Viability of Human Arterial Grafts Monitored by Comet Assay

An analytical method for studying DNA degradation by electrophoresis after cell lysis and visualization of DNA fragments with fluorescent dye, comet assay, was used to evaluate the viability of the endothelial layer of human arterial grafts with the aim of identifying the procedure that will least damage the tissue before cryopreservation. Four groups of samples were studied: cryopreserved arterial grafts that were thawed in two different ways, slowly lasting 2 hours or rapidly for approx. 7 minutes. Arterial grafts that were collected as part of multiorgan procurement with minimal warm ischemia time. Cadaveric grafts were taken as part of the autopsy, so they have a more extended period of warm ischemia. The HeadDNA (%) parameter and others commonly used parameters like TailDNA (%). TailMoment, TailLength, OliveMoment, TailMoment to characterize the comet were used to assess viability in this study. The ratio of non-decayed to decayed nuclei was determined from the values found. This ratio for cadaveric grafts was 0.63, for slowly thawed cryopreserved grafts 2.9, for rapidly thawed cryopreserved grafts 1.9, and for multi-organ procurement grafts 0.68. The results of the study confirmed the assumption that the allografts obtained from cadaveric donors are the least suitable. On the other hand, grafts obtained from multiorgan donors are better in terms of viability monitored by comet assay. Keywords: Arterial grafts, Cryopreservation, Cadaveric, Multiorgan procurement, Viability, Comet assay.

Fast growth of the number of proceedings papers in atypical fields in the Czech Republic is a likely consequence of the national performance-based research funding system

This article compares the growth rates of Web of Science indexed research publications in 11 European countries from 2000 to 2015. The growth of publication output in the Czech Republic was very fast: the annual production increased more than threefold. However, the number of articles increased only 2.6-fold, whereas the number of proceedings papers increased eightfold. During 2013–15 almost one-third of the papers published by researchers based in the Czech Republic were proceedings papers, a much higher share than in any other benchmark country. Such a high share is undesirable, because proceedings papers are generally much less often cited than journal articles. The growth of the number of proceedings papers is fastest in 17 fields belonging to the social sciences which usually do not hold proceedings papers in high regard. Our analysis shows that this undesirable development started after the introduction of national performance-based research funding system (PRFS) in the Czech Republic. Hence, the effort made to publish proceedings papers seems to reflect an optimization strategy in the light of the PRFS. In the Czech PRFS, proceedings papers have been rewarded point values similar to articles in refereed journals and a large portion of the institutional funding is allocated according to the evaluation results. As a consequence of very fast growth of proceedings papers in the social sciences, the university institutional funding in these fields has grown faster than in other fields. In conclusion, the fast growth of proceedings papers represents an adaptive behavior to the context of the PRFS.

Influence of the new standardized clinical cryopreservation/slow thawing protocol on immunogenicity of arterial allografts in rats

Objectives and design

At the present time there are two waiting list for patients with vascular prosthetic infection indicated for arterial transplantation in the Czech Republic. The inclusion of each patient for cold-stored or cryopreserved arterial transplantation is the preference of indicating surgeon. In this experimental work we studied the immunogenicity of rat aortal allografts treated by our new clinical cryopreservation/slow thawing protocol.

Material and methods

Brown-Norway (BN) (N = 6, 203–217 g) or Lewis (LEW) (N = 6, 248–254 g) abdominal aortal grafts treated in accordance with our new clinical cryopreservation/slow thawing protocol were orthotopically transplanted to Lewis recipients (N = 12, 191–245 g). Aortal wall histology and infiltration by recipient immune cells, as well as donor specific anti MHC class I and II antibodies in recipient serum were studied in both isografts and allografts on day 30 postransplant. Core data of cryopreserved allografts were compared to our previous data of cold-stored aortal allografts treated in accordance with our clinical cold-storage protocol.

Results

Cryopreserved allografts showed regular morphology of aortal wall with clear differentiation of all three basic anatomical layers on day 30 postransplant. Intimal layer showed no hyperplasia, luminal surface was covered by endothelial cells. No statistical difference was observed in tunica media thickness between isografts and allografts. The medial layer showed no necrosis, shrinkage or immunoglobuline G deposition in any experimental group. The adventitial infiltration by immune cells was significantly higher (P<0.05) in allografts. Cryopreserved allografts showed significant lower activation of both cell- and antibody mediated immunity compared to historical data of cold-stored allografts.

Conclusion

Aortal wall histology of rat allografts treated by our new standardized clinical cryopreservation/slow thawing protocol was comparable to that of the cryopreserved isografts on day 30 posttranspant. The immunogenicity of cryopreserved aortal allografts was significantly lower compared to that of cold-stored aortal allografts.

Immunosuppressive protocols with tacrolimus after cryopreserved aortal allotransplantation in rats

Objectives and design

The aim of our study was to simulate in rats all aspects and techniques used in our new clinical program of cryopreserved alloarterial transplantation and investigate the influence of two immunosuppressive protocols with tacrolimus on acute rejection of these allografts.

Materials and methods

Cryopreserved abdominal aortic grafts were transplanted between Brown-Norway and Lewis rats. Tacrolimus (0.2 mg/kg daily) was administered from day 1 to day 30 (TAC1) or from day 7 to day 30 (TAC7), respectively. No immunosuppressed isogeneic (ISO) and allogeneic (ALO) rats combination served as control. Aortal wall infiltration by immunocompetent cells (MHC II+ cells of recipient origin) was studied on day 30 after transplantation. Flow cytometry was used for the analysis of day 30 sera for the presence of donor specific anti-MHC class I and II antibodies.

Results

The aortal allografts in both immunosuppressed groups showed regular morphology of aortal wall with no depositions of immunoglobulin G on day 30. The adventitial infiltration of non-immunosuppressed aortal allografts by MHC class II positive cells of recipient origin was significantly higher (ALO 20.7±6.7 cells, P<0.001) compared to both immunosuppressed groups (TAC1 5.9±5.5 cells, TAC7 6.1±5.1 cells). Day 30 sera from the allogeneic non-immunosuppressed animals decreased significantly the binding of fluorescence-labelled MHC class I (46.9±19.4%) and class II (65.8±11.9%) antibody to donors spleen cells compared with day 30 sera from both immunosuppressed groups (TAC1, anti-MHC class I 102.4±4.2%, p < 0.001, anti-MHC class II 102.6±6.0%), (TAC7, anti-MHC class I 79.9±3.3%, p < 0.001, anti-MHC class II 80.9±2.7%).

Conclusion

Both immunosuppressed protocols with tacrolimus (administration from day 1 or from day 7 following transplantation) were able to suppress acute cell- and antibody-mediated rejection of cryopreserved abdominal aortic allografts processed in accordance with our new standardized clinical protocol.

MicroRNA-125b: association with disease activity and the treatment response of patients with early rheumatoid arthritis

BACKGROUND

MicroRNAs (miRNAs) are small RNAs that regulate gene expression by targeting mRNA. It was proved that some miRNAs are significantly deregulated in rheumatoid arthritis (RA). MicroRNA-125b negatively regulates expression of TNF-α, which plays a crucial role in RA pathogenesis. The aim of this study was to determine the treatment outcome of patients with early RA based on the expression of circulating and cellular miR-125b.

METHODS

Total RNA was isolated from the plasma and peripheral blood mononuclear cells (PBMCs) of 58 patients with early RA before and three months after treatment initiation and of 54 age- and sex-matched healthy controls (HC). The expression of miR-125b was measured by TaqMan quantitative PCR. The treatment responders were defined as patients achieving remission or low disease activity (28-joint count disease activity score (DAS28) <3.2). Receiver operating characteristic (ROC) curve and stepwise backward multivariable logistic regression analyses of miR-125b expression were used to predict the disease outcome at three and six months after initiation of treatment.

RESULTS

The expression of miR-125b in the PBMCs and plasma of treatment-naïve early RA patients was significantly lower than that of HC and increased significantly after three months of treatment, particularly in responders. However, only the cellular expression of miR-125b was inversely correlated with disease activity. MiR-125b expression in PBMCs was higher in responders than in non-responders after three months (p = 0.042). Using ROC analysis, the cellular expression of miR-125b, but not the disease activity at baseline, predicted the treatment response after three months of therapy (area under the curve 0.652 (95 % CI 0.510 to 0.793); p = 0.048).

CONCLUSION

The expression of miR-125b in PBMCs of treatment-naïve patients may present a novel biomarker for monitoring the treatment outcome during the early phase of RA.

A randomised controlled trial of roller versus centrifugal cardiopulmonary bypass pumps in patients undergoing pulmonary endarterectomy

Objectives:

There is some controversy as to whether there is a benefit from the use of a centrifugal pump compared with a roller pump during cardiopulmonary bypass to facilitate cardiac surgery. We compared the two pumps, with the primary aim of determining any difference in the effects on inflammation after pulmonary endarterectomy surgery which required prolonged cardiopulmonary bypass and deep hypothermic circulatory arrest.

Methods:

Between September 2010 and July 2013, 58 elective patients undergoing pulmonary endarterectomy were included in this prospective, randomised, controlled study; 30 patients were randomly allocated to the control group, which used a roller pump, and 28 patients to the treatment group, which used a centrifugal pump. Interleukin-6, procalcitonin, C-reactive protein, thromboelastographic parameters, P-selectin, international normalised ratio, activated prothrombin time, free haemoglobin, haematocrit, red blood cell count, white blood cell count, platelet count and protein S100β were recorded during and after the procedure. We also recorded the length of intensive care unit stay, blood loss and transfusion, neurological outcomes and respiratory and renal failure.

Results:

There was a significant difference in the primary outcome measure: Interleukin-6 was significantly higher in the roller pump group (587±38 ng·l-1 vs. 327±37 ng·l-1; p<0.001) 24 hours after surgery, which we interpreted as an increased inflammatory response. This was confirmed by a significant rise in the procalcitonin level in the roller pump group 48 hours following surgery (0.79 (0.08-25.25) ng·ml-1 vs. 0.36 (0.02-5.83) ng·ml-1; p<0.05). There were, however, no significant differences in clinical outcome data.

Conclusions:

We have shown that the use of a centrifugal pump during prolonged cardiopulmonary bypass and deep hypothermic circulatory arrest is associated with a reduced inflammatory response compared to the standard roller pump. Larger multi-centre trials in this area of practice are required.

Differential impact on acute kidney injury incidence between on- and off pump coronary artery bypass grafting in octogenarians

INTRODUCTION

Acute kidney injury (AKI) following surgical myocardial revascularization is associated with high mortality and morbidity. The aim of this study was to evaluate the risk of acute kidney injury in a population of very old patients following different surgical techniques.

PATIENTS AND METHODS

A retrospective study of 310 consecutive patients aged 78 to 93 years, mean 80.5±2.2, who underwent surgery at one cardiac surgery centre. Based on the surgical technique used the patients were divided into: Group I. CABG (n=134) - surgical myocardial revascularization using extracorporeal circulation and arterial and venous grafts. Group II. OPCABG (n=55) - surgical revascularization without extracorporeal circulation but using arterial and venous grafts. Group III. NOTOUCH (n=121) - no handling with the ascending aorta was performed at all.

RESULTS

A statistically insignificant renoprotective trend was found in patients who underwent surgery without extracorporeal circulation regardless of technique. Comparing groups II and III vs. group I, a significantly poorer renal functioning (median difference in creatinine was 10.0 (32.9) vs 17.5 (35.0), P=0.05) was shown for patients in group I.

CONCLUSION

Surgical myocardial revascularization without extracorporeal circulation in very old patients is safe. The results of this study show a renoprotective trend.

Decrease in serum interleukin-21 levels is associated with disease activity improvement in patients with recent-onset rheumatoid arthritis

Interleukin-21 (IL-21) plays an important role in the pathogenesis of rheumatoid arthritis (RA). The aim of our study was to assess serum levels of IL-21 in patients with recent-onset RA in relation to disease activity and response to treatment. We analyzed serum levels of IL-21 in 51 RA patients, both before and 12 weeks after the initiation of treatment and in 36 healthy individuals. Disease activity was assessed at baseline and at weeks 12 and 24 using the Disease Activity Score for 28 joints, serum levels of C-reactive protein, and the total swollen joint count. We found that IL-21 levels were not increased in patients with recent-onset RA compared with healthy controls, but they had significantly decreased from baseline to week 12 during treatment. Baseline levels of IL-21 significantly correlated with measures of disease activity (p<0.02 for all). Although IL-21 levels did not predict achievement of remission, decrease in IL-21 levels correlated with improvement in disease activity after 12 weeks (p<0.02) and also after 24 weeks (p<0.04) of treatment. Our data suggest that circulating IL-21 levels may serve as a biomarker of disease activity and better outcome in early phase of RA.

Ultrasound definition of tendon damage in patients with rheumatoid arthritis. Results of a OMERACT consensus-based ultrasound score focussing on the diagnostic reliability

OBJECTIVE

To develop the first ultrasound scoring system of tendon damage in rheumatoid arthritis (RA) and assess its intraobserver and interobserver reliability.

METHODS

We conducted a Delphi study on ultrasound-defined tendon damage and ultrasound scoring system of tendon damage in RA among 35 international rheumatologists with experience in musculoskeletal ultrasound. Twelve patients with RA were included and assessed twice by 12 rheumatologists-sonographers. Ultrasound examination for tendon damage in B mode of five wrist extensor compartments (extensor carpi radialis brevis and longus; extensor pollicis longus; extensor digitorum communis; extensor digiti minimi; extensor carpi ulnaris) and one ankle tendon (tibialis posterior) was performed blindly, independently and bilaterally in each patient. Intraobserver and interobserver reliability were calculated by κ coefficients.

RESULTS

A three-grade semiquantitative scoring system was agreed for scoring tendon damage in B mode. The mean intraobserver reliability for tendon damage scoring was excellent (κ value 0.91). The mean interobserver reliability assessment showed good κ values (κ value 0.75). The most reliable were the extensor digiti minimi, the extensor carpi ulnaris, and the tibialis posterior tendons. An ultrasound reference image atlas of tenosynovitis and tendon damage was also developed.

CONCLUSIONS

Ultrasound is a reproducible tool for evaluating tendon damage in RA. This study strongly supports a new reliable ultrasound scoring system for tendon damage.

Leukotrienes B4, C4, D4 and E4 in the exhaled breath condensate (EBC), blood and urine in patients with pneumoconiosis

Leukotrienes (LTs) are involved in the pathogenesis of lung fibrosis and were increased in exhaled breath condensate (EBC) of the patients with pneumoconiosis. However the possible influence of extra-pulmonary disorders on the EBC markers is not known. Therefore in parallel with EBC, LTs' levels in the plasma and urine were measured in patients with pneumoconiosis (45 × asbestos exposure, 37 × silica exposure) and in 27 controls. Individual LTs B4, C4, D4 and E4 were measured by liquid chromatography - electrospray ionization - tandem mass spectrometry (LC-ESI-MS/MS). In EBC, LT D4 and LT E4 were increased in both groups of patients (p<0.001 and p<0.05), comparing with the controls. Both LT B4 and cysteinyl LTs were elevated in asbestos-exposed subjects (p<0.05). Asbestosis with more severe radiological signs (s1/s2-t3/u2) and lung functions impairment has shown higher cysteinyl LTs and LT C4 in the EBC (p<0.05) than mild asbestosis (s1/s0-s1/s1). In addition, in the subjects with asbestosis, cysteinyl LTs in EBC correlated with TLC (-0.313, p<0.05) and TLCO/Hb (-0.307, p<0.05), and LT C4 with TLC (-0.358, p<0.05). In pneumoconioses, EBC appears the most useful from the 3 fluids studied.

Transient anorexia, hyper-nociception and cognitive impairment in early adjuvant arthritis in rats

OBJECTIVE

Rheumatoid arthritis (RA) is associated with enhanced pro-inflammatory cytokine levels, pain, anorexia, and cognitive changes. The enhanced production of cytokines appears before the full manifestation of the disease. So far, any experimental data on behavioral effects of early arthritis are lacking. In the present series we describe anorexia early changes in, pain hyper-sensitivity and altered cognitive behavior during the first four days of adjuvant arthritis in rats (AA), when no clinical signs are yet apparent.

METHODS

AA was induced to male Lewis rats by a single injection of complete Freund's adjuvant (cFA) at the base of the tail. Plasma leptin and ghrelin were measured using specific RIA methods. Gene expressions for food-regulatory peptides, neuropeptide-Y (NPY) and interleukin-1β (IL-1β) in the hypothalamic arcuate nuclei (nARC), were quantitated by TaqMan real-time PCR. Pain sensation was measured on all four limbs and tail by the plantar test. Cognitive functions were tested in the Morris water maze (MWM).

RESULTS

Levels of orexigenic ghrelin as well as mRNA expression of orexigenic NPY in nucleus arcuatus (nRC)re significantly enhanced on day 2 of AA only. Reduced body weight and food intake persisted by day 4 with the most profound reduction on day 2. The mRNA for anorexigenic IL-1β in the nARC was significantly enhanced on days 2 and 4. Enhanced pain sensitivity was observed on day 2, as was the cognitive impairment given by longer time to find the hidden platform, longer time spent in thigmotaxis zone, and longer trajectory. The less effective strategy used to find the hidden platform was observed up to the day 4 of AA.

CONCLUSIONS

Early stage of AA brings about reduced body weight, food intake, and activation of central orexigenic pathways. The observed anorexia could be ascribed to the over-expression of anorexigenic IL-1β which dominates over the NPY orexigenic effects. On day 2 of AA higher pain sensitivity and cognitive impairment appear. All the observed change tend to recover by day 4 of the disease.