Impact of contractile reserve on acute response to cardiac resynchronization therapy

Background: Cardiac resynchronization therapy (CRT) provides benefit for congestive heart failure, but still 30% of patients failed to respond to such therapy. This lack of response may be due to the presence of significant amount of scar or fibrotic tissue at myocardial level. This study sought to investigate the potential impact of myocardial contractile reserve as assessed during exercise echocardiography on acute response following CRT implantation. Methods: Fifty-one consecutive patients with heart failure (LV ejection fraction 27% ± 5%, 67% ischemic cardiomyopathy) underwent exercise Doppler echocardiography before CRT implantation to assess global contractile reserve (improvement in LV ejection fraction) and local contractile reserve in the region of the LV pacing lead (assessed by radial strain using speckle tracking analysis). Responders were defined by an increase in stroke volume ≥15% after CRT. Results: Compared with nonresponders, responders (25 patients) showed a greater exercise-induced increase in LV ejection fraction, a higher degree of mitral regurgitation and a significant extent of LV dyssynchrony. The presence of contractile reserve was directly related to the acute increase in stroke volume (r = 0.48, p<0.001). Baseline myocardial deformation as well as contractile reserve in the LV pacing lead region was greater in responders during exercise than in nonresponders (p<0.0001). Conclusions: Heart failure patients referred to CRT have less chance of improving under therapy if they have no significant mitral regurgitation, no LV dyssynchrony and no contractile myocardial recruitment at exercise

Gene Expression Profiles Distinguish the Carcinogenic Effects of Aristolochic Acid in Target (Kidney) and Non-target (Liver) Tissues in Rats

BACKGROUND: Aristolochic acid (AA) is the active component of herbal drugs derived from Aristolochia species that have been used for medicinal purposes since antiquity. AA, however, induced nephropathy and urothelial cancer in people and malignant tumors in the kidney and urinary tract of rodents. Although AA is bioactivated in both kidney and liver, it only induces tumors in kidney. To evaluate whether microarray analysis can be used for distinguishing the tissue-specific carcinogenicity of AA, we examined gene expression profiles in kidney and liver of rats treated with carcinogenic doses of AA. RESULTS: Microarray analysis was performed using the Rat Genome Survey Microarray and data analysis was carried out within ArrayTrack software. Principal components analysis and hierarchical cluster analysis of the expression profiles showed that samples were grouped together according to the tissues and treatments. The gene expression profiles were significantly altered by AA treatment in both kidney and liver (p < 0.01; fold change > 1.5). Functional analysis with Ingenuity Pathways Analysis showed that there were many more significantly altered genes involved in cancer-related pathways in kidney than in liver. Also, analysis with Gene Ontology for Functional Analysis (GOFFA) software indicated that the biological processes related to defense response, apoptosis and immune response were significantly altered by AA exposure in kidney, but not in liver. CONCLUSION: Our results suggest that microarray analysis is a useful tool for detecting AA exposure; that analysis of the gene expression profiles can define the differential responses to toxicity and carcinogenicity of AA from kidney and liver; and that significant alteration of genes associated with defense response, apoptosis and immune response in kidney, but not in liver, may be responsible for the tissue-specific toxicity and carcinogenicity of AA

Disease recurrence in paediatric renal transplantation

Renal transplantation (Tx) is the treatment of choice for end-stage renal disease. The incidence of acute rejection after renal Tx has decreased because of improving early immunosuppression, but the risk of disease recurrence (DR) is becoming relatively high, with a greater prevalence in children than in adults, thereby increasing patient morbidity, graft loss (GL) and, sometimes, mortality rate. The current overall graft loss to DR is 7–8%, mainly due to primary glomerulonephritis (70–80%) and inherited metabolic diseases. The more typical presentation is a recurrence of the full disease, either with a high risk of GL (focal and segmental glomerulosclerosis 14–50% DR, 40–60% GL; atypical haemolytic uraemic syndrome 20–80% DR, 10–83% GL; membranoproliferative glomerulonephritis 30–100% DR, 17–61% GL; membranous nephropathy ∼30% DR, ∼50% GL; lipoprotein glomerulopathy ∼100% DR and GL; primary hyperoxaluria type 1 80–100% DR and GL) or with a low risk of GL [immunoglobulin (Ig)A nephropathy 36–60% DR, 7–10% GL; systemic lupus erythematosus 0–30% DR, 0–5% GL; anti-neutrophilic cytoplasmic antibody (ANCA)-associated glomerulonephritis]. Recurrence may also occur with a delayed risk of GL, such as insulin-dependent diabetes mellitus, sickle cell disease, endemic nephropathy, and sarcoidosis. In other primary diseases, the post-Tx course may be complicated by specific events that are different from overt recurrence: proteinuria or cancer in some genetic forms of nephrotic syndrome, anti-glomerular basement membrane antibodies-associated glomerulonephritis (Alport syndrome, Goodpasture syndrome), and graft involvement as a consequence of lower urinary tract abnormality or human immunodeficiency virus (HIV) nephropathy. Some other post-Tx conditions may mimic recurrence, such as de novo membranous glomerulonephritis, IgA nephropathy, microangiopathy, or isolated specific deposits (cystinosis, Fabry disease). Adequate strategies should therefore be added to kidney Tx, such as donor selection, associated liver Tx, plasmatherapy, specific immunosuppression protocols. In such conditions, very few patients may be excluded from kidney Tx only because of a major risk of DR and repeated GL. In the near future the issue of DR after kidney Tx may benefit from alternatives to organ Tx, such as recombinant proteins, specific monoclonal antibodies, cell/gene therapy, and chaperone molecules

Blocking TGF-β signaling pathway preserves mitochondrial proteostasis and reduces early activation of PDGFRβ+ pericytes in aristolochic acid induced acute kidney injury in wistar male rats

The platelet-derived growth factor receptor β (PDGFRβ)+ perivascular cell activation becomes increasingly recognized as a main source of scar-associated kidney myofibroblasts and recently emerged as a new cellular therapeutic target.In this regard, we first confirmed the presence of PDGFRβ+ perivascular cells in a human case of end-stage aristolochic acid nephropathy (AAN) and thereafter we focused on the early fibrosis events of transforming growth factor β (TGFβ) inhibition in a rat model of AAN.Neutralizing anti-TGFβ antibody (1D11) and its control isotype (13C4) were administered (5 mg/kg, i.p.) at Days -1, 0, 2 and 4; AA (15 mg/kg, sc) was injected daily.At Day 5, 1D11 significantly suppressed p-Smad2/3 signaling pathway improving renal function impairment, reduced the score of acute tubular necrosis, peritubular capillaritis, interstitial inflammation and neoangiogenesis. 1D11 markedly decreased interstitial edema, disruption of tubular basement membrane loss of brush border, cytoplasmic edema and organelle ultrastructure alterations (mitochondrial disruption and endoplasmic reticulum edema) in proximal tubular epithelial cells. Moreover, 1D11 significantly inhibited p-PERK activation and attenuated dysregulation of unfolded protein response (UPR) pathways, endoplasmic reticulum and mitochondrial proteostasis in vivo and in vitro.The early inhibition of p-Smad2/3 signaling pathway improved acute renal function impairment, partially prevented epithelial-endothelial axis activation by maintaining PTEC proteostasis and reduced early PDGFRβ+ pericytes-derived myofibroblasts accumulation