The protection of rat liver autophagic proteolysis from the age-related decline co-varies with the duration of anti-ageing food restriction

Restricting caloric intake (CR) well below that of ad libitum (AL) fed animals retards and/or delays many characteristics of ageing and the occurrence and progression of age-associated diseases, efficacy depending on duration. The hypothesis that the anti-ageing effect of CR might involve stimulation of the cell-repair mechanism autophagy was tested. The effects of ageing and duration of anti-ageing CR on liver autophagic proteolysis (AP) were explored in male AL Sprague-Dawley rats aged 2-, 6-, 12- and 24-months; and 24-month-old rats on a CR diet initiated at 2-, 6- and 12-month of age or initiated at age 2-months and interrupted at age 18 months. The age-related changes in the regulation of AP were studied by monitoring the rate of valine release in the incubation medium from isolated liver cells by an HPLC procedure. Results show that the maximum attainable rate and the regulation of AP decline with increasing age; that changes are prevented by anti-ageing CR initiated at young age, that the protective effects of CR change with the duration of diet. It is concluded that the data are compatible with the hypothesis that AP and improved membrane maintenance might be involved in the antiageing mechanism of CR.     

Cancer procoagulant in acute lymphoblastic leukemia

In a previous study we characterized cancer procoagulant (CP), a 68 kd cysteine proteinase which directly activates coagulation factor X in various subtypes (from M1 to M5) of acute non-lymphoblastic leukemia (ANLL). The aim of this study was to determine whether CP is also expressed by acute lymphoblastic leukemia (ALL) cells. Blasts from 25 ALL patients were extracted and tested for their procoagulant properties. 16 samples (64%) shortened the recalcification time of normal human plasma, and 9 (36%) did not. 8 of the 16 active samples showed properties compatible with CP, i.e. independence from factor VII in triggering blood coagulation and sensitivity to cysteine proteinase inhibitors. Selected samples also cross-reacted with a polyclonal antibody raised against purified CP. The specific activity of CP in ALL extracts was significantly lower than in most ANLL types previously studied (all but M4). These finding indicate that CP can be a property of the lymphoid phenotype although its expression may be lower than in the myeloid phenotype.     

Endothelium and hemorheology

Hemorheological alterations which can be found in ischaemic vascular diseases are well known and widely studied; less clear is the relationship between these alterations and endothelial function. Our studies showed that modifications in endothelial function caused by physical stress are associated with a worsening in hemorheological parameters mainly in patients affected by ischaemic vascular diseases: major vascular alterations have been found in patients with very high levels of plasma markers endothelial dysfunction. The control of the basal tone of the vessels is given by the complex interaction between vasoconstrictor and vasodilator endothelial factors and when this equilibrium is broken we have the endothelial dysfunction. From a methodological point of view we can find an endothelial dysfunction index determining the various substances produced by the endothelium, but it is very difficult to have a value which clearly identifies the real state of the endothelial alteration. The function of the NO, which is one of the more powerful endogenous vasodilators and whose synthesis is catalysed by nitric oxide synthase (NOS), can be determined by the ratio between blood concentrations of citrulline and arginine (the co-product and the precursor of the way of NO synthesis), which represents the level of activity of the enzyme. A very affordable index of the endothelial dysfunction is the asymmetric dimethylarginine (ADMA), a powerful endogenous inhibitor of NOS; in fact several studies demonstrated a strong relationship between ischaemic vascular diseases and high levels of plasma ADMA. Evaluation of these parameters is measured by means of high performance liquid chromatography (HPLC): this technique provides very affordable results and allows to obtain evaluations of substances in very small concentrations, like ADMA.     

Removal of free light chains in hemodialysis patients without multiple myeloma: a crossover comparison of three different dialyzers

Background

Immunoglobulin light chains are classified as middle molecule uremic toxins able to interact with B lymphocyte membranes leading to the activation of transmembrane signaling. The ensuing impairment of neutrophil function can contribute to the chronic inflammation state of uremic patients, and the increased risk of bacterial infections or vascular calcifications. The aim of this crossover observational study was to assess the difference in free light chain removal by three different hemodialysis filters in patients not affected by multiple myeloma.

Methods

Free light chain removal was compared in the polymethylmethacrylate (PMMA) membrane Filtryzer BK-F, the polyphenylene HFR17 filter and the conventional polysulfone filter F7HPS. Twenty chronic hemodialysis patients were enrolled: mean age was 67.7?±?17.0 years, M/F?=?14/6, dialysis vintage (months) 25.5?±?32.0. The patients were randomized into two groups of treatment lasting 6 weeks each. The dialysis sessions checked were the midweek sessions and the blood was drawn at times 0, 120’ and 240’. Kappa (k) and lambda (λ) light chain levels, β2microglobulin (β2M), C reactive protein (CRP) and albumin were checked.

Results

K light chain levels were 345.0?±?100.0 mg/L, λ light chains were 121.4?±?27.0 mg/L. The values of k light chains at times 120’ and 240’ were significantly lower with PMMA and HFR17 than those obtained with F7. The reduction ratio per session (RRs) for k light chains was 44.1?±?4.3% with HFR17, 55.3?±?3.4% with PMMA, 25.7?±?8.3% with F7 (p?=?0.018). The RRs for λ light chains was 30.3?±?2.9% with HFR17, 37.8?±?17.3% with PMMA, 14.0?±?3.9% with F7 (p?=?0.032). As to β2M, RRs was 42.4?±?3.2% with HFR17 vs. 33.9?±?2.8% with PMMA vs. 6.3?±?1.9% with F7 (p?=?0.022). The three filters tested showed no differences in CRP or albumin levels.

Conclusion

In terms of light chain and β2M removal, the PMMA and on-line HFR filters are similar and both are significantly more effective than the F7 filter in chronic dialysis patients.

Trial registration

The present trial was registered retrospectively (NCT02950389, 31/10/2016).

     

Type 2 diabetes and polymorphisms on chromosome 9p21: a meta-analysis

Background and aimsGenome-Wide Association Studies found some variants on chromosome 9p21 associated with type 2 diabetes (T2D). We performed a meta-analysis to estimate strength, accuracy and feature of the association of polymorphisms in 9p21 with T2D.Methods and resultsArticles were retrieved screening electronic databases and cross references. Twenty-two publications were identified, for a total of 38,455 T2D patients and 60,516 controls. Twenty-one studies investigated the role of the SNP rs10811661; in some studies three additional SNPs (rs564398, rs10757278, rs1333040) were genotyped. Population attributable risk (PAR) was computed as: risk allele frequency1(OR-1)/OR, using the per-allele odds ratio (OR).The risk allele (T) of rs10811661 was associated with T2D in most of the studies. In meta-analysis the overall per-allele OR was 1.24 (95% CI: 1.21–1.27; P < 10^?15), with no difference according to ethnicity (P = 0.45), and low heterogeneity (P = 0.040) across studies partly explained by sample size. Modeling of inheritance suggested an additive effect of the T allele. PAR of T2D related to this polymorphism was 15% for Caucasians and 13% for Asians. The overall odds ratio for the T allele of the SNP rs564398 was 1.08 (95% CI: 1.05–1.12; PAR = 6%). The other SNPs showed negligible associations.ConclusionsThis meta-analysis provides accurate and comprehensive estimates of the association of some genetic variants at chromosome 9p21 and T2D. A relatively small but significant role of the T allele of the rs10811661 SNP in increasing by 21–27% the risk of T2D in an additive way was apparent.