The Effect of VPA Treatment on Radiolabeled DOTATATE Uptake: Differences Observed In Vitro and In Vivo

Background: To improve peptide receptor radionuclide therapy (PRRT), we aimed to enhance the expression of somatostatin type-2 receptors (SSTR2) in vitro and in vivo, using valproic acid (VPA). Methods: Human NCI-H69 small-cell lung carcinoma cells were treated with VPA, followed by [111In]In-DOTATATE uptake studies, RT-qPCR and immunohistochemistry analysis. Furthermore, NCI-H69 xenografted mice were treated with VPA or vehicle, followed by [177Lu]Lu-DOTATATE injection. Biodistribution studies were performed, and tissues were collected for further analysis. Results: VPA significantly increased SSTR2 expression in vitro. In animals, a statistically significant increased [177Lu]Lu-DOTATATE tumoral uptake was observed when VPA was administered eight hours before [177Lu]Lu-DOTATATE administration, but increased tumor SSTR2 expression levels were lacking. The animals also presented significantly higher [177Lu]Lu-DOTATATE blood levels, as well as an elevated renal tubular damage score. This suggests that the enhanced tumor uptake was presumably a consequence of the increased radiotracer circulation and the induced kidney damage. Conclusions: VPA increases SSTR2 expression in vitro. In vivo, the observed increase in tumoral [177Lu]Lu-DOTATATE uptake is not caused by SSTR2 upregulation, but rather by other mechanisms, e.g., an increased [177Lu]Lu-DOTATATE circulation time and renal toxicity. However, since both drugs are safely used in humans, the potential of VPA to improve PRRT remains open for investigation.

Urinary Extracellular Vesicles as a Source of NGAL for Diabetic Kidney Disease Evaluation in Children and Adolescents With Type 1 Diabetes Mellitus

BackgroundTubular damage has a role in Diabetic Kidney Disease (DKD). We evaluated the early tubulointerstitial damage biomarkers in type-1 Diabetes Mellitus (T1DM) pediatric participants and studied the correlation with classical DKD parameters.MethodsThirty-four T1DM and fifteen healthy participants were enrolled. Clinical and biochemical parameters [Glomerular filtration Rate (GFR), microalbuminuria (MAU), albumin/creatinine ratio (ACR), and glycated hemoglobin A1c (HbA1c)] were evaluated. Neutrophil gelatinase-associated lipocalin (NGAL), Hypoxia-inducible Factor-1α (HIF-1α), and Nuclear Factor of Activated T-cells-5 (NFAT5) levels were studied in the supernatant (S) and the exosome-like extracellular vesicles (E) fraction from urine samples.ResultsIn the T1DM, 12% had MAU >20 mg/L, 6% ACR >30 mg/g, and 88% had eGFR >140 ml/min/1.72 m2. NGAL in the S (NGAL-S) or E (NGAL-E) fraction was not detectable in the control. The NGAL-E was more frequent (p = 0.040) and higher (p = 0.002) than NGAL-S in T1DM. The T1DM participants with positive NGAL had higher age (p = 0.03), T1DM evolution (p = 0.03), and serum creatinine (p = 0.003) than negative NGAL. The NGAL-E correlated positively with tanner stage (p = 0.0036), the median levels of HbA1c before enrollment (p = 0.045) and was independent of ACR, MAU, and HbA1c at the enrollment. NFAT5 and HIF-1α levels were not detectable in T1DM or control.ConclusionUrinary exosome-like extracellular vesicles could be a new source of early detection of tubular injury biomarkers of DKD in T1DM patients.

Acute Kidney Injury in Cardiac Surgery with Cardiopulmonary Bypass

Changes in classification criteria and active introduction of biomarkers of acute kidney injury (KDIGO, 2012) are changing approaches to diagnosis and treatment of postoperative renal dysfunction including cardiac surgery patients operated with cardiopulmonary bypass (CPB). The objective: to compare the detection rate of AKI after surgery with CPB with the use of biomarkers and kidney disease improving global outcomes criteria, as well as to evaluate the cause and localization of structural changes of the nephron.Subjects and Methods. A monocenter observational study among elective cardiac surgery patients (n = 97) was conducted. Inclusion criteria: age over 18 years, duration of surgery (coronary bypass surgery, prosthetic heart valves) from 90 to 180 minutes, no signs of end stage kidney disease. AKI was diagnosed based on changes in serum creatinine and biomarkers (NGAL, IgG, albumin in urine). The studied parameters were recorded 15 minutes after the start and end of anesthesia, as well as 24 and 48 hours after surgery. Retrospectively, the group was divided into three subgroups: 1) patients without AKI after surgery; 2) patients in whom signs of AKI were detected after 24 hours but regressed by the 48th hour; 3) patients in whom AKI persisted during all 48 hours of follow-up.Results. 24 hours after surgery, AKI based on KDIGO criteria was recorded in 56.3% of patients. Using biomarkers, signs of tubular damage (NGAL) at the end of anesthesia were detected in 95.9% of patients; after 24 hours, they were registered in 73.2% of cases. In a subgroup where AKI persisted for more than 24 hours, glomeruli were damaged in addition to tubules which was manifested not only by selective but also by non-selective proteinuria. The duration of CPB, hemodilution (Hb < 90 g/l), the release of free hemoglobin in the blood (> 1.5 mg/l) at low (< 1 g/l) values of haptoglobin were significantly associated with AKI development.Conclusion. The KDIGO criteria do not allow detecting a subclinical form of renal dysfunction which may occur in about 40% of patients after surgery with CPB. AKI can be caused by damage to both the tubular part of the nephron and glomeruli in cases of prolonged CPB with the development of hemolysis, the release of free hemoglobin in the blood, and persisting anemia at the end of the surgery. The NGAL assessment makes it possible to detect subclinical kidney injury in the absence of elevated serum creatinine levels.

Blood Pressure Elevation of Tubular Specific (P)RR Transgenic Mice and Lethal Tubular Degeneration due to Possible Intracellular Interactions between (P)RR and Alternative Renin Products

The prorenin/renin receptor ((P)RR) is a multifunctional protein that is widely distributed in various organs. Despite intensive research for more than 20 years, this receptor has not been fully characterized. In this study, we generated mice overexpressing the tubular epithelial (P)RR gene ((P)RR-TG mice) to test the previously reported functional role of (P)RR by Ramkumar et al. in 2015 using tubular specific (P)RR KO mice. (P)RR-TG mice were maintained and analyzed in individual metabolic cages and were administered angiotensin II blocker (ARB), direct renin inhibitor (DRI), and bafilomycin, that is, vacuolar ATPase (V-ATPase) antagonist. (P)RR-TG mice were hypertensive and had alkalized urine with lower osmolality and Na+ excretion. ARB and DRI, but not bafilomycin, concurrently decreased blood pressure. Bafilomycin acidized urine of (P)RR-TG mice, or equivalently this phenomenon restored the effect of overexpressed transgene, suggesting that (P)RR functioned as a V-ATPase in renal tubules. Afterall, (P)RR-TG mice were mated with alternative renin transgenic mice (ARen2-TG), which we identified as intracellular renin previously, to generate double transgenic mice (DT-TG). Lethal renal tubular damage was observed in DT-TG mice, suggesting that intracellular renin may be a ligand for (P)RR in tubules. In summary, (P)RR did not substantially affect the tissue renin-angiotensin system (RAS) in our model of tubular specific (P)RR gene over-expression, but alternative intracellular renin may be involved in (P)RR signaling in addition to conventional V-ATPase function. Further investigations are warranted.

Intermittent Fasting before Laparotomy: Effects on Glucose Control and Histopathologic Findings in Diabetic Rats

(1) Background: Intermittent fasting is a nutrition practice in which individuals fast for several hours in a day, mainly with feeding time during the daylight hours. They seek to improve metabolic performance and cellular resistance to stress. In this study, we tested the fasting protocol to investigate the glycemic effect in a laparotomy perioperative period in diabetic rats and histopathologic findings. (2) Methods: The animals were diabetic-induced with alloxan. Two groups were set according to the feeding protocol: free food and intermittent fasting, whose rats could only eat 8 h in the daylight. Both groups were anesthetized, and a laparotomy was performed. We evaluated the glucose levels during the perioperative period, and we accessed organ histology seeking damage of kidney, bowel and liver after surgical trauma, and we evaluated the wound healing process. (3) Results: Glycemic levels were improved in the intermittent fasting group, especially in the post-operative period after laparotomy. Comparing both groups’ tubular damage showed interdependency with mice with worse glycemic level (Z = 2.3; p = 0.0215) and wound-healing parameters showed interdependency with rats with better glycemic status for neovascularization (Z = 2.2; p = 0.0273) and the presence of sebaceous and sweat gland in the healing process (Z = 2.30; p = 0.0215). (4) Conclusions: Intermittent fasting before surgery can be a tool to improve glycemic levels in diabetic rats, with improvement especially in the post-operative period.

Maresin 1 Attenuates Lipopolysaccharide-Induced Acute Kidney Injury via Inhibiting NOX4/ROS/NF-κB Pathway

Sepsis-associated acute kidney injury (S-AKI) is a common complication in hospitalized and critically ill patients, which increases the risk of multiple comorbidities and is associated with extremely high mortality. Maresin 1 (MaR1), a lipid mediator derived from the omega-3 fatty acid docosahexaenoic acid has been reported to protect against inflammation and promote the regression of acute inflammation. This study proposed to systematically investigate the renoprotective effects and potential molecular mechanism of MaR1 in septic acute kidney injury. We established a S-AKI animal model by a single intraperitoneal injection of lipopolysaccharide (LPS), 10 mg/kg, on male C57BL/6J mice. LPS-stimulated (100 μg/ml) mouse kidney tubular epithelium cells (TCMK-1) were used to simulate septic AKI in vitro. The results showed that pretreatment with MaR1 significantly reduced serum creatinine and blood urea nitrogen levels as well as tubular damage scores and injury marker neutrophil gelatinase-associated lipocalin in septic AKI mice. Meanwhile, MaR1 administration obviously diminished pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, and MCP-1), downregulated BAX and cleaved caspase-3 expression, and upregulated BCL-2 expression in the injured kidney tissues and TCMK-1 cells. In addition, MaR1 reduced malondialdehyde production and improved the superoxide dismutase activity of renal tissues while inhibiting reactive oxygen species (ROS) production and protecting the mitochondria. Mechanistically, LPS stimulated the expression of the NOX4/ROS/NF-κB p65 signaling pathway in S-AKI kidneys, while MaR1 effectively suppressed the activation of the corresponding pathway. In conclusion, MaR1 attenuated kidney inflammation, apoptosis, oxidative stress, and mitochondrial dysfunction to protect against LPS-induced septic AKI via inhibiting the NOX4/ROS/NF-κB p65 signaling pathway.

Renal function in β-thalassemia major patients treated with two different iron-chelation regimes

Background Renal injury in transfusion dependent β thalassemia patients (TDT) has been attributed to iron overload, chronic anemia and iron-chelation therapy (ICT) toxicity. We studied renal function in TDT patients treated with two different ICT regimes. Patients and methods We studied 36 TDT patients: 26 received deferasirox (DFX) and 10 were treated with deferoxamine (DFO) +/− deferiprone (DFP). Results Increased uNAG was found in 30% of the DFX group vs. 10% of the DFO+/−DFP group, the mean uNAG level in the DFX group was significantly higher than in the DFO+/−DFP group, (P < 0.05). A moderate negative correlation was found between uNAG levels and mean serum ferritin for the prior 10 years (P = 0.03), more pronounced for the DFO+/−DFP group. Twenty nine patients had had their renal function evaluated 10 years earlier; eGFR significantly declined in patients switched to DFX (P = 0.0093) but not in patients who continued DFO+/−DFP. Conclusions A high prevalence of renal tubular damage was observed in our TDT patients, particularly those treated with DFX; uNAG was negatively associated with mean 10-year serum ferritin, suggesting ICT’s involvement in tubular injury. A significant decline in eGFR compared to a decade earlier was observed only in patients currently treated with DFX. Strict follow-up of renal function in TDT patients is warranted.

Kidney Tubular Damage Secondary to Deferasirox: Systematic Literature Review

Deferasirox is a first-line therapy for iron overload that can sometimes cause kidney damage. To better define the pattern of tubular damage, a systematic literature review was conducted on the United States National Library of Medicine, Excerpta Medica, and Web of Science databases. Twenty-three reports describing 57 individual cases could be included. The majority (n = 35) of the 57 patients were ≤18 years of age and affected by thalassemia (n = 46). Abnormal urinary findings were noted in 54, electrolyte or acid–base abnormalities in 46, and acute kidney injury in 9 patients. Latent tubular damage was diagnosed in 11 (19%), overt kidney tubular damage in 37 (65%), and an acute kidney injury in the remaining nine (16%) patients. Out of the 117 acid–base and electrolyte disorders reported in 48 patients, normal-gap metabolic acidosis and hypophosphatemia were the most frequent. Further abnormalities were, in decreasing order of frequency, hypokalemia, hypouricemia, hypocalcemia, and hyponatremia. Out of the 81 abnormal urinary findings, renal glucosuria was the most frequent, followed by tubular proteinuria, total proteinuria, and aminoaciduria. In conclusion, a proximal tubulopathy pattern may be observed on treatment with deferasirox. Since deferasirox-associated kidney damage is dose-dependent, physicians should prescribe the lowest efficacious dose.

613 Fontan associated nephropathy: does diastolic function play a role?

Aims In Fontan patients, the pathophysiology of diastolic function and its relationship with systemic complications are still not well understood. Methods and results This is a prospective study including patients who underwent Fontan completion in our centre between 1993 and 2016. We excluded patients with major congenital renal anomalies, those who underwent cardiac transplantation and redo-Fontan patients. All the subjects underwent clinical evaluation, laboratory exams with complete renal and hepatic function, transient hepatic elastography, and complete cardiac evaluation. We used Schwartz equation for estimating glomerular filtration rate in patients younger than 18 years, and CDK-EPI equation for adult patients. We enrolled 35 patients, 46% female (N = 16), and 54% male (N = 19). Medium age was 17 years old (range: 10–31 years old). Medium time from Fontan completion was 160 months (range: 57–340 months). Ten patients had a functional single left ventricle (FSLV, 28.5%) and 21 a functional single right ventricle (FSRV, 60%); four patients had an undetermined single ventricle (11.5%). Data from renal function assessment showed a prevalence of stage 2 chronic kidney disease (eGFR: 60–89 ml/min 1.73 mq). Of those, 11% with creatinine-based equation and 26% (N = 9) when using cystatin C-based equation, with one patients showing a moderate reduced loss of kidney function (eGFR: 40–59 ml/min/1.73 mq). Most of the patients with reduced eGFR measured with cystatin C were FSRV (89%). None had laboratory markers of acute tubular damage, but four patients had signs of chronic tubular dysfunction with elevation of beta 2 microglobulin (13%). Echocardiographic evaluation of diastolic function showed two patients with baseline E/A &lt; 1 (6%, tot N = 33) and 11/33 (33%) pts with abnormal E/E′ (&gt;12). All of them were FSRV patients (100%). Interestingly, statistical correlation between diastolic parameters and renal function showed a significant association between tubular damage parameters, such as alfa1microglobulin and beta2microglobulin, and E/E′ (Pearson’s R 0.4 and 0.48, respectively, P &lt; 0.05), both for FSLV and FSRV patients. Diastolic function appeared to be associated also with glomerular filtration: we found a statistically significant direct correlation between diastolic pulmonary wave deceleration time (dt D wave) and creatinine value (Pearson’s R 0.49, P &lt; 0.05). Supporting the role of diastolic function in Fontan systemic complications is the linear correlation we found with hepatic tests: higher values of aspartate aminotransferase and of gamma-glutamyltransferase were associated with worse diastolic ventricular filling (longer dt D wave and E wave deceleration time, lower TDI early diastolic wave; Pearson’s R 0.45, 0.5, and −0.41, respectively, P &lt; 0.05). Conclusions Fontan-related nephropathy is associated with worsening diastolic function, which was more represented in FSRV patients. Diastolic function is also associated with liver disease in Fontan patients. Those data suggest renal and liver function should be closely monitored in patients with impaired diastolic function.

Long Non-Coding RNA Small Nucleolar RNA Host Gene 5 (SNHG5) Regulates Renal Tubular Damage in Diabetic Nephropathy via Targeting MiR-26a-5p

The study explored the diagnostic value of SNHG5 in diabetic nephropathy (DN) and investigated the role and mechanism on DN via establishing the in vitro HK2 cell model. This study recruited 62 types 2 diabetes mellitus (T2DM) patients, 58 DN patients and 60 healthy controls (HC). The expressions of serum SNHG5 and miR-26a-5p were measured by RT-qPCR analysis. The diagnostic value of SNHG5 in DN was assessed by ROC curve. The in vitro cell model was built to estimate the effects of SNHG5 on cell viability, cell apoptosis, inflammation response and oxidative stress. Serum SNHG5 was increased in DN patients (relative expression: 2.04±0.34) and had the diagnostic value in DN. After HK2 cells were treated with high glucose, the cell viability decreased and apoptosis increased, and the production of inflammatory cytokines and ROS enhanced significantly. It was noticed that inhibition of SNHG5 could reverse the above phenomenon caused by high glucose. Besides, serum miR-26a-5p was diminished in DN patients, and luciferase reporter gene revealed that miR-26a-5p is direct target of SNHG5. These results indicated that inhibition of SNHG5 may mitigate HG-induced renal tubular damage via targeting miR-26a-5p, which providing a new insight into the mechanism of renal tubule damage in DN patients.