bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early life stress (ELS) Induces Increased Interleukin 1 beta in Renal Tubular Epithelial Cells in Adult Rats
Authors: Obi Ijeoma , De Miguel Carmen , Ho Dao , Loria Analia , Pollock Jennifer 
Published: November 2023

ELS is an independent risk factor in the development of cardiovascular disease and hypertension. ELS is also associated with enhanced biomarkers of inflammation in adults. There is substantial evidence that inflammation contributes to the development of hypertension and/or hypertension‐induced renal injury. Utilizing a rat model of ELS, maternal separation (MatSep), we previously reported that ELS induces an exaggerated blood pressure response and increased renal vascular injury to pro‐hypertensive stimuli in male adult rats. We hypothesized that ELS induces a systemic and pro‐inflammatory state in adult male rats. MatSep involves separating rat pups from the dam for 3hrs/day from postnatal day 2 (PD2) to PD14. Normally‐reared littermate rats were used as controls. Immune cells were determined by FACS analysis, magnetic bead isolation, and immunohistochemical staining. Renal cytokine expression was assessed by ELISA and immunohistochemical staining. Circulating and renal mononuclear cells (PBMC) and T‐cell absolute numbers were similar between control and Matsep rats (control vs. MatSep; circulating PBMC: 41.1±6.9 vs. 49.3±2.5 x 106 cells/ml; renal PBMC: 52.9±9.2 vs. 56.5±8.3 x 106 cells/kidney; circulating T cells: 3.0±0.3 vs. 3.4±0.4 x 106 cells/ml; renal T cells: 7.3±1.2 vs. 6.7±1.2 x 106 cells/kidney; p < 0.05). In addition, both groups presented similar percentages of circulating macrophages (control vs. MatSep; n=4/group: 33.1±2.5 vs. 33.5±0.7%) and T‐lymphocyte subpopulations (TH cells: 29.9±.3 vs. 29.4±0.9%; TC cells: 15.8±0.9 vs. 13.5±0.6%; Treg cells: 4.2±0.2 vs. 4.9±0.2%); however, B cell numbers were significantly decreased in MatSep rats (23.7±1.2 vs. 20.1±0.7%; p<0.05). Renal expression of interferon gamma, interleukin 6, and interleukin 4 were similar in control and MatSep rats. Renal interleukin 1 beta (IL‐1β) was significantly increased in MatSep rats compared to control (control: 4.4±0.5 pg/mg protein, MatSep: 7.9±1.0 pg/mg protein; p<0.05). Immunohistolocalization showed increased IL‐1β immunoreactivity in MatSep rats, specifically in renal cortical tubular cells. Proximal tubules of MatSep rats showed increased IL‐1β positive staining on the apical membrane as compared to control rats. These findings indicate that MatSep induces increased renal expression of IL‐1β in cortical tubular cells without a change in numbers of renal mononuclear or T cells. Future studies will determine whether increased IL‐1β in MatSep adult rats is linked to the exaggerated blood pressure phenotype in response to a hypertensive stimuli.Support or Funding InformationFunded by APS Porter Fellowship to IEO, T32DK007545 to CDM, K99/R00HL111354 to ASL, F32HL116145 to DHH, and P01HL69999 to JSP
Effect of a dietary and exercise intervention during pregnancy and lactation on white adipose tissue gene profiles and adiposity with maternal obesity
Authors: Symonds Michael , Bloor Ian , Galvez Fernandez , Domfeh Emmanuel , Maicas Blasco , Poston Lucilla , Taylor Paul 
Published: November 2023

Background and aimsThe recent surge in maternal obesity and its associated outcomes has led to an increase in intervention studies designed to attenuate the potential adverse effects on both the mother and offspring. Pregnancy and lactation are periods of great maternal metabolic flux and regulation of adipose tissue metabolism which is one potential determinant of the adverse outcome. This study focuses on the gene expression profile of the inguinal white adipose depot with maternal obesity and its response to an intervention designed to alleviate obesity.MethodsSprague Dawley dams (n=17) were randomized to control (C; n=6), obesity (Ob; n=5) or obesity intervention (ObDEx; dietary (low glycaemic index diet) and physical exercise (n=6)) groups. At late gestation (G20) all dams were euthanized and adipose tissues were weighed and then stored in RNA later. The study was then repeated but all dams were taken through to lactation day 14 before tissue collection. To analyze gene expression for those genes involved in energy sensing, inflammation, lipid handling and beiging, QPCR assays were applied and mRNA abundance was calculated using geNorm.ResultsExpression of genes involved in energy sensing (e.g. Akt, INS‐R1/2, LPL, mTOR), inflammation (e.g. TLR4, TNFα) and lipid handling (e.g. CD36, FATP4, LPL, SREBP) pathways were all significantly higher in pregnancy compared with lactation for controls, whereas beiging (e.g. UCP1) was unaffected. These differences were further increased in the presence of obesity, but attenuated with the intervention during pregnancy but not lactation. ObDex also reduced both fat mass (C: 5.4±0.8; Ob: 8.3±0.7; ObDEx; 4.4±0.3 g (P<0.01)) and serum leptin (C: 4.2±0.7; Ob: 11.9±1.7; ObDEx; 5.0±0.9 ng/ml (P<0.01)) in pregnancy whilst fetal weight was unaffected.ConclusionsA combined dietary and exercise intervention improved the maternal metabolic gene profile within white fat and prevented excess adiposity. This effect appeared to be confined to pregnancy due to the pronounced metabolic adaptations within fat through lactation. The longer term consequences for the offspring are currently being examined.Support or Funding InformationAcknowledgements: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007–2013), project EarlyNutrition under grant agreement no. 289346.
INTRARENAL ANGIOTENSINOGEN PRODUCTION INDUCED BY CHRONIC ANGIOTENSIN II AND HIGH SALT INTAKE IS AUGMENTED IN TUMOR NECROSIS FACTOR‐ALPHA RECEPTOR TYPE 1 KNOCKOUT MICE
Authors: Mehaffey Eamonn P. , Castillo Alexander , Navar L. Gabriel , Majid Dewan S. A. 
Published: November 2023

Chronic angiotensin II (AngII) treatment increases TNF‐α generation in the kidney and also enhances intrarenal angiotensinogen (AGT) formation. However, the link between TNF‐α increase and AGT formation in the kidney remains unclear as it has also been demonstrated in‐vitro that TNF‐α suppresses AGT production in cultured human proximal tubule cells. These findings may indicate differential activation of TNF‐alpha receptors type 1 (TNFR1) and type 2 (TNFR2) signaling pathways induced by chronic AngII infusion. We examined the hypothesis that chronic elevation in AngII levels coupled with high salt (HS) intake reduces TNFR1 activity but enhances TNFR2 activity that induces cellular responses leading to increased formation of intrarenal AGT. We assessed the renal and systemic responses to chronic infusions with AngII (25 ng/min; implanted minipump) with high salt (HS; 4% NaCl) diets for 4 weeks in mice lacking TNFR1 receptors (TNFR1KO; n=7) and in mice lacking TNFR2 (TNFR2KO; n=6) and compared these responses to those in wild‐type (WT; C57BL6 strain, n=6) mice. Systemic blood pressure (SBP) was measured by tail‐cuff plethysmography and 24‐hour urine collections were done using metabolic cages at baseline and at 4 week periods. The urinary excretion rate of AGT (uAGT) was measured as a reflection of intrarenal generation of AGT using ELISA. Urinary excretion rates of sodium (UNaV) and potassium (UKV) were determined by analyzing urinary concentration of these electrolytes using flame photometry. The increase in mean SBP in response to AngII + HS for 4 weeks was greater in TNFR1KO mice (77±2 to 115±3 mmHg; P<0.05) compared to WT mice (76±1 to 102±2 mmHg; P<0.05), while the change in TNFR2KO (78±2 to 99±5 mmHg; P<0.05) had no difference from WT. Interestingly, the increase in uAGT after 4 weeks treatment period was also greater in TNFR1KO mice (6±2 to 167±75 ng/24hr; P<0.05) compared to WT mice (6±3 to 46±16 ng/24hr; P<0.05), while the changes in TNFR2KO mice (8±7 to 65±44 ng/24hr; P=0.11) were not significantly different from the changes in WT mice. All three groups showed similar increases in UNaV (WT, 118±13 to 883±121 mM/24hr; TNFR1KO, 96±15 to 942±86 mM/24hr; TNFR2KO, 94±8 to 733±195 mM/24hr) while no group experienced a significant change in UKV. The results suggest that TNFR1 activity mitigates the hypertensive response to chronic AngII infusion with high salt intake, likely by attenuating the increase in intrarenal AGT formation.Support or Funding InformationGrant support: National Institute of General Medical Sciences IDeA Program (COBRE, P30GM103337) and Tulane Bridge Fund (DSAM).
Deletion of Rag1 prevents high dietary protein‐induced exacerbation of hypertension and renal injury in Dahl SS rats
Authors: Abais‐Battad Justine M , Lund Hayley , Mattson David L 
Published: November 2023

The role of immune mechanisms in the amplification of hypertension has long been appreciated. Previous studies in our laboratory demonstrated how the amount as well as source of dietary protein has a profound influence on the development of hypertension and the renal infiltration of immune cells, specifically T lymphocytes. The current study hypothesized that Dahl SS rats lacking T and B lymphocytes via mutation of recombination‐activating gene 1 (Rag1) will confer protection against hypertension and renal injury exacerbated by high dietary protein intake. Immediately after weaning, Dahl SS rats and Rag1 mutant rats were placed on modified AIN‐76A, isocaloric, 0.4% NaCl diets (Dyets Inc.) custom formulated to contain either low, normal, or high protein (6%, 18%, or 30%, respectively). At 9 weeks of age, rats were switched to a 4.0% NaCl diet containing the same amount of dietary protein, and maintained on this high‐salt diet for 3 weeks. Urine was collected during the low salt period, and after 7, 14, and 21 days of high salt. Blood pressure was measured via femoral arterial catheters which were implanted at 10 weeks of age, with blood pressure recording occurring between 11 and 12 weeks of age. In Dahl SS rats, there was a protein‐dependent elevation in blood pressure and urinary albumin excretion as the amount of dietary protein was increased. Dahl SS rats fed the high protein diet had the highest pressure and albumin excretion (159±3 mmHg and 140.8±16.0 mg/day, respectively) after 21 days on high salt compared to rats fed either normal protein (139±4 mmHg, 69.4±11.3 mg/day) or low protein (113±1 mmHg, 0.4±0.1 mg/day) diets. Compared to SS rats, Rag1 mutant rats on the high protein diet were protected from salt‐induced hypertension and renal damage (143±6 mmHg, 66.2±10.8 mg/day). Flow cytometric analysis demonstrated a corresponding increase in total leukocyte infiltration (CD45+) in the kidneys of both Dahl SS rats and Rag1 mutants as dietary protein was increased. As expected, Rag1 mutants on the high protein diet had fewer CD3+ T lymphocytes and CD45R+ B lymphocytes infiltrating the kidney (2.10 x 105 CD3+ cells/kidney, 0.74 x 105 CD45R+ cells/kidney) versus their Dahl SS counterparts (7.97 x 105 CD3+ cells/kidney, 4.99 x 105 CD45R+ cells/kidney). There was, however, no change in the infiltration of CD11b/c+ antigen presenting cells, suggesting that the protective effects observed in the Rag1 mutants were specific to the reduction of lymphocytes. Together, these results provide evidence that T and B lymphocytes importantly contribute to the exacerbation of salt‐induced hypertension and renal injury in Dahl SS rats caused by high dietary protein intake.Support or Funding InformationDK96859, HL116264, 5T32HL007792, 15SFRN2391002
Lactate dehydrogenase activity, a novel renal cortical imaging bio‐marker of tubular injury
Authors: Nielsen Per Mose , Laustsen Christoffer , Qi Haiyun , Nørlinger Thomas , Mikkelsen Emmeli , Norregaard Rikke , Stødkilde‐Jørgensen Hans 
Published: November 2023

Renal ischemia/reperfusion injury (I/R‐I) is the leading cause of acute kidney injury (AKI) in several disease states, including hypovolemic shock, sepsis, surgery. Imbalance in energy metabolism and mitochondrial function is a hallmark in I/R‐I which can be caused by mechanisms like oxidative stress, apoptosis and inflammation. Lactate dehydrogenase (LDH) activity has previously been suggested as a renal tubular injury marker, but has a major limitation in the sense that it can only be measured in terminal kidneys. Recent advances in magnetic resonance technology, has allowed hyperpolarized [1‐13C]pyruvate magnetic resonance imaging (MRI) to monitor metabolic changes in real time in situ without ionizing radiation. Thus this procedure allows for investigation of renal tissue injury in concern with I/R‐I, by probing the renal metabolism after I/R‐I and especially the LDH activity.Sixteen Wistar Rats were included in the study. Rats were subjected to unilateral (or bilateral) renal ischemia for 60 min followed by reperfusion for 24 hours (n=8). Sham operated rats were prepared in parallel (n=8). A tail vein catheter was inserted for injection of hyperpolarized [1‐13C]pyruvate before the MRI scanning. Temperature, arterial oxygen saturation and respiration rate were monitored throughout the experiment. After MRI scanning, kidneys were excised and stored for further biochemical analyses.I/R‐I resulted in statistically significantly increased plasma creatinine, BUN and decreased creatinine clearance, indicating AKI. Additionally kidney injury molecule 1 (KIM‐1) was significantly increased in rats subjected to I/R‐I, indicating cellular injury. Hyperpolarized [1‐13C]pyruvate showed a reduced LDH activity in the post‐ischemic kidneys, calculated from pyruvate‐to lactate conversion. This was verified by activity measurements of LDH in terminal kidneys. Using a bilateral I/R‐I model increased LDH activity was also observed in urine samples. Like LDH activity a reduced ALT and PDH activity was also found in the I/R‐I model, calculated from pyruvate‐bicarbonate conversion, and pyruvate‐to‐alanine conversion. An increased LDH mRNA transcription, together with a reduced NADH/NAD+ ratio indicates a preference for anaerobic glycolysis in the I/R‐I kidney. This is supported by MR results when comparing lactate‐to‐bicarbonate formation, which individually describes the anaerobic and aerobic glycolysis.In conclusion, a decreased LDH activity is observed in the I/R‐I kidney, and this is correlated with tissue injury. Although the general LDH activity in the I/R‐I kidney is lowered, a weighted preference towards anaerobic metabolism was evident in the I/R‐I kidney.Support or Funding InformationKaren Elise Jenens Foundation
Proteolytic processing of the catalytic subunit of protein kinase A (PKA C) by meprin β in ischemia/reperfusion‐induced acute kidney injury
Authors: Niyitegeka Jean‐Marie Vianney , Sedighi Rashin , Harris Regine S , Ongeri Elimelda Moige 
Published: November 2023

Ischemic/reperfusion (IR) is associated with acute kidney injury. Meprin metalloproteases are the most abundant proteins in the brush border membranes (BBMs) of proximal kidney tubules. Presence of meprins was previously shown to enhance kidney injury in IR. However, the mechanisms by which meprins modulate kidney injury in IR are not fully understood. We are gaining insights from identification of kidney meprin targets, which include extracellular matrix (ECM) proteins, cytoskeletal proteins, tight junction proteins, and members of the AGC kinase family of proteins (e.g protein kinase A and protein kinase C). Meprins are redistributed from the BBM to the cytosol and basolateral membranes in ischemia/reperfusion bringing them in close contact with proteins in these cell compartments. We recently showed that meprins cleave the catalytic subunit of protein kinase A (PKA C) in an isoform specific manner. While both meprin A and meprin B could cleave PKA Cβ1, only meprin B cleaved PKA Cα and PKA Cβ2. In mice subjected to IR‐induced acute kidney injury, fluorescent microscopy showed a decrease in total PKA C in the proximal tubules (which express meprins) but not in distal tubules (which lack endogenous meprins). In fact the levels of PKA C in distal tubules increased at 6h post‐IR, suggesting that the PKA pathway plays a role in the hypoxia response associated with IR.The objective of the current study was to determine how proteolytic processing of PKA C by meprin β affects the levels PKA C isoforms in mice with IR‐induced acute kidney injury. To this end, surgical procedures were used for unilateral nephrectomy coupled with clamping of renal arteries for 27 minutes to induce IR‐associated injury in the contralateral kidneys of 12‐week old male mice on a C57BL/6 background (n=6 meprin β knockout; n=5 wild‐type). Blood samples were collected pre and post IR injury to phenotype kidney. The mice were sacrificed at 6h post IR and kidney tissues processed for proteomic analysis. Serum creatinine levels were determined by ELISA to confirm kidney failure. Western blot analysis with anti‐PKA C and anti‐PKA Cα specific antibodies was used to evaluate the levels of total PKA C and the PKA Cα isoform in kidney proteins. The intensities of the PKA C protein bands were quantified using a calibrated densitometer. Statistical analysis utilized 2‐way ANOVA. Our data showed a decrease in the kidney levels of total PKA C and PKA Cα in WT kidneys subjected to IR. This decrease was not observed in meprin β knockout kidneys. The data suggests increased in vivo proteolytic processing of PKA C present in kidneys by meprin β in IR. Meprin β may thus enhance renal tubular damage via cleaving of PKA C. We will evaluate the impact on downstream targets of the PKA pathway and hypoxia response genes.Support or Funding InformationNIH/NIGMS Grant # SC3GM102049
The Involvement of Iron on Erythropoietin Expression
Authors: Ikeda Yasumasa , Oshima Keisuke , Horinouchi Yuya , Izawa‐Ishizawa Yuki , Kihira Yoshitaka , Ishizawa Keisuke , Tsuchiya Koichiro , Tamaki Toshiaki 
Published: November 2023

BackgroundRenal anemia is often seen in the development of chronic renal failure (CRF). Therefore, Iron supplementation, as well as erythropoiesis‐stimulating agents, are used for treatment of renal anemia. Meanwhile, iron is shown to cause oxidative stress through toxic hydroxyl radical production via iron catalyzed‐Fenton reaction. Therefore, iron supplementation might damage remnant renal function including erythropoietin (EPO) production in CRF. In the present study, we studied iron action on erythropoietin expression.Methods and ResultsIn mice with unilateral ureter obstruction (UUO), EPO gene was reduced, and renal iron content was elevated in kidney of UUO side. Similarly, EPO gene was suppressed in mice with iron treatment. The expression of hypoxia‐inducible factor‐2 alpha (HIF‐2a), a positive regulator of EPO gene, was also diminished in both UUO‐ and iron‐treated kidney. In in vitro experiments using HepG2 cells, iron stimulation reduced the expression of EPO gene, as well as HIF‐2a, in a dose‐dependent manner. Iron also suppressed CoCl2‐induced EPO gene upregulation under hypoxia‐mimicked condition. Moreover, iron treatment augmented oxidative stress production, and iron‐induced reduction of EPO and HIF‐2a expression was restored by an anti‐oxidant agent treatment.ConclusionThese findings suggested that Iron supplementation reduced EPO gene expression through oxidative stress‐HIF‐2a‐dependent manner.
Kidney decapsulation reduces ischemia‐reperfusion‐induced proteinuria
Authors: Nensén Oskar , Hansell Peter , Fasching Angelica , Palm Fredrik 
Published: November 2023

Ischemia‐reperfusion injury (IRI) alters the integrity of the glomerular barrier integrity resulting in proteinuria. Decapsulation reduces interstitial pressure in the kidney; a procedure which we have previously reported to reduce diabetes‐induced glomerular protein leakage. Therefore, the present study determined if the same beneficial effects of decapsulation on proteinuria is achieved during the acute phase following IRI in rats.Measurements of urinary protein leakage, tubular pressures and renal blood flow (RBF) were determined before and immediately after thirty minutes of warm complete unilateral ischemia in normal and decapsulated adult male Sprague Dawley rats.Decapsulation per se completely prevented the IRI‐induced proteinuria. Decapsulation concomitantly reduced both baseline tubular free flow pressure (Pff; 14.0±0.6 versus 11.9±0.8 mmHg) and tubular stop flow pressure (Psf; 32.1±0.8 versus 30.2±0.7 mmHg) resulting in similar net filtration pressures (Pnet) in both groups (18.1±0.5 and 18.3±0.7 mmHg). IRI resulted in increased Pff in both groups (+5.0±1.0 and +4.9±0.8 mmHg for controls and decapsulated, respectively). Psf was unaltered by IRI resulting in similar reduction in Pnet after IRI in both groups. Interestingly, decapsulation reduced baseline RBF (7.8±1.1 versus 6.6±0.5 ml/min/kidney) but significantly mitigated the IRI‐induced reduction in RBF (−3.6±1.6 versus −1.9±0.7 ml/min/kidney for control and decapsulated, respectively).These data demonstrate that decapsulation prevents IRI‐induced proteinuria, possibly by reducing interstitial hydrostatic pressure. It is tempting to speculate that therapies lowering renal interstitial pressure could potentially be used to prevent IRI‐induced proteinuria and protect long‐term kidney function.
Low salt diet does not protect kidney function in normotensive rat model of chronic kidney disease
Authors: Patinha Daniela , Pihl Liselotte , Fashing Angelica , Palm Fredrik 
Published: November 2023

Intrarenal hypoxia has been shown to cause renal damage. Na+‐restriction in normotensive rats reverses the normal cortical‐medullary oxygen gradient, an alteration that may compromise long‐term kidney function. Indeed, two weeks of low salt (LS) diet to rats induces both glomerular and tubulointerstial fibrosis. We hypothesized that chronic LS diet may also aggravate kidney damage in chronic kidney disease (CKD).Male Sprague Dawley rats were subjected to a two‐step surgery with right nephrectomy and surgical ablation of the upper and lower poles of the left kidney (5/6Nx). This produces a normotensive salt‐sensitive animal model of CKD. After one week recovery, animals where fed normal (NS, 0.4%) or low (LS, 0.01%) salt diet during the following four weeks. Thereafter, catheters were placed in the carotid artery and femoral vein for blood pressure measurement and infusion of saline containing 3H‐inulin, respectively, in thiobutabarbital anesthetized animals. Oxygen consumption (QO2) was estimated from the arterio‐venous difference in O2 content multiplied by renal blood flow (RBF, transonic flow probe). Renal cortical and medullary partial pressures of oxygen (PO2) were measured using Clark‐type electrodes. At the end of the experiment, a bolus injection of angiotensin II AT1 receptor blocker candesartan (1 mg/kg) was given intravenously in order to determine the degree of renin‐angiotensin system (RAS) activation.Mean arterial blood pressure, glomerular filtration rate and RBF were similar in healthy control and 5/6Nx. RAS activation was confirmed by the more pronounced decrease in MAP following systemic angiotensin II AT1 receptor blockade in LS. 5/6Nx on both diets had incerased QO2 and lower Na+ transport efficiency when compared with controls. Reduced cortical PO2 was also observed in 5/6Nx animals on both diets, whereas medullary PO2 was increased only in 5/6Nx on LS. Increased TBARS were not improved and total protein excretion was further increased in 5/6Nx animals by LSTaken together, these results indicate that LS diet does not normalize renal QO2, prevents cortical hypoxia or TBARS in the 5/6Nx model of CKD. Actually, LS diet to 5/6Nx magnified the already existing proteinuria, which may imply that LS and subsequent RAS activation may have detrimental effect on long term kidney function in CKD.Support or Funding InformationThis work was supported by the Swedish Heart and Lung Foundation and the Swedish Research Council.