[Results of a health surveillance program for health care workers exposed to a patient affected by tuberculosis]

A health surveillance program was implemented in 71 health care workers (HCW) exposed to a patient with active TB infection. A two-step tuberculin skin test (TST) was performed in all the exposed, and a QuantiFERON-TB Gold (QTF) test was scheduled for positive TST subjects. Clinical-radiological surveillance (CRS) was scheduled for subjects positive to TST and QTF or symptomatic. Thirty eight percent HCW were TST positive; 19% of them were also QTF positive and were referred to CRS. No clinical TB was observed among the exposed HCW. Comprehensive health surveillance allows to increase risk perception, compliance to HS and to reduce cost in respect to less cost-effective practices.

[Electrocardiogram changes in shift workers]

BACKGROUND

Besides a significant deterioration in their family and personal life, shift workers also suffer health problems ranging from chronic fatigue to gastro-intestinal disorders, changes in sleep rhythm and cardiovascular disease, including arrhythmia and ischaemic heart disease.

OBJECTIVES

The aim of the study was to assess the prevalence of electrocardiographic changes, such as conduction disorders, alterations in the repolarization phase and frequency-adjusted QT interval (QTc) in relation to shift work.

METHODS

We conducted a cross sectional survey of 125 male subjects, 60 of whom worked fixed hours, and 65 were shift workers on two different schedules: 32 were on duty for 24 hours followed by 96 hours rest, and 33 worked 8-hour shifts (3 x 8). During periodical health assessment we examined their electrocardiograms (ECG), classified the morphology and measured the QTc interval.

RESULTS

The QTc interval did not differ by type of work shift or by the presence of morphological changes in the ECG, including concurrent conduction disorders, or alterations in the repolarization phase. However, unlike day workers and 24-h shift workers, the QTc interval tended to increase with age among 8-h shift workers (r = 0.338; p = 0.05). Also, risk of conduction disorders was moderately, but not significantly, elevated among 8-h shift workers compared with subjects working fixed hours (OR = 1.9; I.E 95% 0.6, 5.7).

CONCLUSIONS

Our study did not reveal significant changes in the ECG morphology in relation to the type of work shift.

An extract of Lannea microcarpa: composition, activity and evaluation of cutaneous irritation in cell cultures and reconstituted human epidermis

Lannea microcarpa (Anacardiaceae) is a tropical tree used in African folk medicine and commercial dermopharmaceutical formulations. Fractionation and analysis of its polar extract allowed the identification of 4′-methoxy-myricetin 3-O-α-l-rhamnopyranoside, myricetin 3-O-α-l-rhamnopyranoside, myricetin 3-O-β-d-glucopyranoside, vitexin, isovitexin, gallic acid and epi-catechin, as the major constituents. In-vivo assay (the croton oil ear test in mice) showed that the extract had significant anti-inflammatory effect (ID50 = 900 μg cm2) but ten times lower than that of indometacin (ID50 = 93 μg cm2), the non-steroidal anti-inflammatory drug used as reference. Cytotoxicity and cutaneous irritation of the extract and its constituents were investigated. The crude extract and its major components did not affect cell viability in-vitro either in three different cultures (J774.A1, WEHI-164 and HEK-293) of cells grown in monolayers or in the reconstituted human epidermis (RHE, 3D model), nor did they cause release of pro-inflammatory mediators (IL-1α) or histomorphological modification of RHE.

A sensitive FRET probe assay for the selective detection of Mycobacterium marinum in fish

Mycobacterium marinum is the causative agent of mycobacteriosis in wild and cultured fish and of atypical infection in humans. For the diagnosis of M. marinum, cultural and traditional polymerase chain reaction (PCR) methods are currently used. However, these protocols, although able to discriminate within Mycobacterium spp., have proved to be time-consuming or difficult to carry out. For this reason, the aim of this study was to obtain a rapid and specific diagnostic tool to quantify fish Mycobacterium spp. or to discriminate M. marinum from other mycobacteria. A primary PCR amplification with SYBR Green had a detection limit (dl) of 10(2)Mycobacterium DNA copies with a log-linear quantification range up to 10(4) (R(2) = 0.99). The second PCR using FRET probes, flanking a region containing species specific nucleotide variations, was designed and validated with synthetic erp gene fragments corresponding to different mycobacterial species, different whole mycobacteria suspensions, experimentally infected fish tissues, tissues from experimentally infected fish, and samples of cultured fish. The results show that the FRET probes demonstrate a high specificity as the melting curve analysis allowed efficient discrimination of M. marinum from Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium pseudoshottsii, Mycobacterium shottsii and Mycobacterium ulcerans. The kidney is the organ with the strongest detection signal and using fish tissues the method has a mean sensitivity of 50 DNA copies/PCR.

The transformation sequence of cement-asbestos slates up to 1200 degrees C and safe recycling of the reaction product in stoneware tile mixtures

Cement-asbestos is the main asbestos containing material still found in most of the European countries such as Italy. Man- and weathering-induced degradation of the cement-asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. This concern is the main prompt for the actual policy of abatement and disposal of asbestos containing materials in controlled wastes. An alternative solution to the disposal in dumping sites is the direct temperature-induced transformation of the cement-asbestos slates into non-hazardous mineral phases. This patented process avoids the stage of mechanical milling of the material before the treatment, which improves the reactivity of the materials but may be critical for the dispersion of asbestos fibres in working and life environment. For the first time, this paper reports the description of the reaction path taking place during the firing of cement-asbestos slates up to the complete transformation temperature, 1200 degrees C. The reaction sequence was investigated using different experimental techniques such as optical and electron microscopy, in situ and ex situ quali-quantitative X-ray powder diffraction. The understanding of the complex reaction path is of basic importance for the optimization of industrial heating processes leading to a safe recycling of the transformed product. For the recycling of asbestos containing materials, the Italian laws require that the product of the crystal chemical transformation of asbestos containing materials must be entirely asbestos-free, and should not contain more than 0.1 wt% fraction of the carcinogenic substances such as cristobalite. Moreover, if fibrous phases other than asbestos (with length to diameter ratio >3) are found, they must have a geometrical diameter larger than 3 microm. We have demonstrated that using an interplay of different experimental techniques, it is possible to safely verify the complete transformation of asbestos minerals in this temperature-induced process. The product of transformation of cement-asbestos (CATP) has a phase composition similar to that of a natural or a low temperature clinker with the exception of having a larger content of aluminium, iron and magnesium. This product can be safely recycled for the production of stoneware tile mixtures. The addition of 3-5 mass% of CATP does not bear significant variations to the standard parameters of white porcelain tile mixtures.

Nitropravastatin stimulates reparative neovascularisation and improves recovery from limb Ischaemia in type-1 diabetic mice

BACKGROUND AND PURPOSE

Mature endothelial cells and their progenitors are dysfunctional in diabetes, resulting in deficient neovascularisation following arterial occlusion. This study aimed to evaluate the therapeutic activity of a nitric oxide (NO) releasing statin in the setting of experimental diabetes and peripheral ischaemia.

EXPERIMENTAL APPROACH

The effects of NCX 6550, an NO-releasing pravastatin derivative, on angiogenesis in ischaemic limbs was studied in normoglycaemic mice or mice made diabetic by treatment with streptozotocin (STZ). Control mice received an equimolar dosage of the parent statin compound, pravastatin. The therapeutic action of NCX 6550 was also tested in mice lacking the gene for endothelial nitric oxide synthase (eNOS).

KEY RESULTS

In normoglycaemic or STZ-diabetic CD1 mice, only NCX 6550 stimulated skeletal muscle revascularisation. In addition, NCX 6550 induced greater improvement in limb reperfusion and salvage, than pravastatin. The number of circulating endothelial progenitor cells was decreased in STZ-diabetic mice, this defect being prevented by NCX 6550 and, to a lesser extent by pravastatin. In vitro, high glucose concentrations reduced the migratory capacity of endothelial progenitor EPCs, which was partly reversed by preincubation with pravastatin and completely reversed by NCX 6550. The postischaemic recovery of eNOS knockout mice was severely impaired as a consequence of depressed angiogenesis and this recovery was improved by treatment with NCX 6550, but not with pravastatin.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that incorporation of a bioactive NO moiety improves the therapeutic profile of statins for the treatment of peripheral vascular disease.

Murine models of myocardial and limb ischemia: Diagnostic end-points and relevance to clinical problems

Ischemic disease represents the new epidemic worldwide. Animal models of ischemic disease are useful because they can help us to understand the underlying pathogenetic mechanisms and develop new therapies. The present review article summarizes the results of a consensus conference on the status and future development of experimentation in the field of cardiovascular medicine using murine models of peripheral and myocardial ischemia. The starting point was to recognize the limits of the approach, which mainly derive from species- and disease-related differences in cardiovascular physiology. For instance, the mouse heart beats at a rate 10 times faster than the human heart. Furthermore, healing processes are more rapid in animals, as they rely on mechanisms that may have lost relevance in man. The main objective of the authors was to propose general guidelines, diagnostic end points and relevance to clinical problems.

Benfotiamine accelerates the healing of ischaemic diabetic limbs in mice through protein kinase B/Akt-mediated potentiation of angiogenesis and inhibition of apoptosis

AIMS/HYPOTHESIS

Benfotiamine, a vitamin B1 analogue, reportedly prevents diabetic microangiopathy. The aim of this study was to evaluate whether benfotiamine is of benefit in reparative neovascularisation using a type I diabetes model of hindlimb ischaemia. We also investigated the involvement of protein kinase B (PKB)/Akt in the therapeutic effects of benfotiamine.

METHODS

Streptozotocin-induced diabetic mice, given oral benfotiamine or vehicle, were subjected to unilateral limb ischaemia. Reparative neovascularisation was analysed by histology. The expression of Nos3 and Casp3 was evaluated by real-time PCR, and the activation state of PKB/Akt was assessed by western blot analysis and immunohistochemistry. The functional importance of PKB/Akt in benfotiamine-induced effects was investigated using a dominant-negative construct.

RESULTS

Diabetic muscles showed reduced transketolase activity, which was corrected by benfotiamine. Importantly, benfotiamine prevented ischaemia-induced toe necrosis, improved hindlimb perfusion and oxygenation, and restored endothelium-dependent vasodilation. Histological studies revealed the improvement of reparative neovascularisation and the inhibition of endothelial and skeletal muscle cell apoptosis. In addition, benfotiamine prevented the vascular accumulation of advanced glycation end products and the induction of pro-apoptotic caspase-3, while restoring proper expression of Nos3 and Akt in ischaemic muscles. The benefits of benfotiamine were nullified by dominant-negative PKB/Akt. In vitro, benfotiamine stimulated the proliferation of human EPCs, while inhibiting apoptosis induced by high glucose. In diabetic mice, the number of circulating EPCs was reduced, with the deficit being corrected by benfotiamine.

CONCLUSIONS/INTERPRETATION

We have demonstrated, for the first time, that benfotiamine aids the post-ischaemic healing of diabetic animals via PKB/Akt-mediated potentiation of angiogenesis and inhibition of apoptosis. In addition, benfotiamine combats the diabetes-induced deficit in endothelial progenitor cells.