bluuebunny/crossref_metadata_2025_split huggingface dataset:
Daunorubicin‐induced heart failure elevates hippocampal TNF‐a and caveolin‐1 in rabbits
Authors: Zhang Zheng , Alas Basheer , Zemljic‐Harpf Alice , Ichikawa Yasuhiro , MicKirnan M. Dan , Hammond H. Kirk , Patel Hemal H. , Roth David M. , Head Brian P. 
Published: November 2023

IntroductionAnthracyclines are chemotherapy agents used to treat various cancers. Daunorubicin (Dau), a member of the anthracycline family, is cardiotoxic leading to heart failure. Heart failure, resulting in reduced cardiac output, affects multiple organs including the brain. Cognitive and mood impairments including short‐term memory loss and depression as well as changes in hippocampal structure have been observed in heart failure patients. It has been reported that tumor necrosis factor‐α (TNF‐α) is elevated in the brains of heart failure rats which indicates the critical role TNF‐α plays in neuroinflammation in heart failure. We have shown a protective role for caveolin‐1 (cav‐1) in neuronal injury and cav‐1 has been reported to be elevated by TNF‐α in endothelial cells. Here in the Dau induced heart failure rabbits, we probed the expression of hippocampal TNF‐α and its downstream singling molecules including caspase‐3, NF‐kB, phosphorylated NF‐kB and cav‐1.MethodsNew Zealand rabbits were administered weekly, intravenous Dau injections for 9 weeks at a dose of 3 mg/kg. Echocardiography was performed pre‐injection and weekly six weeks after the initial injection. Left Ventricle Fractional Shortening (LVFS) was measured by echocardiography. Rabbits were sacrificed when LVFS fell below 20%, hippocampi were collected, and homogenized. Western blots were performed to measure TNF‐α, caspase‐3, NF‐kB, phosphorylated NF‐kB and caveolin‐1 expression. Liver and lung wet/dry ratio were measured as indications of systemic and pulmonary congestion, as is expected in heart failure.ResultsLVFS was significantly reduced in Dau treated animals (control; 35%, n=4 vs Dau; 16%, n=4, p<0.001). The wet/dry ratio of lung (control; 2.3, n=4 vs Dau; 4.0, n=4, p<0.05) and liver (control; 2.5, n=4 vs Dau; 3.4, n=4, p=0.001) was higher in the Dau treated group. Western blots showed that the Dau treated group (n=4) had higher TNF‐α (p<0.05) and cav‐1 (p=0.004) in the hippocampus compared to the control group (n=4). No significant changes of caspase‐3, NF‐kB, or phosphorylated NF‐kB were observed.ConclusionsOur data show for the first time that Daunorubicin induced‐heart failure elevates hippocampal TNF‐α and cav‐1 protein expression.
Doxorubicin may damage cardiomyocytes more than cardiac progenitor cells
Authors: Edwards John , Mitry Maria , Laurent Dimtri 
Published: November 2023

Long term survival of childhood cancers is now more than 70%. Unfortunately, adult survivors of childhood cancer are at risk for treatment‐related adverse health outcomes. Survivors with a median time from diagnosis of 25 years found 56% had cardiac dysfunction. Analysis of heart transplantation patients found doxorubicin as the underlying cause in 2–3% of all cases. Doxorubicin is a topoisomerase poison that accumulates in the nucleus and the mitochondria. Doxorubicin impacts heavily on the mitochondria as significant mtDNA depletion and mtDNA rearrangements have been reported. Unfortunately nearly all preclinical studies have only determined short effects. Very few studies have examined the long term effects of doxorubicin or used doses that were comparable to clinical treatment protocols. We have developed a murine model for late onset doxorubicin induced heart failure in which the onset was delayed and mimicked that seen clinically (~18 human years). Doxorubicin was injected (1–45 mg/kg, i.p.) at 3 weeks of age. We observed no change in cardiovascular function 2–4 months post‐injection, but a significant decrease in ejection shortening was observed after 6–8 months post‐injection. Low doses of doxorubicin (1–15 mg/kg) did not significantly alter cardiovascular function even out to 16 months post injection. Using flow cytometry we examined cell populations from the left ventricle, circulating non‐RBC cells, and bone marrow. Despite degradation of cardiovascular function we observed significant increases (p<.05) in c‐kit+, SSEA1+, and Nkx2.5+ cells within the heart. In contrast, significant decreases of the c‐kit+, SSEA1+ cells were found in the circulating cells, while no changes were observed in the cell populations from the bone marrow compartment. We assessed mtDNA damage and observed significant increases in mtDNA damage in the ventricular cells and but not ventricular c‐kit+ cells. In cultured neonatal cardiomyocytes, doxorubicin increased mtDNA damage and promoted cell death below the threshold that significantly increase intramitochondrial superoxide levels. Measuring mitochondrial topoisomerase function we observed that H2O2 significantly increased DNA relaxation of supercoiled DNA suggesting that low levels of ROS alter mitochondrial topoisomerase function to promote DNA strand breakage. These findings suggest the heart attempted to regenerate by increased replacement of healthy cardiac progenitor cells but that degradation cardiomyocytes may have been the underlying cause of cardiovascular dysfunction. This suggests that the ability of the heart to direct self repair may be limited and that although the stem cell compartment attempted to compensate for cardiomyocyte loss, the degradation of cardiac function indicated that it was not successful.Support or Funding InformationSupported in part by NIH RO3HD065551
Role of Metabolic and Inflammatory Biomarkers on Femoral Artery Responsiveness in Trained Rats Fed with Hight‐Fat Diet
Authors: Delbin Maria A , Sponton Amanda CS , Araujo Hygor N , da Silva Carmem P Valgas , de Moraes Camila , Zanesco Angelina 
Published: November 2023

Atherosclerosis is considered the main cause of peripheral artery disease (PAD). In addition, exercise training has been prescribed to patients with PAD to diminish the pain and to improve blood flow. However, the insight mechanisms of these beneficial effects are not clear. The aim of this study was to examine the femoral artery responsiveness in trained rats fed with high‐fat diet (CEUA 3203‐1). Male Wistar rats were divided into: sedentary (SD), high‐fat diet sedentary (HF‐SD) and high‐fat diet trained (HF‐TR) groups. For sixteen weeks, animals from SD group were fed with standard chow and animals from HF‐SD and HF‐TR were fed with high‐fat diet (56% carbohydrate, 18% protein and 26% fat). After eight weeks, HF‐TR initiated the aerobic exercise training (AET) on treadmill, 5 days/week, 60 min/session and at 50–60% of maximum speed. Concentration‐response curves (CRC) to acetylcholine (ACh), sodium nitroprusside (SNP), phenylephrine (PHE) and the thromboxane A2 analogue (U46619) were obtained in femoral artery. Vascular protein expressions of eNOS, Cu/Zn‐SOD, Mn‐SOD, Ec‐SOD, adiponectin and leptin receptors were determined. Vascular nitric oxide (NO) production and reactive oxygen species (ROS) generation were evaluated. Plama inflammatory biomarkers were also evaluated. AET was effective in reducing body weight and epididymal fat. The maximal response (EMAX) in the CRC to ACh was reduced in femoral artery from HF‐SD group (17%) that was accompanied by reduced eNOS (40%) and Cu/Zn‐SOD (30%) protein expressions as well as NO production, associated with an increase in ROS generation. A positive effect was observed in HF‐TR group on relaxing response to ACh as well as the eNOS and Cu/Zn‐SOD protein expressions were restored. Increased NO production and reduction in ROS generation were also found. No changes in CRC to SNP, PHE and U46619 were observed in all groups. Regarding metabolic parameters, insulin concentration was restored at control values in trained animals (SD: 3±1; HF‐SD: 6±1; HF‐TR: 3±0.5 ng/ml). Inflammatory mediators were also normalized in HF‐TR group (leptin: 9±2 ng/ml; TNF‐α: 0.25±0.02 pg/ml; MCP‐1: 48±12 pg/ml and PAI‐1: 23±9 pg/ml) compared with HF‐SD (leptin: 41±9; TNF‐α: 0.41±0.04, MCP‐1: 138±23 and PAI‐1: 120±23). In contrast, blood glucose, total cholesterol and adiponectin were not different in all groups. Interestingly, the protein expression of leptin receptor was significantly reduced in HF‐SD (30%) group and normalized in HF‐TR group. Our findings show that AET for eight weeks promoted protective effects on metabolic and inflammatory mediators that it was reflected in improvement of endothelium‐dependent relaxation in femoral artery from rats fed high fat‐diet.Support or Funding InformationCNPq and FAPESP
Putative Sarcomeric Targets of Doxorubicin Induced Matrix Metalloproteinase‐2 Activity in Cardiomyocyctes
Authors: Roczkowsky Andrej , Chan Brandon Y.H. , Hughes Bryan G. , Schulz Richard 
Published: November 2023

Anthracyclines, such as doxorubicin, are used to treat a variety of cancers. However, doxorubicin's therapeutic utility is limited because it causes dose‐dependent myocardial injury, which may lead to heart failure in up to 11% of patients. Doxorubicin triggers this injury, in part, by stimulating cellular oxidative stress. Oxidative stress is known to activate matrix metalloproteinase‐2 (MMP‐2), an extra‐ and intra‐cellular protease, which has been implicated in many heart pathologies. Activated intracellular MMP‐2 has been shown to proteolyze sarcomeric proteins α‐actinin, troponin I, and the regulatory protein glycogen synthase kinase‐3β (GSK‐3β) in cardiac tissue or cells under oxidative stress, impairing contractile function. We hypothesized that intracellular MMP‐2 plays a role in doxorubicin cardiotoxicity by proteolyzing these substrates. Neonatal rat ventricular myocytes (NRVM) and human fibrosarcoma (HT1080) cells were treated with doxorubicin (0.5 μM) ± selective MMP‐2 inhibitors ARP‐100 (1 μM) or ONO‐4817 (1 μM) for 2–48 hr. Cell death was evaluated by lactate dehydrogenase release, MMP‐2 activity was measured by gelatin zymography, and MMP‐2 protein and its protein target levels were analyzed by immunoblot. Doxorubicin was used at a concentration which caused 15% cell death in neoplastic HT1080 cells but none in NRVM after 24 hr. In NRVMs, 24 hr doxorubicin increased intracellular MMP‐2 activity up to 311% relative to vehicle control, and this was attenuated by 60% with ARP‐100 or ONO‐4817. 24 hr doxorubicin‐induced MMP‐2 activation is caused, in part, by a 213% increase in MMP‐2 protein levels. Doxorubicin reduced troponin I levels by 40%, however, this was not normalized by ARP‐100 or ONO‐4817. There were no significant changes in α‐actinin or GSK‐3β levels. Doxorubicin at an antitumour concentration activates myocardial MMP‐2 in part by increasing MMP‐2 protein levels. The role of doxorubicin‐induced MMP‐2 activation on the reduction of cellular troponin I levels needs further investigation. Other potential MMP‐2 targets in the sarcomere (eg. titin, myosin light chain‐1) and in other cellular compartments need to be analyzed to better understand the pathophysiological actions of doxorubicin in cardiac myocytes.Support or Funding InformationCanadian Institutes of Health Research Foundation Scheme Grant (to RS); Women and Children's Health Research Institute Summer Studentship (to AR).
Nitric Oxide Synthase and Soluble Guanylyl Cyclase Mediate Endothelial Responses in Aged Female Endothelial Nitric Oxide Synthase (eNOS)‐Deficient Mice
Authors: Didion Sean P. 
Published: November 2023

We have shown previously that endothelial responses are normal in adult heterozygous eNOS deficient male and female mice and with aging endothelial function is markedly impaired in male eNOS+/−, but not female eNOS+/−, mice. The goal of the present study was to determine whether the preserved responses observed in aged female heterozygous eNOS+/− mice are due to NOS‐ and soluble guanylyl cyclase (sGC)‐dependent mechanisms. Endothelium‐dependent and ‐independent responses of carotid arteries from adult (6 months of age) and old (22–24 months of age) female eNOS+/+ and eNOS +/− mice were examined in the presence of vehicle (saline), L‐NNA (a NOS inhibitor), or ODQ (an inhibitor of sGC). Carotid artery responses to acetylcholine were similar (P>0.05) in adult and old female eNOS +/+ and eNOS+/− mice and were significantly inhibited (P<0.05) by L‐NNA and ODQ. Responses to nitroprusside were also similar in both groups of mice and were inhibited (P<0.05) by ODQ but not L‐NNA. The degree of inhibition produced by L‐NNA and/or ODQ was similar (P>0.05) in adult and old mice irrespective of genotype. These findings demonstrate that endothelial responses in old female eNOS+/− mice are not affected by aging and despite a 60% reduction in eNOS protein expression maintain their dependency on NOS and sGC.Support or Funding InformationSupported by NIH HL‐089884 and HL‐107632.
Differences in Cerebral Blood Flow Regulation in Male and Female Rugby Players with Concussions
Authors: Serrador Jorge , Reyes Levy , Tosto Jenna , Falvo Michael 
Published: November 2023

Increasing evidence is suggesting that concussions are a possible significant cause of long term cognitive and health problems among athletes. Despite this increasing evidence, there is a lack of data on the physiological effects of a concussion on cerebral blood flow regulation. The goal of this work was to determine if concussion cause impairment of cerebral blood flow regulation in the first few hours after injury and to determine if there is a sex difference in there sponse.During are creational rugby tournament a total of 91 players were recruited. Of these players, 59 were recruited as controls (12 females) and 34 had suffered a concussion (8 females). All testing was performed on the field to assess cerebral blood flow using Doppler, beat‐by‐beat blood pressure, and end‐tidal CO2. Subjects performed three sit to stand. Data was collected 131±23 min following the head trauma.We had previously found that concussed players demonstrated greater mean arterial pressure than controls. Both males and females demonstrated greater mean arterial pressures in the concussed players (Males – Ctrl 91±1 vs mTBI 96±2; Females Ctrl 82±3 vs mTBI 90±3 mmHg, P=0.004), with no effect of sex. In contrast cerebral flow velocity while standing tended to be more severely impacted in the females players (Males – Ctrl 95±1 vs mTBI 95±1; Females Ctrl 96±1 vs mTBI 93±1 %), sex interaction (P=0.081). Despite this greater decrease when standing, baseline internal carotid blood flow when seated was not different between sexes with both demonstration significantly lower flow int eh concussed players(Males – Ctrl 479±31 vs mTBI 361±56; Females Ctrl 426±62 vs mTBI 368±76 mL/min).These data suggest that while both males and females had similar hypertensive responses following a sports related concussion, a tendency towards a greater decrease in cerebral flow when standing was found in the females. Thus further work is necessary to both understand the physiological response following concussion, but specifically with regards to sex differences.Support or Funding InformationThis work was supported by the War Related Illness and Injury Study Center within the Department of Veteran Affairs.
Heterodyning in Tubuloglomerular Feedback Induced Oscillations in Coupled Model Nephrons
Authors: Kesseler Kevin J. , Layton Harold E. 
Published: November 2023

In each nephron of the mammalian kidney, a negative feedback mechanism, tubuloglomerular feedback (TGF), participates in the regulation of the glomerular filtration rate. In a previous study, we used a mathematical model to predict the effects of coupling between the TGF systems of two short‐looped rat nephrons (Bull. Math. Biol. 66(6): 1463–1492, 2004). That study predicted parameter regions in which a perturbation of a time‐independent steady state results in a transition to sustained and stable oscillations in the glomerular filtration rate and thus oscillations in nephron tubular flow. These oscillations were predicted to arise for sufficiently large TGF gains and for sufficiently long time delays in TGF response. In the present study, we have used the same two nephron model to investigate how the oscillations are affected by varying time delays in TGF response. We found that when the TGF gains are equal and the TGF delays are sufficiently close, the oscillations in the two model nephrons synchronize: they have identical fundamental frequencies and they oscillate in phase. However, when the delays differ sufficiently, the oscillations in the two model nephrons have differing fundamental frequencies and may exhibit complex behaviors. Power spectra computed from time series generated by the model reveal both harmonic and heterodyne frequencies. These model results may help explain power spectra obtained in experimental studies of rat kidneys: in both normotensive rats and spontaneously hypertensive rats the power spectra frequently exhibit power at non‐fundamental frequencies.Support or Funding InformationThis research was supported by National Institutes of Health grant DK‐42091.
A Newly Developed Technique of in vivo Synchrotron Radiation Renal Micro‐angiography in Spontaneously Hypertensive and Normotensive Rats
Authors: Miya Ken , Matsushita Shonosuke , Hyodo Kazuyuki , Tokunaga Chiho , Sakamoto Hiroaki , Mizutani Taro , Hiramatsu Yuji 
Published: November 2023

IntroductionAlthough real‐time imaging of renal arterioles and glomeruli is desirable, conventional angiography is not capable of such visualization, due to limitations in spatial resolution. We have developed a novel method of visualizing renal arterioles and glomeruli in real‐time in in‐vivo rats, without exteriorizing kidneys, utilizing synchrotron radiation (SR) derived X‐rays. In this study, we aimed to detect morphological differences in the kidney by utilizing SR renal micro‐angiography (SRRM) in normotensive and hypertensive rats.MethodSRRM was performed at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan). The SR derived X‐rays are characterized by high collimation and photon flux, thus resulting in higher spatial resolution compared with conventional X‐ray. Male Wistar rats (WR; n=5) and spontaneously hypertensive rats (SHR; n=5) were anesthetized and iodine contrast agent was administrated via polyethylene tube for angiography inserted into the infra‐renal aorta via laparotomy with its tip just above renal arteries.ResultIn both groups, renal arterioles and glomeruli were clearly visualized (Fig. 1). The average diameter of glomeruli in the WR group was 197±42 micrometer and 193±37 micrometer in the SHR group, respectively. It was also possible to detect local stenosis of interlobular arterioles in SHR rats with diameters of 50 micrometer. Compared with the WR group (Fig. 2), perfusion of contrast agent was apparently decreased in the SHR group (Fig. 3).ConclusionThe result shows the effectiveness of SRRM for visualizing renal arterioles and glomeruli in in‐vivo rats, in real‐time, without exteriorizing kidneys. The SRRM is a promising method for the investigation of renal physiology as well as pathology.
Meprin β deficiency associated with higher levels of neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule (KIM‐1) in mice with streptozotocin induced type 1 diabetes
Authors: Kenley Sharneice Renee , Niyitegeka Jean‐Marie Vianney , Sedighi Rashin , Gooding Jessica , Sumner Susan , Ongeri Elimelda Moige 
Published: November 2023

Diabetic nephropathy (DN) is the leading cause of end stage renal disease, and is associated with high morbidity and mortality rates. The pathophysiology of DN includes both glomerular and tubulointerstitial damage. Meprins are metalloproteinases which are most abundantly expressed in the brush border membranes of proximal kidney tubules. Meprins are also expressed in leukocytes (monocytes and macrophages) and podocytes. Meprins have been implicated in the pathology of acute and chronic kidney injury. Single nucleotide polymorphisms (SNPs) in the meprin β gene were associated in human DN in the Pima Indians, suggesting a role for meprins in the pathophysiology of DN. The current study was done to determine the mechanisms by which meprins modulate the progression of DN in mice. Low dose streptozotocin (STZ) was used to induce type 1 diabetes in 8 week old male wild‐type (WT) and meprin β knockout mice (βKO) on a C57BL/6 background. Control mice were injected with sodium citrate buffer. Urine and blood samples were collected at 4 and 8 weeks post STZ injection. The mice were sacrificed at 8 weeks post‐STZ injection and kidney tissue harvested for analysis using metabolomics and proteomic approaches. Enzyme‐linked immunosorbent assays (ELISA) were used to determine the levels of two tubular kidney injury markers, neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule 1 (KIM‐1). When compared to non‐diabetic controls, meprin β KO mice with STZ‐induced type 1 diabetes had significantly higher levels of plasma NGAL at 4 weeks but not at 8 weeks post STZ injection. The levels of urinary KIM‐1 were significantly higher in meprin βKO mice at both 4 weeks and 8 weeks when compared to their wild‐type counterparts. Taken together, the data suggest that presence of meprin β partially protects mice from the tubular kidney injury associated with diabetes. This is in contrast to outcomes in ischemia/reperfusion induced acute kidney injury where meprin deficiency was previously shown to be protective. Further analysis will determine the kidney meprin targets and metabolic pathways which play a role in the progression of DN.Support or Funding InformationNIH/NIGMS # SC3GM102049
Effect of SGLT Inhibition on Medullary Oxygen Consumption: A Multi‐Nephron Model of the Rat Kidney
Authors: Layton Anita , Vallon Volker , Edwards Aurelie 
Published: November 2023

The objective of this study was to investigate how changes in sodium reabsorption in the proximal tubule affect oxygen (O2) consumption and the metabolic efficiency of the kidney. To do so, we developed a detailed mathematical model of solute transport in a multi‐nephron representation of the rat kidney. The model represents one superficial nephron and five juxtamedullary nephrons with loops of Henle reaching to differing depths of the inner medulla. The six representative nephrons merge at the entrance of the cortical collecting duct. Glucose is reabsorbed via sodium‐glucose cotransporters (SGLTs) in the proximal tubules, which express SGLT2 in S1–S2 and the SGLT1 in S3. We used the model to investigate the effect of inhibiting SGLT2, a novel treatment for reducing proximal tubule glucose uptake in diabetes, on renal Na+ transport and renal oxygen consumption (QO2). Inhibiting SGLT2 shifts Na+ transport to downstream nephron segments, increasing their QO2. In particular, the S3 segment and medullary thick ascending limb (mTAL) are at risk for hypoxic injury. Dual SGLT1‐SGLT2 inhibition protects the S3 segment, but could further lower mTAL oxygenation. We considered the importance of the GFR‐lowering effect of SGLT2 inhibitors. Additionally, we used the model to determine the optimal combination of SGLT1 and SGLT2 inhibition, in terms of reducing tubular glucose uptake while maintaining sufficiently low S3 and mTAL QO2.Support or Funding InformationThis research was supported in part by NIH grant DK‐89066.