Development of cationic solid lipid nanoparticles incorporating cholesteryl-9-carboxynonanoate (9CCN) for delivery of antagomiRs to macrophages.

Lipid-based nanoparticles are a useful tool for nucleic acids delivery and have been regarded as a promising approach for diverse diseases. However, off-targets effects are a matter of concern and some strategies to improve selectivity of solid lipid nanoparticles (SLNs) were reported. The goal of this study was to test formulations of SLNs incorporating lipid cholesteryl-9-carboxynonanoate (9CCN) as "eat-me" signal to target antagomiR oligonucleotides to macrophages. We formulate four SLNs, and those with a mean diameter of 200 nm and a Z-potential values between 25 and 40 mV, which allowed the antagomiR binding, were selected for in vitro studies. Cell viability, transfection efficiency and cellular uptake assays were performed within in vitro macrophages using flow cytometry and confocal imaging and the SLNs incorporating 25 mg of 9CCN proved to be the best formulation. Subsequently, we used a labeled antagomiR to study tissue distribution in in-vivo ApoE-/- model of atherosclerosis. Using the ApoE-/- model we demonstrated that SLNs with phagocytic signal 9-CCN target macrophages and release the antagomiR cargo in a selective way.

Is Generative Artificial Intelligence the Next Step Toward a Personalized Hemodialysis?

ABSTRACT Artificial intelligence (AI) generative models driven by the integration of AI and natural language processing technologies, such as OpenAI's chatbot generative pre-trained transformer large language model (LLM), are receiving much public attention and have the potential to transform personalized medicine. Dialysis patients are highly dependent on technology and their treatment generates a challenging large volume of data that has to be analyzed for knowledge extraction. We argue that, by integrating the data acquired from hemodialysis treatments with the powerful conversational capabilities of LLMs, nephrologists could personalize treatments adapted to patients' lifestyles and preferences. We also argue that this new conversational AI integrated with a personalized patient-computer interface will enhance patients' engagement and self-care by providing them with a more personalized experience. However, generative AI models require continuous and accurate updates of data, and expert supervision and must address potential biases and limitations. Dialysis patients can also benefit from other new emerging technologies such as Digital Twins with which patients' care can also be addressed from a personalized medicine perspective. In this paper, we will revise LLMs potential strengths in terms of their contribution to personalized medicine, and, in particular, their potential impact, and limitations in nephrology. Nephrologists' collaboration with AI academia and companies, to develop algorithms and models that are more transparent, understandable, and trustworthy, will be crucial for the next generation of dialysis patients. The combination of technology, patient-specific data, and AI should contribute to create a more personalized and interactive dialysis process, improving patients' quality of life.

Measurement of apixaban concentrations in different human biological fluids by UHPLC-MS/MS. Clinical pharmacokinetic application in a subject with chronic kidney disease and nonvalvular atrial fibrillation on haemodialysis.

BACKGROUND: Apixaban's technical sheet does not recommend its use in clinical practice for patients with chronic kidney disease undergoing haemodialysis. However, recent studies indicate that apixaban could be a safe oral anticoagulant in these kinds of patients who do not present valvular atrial fibrillation. We developed and validated ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) procedures for measuring apixaban concentrations in plasma, dialysate liquid, and urine. MATERIAL AND METHODS: Simple protein precipitation was implemented to prepare samples. Chromatographic separations were achieved on an Acquity®-UPLC®-BEHTM (2.1x100 mm id, 1.7 µm) reverse-phase C18 column using a water/acetonitrile non-linear gradient containing 0.1 % formic acid at a 0.4 mL/min flow rate. Apixaban and its internal standard (apixaban-d3) were detected by electrospray ionisation mass spectrometry in positive and multiple reaction monitoring modes, using transitions of 460.3 â†’ 199.0/443.2 and 463.3 â†’ 202.0, respectively. RESULTS: No significant interferences and carry-overs were observed. Precisions, absolute relative biases, normalised-matrix factors, and normalised recoveries were ≤ 12.2%, ≤8.0%, 94.3-105.1%, and 93.9-105.4%, respectively. Linearity was observed between 5 and 500 µg/L for plasma/dialysate liquid and 5-1000 µg/L for urine. CONCLUSIONS: The validated UHPLC-MS/MS procedures could help support a pharmacokinetic study in non-valvular atrial fibrillation subjects with chronic kidney disease undergoing haemodialysis and apixaban-based anticoagulant therapy.

MiR-125b downregulates macrophage scavenger receptor type B1 and reverse cholesterol transport.

OBJECTIVE: To determine whether miR-125b regulates cholesterol efflux in vivo and in vitro through the regulation of scavenger receptor type B1 (SR-B1). APPROACH AND RESULTS: We demonstrated that miR-125b is up-regulated in the human aortas of patients with CAD and is located in macrophages and vascular smooth muscle cells (VSMCs). We identified SCARB1 as a direct target of miR-125b by repressing the activity of the SCARB1 3'-untranslated region reporter construct. Moreover, the overexpression of miR-125b in both human and mouse macrophages as well as VSMCs was found to downregulated the expression of the SCARB1 and the SR-B1 protein levels, thereby impairing α-HDL-mediated macrophage cholesterol efflux in vitro. The in vivo reverse cholesterol transport (RCT) rate from non-cholesterol-loaded macrophages transfected with miR-125b to feces was also found to be decreased when compared with that of control mimic-transfected macrophages. CONCLUSIONS: Together, these results provide evidence that miR-125b downregulates SCARB1 and SR-B1 in both human and mouse macrophages as well as VSMCs, thereby impairing macrophage cholesterol efflux in vitro and the whole macrophage-specific RCT pathway in vivo.

ncRNAs in Therapeutics: Challenges and Limitations in Nucleic Acid-Based Drug Delivery.

Non-coding RNAs (ncRNAs) are emerging therapeutic tools but there are barriers to their translation to clinical practice. Key issues concern the specificity of the targets, the delivery of the molecules, and their stability, while avoiding "on-target" and "off-target" side effects. In this "ncRNA in therapeutics" issue, we collect several studies of the differential expression of ncRNAs in cardiovascular diseases, bone metabolism-related disorders, neurology, and oncology, and their potential to be used as biomarkers or therapeutic targets. Moreover, we review recent advances in the use of antisense ncRNAs in targeted therapies with a particular emphasis on their basic biological mechanisms, their translational potential, and future trends.

Chronic Kidney Disease-Associated Inflammation Increases the Risks of Acute Kidney Injury and Mortality after Cardiac Surgery.

Cardiovascular mortality increases with decreasing renal function although the cause is yet unknown. Here, we have investigated whether low chronic inflammation in chronic kidney diseases (CKD) could contribute to increased risk for coronary artery diseases (CAD). Thus, a prospective case-control study was conducted in patients with CAD and CKD undergoing coronary artery bypass graft surgery with the aim of detecting differences in cardiovascular outcomes, epicardial adipose tissue volume, and inflammatory marker activity associated with renal dysfunction. Expression of membrane CD14 and CD16, inflammatory cytokines and chemokines, mitogen-activated protein (MAP) kinases and hsa-miR-30a-5p were analyzed in peripheral blood mononuclear cells (PBMCs). Epicardial fat volume and tissue inflammation in perivascular adipose tissue and in the aorta were also studied. In the present study, 151 patients were included, 110 with CAD (51 with CKD) and 41 nonCAD controls (15 with CKD). CKD increased the risk of cardiac surgery-associated acute kidney injury (CSA-AKI) as well as the 30-day mortality after cardiac surgery. Higher counts of CD14++CD16+ monocytes were associated with vascular inflammation, with an increased expression of IL1ß, and with CKD in CAD patients. Expression of hsa-miR-30a-5p was correlated with hypertension. We conclude that CKD patients show an increased risk of CSA-AKI and mortality after cardiovascular surgery, associated with the expansion of the CD14++CD16+ subset of proinflammatory monocytes and with IL1ß expression. We propose that inflammation associated with CKD may contribute to atherosclerosis (ATH) pathogenesis.

Integrated miRNA/mRNA Counter-Expression Analysis Highlights Oxidative Stress-Related Genes CCR7 and FOXO1 as Blood Markers of Coronary Arterial Disease.

Our interest in the mechanisms of atherosclerosis progression (ATHp) has led to the recent identification of 13 miRNAs and 1285 mRNAs whose expression was altered during ATHp. Here, we deepen the functional relationship among these 13 miRNAs and genes associated to oxidative stress, a crucial step in the onset and progression of vascular disease. We first compiled a list of genes associated to the response to oxidative stress (Oxstress genes) by performing a reverse Gene Ontology analysis (rGO, from the GO terms to the genes) with the GO terms GO0006979, GO1902882, GO1902883 and GO1902884, which included a total of 417 unique Oxstress genes. Next, we identified 108 putative targets of the 13 miRNAs among these unique Oxstress genes, which were validated by an integrated miRNA/mRNA counter-expression analysis with the 1285 mRNAs that yielded 14 genes, Map2k1, Mapk1, Mapk9, Dapk1, Atp2a2, Gata4, Fos, Egfr, Foxo1, Ccr7, Vkorc1l1, Rnf7, Kcnh3, and Mgat3. GO enrichment analysis and a protein-protein-interaction network analysis (PPI) identified most of the validated Oxstress transcripts as components of signaling pathways, highlighting a role for MAP signaling in ATHp. Lastly, expression of these Oxstress transcripts was measured in PBMCs from patients suffering severe coronary artery disease, a serious consequence of ATHp. This allowed the identification of FOXO1 and CCR7 as blood markers downregulated in CAD. These results are discussed in the context of the interaction of the Oxstress transcripts with the ATHp-associated miRNAs.

Silencing of CD40 in vivo reduces progression of experimental atherogenesis through an NF-κB/miR-125b axis and reveals new potential mediators in the pathogenesis of atherosclerosis.

BACKGROUND AND AIMS: CD40/CD40L signaling exerts a critical role in the development of atherosclerosis, and microRNAs (miRNAs) are key regulators in vascular inflammation and plaque formation. In this work, we investigated mRNA/miRNA expression during progression of atherosclerotic lesions through CD40 silencing. METHODS: We silenced CD40 with a specific siRNA in ApoE-/- mice and compared expression of mRNA/miRNA in ascending aorta with scrambled treated mice. RESULTS: siRNA-CD40 treated mice significantly reduced the extension and severity of atherosclerotic lesions, as well as the number of F4/80+, galectin-3+ macrophages and NF-κB+ cells in the intima. Genome-wide mRNA/miRNA profiling allowed the identification of transcripts, which were significantly upregulated during atherosclerosis; among them, miR-125b and miR-30a, Xpr1, a regulator of macrophage differentiation, Taf3, a core transcription factor and the NF-κB activator Ikkß, whereas, the NF-κB inhibitor Ikbα was downregulated during disease progression. All those changes were reversed upon CD40 silencing. Interestingly, TAF3, XPR1 and miR-125b were also overexpressed in human atherosclerotic plaques. Murine Taf3 and Xpr1 were detected in the perivascular adipose tissue (PVAT), and Taf3 also in intimal foam cells. Finally, expression of miR-125b was regulated by the CD40-NF-κB signaling axis in RAW264.7 macrophages. CONCLUSIONS: CD40 silencing with a specific siRNA ameliorates progression of experimental atherosclerosis in ApoE-/- mice, and evidences a role for NF-κB, Taf3, Xpr1, and miR-125b in the pathogenesis of atherosclerosis.

Early subclinical rejection as a risk factor for late chronic humoral rejection.

BACKGROUND: Subclinical rejection and interstitial fibrosis and tubular atrophy (IF/TA) in protocol biopsies are associated with outcome. We study the relationship between histologic lesions in early protocol biopsies and histologic diagnoses in late biopsies for cause. MATERIALS AND METHODS: Renal transplants with a protocol biopsy performed within the first 6 months posttransplant between 1988 and 2006 were reviewed. Biopsies were evaluated according to Banff criteria, and C4d staining was available in biopsies for cause. RESULTS: Of the 517 renal transplants with a protocol biopsy, 109 had a subsequent biopsy for cause which showed the following histological diagnoses: chronic humoral rejection (CHR) (n=44), IF/TA (n=42), recurrence of the primary disease (n=11), de novo glomerulonephritis (n=7), T-cell-mediated rejection (n=4), and polyoma virus nephropathy (n=1). The proportion of retransplants (15.9% vs. 2.3%, P=0.058) and the prevalence of subclinical rejection were higher in patients with CHR than in patients with IF/TA (52.3% vs. 28.6%, P=0.0253). Demographic donor and recipient characteristics and clinical data at the time of protocol biopsy were not different between groups. Logistic regression analysis showed that subclinical rejection (relative risk, 2.52; 95% confidence interval, 1.1-6.3; P=0.047) but not retransplantation (relative risk, 6.7; 95% confidence interval, 0.8-58.8; P=0.085) was associated with CHR. CONCLUSION: Subclinical rejection in early protocol biopsies is associated with late appearance of CHR.

Intragraft expression of the IL-10 gene is up-regulated in renal protocol biopsies with early interstitial fibrosis, tubular atrophy, and subclinical rejection.

Grafts with subclinical rejection associated with interstitial fibrosis and tubular atrophy (SCR+IF/TA) show poorer survival than grafts with subclinical rejection without IF/TA (SCR). Aiming to detect differences among SCR+IF/TA and SCR, we immunophenotyped the inflammatory infiltrate (CD45, CD3, CD20, CD68) and used a low-density array to determine levels of T(H)1 (interleukin IL-2, IL-3, gamma-interferon, tumor necrosis factor-alpha, lymphotoxin-alpha, lymphotoxin-beta, granulocyte-macrophage colony-stimulating factor) and T(H)2 (IL-4, IL-5, IL-6, IL-10, and IL-13) transcripts as well as of IL-2R (as marker for T-cell activation) in 31 protocol biopsies of renal allografts. Here we show that grafts with early IF/TA and SCR can be distinguished from grafts with SCR on the basis of the activation of IL-10 gene expression and of an increased infiltration by B-lymphocytes in a cellular context in which the degree of T-cell activation is similar in both groups of biopsies, as demonstrated by equivalent levels of IL-2R mRNA. These results suggest that the up-regulation of the IL-10 gene expression, as well as an increased proportion of B-lymphocytes in the inflammatory infiltrates, might be useful as markers of early chronic lesions in grafts with SCR.

Immunophenotype of infiltrating cells in protocol renal allograft biopsies from tacrolimus-versus cyclosporine-treated patients.

The prevalence of subclinical rejection is lower in patients receiving tacrolimus than in patients treated with cyclosporine. However, it is not known whether this difference is related to the modulation of a specific cell immunophenotype. We perform a two case-one control study in patients treated with tacrolimus (n=44) or cyclosporine (n=22) with a protocol biopsy performed at 4 to 6 months. Immunophenotype of infiltrating cells was evaluated with monoclonal antibodies directed against CD45 (all leukocytes), CD3 (T lymphocytes), CD68 (monocytes/macrophages), and CD20 (B lymphocytes) and expressed as interstitial positive cells/mm(2). The number of interstitial CD45 (290+/-209 vs. 696+/-560; P<0.01), CD3 (121+/-84 vs. 208+/-104; P<0.01), and CD68 (155+/-232 vs. 242+/-280; P<0.05) but not CD20 (137+/-119 vs. 197+/-154) positive cells was lower in tacrolimus-treated patients. T lymphocytes and macrophages interstitial infiltration was reduced in tacrolimus treated patients evaluated with protocol biopsies in comparison to cyclosporine-treated patients.

Relationship between subclinical rejection and genotype, renal messenger RNA, and plasma protein transforming growth factor-beta1 levels.

BACKGROUND: Transforming growth factor (TGF)-beta(1) is increased in allograft rejection and its production is associated with single nucleotide polymorphisms (SNPs). METHODS: The contribution of SNPs at codons 10 and 25 of the TGF-beta(1) gene to renal allograft damage was assessed in 6-month protocol biopsies and their association with TGF-beta(1) production. TGF-beta(1) genotypes were evaluated by polymerase chain reaction (PCR)/restriction fragment length polymorphism. Intragraft TGF-beta(1) messenger RNA (mRNA) was measured by real-time PCR and TGF-beta(1) plasma levels were assessed by enzyme-linked immunosorbent assay. RESULTS: Eighty consecutive patients were included. Allele T at codon 10 (risk ratio, 6.7; P = 0.02) and an episode of acute rejection before protocol biopsy (risk ratio, 6.2; P = 0.01) were independent predictors of subclinical rejection (SCR). TGF-beta(1) plasma levels, but not those of TGF-beta(1) mRNA, were increased in patients with SCR (2.59 ng/mL +/- 0.91 [n = 22] vs. 2.05 ng/mL +/- 0.76 [n = 43]; P = 0.01). There was no association between allele T and TGF-beta(1) plasma or intragraft levels. CONCLUSIONS: Allele T at codon 10 of the TGF-beta(1) gene is associated with a higher incidence of SCR.

Resistive index and chronic allograft nephropathy evaluated in protocol biopsies as predictors of graft outcome.

INTRODUCTION: The presence of chronic allograft nephropathy (CAN) in protocol biopsies is negatively associated with graft survival. Although recent studies have indicated that the resistive index (RI) is a predictor of graft failure, it does not correlate with CAN in stable grafts. We therefore studied the relationship between RI and CAN and examined the predictive value of both parameters on graft outcome. METHODS: Included were patients transplanted between 1997 and 2002 and who had protocol biopsies and RI determinations. Renal lesions were blindly evaluated according to Banff 97 criteria. Mean glomerular volume, cortical interstitial volume fraction and intimal arterial volume fraction were estimated using a point counting technique. RI was determined before biopsy in at least two different renal locations. The outcome variable was defined as graft failure or a 30% serum creatinine increase between protocol biopsy and last follow-up. RESULTS: Eighty-seven patients were included. RI correlated with recipient age (R = 0.52, P < 0.0001), diastolic blood pressure (R = -0.36, P = 0.0006), pulse pressure index (R = 0.27, P = 0.009) and g-score for histological glomerulitis (rho = 0.30, P = 0.0054), but there were no correlations between RI and chronic Banff scores or any morphometric parameter. The presence of CAN (relative risk, 3.5; 95% confidence interval 1.2-10.2; P = 0.02) but not RI was associated with the outcome variable. CONCLUSION: RI was associated with surrogate measures of vascular compliance such as recipient age and pulse pressure index but not with chronic allograft damage, even when it was evaluated by histomorphometry. Our results indicate that histology may be superior to RI in predicting graft function deterioration, at least in patients with stable renal function.

Baseline immunosuppression is associated with histological findings in early protocol biopsies.

BACKGROUND: Protocol biopsies performed in stable renal allografts show different degrees of acute and chronic lesions that have been related with graft outcome. However, the utility of protocol biopsies to manage baseline immunosuppression has not been well characterized. METHODS: We performed a case-control study to compare histological lesions observed in protocol biopsies in 49 patients treated with tacrolimus (TAC), mycophenolate mofetil (MMF), and prednisone to 49 patients treated with cyclosporine Neoral (CsA), MMF, and prednisone. Histological lesions were graded according to 1997 Banff criteria. The analysis was done according to an intention-to-treat basis. RESULTS: Patients treated with TAC displayed in the protocol biopsy a lower acute score (0.61+/-1.01 vs. 1.26+/-1.45; P=0.0115) and a similar chronic score (1.57+/-1.97 vs. 1.51+/-1.59; P=NS). Transplant glomerulopathy was also lower in TAC treated patients (0.02+/-0.14 vs. 0.20+/-0.41; P=0.0037). Univariate and multivariate logistic regression analysis showed that the presence of acute inflammation was associated with tacrolimus treatment (relative risk [RR]: 0.30, 95% confidence interval [CI]: 0.11-0.84; P=0.0211) and the time of biopsy (RR per month: 0.56, 95% CI: 0.32-0.97; P=0.0394). The presence of chronic lesions was only associated with serum creatinine at the time of biopsy (RR: 1.01, 95% CI: 1.00-1.02; P=0.0439). CONCLUSIONS: The incidence of inflammatory lesions and transplant glomerulopathy is lower in patients treated with TAC than in patients treated with CsA. These data suggest that baseline immunosuppression could influence the severity of histological lesions in stable grafts.

Angiotensin converting enzyme genotype and chronic allograft nephropathy in protocol biopsies.

Genotype DD of the angiotensin-converting enzyme (ACE) is not associated with an increased incidence of native renal diseases, although it could modulate progression to renal failure in patients who already display chronic lesions. Because its role in renal allograft degeneration is not well characterized, whether ACE genotype was associated with the prevalence of chronic allograft nephropathy (CAN) was studied, in a group of protocol biopsies from 180 patients, or with the incidence of CAN in 152 patients with at least two sequential biopsies. As a control group, ACE genotype was also studied in 41 donors and 72 healthy subjects. For analyzing the influence of ACE genotype in graft survival, patients were grouped into six categories (II-normal biopsy, ID-normal, DD-normal, II-CAN, ID-CAN and DD-CAN). Finally, relative renal ACE mRNA levels were measured in 67 cases by real-time PCR using the delta threshold cycle method. ACE-DD genotype was more frequent in patients who received a transplant than in control subjects (43.3% versus 30.1%, P = 0.026), but prevalence (DD = 42.7% versus non-DD = 42.2%) or incidence (DD = 24.6% versus non-DD = 29.9%) of CAN was not different regarding recipient ACE genotype. Furthermore, patients with the ACE-DD genotype and CAN had the poorest graft survival (II-normal = 100%, ID-normal = 91%, DD-normal = 84%, II-CAN = 100%, ID-CAN = 66%, and DD-CAN = 36%; P = 0.034) and higher ACE mRNA levels than non-DD and CAN (DD = -3.36 +/- 2.35 versus non-DD = -5.65 +/- 1.72-fold in ACE copies; P = 0.012). It is concluded that ACE-DD genotype is not associated with an increased prevalence or incidence of CAN but is actually associated with higher ACE mRNA levels and poorer graft survival in patients who already display CAN.

Splicing alterations in human renal allografts: detection of a new splice variant of protein kinase Par1/Emk1 whose expression is associated with an increase of inflammation in protocol biopsies of transplanted patients.

Protein kinase Emk1/Par1 (GenBank accession no. X97630) has been identified as a regulator of the immune system homeostasis. Since immunological factors are critical for the development of chronic allograft nephropathy (CAN), we reasoned that expression of Par1/Emk1 could be altered in kidney allografts undergoing CAN. In this paper, we have analysed the association among renal allograft lesions and expression of Par1/Emk1, studied by RT-PCR on total RNA from 51 protocol biopsies of transplanted kidneys, five normal kidneys, and five dysfunctional allografts. The most significant result obtained has been the detection of alterations in the normal pattern of alternative splicing of the Par1/Emk1 transcript, alterations that included loss of expression of constitutively expressed isoforms, and the inclusion of a cryptic exon to generate a new Emk1 isoform (Emk1C). Expression of Emk1C was associated with an increase in the extension of the interstitial infiltrate (0.88+/-0.33 in Emk1C([+]) vs. 0.41+/-0.50 in Emk1C([-]); P<0.011), and with a trend to display higher interstitial scarring (0.66+/-0.70 vs. 0.29+/-0.52; P=0.09) in protocol biopsies when evaluated according to the Banff schema. Moreover, a higher mean arterial pressure (MAP) was also observed (110+/-11 vs. 99+/-11 mm Hg; P=0.012). From these results we propose that Par1/Emk1 could have a role in the development of CAN in kidney allografts.

Reliability of chronic allograft nephropathy diagnosis in sequential protocol biopsies.

BACKGROUND: Chronic allograft nephropathy (CAN) progresses rapidly during the first few months and slowly thereafter. Although the presence of CAN in protocol renal biopsies is a predictor of outcome, the reliability of this diagnosis according to Banff criteria has not been characterized. METHODS: Renal lesions were evaluated according to the Banff criteria in sequential protocol biopsies performed at 4 and 14 months in 310 biopsies obtained from 155 patients. RESULTS: CAN progressed from 40 to 53% (P=0.001) while serum creatinine remained stable (146 +/- 44 vs. 147 +/- 48 micromol/L, P=NS). Graft survival in patients with and without CAN in the first biopsy was 74 versus 91% (P < 0.05), and in the second biopsy 75 versus 94% (P < 0.05). In 54 patients (35%) no CAN was present in both biopsies, 39 (25%) showed progression to CAN, 19 (12%) showed regression of CAN, and 43 (28%) showed CAN in both biopsies. Graft survival was: 100%, 81.6%, 82.6% and 69.4%, respectively (P < 0.01). Assuming that CAN does not regress and sampling error is normally distributed, we estimated that 25% of biopsies cannot be properly classified. CONCLUSIONS: The increase in the incidence of CAN between the 4th and 14th month is lower than the proportion of misclassified biopsies. Thus, monitoring the progression of CAN by means of two sequential biopsies at 4 and 14 months is inaccurate. We suggest that progression of scarring be monitored by means of a donor and a protocol biopsy performed during the first year evaluated with a quantitative approach.