Plasma Levels Research Articles

#2084 Biologic effect evaluation of de novo long-term release tacrolimus on metabolizer phenotype and T cell composition after kidney transplantation

Abstract Background and Aims Kidney transplantation (KTX) is the current treatment of choice in patients with kidney failure. Since immunosuppressive medication to prevent acute rejection is still needed in high doses with frequent adverse events, new strategies to achieve risk-appropriate personalization of immunosuppression are needed. Calcineurin inhibitors are the cornerstone of T cell suppression, currently available in different release formulations including once daily long-term release tacrolimus (LCPT) and regular twice daily immediate release tacrolimus (IRT). Little is known about the temporal evolution of tacrolimus metabolism potentially influencing T cell composition and clinical endpoints between different tacrolimus formulations after KTX. Method To evaluate the influence of de novo LCPT on clinical endpoints, metabolizer phenotype and immune cell composition after KTX, subgroup analysis of a single-center, prospective, observational cohort study including 32 patients started on LCPT (0.1 mg/kg) and 55 patients started on IRT (0.1 mg/kg) was conducted. Peripheral blood mononuclear cells were isolated from whole blood samples drawn before KTX, 2 months and 12 months after KTX for flow cytometry analysis. Study visits were simultaneously conducted to obtain tacrolimus dosing, plasma levels, acute rejection and infection incidence. Statistical analysis was done using GraphPad Prism (v10), accepting significance for p < 0.05, and flow cytometry analysis was done using FlowJo (v10) software. Results The cohort represented KTX recipients with a median age of 60 years and similar distributions of gender, HLA-mismatches and induction therapy. Clinical outcome data showed a trend towards lower acute rejection rate, lower serum-creatinine values and increased incidence of BK-viremia in LCPT treated patients. Rejection rate was associated with a fast-metabolizer phenotype (HR 3.9; 1.1-6.8, p < 0.01) and HLA mismatch > 3 (HR 4.0; 1.2-7.3, p < 0.01) while this effect was blunted in the LCPT group (HR 1.9; 0.7-3.2, p = 0.67 and HR 0.9; 0.3-1.4, p = 0.38 respectively) in a multivariate Cox-regression model. Cluster exploration and tSNE analysis of flow cytometry data revealed diminution of activated-proliferative effector and regulatory T cell trajectories, with significant reduction in cell counts of CD4+CD15s+/CD45RA-Ki67+Foxp3+ Treg and in CD4+CD147high/CD45RA-LAP+HLADR+FcRL3+ effector T cells in LCPT treated patients after KTX. Conclusion Induction with de novo LCPT was associated with a blunted influence of metabolizer phenotype and HLA-mismatch on acute rejection in our cohort. Major changes were detected in peripheral T cell composition after transplantation, with signs of a stronger immunosuppressive effect of LCPT on circulating activated T cells. Therefore, LCPT may be considered for KTX recipients with higher HLA-mismatch (i.e. “old-for-old”) or fast-metabolizer phenotype. Inclusion of changes in T cell composition as biologic effect measures may be worthwhile in future studies evaluating biomarkers to guide immunosuppression and predict complications after KTX.

Polyarticular juvenile idiopathic arthritis has a distinct co-inhibitor receptor profile.

Juvenile Idiopathic Arthritis (JIA) is the most common rheumatic disease of childhood; the pathogenesis is associated with T cell activation. T cell activation can be counter-balanced by signals generated by inhibitory receptors (IRs) such as CTLA-4, PD-1, LAG-3, and TIM-3. Here, we identify the role of IRs in the pathogenesis of different JIA subtypes. In total, we included 67 oligoarticular JIA, 12 IgM-RF negative polyarticular JIA, 17 enthesitis related arthritis, 11 systemic JIA patients and 10 healthy controls. We collected plasma (and synovial fluid) samples from the patients either at the onset or during a flare of their disease. We measured the soluble levels of co-IRs (IL-2Rα, 4-1BB, CD86, TGF-β1, CTLA-4, PD-L1, PD-1, TIM-3, LAG- 3, Galectin-9) by cytometric bead array kits and their cellular expression (PD-1, CTLA-4, TIM-3, LAG-3) by flow cytometry. We compared the plasma levels and cellular expressions of different co-IRs within different JIA subgroups. The polyarticular-JIA group was different from the three other examined JIA subgroups, having higher levels of plasma sCTLA-4(p< 0.001), sPD-1(p< 0.05), and s4-1BB(p< 0.05) when compared with the other JIA subgroups and healthy controls. We analyzed the cellular surface expression of different co-IRs on the PBMCs of different JIA subtypes. Similar to plasma levels, both the percentage(p< 0.05) and the MFI (mean fluorescence intensity) (p< 0.01) of CTLA4 expression were higher in the poly-JIA subgroup. This is the first report studying the expression profile of different co-IRs in different subtypes of JIA. Polyarticular JIA patients had a different co-IR profile, having more CTLA-4, PD-1 and 4-1BB in their plasma than the other subtypes of JIA.

Metabolic syndrome and pharmacotherapy outcomes in patients with type 2 diabetes mellitus

BackgroundMetabolic syndrome is a group of metabolic abnormalities that increase predisposition to several diseases including ischemic heart disease and diabetes mellitus. The study aimed to investigate metabolic syndrome among patients with type-2 diabetes mellitus (DM), and its impact on pharmacotherapy outcomes.MethodsAn observational cross-sectional study was performed on 910 patients with type-2 DM between June and December 2023. Fasting blood sugar, triglycerides, high-density lipoproteins (HDL), blood pressure, and abdominal obesity were measured. Metabolic syndrome was identified according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Pharmacotherapy outcomes were assessed according to American Association of Clinical Endocrinologists and American Diabetes Association guidelines using the ability to achieve adequate glycemic control and normal levels of blood pressure and fasting plasma lipoproteins.ResultsIn total, 87.5% of type-2 DM patients had metabolic syndrome; the prevalence increased with age and was higher among females. Metabolic syndrome showed the following distribution of risk factors: insulin resistance (100%), low HDL (95.3%), elevated blood pressure (83%), triglycerides dyslipidemia (80.1%), and abdominal obesity (62.5%). Majority of the patients had either 5 or 4 risk factors of metabolic syndrome. The most common comorbidities were dyslipidemia (97.7%) and hypertension (83%). Treatment outcomes were insufficient where adequate glycemic control was only achieved in 12% of type-2 DM patients, and proper management of comorbid dyslipidemia and hypertension was achieved in 29% and 40.9% of patients, respectively. Adequate blood pressure control was less achieved in patients with metabolic syndrome (34.4%) than those without metabolic syndrome (77.2%). Similarly, dyslipidemia was less controlled in patients with metabolic syndrome (26.9%) than in those without metabolic syndrome (47.3%).ConclusionPharmacotherapy outcomes were inadequate for most patients with type-2 diabetes mellitus. Adopting early preventive and therapeutic interventions for metabolic syndrome is advised to improve treatment outcomes of the comorbid dyslipidemia and hypertension.

Sperm melatonin receptors, seminal plasma melatonin and semen freezability in goats

Goat bucks are seasonal breeders that show variation in sperm quality, endogenous melatonin (MLT), and presumably in the expression of MLT receptors on the sperm throughout the year, which may modify sperm freezability. The aim of this study was to determine whether sperm freezability is associated with (i) endogenous melatonin levels in seminal plasma and (ii) the expression of sperm plasma membrane melatonin receptors (MT1, MT2). To evaluate this, spermatozoa from seven Saanen goat bucks were cryopreserved throughout the year in Mexico using a standard freezing protocol. Seminal plasma MLT concentrations were determined by ELISA and the expression and localization of MT1 and MT2 were detected by immunocytochemistry and confirmed by western blotting. The recovery rate of progressive motility after thawing was higher in spring than autumn and winter; in contrast, the F pattern (CTC assay) was higher in winter than in the other seasons. A proportional increase in the AR pattern (CTC assay) was smaller in winter than in the other seasons and the proportion of sperm showing high plasma membrane fluidity was higher in spring than in summer and autumn. The seminal plasma MLT concentrations showed no significant interseasonal differences. The MT1 receptor was immunolocalised at the apical region of the sperm head, while MT2 was mainly localised in the neck. The relative expression of MLT receptors showed significant differences between summer and winter for all bands, except at 75 kDa of MT2. In conclusion, there was an association between the relative expression of MT1 and MT2 receptors throughout the year and sperm freezability in goat bucks in México. Post-thaw sperm quality is enhanced in semen samples collected during breeding season.

#3023 Dietary protein intake modulates the tubular handling of the uremic retention solute indoxyl sulfate

Abstract Background and Aims Nutritional intervention constitutes a key part of the clinical management of individuals with chronic kidney disease (CKD). The gut emerged as an important source of uremic retention solutes, including indoxyl sulfate, p-cresyl sulfate and TMAO among the others. Indoxyl sulfate (IS) is produced through the gut microbial fermentation of tryptophan into indole and its conversion into indoxyl sulfate in the liver. Previous authors hypothesised that higher amounts of gut microbial metabolites can be sensed by kidney's proximal tubule cells through the use of receptors and signaling pathways. Particular evidence points to the involvement of kidney Organic Anion Transporters’(OATs') in controlling the gut-kidney communication. According to the so-called remote sensing hypothesis, kidney tubular cells respond to uremic toxins plasma fluctuations altering the activity of OAT1. Few studies have investigated whether in CKD the protein content in the diet affects gut generation, plasma retention and excretion mechanisms of indolic uremic toxins including kidney cells OAT1 expression. Method Eighteen male Sprague-Dawley rats (Janvier, France) aged 7-8 weeks and weighing between 270 and 388 g were randomly assigned to a low protein (LP) diet (n = 10) or a high protein (HP) diet (n = 8) after undergoing a 5/6 nephrectomy to develop CKD. For each diet, a sham-operated control group (n = 7 and n = 8 correspondingly) was used. After 7 weeks, urine was collected, and 8 weeks after the disease was induced, euthanasia was performed. Samples of kidney and blood were taken. mRNA and protein expression of OAT1 were sought via qPCR and Western blot. Forty patients with CKD were recruited in a cross-sectional study investigating eating habits and uremic toxins levels. Eating habits were searched via a food diary. Protein and energy intake were therefore calculated. Blood and 48 h-urine were collected. Blood creatinine and urea were determined with standard laboratory techniques. Total plasmatic and urinary IS concentrations were measured using LC-MS/MS. The fractional excretion (FE) i.e. the percentage of IS excreted relatively to the kidney filtered load, was calculated to assess IS remote sensing. Results Rats with chronic kidney disease (CKD) had considerably higher plasmatic levels of IS (p &amp;lt; .001) than sham rats. Rats with CKD on an HP diet, however, did not differ in plasma IS from rats fed an LP diet (p = .63). On the other hand, CKD rats fed an HP diet showed a substantial rise in 24-hour urinary IS (p &amp;lt; .001). The FE of IS was significantly higher (p = .005) in CKD rats on a HP diet and correlated with 24 h-urinary IS (Spearman r = .51, p value=.03) and with protein intake (Spearman r = .52, p value=.03) in CKD rats. OAT1 mRNA and protein expression was significantly higher in CKD rats given a HP diet (p = .025 and p = .009, respectively). By dividing the CKD patients into two groups by the median of protein intake, the FE of IS was significantly higher (p = .018) in the patients consuming a larger portion of proteins. Conclusion A diet higher in protein content in 5/6 nephrectomized CKD rats as well as in CKD patients likely leads to an increased production of indole in the colon. This results in increased IS fractional excretion but unchanged IS plasma retention. These findings offer more evidence for the mechanisms behind the remote sensing and signaling of uremic toxins derived from indole. In summary, a low-protein diet is still advised for people with chronic kidney disease.

#1257 Complement system is overactivated in patients with IgA nephropathy after COVID-19

Abstract Background and Aims Since the coronavirus disease of 2019 (COVID-19) pandemic swept across the world, the flare of immune-mediated disease following SARS-CoV-2 infection has emerged rapidly. IgA nephropathy (IgAN), which has been confirmed as a complement mediated autoimmune disease, is also one of the common glomerulonephritis associated with COVID-19. Here, we aim to investigate the clinical and immunological characteristics of patients with IgAN after COVID-19. Method From December 2022 to April 2023, 33 patients with renal biopsy-proven IgAN (Group CoV) at Beijing Anzhen hospital who had experienced COVID-19 before renal biopsy were enrolled. Meanwhile, 44 patients with IgAN (Group non-CoV) diagnosed from December 2018 to April 2019 (the same period in the previous year, with no COVID-19) were enrolled as control. Plasma FHR-5, MBL, C5a, soluble C5b-9, serum Gd-IgA1 and IgA immune complex were detected by enzyme-linked immunosorbent assay. Glomerular staining for FHR-5, C3c, MAC and Gd-IgA1 were detected by immunofluorescence. SARS-CoV-2 nucleocapsid was detected by immunohistochemistry. Clinicopathological and immunological features between the two groups were analyzed. Results The median time between onset of COVID-19 symptoms and the time of renal biopsy was 12 (6, 18) weeks, ranging from 1 to 26 weeks. SARS-CoV-2 nucleocapsid antigen expression in the renal tubular epithelial cells were observed in 11/33 (33.3%) patients. Compared with Group non-CoV, the level of eGFR was significantly lower in Group CoV[67.30 (52.94, 96.43) ml/min per 1.73 m2 vs. 101.04 (74.35, 120.98) ml/min per 1.73 m2, p = 0.010]. Histologically, compared with Group non-CoV, Group CoV presented with more percentages of segmental glomerulosclerosis/adhesion (p = 0.003) and less percentages of mesangial hypercellularity (p = 0.017). The level of plasma level of C5a [16.45 (10.48, 22.07) ng/ml vs. 3.68 (2.70, 4.47) ng/ml], soluble C5b-9 [614.43 (481.66, 770.02) ng/ml vs. 358.08 (304.83, 471.77) ng/ml], FHR5 [4.01 (3.51, 4.48) ug/ml vs. 2.73 (2.25, 3.21) ug/ml]were all significantly higher in Group CoV compared with Group non-CoV, respectively (p &amp;lt; 0.001). Although the plasma level of MBL showed no difference in Group CoV and Group non-CoV, the proportion of high levels of MBL in Group CoV was higher than in Group non-CoV (p = 0.025). Compared with Group non-CoV, the intensity of glomerular MAC deposition was much stronger in Group CoV. There were no significant differences in serum levels of IgA, Gd-IgA1, IgA immune complex between two Groups. However, a greater intensity of Gd-IgA1 deposition in glomerular mesangial and capillary areas has been exhibited in Group CoV than those in Group non-CoV (p = 0.005). Conclusion For IgAN after COVID-19, mucosal immune responses to SARS-CoV-2 infection may result in the overactivation of systemic and renal local complement system, which is the first hit, and increased glomerular deposition of Gd-IgA1 is the second hit. We think that these two hits may lead to renal dysfunction and promote renal progression in IgAN patients. It is crucial to emphasize the necessity for long term follow-up in these patients of IgAN after COVID-19. Additionally, we propose that inhibitors targeting the mediators of complement activation might be a promising therapy for these IgAN patients after SARS-CoV-2 infection.

#2377 Association of uremic toxins with morbidity and mortality in patients on hemodialysis

Abstract Background and Aims Morbidity and mortality are increased in patients on hemodialysis (HD), and the possible impact of protein bound uremic toxins (PBUT) is of great interest. We assessed the association between PBUT serum levels and clinical events including cardiovascular (CVE), severe infections (hospitalization due to infection, respiratory infection) and all-cause mortality. Method In this prospective observational study, PBUT plasma levels [hippuric acid (HA), indoxyl sulfate (IxS), p-cresyl sulfate (pCS), p-cresyl glycuronide (pCG), indole-3-acetic acid (IAA), 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF)] were quantified by ultra-performance liquid chromatography in 54 patients on HD (Age 51.3±16.91 years) and the association with future clinical events (CVE, hospitalization due to severe infection, respiratory infection and all-cause mortality) during 24 months follow up (FU), was assessed. Results In patients who died during FU (n=6), increased levels of total HA 6.42 (4.54) vs 2.75 (3.03)mg/dl (p=0.007), free HA 4.79 (3.93) vs 1.363 (1.85)mg/dl (p=0.004); free IxS 0.29 (0.29) vs 0.13 (0.17)mg/dl (p=0.045); total pCG 0.36 (0.5) vs 0.19 (0.28)mg/dl (p=0.045), free pCG 0.33 (0.43) vs 0.18 (0.26)mg/dl (p=0.042) were found. Moreover, in patients who experienced a CVE (n=11), a higher concentration of CMPF [0.39 (0.67) vs 0.15 (0.19)mg/dl (p=0.015)] was observed. No significant correlations were found between pCS and IAA levels with morbidity and mortality in this study. A logistic regression model, describing the effect of each PBUT on death probability could explain 44% (Nagelkerke R2) of the variance in death and correctly classified 90.7% of cases. Patients with increased levels of free IxS, total and free HA were more likely to die within a 2-year FU period (p=0.047, p=0.013, p=0.003, respectively). PBUT levels were not different among HD patients with and without severe infections. Conclusion Increased levels of PBUT (HA and free IxS) in patients on HD, associate with increased risk of death and CMPF with cardiovascular events.

#1999 Retrospective observational study of uremic pruritus prevalence on dialysis

Abstract Background and Aims In Spain, the prevalence of moderate-severe Uremic Pruritus (UP) was 46% and 40% in the DOPPS I and DOPPS. This symptom is usually underdiagnosed and could worsen the quality of life, as some recent studies have revealed. The last reports regarding UP prevalence date back to 2004, hence we decided to assess its current frequency of this while exploring the degree of recognition along with other UP-associated factors. Method This study includes 192 patients in renal replacement therapy (RRT), retrospectively recruited from our centre. Data were collected from revisit medical records in 2021. UP was evaluated using a visual analogic scale (VAS). In addition, age, time on dialysis, UP treatment, haemoglobin, eosinophils, plasma levels of calcium, phosphorus, urea, parathyroid hormone, c-reactive protein (CRP), and clearance (measured by KT/V) were also recorded. Results Average patient age was 61.3 years old, with an average time in dialysis of 37.4 months. The most common group of chronic kidney disease was glomerular diseases (25.5%). The patient distribution by RRT was: 51.9% in haemodialysis (HD), 36.5% in peritoneal dialysis (PD), and 11.6% in home haemodialysis (HHD). UP average prevalence was 56.7% (50% in HHD, 55.2% in HD and 60.9% in PD), of which 69.8% had a VAS ≥ 5. UP was statistically associated with older age (p = 0.017) and higher plasmatic phosphorus (p = 0.015). Notably, only 51.9% UP patients had been prescribed specific drugs for itching. Among UP treated patients, 70.9% improved 3 or more VAS points (with no differences among drugs). Interestingly, this improvement was associated with lower calcium levels (p &amp;lt; 0.0001), the absence of peripheral artery disease (PAD) (p = 0.035), and the shortest time on dialysis (p = 0.001). Conclusion Despite the advances made in HD techniques and the recent incorporation of biocompatible solutions in PD, UP remains a frequent symptom among dialysis patients, without relevant prevalence improvements over the last 20 years. UP was misdiagnosed and mistreated in our unit, since just 51.9% of patients with UP were under treatment. In addition, clinical response to treatment was appropriate in 70.9% of patients, and our results suggest that calcium, PAD, and time on dialysis could predict the response to the treatment. Therefore, our study supports previous data, highlighting UP as a frequent underdiagnosed symptom among dialysis patients; and opens the path for new research in the identification of novel prognosis markers.

#1502 Short-term effects of gadolinium and gadoteric acid on kidney — impact on inflammation

Abstract Background and Aims The nephrotoxicity of free gadolinium [Gd (III)] has been reported, raising concerns about the safety of gadolinium-based contrast agents (GBCA), widely used in magnetic resonance imaging. The GBCA with macrocyclic structure, such as gadoteric acid (Gd-DOTA), appear as more stable. Using human proximal tubular cells cultures, we found that free Gd (III) triggers death by apoptosis and necrosis, and increases the expression of modulators of inflammation, hypoxia and fibrosis, which are known as major risk factors for the development and worsening of kidney disease. Our aim was, using animal models, to evaluate the short-term effects of Gd (III) and of gadoteric acid on inflammatory biomarkers, at blood and renal tissue levels. Method Wistar rats were exposed to a single dose of Gd (III) or Gd-DOTA (groups A and B, respectively); a control group was also included (C). After 48h, blood and kidney samples were collected. The plasma levels of interleukin (IL)6 and transforming growth factor (TGF) beta 1 were assessed by ELISA; the kidney gene expression of IL6 (il6), TGF beta 1 (tgbf1) and nuclear factor-kappa B (nfkb1) was determined through qPCR. Results Gd (III) group (A) presented higher circulating IL6 levels (P = 0.001) and increased kidney gene expression of il6 (P = 0.013), tgbf1 (P = 0.006) and nfkb1 (P = 0.011) than the control group (C); compared to Gd-DOTA group (B), the IL6 plasma concentration (P = 0.005) and tgbf1 mRNA levels were also higher (P = 0.004). The Gd-DOTA group (B) presented increased gene expression of il6 (P = 0.006) than the control group (C). Conclusion Short-term exposition to free Gd (III) induced an inflammatory response, shown by the increase in circulating IL6, and in kidney gene expression of il6, tgbf1 and nfkb1. The exposition to Gd-DOTA was associated with a lower inflammatory response, showing only increased kidney gene expression of il6. Despite the much safer profile for Gd-DOTA, further studies are warranted, evaluating other biomarkers, to clarify the short-term, and even the long-term effects, of these compounds. Acknowledgements This work was financed by FCT through the project 2022.08400.PTDC; FCT, in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB.

#2070 Associations of fecal and plasma levels of SCFAs with gut microbiota and clinical characteristics in non-dialysis renal anemia patients

Abstract Background and Aims Renal anemia is one of the most common complications of Chronic Kidney Disease (CKD). The gut-kidney axis hypothesis has led to numerous studies showing that patients with CKD have a distinct gut microbiota structure compared with controls and that changes in gut microbiota correlate with disease severity and progression. The short-chain fatty acids (SCFAs) are speculated to be pivotal in the gut-kidney crosstalk. However, the role of SCFAs in renal anemia has not been elucidated. This study aimed to explore and compare the fecal and plasma levels of SCFAs in non-dialysis renal anemia patients and healthy controls to reveal the potential interactions among SCFAs, gut microbiota, and clinical features of renal anemia, which may provide new light on further studies. Method A cohort of 30 non-dialysis renal anemia patients and 20 healthy controls were recruited from the First Affiliated Hospital of Zhengzhou University. Gut microbiota was analyzed using 16S rRNA gene amplification sequencing. Fecal and plasma concentrations of SCFAs were measured using GC-MS/MS platform. The clinical characteristics of patients with renal anemia and controls were evaluated. Results Renal anemia patients displayed altered microbiota composition compared to healthy subjects. The relative abundance of Enterobacterales, Enterobacteriaceae, Escherichia-Shigella, and Escherichia-coli were higher in patients with renal anemia, and the Lachnospiraceae family decreased in renal anemia patients. In contrast, the relative abundance of Lachnospirales, Lachnospiraceae, and Bacteroides vulgatus was higher in the control group. Patients with renal anemia had higher fecal and plasma concentrations of SCFAs compared to controls. The fecal and plasma concentrations of SCFAs were significantly different not only between the patients with renal anemia and controls but also in the different severity of renal anemia. Moreover, different types of SCFAs are intimately associated with clinical characteristics. The applications of medications may exert effects on the fecal and plasma SCFAs. A positive correlation was obtained between Lachnospirales and the plasma SCFAs. The levels of acetic acid and caproic acid in fecal and the levels of acetic acid, propionic acid, and butyric acid in plasma were all positively correlated with the abundance of Cyanobacteria. Conclusion The gut metabolites SCFAs are tightly linked to the alterations of gut microbiota and clinical characteristics of renal anemia. Further studies are warranted to elucidate the relationships more in-depth.

#2158 Circulating kidney injury molecule-1 a valuable marker of mortality in hemodialysis patients?

Abstract Background and Aims The importance of finding reliable biomarkers of mortality in CKD, and especially in patients treated with hemodialysis has become evident. Plasma KIM-1 has been mentioned as a marker of cardiovascular morbidity.. The aim of this study is to assess the level of plasma Kidney Injury Molecule- 1 (KIM-1) as a marker of mortality in patients treated with hemodialysis. Method We conducted a single-center study that included 63 CKD G5D patients (hemodialysis for 1-5 years) followed up for 48 months and a control group consisting of 52 patients diagnosed with CKD stages G1-G5, without HfrEF. All patients have been assessed at baseline, regarding cardiovascular disease (medical history, echocardiography and ECG). Circulating plasma KIM-1 levels were determined with single molecule counting immunoassay technology using the Enzyme-linked immunosorbent assay, we performed using standard methods blood biochemistry, and markers of inflammation (CRP, IL-6) and markers of anemia (complete blood count, serum ferritin, transferrin saturation- TSAT). Results Mean plasma KIM1 levels were 403.8 +/-546.8pg/ml) in the group of patients treated with hemodialysis, and was statistically significantly higher compared to the level in the control group (217.48 +/-267.10 pg/ml). In the group of patients treated with hemodialysis plasma KIM-1 levels showed a statistically significant correlation with inflammation (mean CRP- R=0.28, p=0.02 and IL6- R=0.36, p=0.005) and with anemia (hematocrit- R= -0.5, p=-0,0316; hemoglobin - R= -0.5, p=0.02 We found out using ANOVA that patients which presented left ventricular hypertrophy on echocardiography (37 out of 62) had significantly lower mean levels of plasma KIM-1 (155,51 vs 432,12 pg/ml; p=0,026). The group of patients with vascular calcifications on echocardiography (48 out of 62) had lower levels of serum KIM1 (210.01 vs 462.58 pg/ml, p=0.04). After 24 months of follow up we found a mortality rate of 22.23%, while after 48 months the mortality rate was of 50.73%. Using a Cox proportion-hazards regression analysis of predicting factors of mortality we found that regarding the relationship between plasma levels of KIM-1 and mortality there is a significantly decreased survival in patients with low KIM-1&amp;lt;81.98 pg/ml (p&amp;lt;0.001), with a cut-off point for plasma KIM-1 levels= 81.98 pg/ml. Conclusion Plasma KIM-1 levels were significantly higher in patients treated with hemodialysis compared to the control group (ND CKD patients). However, surprisingly, low levels of plasma KIM1 were associated with some cardiovascular changes and also to an increased risk of mortality (at 4 years, not after few months).

Proteome-wide Mendelian randomization identifies potential therapeutic targets for nonalcoholic fatty liver diseases

Nonalcoholic fatty liver disease (NAFLD) is the predominant cause of liver pathology. Current evidence highlights plasma proteins as potential therapeutic targets. However, their mechanistic roles in NAFLD remain unclear. This study investigated the involvement of specific plasma proteins and intermediate risk factors in NAFLD progression. Two-sample Mendelian randomization (MR) analysis was conducted to examine the association between plasma proteins and NAFLD. Colocalization analysis determined the shared causal variants between the identified proteins and NAFLD. The MR analysis was applied separately to proteins, risk factors, and NAFLD. Mediator shares were computed by detecting the correlations among these elements. Phenome-wide association studies (phewas) were utilized to assess the safety implications of targeting these proteins. Among 1,834 cis-protein quantitative trait loci (cis-pQTLs), after-FDR correction revealed correlations between the plasma levels of four gene-predicted proteins (CSPG3, CILP2, Apo-E, and GCKR) and NAFLD. Colocalization analysis indicated shared causal variants for CSPG3 and GCKR in NAFLD (posterior probability > 0.8). Out of the 22 risk factors screened for MR analysis, only 8 showed associations with NAFLD (p ≤ 0.05), while 4 linked to CSPG3 and GCKR. The mediator shares for these associations were calculated separately. Additionally, reverse MR analysis was performed on the pQTLs, risk factors, and NAFLD, which exhibited a causal relationship with forward MR analysis. Finally, phewas summarized the potential side effects of associated-targeting proteins, including CSPG3 and GCKR. Our research emphasized the potential therapeutic targets for NAFLD and provided modifiable risk factors for preventing NAFLD.

Early Alteration of Right Ventricle-Pulmonary Artery Coupling in Experimental Heart Failure With Preserved Ejection Fraction.

Pulmonary hypertension and right ventricular (RV) dysfunction are major prognostic determinants in patients with heart failure with preserved ejection fraction (HFpEF). The underlying pathomechanisms remain unknown. In this context, we sought to study the pathogenesis of pulmonary hypertension and RV dysfunction in a rat model of obesity-associated HFpEF. HFpEF was induced in obesity-prone rats fed a high-fat diet (n=13) and compared with obesity-resistant rats fed with standard chow (n=9). After 12 months, the animals underwent echocardiographic and hemodynamic evaluation followed by tissue sampling for pathobiological assessment. HFpEF rats presented mild RV pressure overload (with increased RV systolic pressure and pulmonary vascular resistance). No changes in pulmonary artery medial thickness and exvivo vasoreactivity (to acetylcholine and endothelin-1) were observed and RNA sequencing analysis failed to identify gene clustering in HFpEF lungs. However, released nitric oxide levels were decreased in HFpEF pulmonary artery, while lung expression of preproendothelin-1 was increased. In HFpEF rats, RV structure and function were altered, with RV enlargement, decreased RV fractional area change and free wall longitudinal fractional shortening, together with altered right ventricle-pulmonary artery coupling (estimated by tricuspid annular plane systolic excursion/systolic pulmonary artery pressure). Hypertrophy and apoptosis (evaluated by transferase biotin- dUTP nick-end labeling staining) were increased in right and left ventricles of HFpEF rats. There was an inverse correlation between tricuspid annular plane systolic excursion/systolic pulmonary artery pressure and RV apoptotic rate. Plasma levels of soluble suppression of tumorigenicity-2, interleukin-1β, -6 and -17A were increased in HFpEF rats. Obesity-associated HFpEF in rats spontaneously evolves to pulmonary hypertension-HFpEF associated with impaired right ventricle-pulmonary artery coupling that appears disproportionate to a slight increase in RV afterload.

Mediterranean Diet Combined with Regular Aerobic Exercise and Hemp Protein Supplementation Modulates Plasma Circulating Amino Acids and Improves the Health Status of Overweight Individuals.

Plant protein is considered a sustainable health-promoting strategy to prevent metabolic syndrome. Lifestyle changes (including dietary patterns and exercise) have been demonstrated to exert an effect on human health by modulating the biochemical status in humans. The objective of this study was to assess whether supplementation with hemp protein within a Mediterranean diet context together with exercise could help to ameliorate the metabolic statuses of patients prone to developing metabolic syndrome. For this study, 23 patients followed with Mediterranean diet and engaged in aerobic exercise according to the WHO's recommendations, while also being supplemented with hemp protein, for 12 weeks. A comparison of anthropometric, biochemical, and mineral data as well as amino acid values was made between the start and the end of the study, with the subjects acting as their own control group. Statistical analyses included a paired t-test, Wilcoxon paired test, Pearson correlation coefficient, and Sparse Partial Least Squares Discriminant Analysis to evaluate significant differences and correlations among parameters. There were statistically significant changes in total cholesterol, HDL-C (+52.3%), LDL-C (-54.0%), and TAG levels (-49.8%), but not in glucose plasma levels. Following the intervention, plasma concentrations of some amino acids, including α-aminoadipic acid, phosphoethanolamine, and 1-metylhistidine, increased, whereas those of asparagine and alanine declined. Different correlations between amino acids and the other parameters evaluated were reported and discussed. A Mediterranean diet combined with regular aerobic exercise, together with protein supplementation, can highly improve the metabolic parameters and anthropometric parameters of subjects with obesity and impaired glucose levels, ameliorating their health status and likely delaying the development of metabolic syndrome.

#233 Marine n-3 polyunsaturated fatty acids and cardiovascular events in patients with end-stage renal disease receiving hemodialysis

Abstract Background and Aims Cardiovascular (CV) disease is the leading cause of death in patients with end-stage renal disease (ESRD) receiving hemodialysis (HD). The two major marine n-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may have cardioprotective effects. This study aimed to investigate the predictive value of plasma n-3 PUFAs on CV events and all-cause mortality in patients with ESRD receiving HD. Method A validated prospective multicenter cohort study of 336 patients with ESRD receiving HD with 5 years of follow-up was conducted. Blood samples were collected at baseline and analyzed for the plasma levels of EPA and DHA expressed as a weight percentage (wt%) of total plasma fatty acids. The primary outcome was CV events defined as acute myocardial infarction, unstable angina pectoris, stroke, transient ischemic attack, peripheral artery disease (PAD), or cardiovascular mortality. The secondary outcomes were all-cause mortality and each individual component of CV events. The sum of EPA and DHA (EPA+DHA) was used in all analyses and expressed as n-3 PUFAs in wt%. The population was divided into three groups according to n-3 PUFA tertiles. Kaplan-Meier curves and multivariable Cox regressions adjusted for relevant confounders were used to analyze the association between plasma n-3 PUFA levels and study outcomes. Results Median follow-up time was 5.05 years (IQR, 5.02-5.07). Mean age was 65 ± 15 years and plasma n-3 PUFA levels ranged from 2.1 to 16.8 wt%, with a median of 5.7 wt% (IQR, 4.72-6.96 wt%). During follow-up 60% of the cohort died, 17% died of CV disease, and 42% had a CV event. Figure 1 shows the unadjusted associations between the plasma n-3 PUFA tertiles and the risk of CV events. A n-3 PUFA level between 5.06-6.52 wt% was associated with a 36% lower risk of CV events [unadjusted HR 0.64 (95% CI 0.43-0.96)]. Additionally, a n-3 PUFA level above 6.52 wt% was associated with a 34% lower risk of CV events [unadjusted HR 0.66 (95% CI 0.44-0.98)], both in comparison to levels below 5.06 wt%. After adjusting for relevant confounders, as shown in Figure 2, n-3 PUFA levels between 5.06 to 6.52 wt% were associated with a significantly lower risk of CV events [adjusted HR 0.60 (95% CI 0.40-0.92)], PAD [adjusted HR 0.44 (95% CI 0.22-0.88)], and all-cause mortality [adjusted HR 0.61 (95% CI 0.42-0.86)], when compared to levels below 5.06 wt%. Conclusion In this study of patients with ESRD receiving HD, a low plasma level of n-3 PUFA was associated with a higher risk of CV events, peripheral artery disease, and all-cause mortality.

#2890 Role of alternative pathway of complement system in membranous nephropathy: a study from STARMEN clinical trials

Abstract Background and Aims Membranous nephropathy (MN) is an antibody-mediated autoimmune disease characterized by glomerular immune complexes containing complement components. A recent animal model of PLA2r antibody-induced MN induced has demonstrated the crucial role of complement pathway, although is still unclear which complement pathway is most involved in its pathogenesis This study aimed to explore the role of alternative pathway of complement cascade in a cohort of patients from STARMEN clinical trial. Method We analyzed longitudinal plasma samples from 51 patients from STARMENT cohort stored in a biobank. Samples were stored at enrollment and longitudinally throughout the follow up at 3, 6, 9, 12, 18 and 24 months. We measured the circulating plasma levels of C3, FB, FH, FHR1, FHR2 and FHR5 in every time. Results Fifty-two patients with a mean age of 56 ± 10 years and 60% male were included. 44% were treated with tacrolimus+Rituximab and 56% with ponticelli regimen. The basal creatinine was 0.9 ± 0.3 mg/dl, median proteinuria/day was 8.8 g/day (IQR 5.7-11.6 gr/day) and serum albumin of 2.6 g/dl (IQR 2.3-2.9 g/dl). All patients were followed-up for two years. Thirty-four patients achieved complete remission (CR), 11 patients partial remission (PR) and 15 did not respond (including relapse). During active disease, the mean concentration of FH, FHR-1 and FHR-2 were significantly increased compared with remission status (complete or partial). We did not find different in other factors: FB or FHR-5. Moreover, a positive correlation was observed between FH and FB with C3. There were no differences according to treatment arm. PLA2r antibodies tested positive in 68%. The median of baseline anti-PLA2R title levels was 80 RU/ml (IQR 43-141). Circulating plasma levels of FHR1 at baseline were significantly higher in PLA2r testing negative vs positive patients (199 ± 108 vs 249 ± 41 µg/ml, p = 0.021). This significant difference was present when remission was achieved (205 ± 97 vs 264 ± 49 µg/ml, p = 0.023). Similar tendency was observed for FB. Conclusion These data provide evidence of complement system activation through the alternative pathway in membranous nephropathy. We know that different subtypes of IgG are behind the different antibodies-induced MN induced, and that every subtype active different complement pathway. The results of this study lead to speculate that not all the antigens that induced MN active complement pathway in the same way.

#1940 Plasma complement activation profile in kidney transplant recipients with IgAN supports the importance of the complement alternative pathway in IgAN

Abstract Background and Aims The alternative complement and lectin pathways are key players in IgA nephropathy (IgAN). However, the precise dynamics of complement activation in IgAN remain poorly understood. Non-invasive complement biomarkers are urgently needed in view of the evolving landscape of complement-targeting therapies under evaluation in IgAN. Method We analyzed plasma complement activation biomarkers in a cohort of 87 kidney transplant recipients (KTR) with IgAN and 30 controls consisting of autosomal dominant polycystic kidney disease (ADPKD) KTR (NCT05234463, DC-2013-1990). Patients were excluded if 1) they had a biological inflammatory syndrome at the time of sampling or 2) they had experienced a cellular/humoral rejection in the year prior to or after sampling. We simultaneously measured a large panel of complement activation and regulation fragments (C3a, C5a, C4a, sC5b-9, Ba, Bb) and intact proteins (C3, C4, FI, FH, properdin) in plasma using multiplex ELISA (Quidel Ortho®, A900), nephelometry and in-house ELISA. Results There was no consumption of C3 and C4 proteins in IgAN patients. However, C3a and Bb concentrations were elevated in IgAN patients compared to ADPKD patients (161 [98-227] vs. 102 [66-172] ng/mL, p = 0.007; 3.0 [2.6-4.0] vs. 2.5 [2.0-2.8] µg/mL, p &amp;lt; 0.0001). Overall, 70/87 IgAN patients (80.5%) had elevated Bb levels. The plasma concentration of C5a was elevated in IgAN patients compared to ADPKD patients (6.3 [3.8-9.2] vs. 4.9 [2.8-6.3] ng/mL, p = 0.0274), with values within the reference range in 92.0% of IgAN patients. There was no difference in plasma levels of sC5b-9 between the two groups (p = 0.186). The combined analysis of C3a, C5a and sC5b-9 allowed us to distinguish 4 clusters of patients (Fig. 1). A total of 48 patients (55.2%) show evidence of C3 convertase activity in plasma (clusters 3 and 4), including 16 patients (18.4%) with the highest plasma concentrations of sC5b-9, C3a and Bb. In contrast, 15 patients (17.2%, cluster 1) have no (or very low) complement activation. The last group (n = 32, 36.8%, cluster 2) shows an isolated increase in sC5b-9 without evidence of plasma C3 convertase activity. Proteinuria was significantly increased in groups 3 and 4, which had the highest C3a concentrations, compared to groups 1 and 2 (p = 0.0051). Conclusion This study provides insights into the mechanisms of complement activation in IgAN, with a pivotal role for the activity and regulation of the alternative C3 pathway convertase. In addition, the combined analysis of complement biomarkers identified, for the first time, clusters of patients who may benefit from complement targeting therapies.

#1943 The association of uncarboxylated, non-phosphorylated Matrix Gla protein with arterial stiffness in hemodialysis and peritoneal dialysis patients

Abstract Background and Aims Vitamin K deficiency has been identified as a marker of vascular calcification AND STIFNESS and an independent cardiovascular risk factor in hemodialysis (HD) and peritoneal dialysis (PD) patients, as the most powerful inhibitor of vascular calcification, Matrix Gla Protein requires vitamin K to become activated. However, until to date, it has not yet been clarified whether hepatic or extrahepatic markers of vitamin K status reflect the arterial status of dialysis patients. In this study we aimed to investigate the association of vitamin K deficiency with arterial stiffness in End-Stage Kidney Disease (ESKD) patients. Method In 42 ESKD patients undergoing either HD or PD, we measured plasma levels of the inactive vitamin-K dependent Matrix Gla Protein (dp-ucMGP) and serum levels of prothrombin (PIVKA-II) as markers of extrahepatic and hepatic insufficiency of vitamin K (CARIM Institute, Maastricht, Netherlands). In these patients we determined arterial stiffness parameters (pulse wave velocity-PWV) by the Mobil-O-Graph device (IEM, Stolberg, Germany). Results Serum PIVKA-II was associated with T2D duration (r = −0.38, p = 0.013), phosphorus levels (r = −0.41, p = 0.009) serum albumin (r = −0.33, p = 0.036) Spearman's rho test, and the type of transporter in PD patients (p = 0.039), Kruskal-Wallis test. Plasma dp-ucMGP was associated with PWV (r = 0.51, p = 0.001), peripheral (r = −0.37, p = 0.016) and central diastolic blood pressure (BP) (r = −0.34, p = 0.026) and age (r = 0.41, p = 0.007), Spearman's rho. Patients with T2DM, history of acute myocardial infarction and those receiving warfarin had significantly increased levels of circulating dp-ucMGP (p = 0.036, p = 0.039 and p &amp;lt; 0.0001, respectively, Kruskal-Wallis). Warfarin was associated with a 2.5-fold and a 23-fold increase in dp-ucMGP and PIVKA-II levels, respectively. Stepwise multiple regression analysis showed that PWV (p = 0.001, B = 494, 95% CI: 242-746) was an independent predictor of dp-ucMGP, independent of age, T2T2, history of myocardial infraction and diastolic BP. Conclusion Elevated plasma dp-ucMGP levels (suggesting extrahepatic vitamin K deficiency) were associated with increased arterial stiffness in dialysis patients.

#2929 Plasma levels of brain injury markers NfL and GFAP are independently predicted by glomerular filtration rate in patients with chronic kidney disease

Abstract Background and Aims Patients with chronic kidney disease (CKD) have a high prevalence of cerebrovascular disease and cognitive impairment. The aim of the present study was to measure brain injury biomarkers in plasma in a cohort of patients with CKD stages 3 and 4, without a diagnosis of cerebrovascular disease, and to determine factors that independently predicted plasma levels of these biomarkers. Method This was a cross-sectional cohort study including 110 patients with CKD stages 3 and 4, and 55 healthy, matched, controls, recruited from the outpatient clinic at Sahlgrenska university hospital, Gothenburg, Sweden. None of the included study subjects had a diagnosis of cerebrovascular disease, cognitive impairment, or any other neurological disease. Plasma concentrations of neurofilament light (NfL), glial fibrillary acidic protein (GFAP) and phosphorylated Tau (p-Tau231) were analyzed with ultrasensitive single molecule array (SIMOA). Measured GFR (mGFR) was determined by plasma clearance of ⁵¹Cr-EDTA. Values are medians [interquartile range]. For linear regression analyses standardised beta coefficients (β) are presented. Results Characteristics of CKD patients and healthy controls are presented in Table 1. Plasma concentrations of NfL (37.5 [22.1-47.5] vs. 13.4 [10.5-16.7] ng/L, p &amp;lt; 0.001), p-Tau231 (25.7 [19.1-38.7] vs. 13.9 [10.5-16.3] ng/L, p &amp;lt; 0.001) and GFAP (190 [140-281] vs. 153 [116-211] ng/L, p = 0.001) were significantly elevated in patients with CKD vs. controls. In CKD patients, mGFR showed statistically significant inverse correlations to plasma concentrations of NfL, p-Tau231, and GFAP (Table 2). In multiple regression analyses, mGFR was associated with plasma levels of NfL (β = −0.457, p &amp;lt; 0.001) and GFAP (β = −0.322, p &amp;lt; 0.001) independently of diabetes, age, troponin-T, b-hemoglobin, and aortic pulse-wave velocity. However, mGFR was not significantly associated with plasma levels of p-Tau231 in a multiple regression analysis. Conclusion Plasma levels of brain injury markers NfL, p-Tau231 and GFAP were elevated in patients with CKD stages 3 and 4, without a history of cerebrovascular disease, compared to healthy controls. Furthermore, mGFR independently predicted plasma concentrations of NfL and GFAP in multiple regression models. These results raise the possibility that reduced GFR per se may be associated with subclinical brain injury.

Differences in IDO1+ dendritic cells and soluble CTLA-4 are associated with differential clinical responses to methotrexate treatment in rheumatoid arthritis.

Antigen-presenting dendritic cells (DCs) and monocytes play an essential role in rheumatoid arthritis (RA) pathogenesis, however, their tolerogenic potential remains unclear. Herein, the tolerogenic profiles of DCs are characterized in treatment-naïve RA patients to determine their role to inflammatory arthritis management. Thirty-six treatment-naïve RA patients were enrolled, of which 62% were non-responders to methotrexate (MTX) monotherapy based on disease activity score (DAS) after 6-months of therapy. DC and monocyte subset frequencies, activation (CD40, CD86, CD209 expression), and tolerogenic profile (intracellular indoleamine-2,3-dioxygenase [IDO1] and cytotoxic T lymphocyte antigen 4 [CTLA-4] expression) were examined in the baseline peripheral blood by multicolor flow-cytometry. Soluble CTLA-4 (sCTLA-4) levels in plasma were measured. DC subsets were decreased in RA compared to healthy controls (HC), and the frequency of conventional DCs (cDC) inversely correlated with inflammatory markers and improvement in disease activity. CD141+ cDC1s were the major IDO1-expressing cells. IDO1+cDC1s were reduced in RA patients compared to HC. The baseline frequency of IDO1+cDC1s inversely correlated with improvement in disease activity. CTLA-4 expression in CD1c+ cDC2s and monocytes was lower in RA patients compared to HC. Moreover, MTX-responders had a significantly lower frequency of IDO1+cDC1 cells and higher level of sCTLA-4 in the plasma compared to MTX non-responders. There was a strong predictive association of low IDO1+cDC1 cells, low sCTLA-4 and non-response to MTX. Our findings reveal altered DC and monocytes immunophenotypes that are associated with RA pathology and treatment response. The frequencies of tolerogenic IDO1+cDC1s and the low level of sCTLA-4 are strongly associated with MTX non-responsiveness and therapeutic outcome. These results suggest that investigation of the association IDO1+cDC1 and sCTLA-4 with response to treatment may be more generalizable to other autoimmune diseases.