The influence of physical exercise on the generation of TGF-β1, PDGF-AA, and VEGF-A in adipose tissue

Adipose tissue is an important organ that produces and secretes hormones and cytokines, including TGF-β1, PDGF-AA, and VEGF-A. The goal of the present study was to investigate the influence of a single session of acute exercise, as well as the prolonged endurance training on the production of TGF-β1, PDGF-AA, and VEGF-A in the subcutaneous white adipose tissue in rats. Rats were randomly divided into two groups: untrained (UT, n = 30) and trained rats (T, subjected to 6-week endurance training with increasing load, n = 29). Both groups were subjected to an acute exercise session with the same work load. The rats were killed before (UTpre, Tpre), immediately after (UT0h, T0h), or 3 h (UT3h, T3h) after exercise and adipose tissue samples collected. Growth factor mRNA was evaluated using RT-PCR; the protein levels were measured before and after training (UTpre and Tpre) using the immunoenzymatic method. TGF-β1 and PDGF-AA mRNA levels were decreased in the UT3h rats compared to the UTpre rats (P = 0.0001 and P = 0.03, respectively), but the VEGF-A mRNA level remained unchanged in the UT0h and UT3h rats compared to UTpre rats. TGF-β1, PDGF-AA and VEGF-A mRNA levels were decreased in the T3h rats compared to Tpre (P = 0.0002, P = 0.02, and P = 0.03, respectively). TGF-β1, PDGF-AA and VEGF-A mRNA levels significantly increased in the Tpre rats compared to UTpre (all P = 0.0002). However, the protein levels remained constant. In conclusion, prolonged physical exercise increases growth factor mRNA in adipose tissue but not protein levels

Quantifying the Proteolytic Release of Extracellular Matrix-Sequestered VEGF with a Computational Model

BACKGROUND: VEGF proteolysis by plasmin or matrix metalloproteinases (MMPs) is believed to play an important role in regulating vascular patterning in vivo by releasing VEGF from the extracellular matrix (ECM). However, a quantitative understanding of the kinetics of VEGF cleavage and the efficiency of cell-mediated VEGF release is currently lacking. To address these uncertainties, we develop a molecular-detailed quantitative model of VEGF proteolysis, used here in the context of an endothelial sprout. METHODOLOGY AND FINDINGS: To study a cell's ability to cleave VEGF, the model captures MMP secretion, VEGF-ECM binding, VEGF proteolysis from VEGF165 to VEGF114 (the expected MMP cleavage product of VEGF165) and VEGF receptor-mediated recapture. Using experimental data, we estimated the effective bimolecular rate constant of VEGF165 cleavage by plasmin to be 328 M(-1) s(-1) at 25 degrees C, which is relatively slow compared to typical MMP-ECM proteolysis reactions. While previous studies have implicated cellular proteolysis in growth factor processing, we show that single cells do not individually have the capacity to cleave VEGF to any appreciable extent (less than 0.1% conversion). In addition, we find that a tip cell's receptor system will not efficiently recapture the cleaved VEGF due to an inability of cleaved VEGF to associate with Neuropilin-1. CONCLUSIONS: Overall, VEGF165 cleavage in vivo is likely to be mediated by the combined effect of numerous cells, instead of behaving in a single-cell-directed, autocrine manner. We show that heparan sulfate proteoglycans (HSPGs) potentiate VEGF cleavage by increasing the VEGF clearance time in tissues. In addition, we find that the VEGF-HSPG complex is more sensitive to proteases than is soluble VEGF, which may imply its potential relevance in receptor signaling. Finally, according to our calculations, experimentally measured soluble protease levels are approximately two orders of magnitude lower than that needed to reconcile levels of VEGF cleavage seen in pathological situations

Elevated serum neutrophil elastase is related to prehypertension and airflow limitation in obese women

<p>Abstract</p> <p>Background</p> <p>Neutrophil elastase level/activity is elevated in a variety of diseases such as atherosclerosis, systolic hypertension and obstructive pulmonary disease. It is unknown whether obese individuals with prehypertension also have elevated neutrophil elastase, and if so, whether it has a deleterious effect on pulmonary function. Objectives: To determine neutrophil elastase levels in obese prehypertensive women and investigate correlations with pulmonary function tests.</p> <p>Methods</p> <p>Thirty obese prehypertensive women were compared with 30 obese normotensive subjects and 30 healthy controls. The study groups were matched for age. Measurements: The following were determined: body mass index, waist circumference, blood pressure, lipid profile, high sensitivity C-reactive protein, serum neutrophil elastase, and pulmonary function tests including forced expiratory volume in one second (FEV₁), forced vital capacity (FVC) and FEV₁/FVC ratio.</p> <p>Results</p> <p>Serum neutrophil elastase concentration was significantly higher in both prehypertensive (405.8 ± 111.6 ng/ml) and normotensive (336.5 ± 81.5 ng/ml) obese women than in control non-obese women (243.9 ± 23.9 ng/ml); the level was significantly higher in the prehypertensive than the normotensive obese women. FEV1, FVC and FEV1/FVC ratio in both prehypertensive and normotensive obese women were significantly lower than in normal controls, but there was no statistically significant difference between the prehypertensive and normotensive obese women. In prehypertensive obese women, there were significant positive correlations between neutrophil elastase and body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride, low density lipoprotein cholesterol, high sensitivity C-reactive protein and negative correlations with high density lipoprotein cholesterol, FEV1, FVC and FEV1/FVC.</p> <p>Conclusion</p> <p>Neutrophil elastase concentration is elevated in obese prehypertensive women along with an increase in high sensitivity C-reactive protein which may account for dyslipidemia and airflow dysfunction in the present study population.</p

The paradox of the 21st century &amp;ndash; is there really an epidemic of most common killers?

Leszek Paczek, Marcin NowakTransplantation Institute, Department of Immunology, Transplantology and Internal Diseases, Medical University of Warsaw, Warsaw, PolandAbstract: Over the last 110 years, average global life expectancy has more than doubled from 31 years of age to 65 years of age. This trend is expected to continue, and many of the children born after the year 2000 can expect to live to celebrate their hundredth birthday. In the last 20 years alone, average life expectancy has increased globally by 6 years. During the same period, doctors have announced a global epidemic of the most common killers: cardiovascular disease, diabetes, chronic kidney, and chronic obstructive pulmonary disease. One of the most important reasons for the more frequent recognition of these diseases is the fact that their diagnostic criteria have changed and become much more acute during the past few years.These changes in diagnostic criteria have made it difficult, or even impossible, to compare the present statistical data regarding these diseases to historical data for the same illnesses. Due to this difficulty, there is no evidence-based comparison of the prevalence of any disease at present and in the past. Before announcing a global epidemic, a fair epidemiological comparison should be made, based upon the same definitions and using identical diagnostic tools. Keywords: global life expectancy, epidemic of CVD, DM, CKD, COP

Machine learning models for predicting patients survival after liver transplantation

In our work, we have built models predicting whether a patient will lose an organ after a liver transplant within a specified time horizon. We have used the observations of bilirubin and creatinine in the whole first year after the transplantation to derive predictors, capturing not only their static value but also their variability. Our models indeed have a predictive power that proves the value of incorporating variability of biochemical measurements, and it is the first contribution of our paper. As the second contribution we have identified that full-complexity models such as random forests and gradient boosting lack sufficient interpretability despite having the best predictive power, which is important in medicine. We have found that generalized additive models (GAM) provide the desired interpretability, and their predictive power is closer to the predictions of full-complexity models than to the predictions of simple linear models

Hernando Morata, Isabel, project lead. Calderón en Red/Una Biblioteca Calderoniana (Calderón on the Web/A Calderón library). Other.

A prospective randomized multicenter study of tacrolimus in combination with sirolimus in renal-transplant recipients. van Hooff JP, Squifflet JP, Wlodarczyk Z, Vanrenterghem Y, Paczek L. Academisch Ziekenhuis Maastricht, Department of Internal Medicine, Maastricht, The Netherlands. [email protected] BACKGROUND: Recently, sirolimus (SRL) was introduced as an immunosuppressant in solid-organ transplantation. This study evaluated combinations of SRL and tacrolimus (Tac). METHODS: This 6-month study investigated the safety and efficacy of Tac and steroids in combination with three different doses of SRL in renal-transplant recipients. A total of 104 patients were randomized in four groups: one group received Tac and steroids (control n=28), and three groups also received the following daily SRL doses: 0.5 mg (TacSRL0.5, n=25), 1 mg (TacSRL1, n=25), or 2 mg (TacSRL2, n=26). Tac doses were adjusted to whole-blood trough levels. Steroids were tapered from 20 mg per day to 5 mg per day. The SRL groups underwent a second randomization to discontinue SRL at either month 3 or 5. RESULTS: At month 6, patient survival rates were 100%, 100%, 96.0%, and 100%, and graft survival rates were 96.4%, 84.0%, 88.0%, and 84.6%, respectively. The overall safety profile was similar in all groups. The incidences of infections during months 1 to 3 were similar in all groups (control 46.4%, TacSRL0.5 32.0%, TacSRL1 56.0%, TacSRL2 46.2%). The 3-month incidences of hypercholesteremia (cholesterol >240 mg/dL or low-density lipoprotein cholesterol >160 mg/dL) were 21.4%, 36.0%, 48.0%, and 50.0% (P=0.019). Lipid levels improved after withdrawal of SRL. The 3-month incidences of biopsy-proven acute rejection were 28.6% (control), 8.0% (TacSRL0.5), 8.0% (TacSRL1), and 3.8% (TacSRL2) (P=0.014). CONCLUSION: Tac in combination with low doses of SRL provides a very effective and safe regime

Steroid withdrawal or steroid avoidance in renal transplant recipients: focus on tacrolimus-based immunosuppressive regimens

Steroid-induced adverse effects after transplantation include cosmetic, metabolic, and cardiovascular complications. Steroid withdrawal or avoidance with cyclosporine-based regimens have been hampered by an unacceptably high rate of acute rejections and increased rates of graft loss. Recently the results of several large, randomized trials of steroid withdrawal/avoidance with tacrolimus-based immunosuppression in renal transplant recipients became available. A review of these trials appeared to be of clinical interest. Data from the THOMAS trial clearly indicate that steroid withdrawal from a regimen of tacrolimus, mycophenolate mofetil (MMF), steroids after 3 months after transplantation is safe with regard to acute rejection rate and graft survival. If an induction therapy with daclizumab is used in combination with tacrolimus and MMF (CARMEN trial), even steroid avoidance is safe with regard to acute rejection rate and graft survival. Finally, in the ATLAS trial, steroid avoidance with basiliximab in combination with tacrolimus (resulting in tacrolimus monotherapy) or alternatively with tacrolimus and MMF both resulted in similar graft survival, but higher rates of acute rejection. In conclusion, steroid withdrawal is safe from a triple-drug regimen of tacrolimus, MMF, and steroids after 3 months after transplantation, and steroid use may completely be avoided with tacrolimus, and MMF combined with daclizumab induction. Tacrolimus monotherapy may be achieved using basiliximab induction at the price of higher rates of acute rejection, but with unaffected graft survival. Thus tacrolimus-based immunosuppression with or without interleukin-2 receptor antagonist induction has made steroid withdrawal or avoidance a realistic option in renal transplantation