bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporally‐Induced Nephron Polycystin‐1 Knockout Causes Salt and Water Wasting and Reduced Blood Pressure in the Absence of Polycystic Kidney Disease
Authors: Kohan Donald , Lakshmipathi Jayalakshmi , Stuart Deborah , Ramkumar Nirumpama , Gao Yang
Published: June 2021

Polycystic kidney disease (PKD) is characterized by the early onset of hypertension that does not strictly correlate with cyst formation. Since deficiency of polycystin‐1 is the major cause of PKD, it may be that polycystin‐1 is directly involved in regulation of renal salt excretion and blood pressure regulation, i.e., it may exert physiological effects on kidney function independent of its involvement in cystogenesis. One previous study showed that distal nephron PC‐1 knockout caused fluid and electrolyte wasting, however these mice had dilated tubules, increased kidney size and increased renal cell proliferation, hence renal injury may have confounded findings. To address this, we administered doxycycline to Pax8‐rtTA/tetO7‐CMV*‐Cre/homozygous floxed Pkd1 mice at 3 months of age and studied the mice over the next 2–3 months. These mice demonstrated nephron‐specific Pkd1gene targeting. No cysts or tubule dilation were evident in any of the KO kidneys for at least 3 months after doxycycline administration. Food and water intake were similar between control (no doxycycline) and KO mice (same genotype as controls + doxycycline) on a normal, low and high Na+ intake (5–7 days each diet). Urine volume, urinary K+ excretion and urinary Na+ excretion were higher in KO vs. control mice during the first 2 days of high salt intake. Systolic and diastolic blood pressure were lower (by 4–5 mmHg) in KO mice during all diets. Plasma renin concentration was similar between control and KO mice on a normal Na+ diet and fell to the same degree in both genotypes on a high Na diet. Urinary endothelin‐1 and urinary nitrite/nitrate excretion were similar between control and KO mice on a normal Na+ diet and increased to the same degree in both genotypes on a high Na+ diet. KO mice had more rapid Na+ and K+ excretion following an acute intraperitoneal NaCl load and excreted more Na+ and K+ over the 7 hr following salt loading. Taken together, these data suggest that polycystin‐1 is involved in regulating renal electrolyte excretion in the absence of renal pathology. Surprisingly, nephron polycystin‐1 may exert a net Na+ and K+ retaining effect. Functional polycystin‐1 disruption in PKD does not appear to explain, independent of cyst formation, the hypertension observed early in the course of PKD.

Support or Funding Information

NIH P01 HL136267

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
VEGF Therapy Shifts Macrophage Phenotype and Improves Renal Recovery in Chronic Kidney Disease
Authors: Engel Jason Edward , Guise Erika , Williams Maxx , Bidwell Gene , Chade Alejandro
Published: June 2021

Chronic kidney disease (CKD) is universally associated with renal microvascular (MV) rarefaction and inflammation. We previously developed a fusion of rh‐vascular endothelial growth factor (VEGF) conjugated to an elastin like polypeptide (ELP) vector. We showed that ELP‐VEGF therapy is renoprotective in a model of unilateral renovascular disease (RVD). Here we test the hypothesis that ELP‐VEGF therapy in a novel model of CKD will recover renal function and MV rarefaction driven partly by modulation of renal macrophages to a pro‐angiogenic phenotype.

CKD was induced in 10 pigs by bilateral RVD combined with diet‐induced hypercholesterolemia. After 6 weeks, pigs received a single intrarenal dose of ELP‐VEGF or placebo and were observed for 8 weeks. Renal blood flow (RBF) and glomerular filtration rate (GFR) were quantified using multidetector computed tomography before, and 4 and 8 weeks after ELP‐VEGF therapy. Blood and urine were collected to quantify serum creatinine and albuminuria. Pigs were then euthanized and renal MV density, VEGF expression, and inflammation were quantified. Renal macrophage infiltration and phenotype was determined by concurrent staining for CD68, indoleamine 2,3 dioxygenase (IDO), and mannose receptor c type 1 (MRC1) (indicating total, M1, and M2 macrophages respectively). Further staining was performed to colocalize MRC1 and VEGF. An additional 5 pigs served as normal controls.

RBF and GFR were reduced in all pigs at 6 weeks. ELP‐VEGF therapy induced a progressive recovery of RBF and GFR, accompanied by improved MV density, VEGF expression, and reduced albuminuria (1.8 ± 0.3 mg/dL vs. 2.9 ± 0.9 mg/dL in untreated CKD, p < 0.05) and creatinine (160 ± 10 μmol/L vs. 202 ± 16 μmol/L in untreated CKD, p < 0.05). Heavy IDO+/MRC1− pro‐inflammatory M1 macrophage infiltration was observed in untreated CKD and was shifted to a IDO−/MRC1+ anti‐inflammatory M2 phenotype after ELP‐VEGF therapy. Furthermore, augmented co‐expression of VEGF was observed in the MRC1+ renal macrophages (Figure).

The progressive recovery of renal function far outlasted the life of administered ELP‐VEGF, suggesting that this single dose activates an endogenous mechanism of renal repair to sustain long term improvement. Accumulation of VEGF expressing M2 macrophages in the renal parenchyma may account for the recovery of MV rarefaction and renal hemodynamics after ELP‐VEGF treatment in CKD. These results suggest that modulation of macrophages towards a highly angiogenic M2 phenotype may constitute a prominent mechanism of renal recovery after ELP‐VEGF therapy in CKD.

Support or Funding Information

Support: HL95638, HL51971, GM104357, HL121527 (NIH), and EIA18490005 and IPA34170267 (AHA).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Kidney Specific Disruption of the Circadian Gene BMAL1 in Mice Produces a Sex‐ Dependent Effect on Systolic and Diastolic Blood Pressure
Authors: Glasford Krystal B , Crislip Gene Ryan , Douma Lauren G , Lynch Irma J , Cheng Kit‐Yan , Wingo Charles S , Gumz Michelle L
Published: June 2021

Introduction

Fluctuations in physiological functions that occur in all living organisms within a 24‐hour period are referred to as circadian rhythms. Disruptions in these rhythms are associated with cardiovascular diseases. A major goal of our lab is to find the link between circadian rhythms and cardiovascular health. Our internal clock is regulated by isoforms of four main transcriptions factors; PER, BMAL1, CLOCK and CRYPTOCHROME. Curtis et al., 2007, found that male global BMAL1 knockout mice have 10 mmHg lower blood pressure than control mice and lose their circadian rhythm. Our understanding of the regulation of circadian rhythms in blood pressure is incomplete. Thus, our objective was to investigate the effect of kidney specific BMAL1 knock out on the circadian rhythm of the diastolic blood pressure (DBP) and systolic blood pressure (SBP).

Hypothesis

We hypothesize that kidney‐specific BMAL1 knockout mice (KO) would lose their circadian rhythm of SBP and DBP.

Methods

Mouse models were generated using the Cre‐lox system. Telemeters were surgically inserted into the mice to continuously monitor blood pressure for 3 days. Blood pressure recordings were analyzed using Cosinor software to determine the MESOR, amplitude and period of the DBP and SBP data. The MESOR refers to the midline estimating statistic of rhythm which is a rhythm adjusted mean. The amplitude measures the extent of predictable change within a cycle and the period refers to the duration of a cycle, from peak to peak. WT and KO values were compared by t‐test.

Results

Refer to table 1 for MESOR, amplitude and period values. For SBP, male KO had significantly lower MESOR compared to WT (P=0.03). Similarly, for DBP, male KO had significantly lower MESOR compared to WT (P=0.04). For males, there were no significant differences in the amplitude or period of SBP or DBP. For females, there were no difference seen in the MESOR, amplitude or period for SBP or DBP.

Conclusion

Our data indicate that BMAL1 in the kidney does not contribute to circadian rhythms of blood pressure. However, BMAL1‐ dependent renal mechanisms contribute to a sex‐dependent effect on BP where only male KO experience lower mean arterial pressure compared to male WT.

Support or Funding Information

American Physiological Society Short‐ Term Research Education Program to Increase Diversity in Health Related Research (STRIDE); Gatorade Trust through the Department of Medicine; NIH grants R01 DK109570 (MLG), T32HL083810 (GRC) and T32DK104721 (LGD); National Heart, Lung and Blood Institute (Grant #1 R25 HL115473‐01)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Prevention of Vascular Congestion Improves Renal Recovery and Function Post Renal Ischemia‐Reperfusion in Male Spontaneous Hypertensive Rats
Authors: Mohamed Riyaz , Crislip Gene Ryan , Ray Sarah , Wei Qingqing , O'Connor Paul M , Sullivan Jennifer C
Published: June 2021

Acute kidney injury (AKI) due to ischemia‐reperfusion (IR) is a serious and frequent complication in clinical settings and often progresses to kidney failure. The male gender is associated with greater severity and mortality following AKI, and young males have a greater prevalence of hypertension vs. age‐matched females. Despite the widespread prevalence of hypertension as a common co‐morbid condition with AKI, the impact of established hypertension on the progression of renal injury post‐AKI in either sex is poorly understood. Vascular congestion in the outer medulla is an early event occurring after IR, and congestion has been linked to worse renal outcomes following IR. The present study tested the hypothesis that increased vascular congestion in hypertensive males leads to impaired renal recovery compared to hypertensive females following renal IR. 13 wk old male and female normotensive Sprague Dawley rats (SD) and Spontaneous Hypertensive Rats (SHR) were subjected to sham or 25‐minute warm bilateral ischemia followed by reperfusion (n=6). Blood and urine were collected at 24 hrs and 7 days after IR; kidneys were harvested at 7 days for histological analysis. IR increased plasma creatinine (Pcr), BUN and proteinuria in all groups compared to respective sham controls at 24 hrs, with a sex difference in IR‐induced increases in Pcr observed in SD but not in SHR (SD Scr: Psex*IR<0.05; SHR Pcr: Psex*IR=0.4). At 7 days post‐IR, Pcr and BUN remained elevated only in male SHR compared to sham control (Pcr: PIR=0.03; BUN: PIR<0.05); Pcr and BUN returned to sham levels in all other groups. Histological examination of SHR kidneys at 7 days post‐IR showed sustained increases in vascular congestion (PIR=0.01; Psex*IR=0.002), damaged tubules (PIR=0.0003; Psex*IR=0.0019) and tubular cell apoptosis (P IR=0.001; Psex*IR=0.001) compared to sham controls in male SHR but not in females. Further, to study the role of IR induced vascular congestion on impaired recovery and loss of renal function in male SHR, additional SHR were pretreated with heparin (1500U/kg, n=6) prior to IR. Pre‐treatment with heparin prevented IR‐induced vascular congestion (PIR*Heparin=0.04) and tubular damage (PIR*Heparin=0.02) and improved renal function in male SHR 7 days post‐IR (Scr‐PIR*Heparin<0.05; BUN: PIR*Heparin=0.02) compared to heparin treated sham controls. Heparin pretreatment did not alter kidney function in female SHR 7 days post‐IR (Pcr‐PIR*Heparin=0.9; BUN: PIR*Heparin=0.2). In conclusion, our data demonstrated that persistent IR‐induced vascular congestion is a major driving factor to long‐term impaired renal recovery post IR in hypertensive males.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sex‐Differences in Renal Na+ Regulatory Mechanisms During Acclimation to a High Salt Diet
Authors: Gohar Eman Y. , De Miguel Carmen , Obi Ijeoma E. , Daugherty Elizabeth M. , Becker Bryan K. , Jin Chunhua , Johnston Jermaine G. , Liu Pengyuan , Speed Joshua S. , Mitchell Tanecia , Kriegel Alison , Pollock Jennifer S. , Pollock David M.
Published: June 2021

Hypertension is more prevalent in men compared to premenopausal women. Maintenance of Na+ homeostasis is an essential component of blood pressure regulation, and defects in the renal capacity to appropriately excrete Na+ are fundamental mechanisms involved in the initiation of salt‐sensitive hypertension. We recently reported that female rats elicit a more rapid natriuretic response to a high salt (HS) diet compared to males. The overall goal of the current study was to determine the natriuretic signaling pathway(s) involved in the enhanced ability of females to handle HS challenges. Male and female Sprague Dawley rats (16–18 weeks old) were placed into metabolic cages on normal salt (NS, 0.49% NaCl) followed by HS (4% NaCl) diet for 5 days. 24‐hour urine samples were assessed for endothelin‐1 (ET‐1), aldosterone (ALD) and norepinephrine (NE). On NS, urinary ET‐1 was significantly higher in females, compared to males; no sex‐differences were detected in urinary ALD or NE. In males, urinary ET‐1 was increased (10.2±0.8 vs. 5.6±1.0 pg/kg/day, n=8 each, p=0.002) and urinary ALD was decreased on day 1 HS relative to NS (6.1±0.7 vs. 15.2±2.6 μg/kg/day, n=5 each, p=0.02); no significant changes were observed in ET‐1 or ALD in females on day 1 HS. Urinary NE remained unchanged during the HS challenge in both sexes. Ingenuity Pathway Analysis (IPA) of RNA sequencing data from inner medullae from males and females on NS identified an enrichment (p=3.11E‐04) of transcripts in the ET‐1 signaling pathway in females, with the abundance of 35/190 (18.4%) of pathway transcripts being at least 1.5‐fold different in abundance between sexes. Further, IPA predicted that ET‐1 signaling is activated in female inner medulla, relative to males. Previous studies showed that interleukin‐1β (IL‐1β) stimulates renal ET‐1 production. Thus we tested whether renal IL‐1β is upregulated in response to HS in a sex‐dependent manner. Renal IL‐1β was assessed by ELISA and IHC. Renal cortical IL‐1β was significantly increased on day 1 HS, relative to NS, only in males (8.1±0.3 vs. 6.4±0.3 pg/mg protein, n=9 each, p=0.03). Our data suggest that activation of IL‐1β/ET‐1 and inhibition of ALD signaling pathways contribute to acclimation to HS challenges in males. We further suggest that the already activated renal ET‐1 signaling in females under NS may contribute to the enhanced ability to acclimate to HS challenges observed in females.

Support or Funding Information

Funded by AHA 18CDA34110010 and 15POST25090329 to EYG, and P01 HL136267 to JSP and DMP. We appreciate Drs. Celso and Elise Gomez‐Sanchez's help with ALD assay.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
High Salt Diet Induces HDAC1‐Dependent Disruption of Nitric Oxide Signaling in the Renal Microvasculature
Authors: Dunaway Luke S , Cook Anthony K , Pollock David M , Hyndman Kelly A , Inscho Edward W , Pollock Jennifer S
Published: June 2021

Our lab previously reported that in cultured endothelial cells, histone deacetylase 1 (HDAC1) mediates reduced endothelial nitric oxide synthase (NOS3)‐derived NO production and decreased lysine acetylation of NOS3. Recently, we also observed that a high salt diet (HS) increases expression of HDAC1 in the kidney. The objectives of this study were: 1) to test the hypothesis that HS increases HDAC1 abundance or activity in intra‐renal resistance arteries, and, 2) to test the hypothesis that HS mediates HDAC1‐dependent loss of NO signaling in the vasculature. We isolated intra‐renal arteries from male Sprague Dawley rats fed either normal salt diet (NS; 0.49% NaCl) or 2 weeks of HS (4.0% NaCl). HDAC activity was increased as detected by a decrease in histone H3 lysine acetylation status (NS: 1.0 ± 0.033 RDU vs HS: 0.56 ± 0.096 RDU, n=3, p<0.05). This change in HDAC activity was not due to changes in abundance of Class I HDACs: HDAC1 (NS: 1.0 ± 0.11 RDU vs HS: 1.19 ± 0.15 RDU, n=5–8, p>0.05), HDAC2 (NS: 1.0 ± 0.25 RDU vs HS: 1.17 ± 0.13 RDU, n=3–5, p>0.05), HDAC3 (NS: 1.0 ± 0.21 RDU vs HS: 0.99 ± 0.13 RDU, n=3–5, p>0.05), and HDAC8 (NS: 1.0 ± 0.07 RDU vs HS: 0.94 ± .07 RDU, n=3–5, p>0.05). To test the second hypothesis, rat afferent arteriolar vasoconstrictor responses to the NOS inhibitor, LNAME, were monitored using the in vitro, blood perfused juxtamedullary nephron preparation. Arterioles from HS fed rats had significantly blunted L‐NAME‐induced vasoconstriction compared to vehicle treated arterioles from NS fed rats (96 ± 2% of Con vs 76 ± 2% of Con for HS vs. NS; respectively, P<0.05); however, HDAC1 inhibition with 300 nM MS‐275 restored the arteriolar constrictor responses in HS rats (79 ± 3% of Con) to be similar to NS fed rats (P>0.05) and to NS rats + MS‐275 (79 ± 1% of Con; P>0.05). These findings support our hypothesis that HDAC1 regulates NO‐dependent signaling in the renal microvasculature.

Support or Funding Information

Supported by T32 GM 109780‐3 to LSD, K01 DK105038 to KAH, P01 HL069999 to JSP and DMP, and P01 HL136267 to JSP, EWI, and DMP.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effects of Two Creatine Monohydrate Feeding Protocols on Doxorubicin‐Induced Skeletal Muscle Dysfunction
Authors: Torok Zoltan A , Busekrus Raquel B , Hydock David
Published: June 2021

The chemotherapy drug doxorubicin (Dox) can negatively impact skeletal muscle function, and interventions to address this side effect are important to improving cancer patient quality of life. The purpose of this study was to investigate the effects of creatine monohydrate (Cr) feeding prior to Dox treatment on skeletal muscle function. Male Sprague‐Dawley rats were randomly assigned to one of four groups: standard chow feeding for four weeks followed by a bolus i.p. 15 mg/kg Dox injection (Dox group); 2% Cr chow feeding for four weeks followed by a bolus i.p. 15 mg/kg Dox injection (Cr1+Dox group); 4% Cr chow feeding for one week then 2% Cr chow feeding for three weeks followed by a bolus i.p. 15 mg/kg Dox injection (Cr2+Dox group); or standard chow feeding for four weeks followed by a bolus i.p. 0.9% NaCl injection to act as a control (Con group). Grip force measurements were obtained prior to the start of nutritional interventions (baseline), prior to injection (after four‐week nutritional intervention), and three days post‐injection. Animals were anesthetized three days post‐injection, the soleus (SOL) and extensor digitorum longus (EDL) muscles were excised, and function was assessed ex vivo using a 100 second fatigue protocol. No grip force differences were observed at baseline or following the four‐week nutritional interventions. Three days after injections, however, the Dox and Cr1+Dox groups had lower grip forces than Con (p<0.05), but this difference was not observed in Cr2+Dox (p>0.05). In the SOL, no between group force differences were observed at baseline or at any of the 10 second time points throughout the fatigue protocol (p>0.05). EDLs from the Dox group generated significantly less force than Con throughout the protocol except the 50 s and 60 s time points (p<0.05). These differences in EDL force production throughout the protocol, however, were not observed in Cr1+Dox and Cr2+Dox (p>0.05). In conclusion, Cr1 and Cr2 feeding protected against Dox‐induced declines in force production in the type II, EDL muscle, and grip force was preserved only with Cr2 feeding. These results suggest that Cr's protection against Dox myotoxicity may be dependent upon Cr dose and skeletal muscle type.

Support or Funding Information

David S. Hydock, PhD was supported by a Pilot and Exploratory Projects in Palliative Care of Cancer Patients and Their Families, PEP‐17‐193‐01 ‐ PCSM, from the American Cancer Society.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Fasting Regulation of Muscle Autophagy during Cancer‐Cachexia
Authors: Fix Dennis , Counts Brittany , VanderVeen Brandon , Carson James A.
Published: June 2021

Introduction

Cancer cachexia is a characterized by accelerated skeletal muscle protein turnover that contributes to muscle mass loss. The adenosine monophosphate protein kinase (AMPK) is cellular energy sensor that is activated in response to energy stress and regulates the initiation of autophagy. The autophagy process involves lysosomal removal of cellular organelles and protein aggregates through sequestration of cytosolic substrates and tagging with ubiquination‐linked proteins such as LC3 and P62. While our understanding of AMPK's role in suppressed protein synthesis during cancer cachexia has improved, the regulation of autophagic processes by AMPK during cancer cachexia requires additional work. The purpose of this study is to examine the effect of nutrient deprivation on AMPK activation and autophagy initiation during cancer cachexia.

Methods

Male C57BL/6 (B6, N=16) and ApcMin/+ (Min, N=18) mice were subjected to a 12 hour fast. B6 and Min mice fed ad‐libitum served as controls. Following the 12‐hour fast, hindlimb muscles were harvested and the gastrocnemius homogenized for protein analysis.

Results

Min mice exhibited body weight loss and reduced gastrocnemius mass when compared to B6 mice. In the fed state muscle AMPK phosphorylation (T172) was induced in the Min compared to B6. Fasting did not induce AMPK phosphorylation in B6 mice; however, AMPK was induced in Min mice following a fast. AKT phosphorylation (T308) was reduced following a fast in both B6 and Min mice. Furthermore, fasting suppressed FOXO1 phosphorylation in Min mice, similarly to B6 mice. However, fasted MIN mice had a reduction in P62 expression and an induction of LC3 II/I protein expression not seen in fasted B6 mice.

Conclusions

Taken together our results suggest that cachectic skeletal muscle has increased sensitivity to acute nutrient deprivation demonstrated by AMPK activation and the initiation of autophagy when compared to healthy adult skeletal muscle.

Support or Funding Information

This work was supported by NIH/NCI grant RO1CA121249 awarded to James A. Carson

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Testosterone Is Not Required for The Maintenance of Muscle Mass in Fully Matured and Elderly Male Mice
Authors: Davidyan Arik , Baar Keith , Bodine Sue C
Published: June 2021

Testosterone (T), the main androgenic hormone, is assumed to play an important role in the maintenance of skeletal muscle mass and function through its effects on satellite cell proliferation and differentiation, as well as its activation of pathways downstream of the IGF‐1 receptor and AKT. T depletion through chemical castration as a treatment for prostate cancer and the use of T to treat sarcopenia are both common practices in older humans, yet the majority of animal studies aimed at elucidating T's role in the maintenance of skeletal muscle mass are performed in young rodents under the age of 3 months. In addition, the role of T's activity in skeletal muscle health remains equivocal, with some studies showing circulating T to have great importance, while others suggest a limited or non‐significant role. Hence, the aim of this project was to characterize the phenotypic outcome of T depletion on skeletal muscle across lifespan and identify the contributing molecular pathways.

To elucidate T's role on skeletal muscle throughout life, C57Bl/6 male mice were castrated at 4 different ages (1.5, 5, 12, or 24 months) and returned to normal cage activity for one month before muscle mass, protein synthesis and degradation, mTORC activity, and fiber cross sectional area were analyzed. Consistent with current literature, skeletal muscle mass reached a peak at 6 months before progressively declining (11.4% and 23.1% in the TA and gastrocnemius muscles, respectively) by 25‐months of age. In young animals, the removal of circulating T resulted in a decrease of the TA muscle mass (12.2% and 16.7% in the 1.5‐ and 5‐month old groups, respectively). Castration also slowed the growth of the gastrocnemius muscle with the 1.5‐ and 5‐month groups presenting muscles that are 9.4% and 11.6% smaller, respectively. Conversely, T depletion had no effect on muscle mass in the 12 months and 24 months groups. The decrease in cross sectional area in the absence of T in the young groups was similar to the decrease in muscle mass. Statistical analysis revealed a stronger interaction between age and treatment in the TA (P = 0.011) compared to the Gastrocnemius (P = 0.24). Together these data suggest that in skeletally immature animals, circulating T plays an important role in the regulation of muscle mass. In contrast, once muscle mass peaks and begins to decline naturally, circulating T no longer appears to affect muscle mass. Since T primarily affects skeletal maturation, it is essential that age appropriate animals are used when determining the role of T on skeletal muscle function. Specifically, studies on the anabolic effects of T need to use C57Bl/6 mice that are older than 6 months in order to translate to humans.

Support or Funding Information

UC Davis Clinical and Translational Science Center

UC Davis Office of Graduate Studies

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Lysophosphatidic acid signaling restores mislocalization of brush border proteins in MYO5B deficient mice
Authors: Kaji Izumi , Roland Joseph TE , Engevik Amy C , Goldstein Anna E , Dudeja Pradeep K , Goldenring James R
Published: June 2021

Background & Aim

Myosin Vb (MYO5B) is an essential trafficking protein for membrane protein recycling in gastrointestinal (GI) epithelial cells and its mutation causes the congenital diarrheal disease, microvillus inclusion disease (MVID). Our group has reported that MYO5B loss results in a decrease in the brush border localization of nutrient transporters and enzymes, but CFTR expression is maintained, causing malabsorption and secretory diarrhea in MVID patients and MYO5B KO mice. Activation of lysophosphatidic acid (LPA) receptors (LPA2 and LPA5) can inhibit CFTR and activate NHE3 in the intestinal epithelium. This study tested whether LPA treatment reverses the functional expression of apical proteins in MYO5B knockout (KO) mice.

Methods

Adult tamoxifen‐induced, intestine‐specific, MYOB KO mice (VilCreERT2;Myo5bflox/flox) and littermate control mice were treated with LPA (18:1 at 1 or 3 mg/kg/day) or vehicle, orally or intraperitoneally for 4 days after a single injection of tamoxifen (2 mg/mouse, i.p.). Apical transporter activities in jejunum and ileum were measured by an Üssing chamber system and the localization of apical proteins were evaluated immunostaining with whole‐slide imaging and digital image analysis.

Results

Following tamoxifen injection, F‐actin‐positive inclusions appeared in the upper small intestine of VilCreERT2;Myo5bflox/flox mice and the brush border localization of phospho‐ezrin, SGLT1, NHE3, DRA, PEPT1, alkaline phosphatase, and DPPIV were lost throughout the intestine. Treatment with LPA partially restored apical localization of phospho‐ezrin, SGLT1, NHE3, alkaline phosphatase, and DPPIV particularly in villus epithelial cells. Consistent with these observations, SGLT1‐dependent short‐circuit current (Isc) was 3 times higher in LPA (3 mg/kg)‐treated jejunum and ileum than that of vehicle‐treated VilCreERT2;Myo5bflox/flox mice. LPA dose‐dependently decreased CFTR‐dependent Isc in the steady state, but had no effect on CFTR dependence in carbachol‐ and forskolin‐stimulated Isc, which was increased by MYO5B loss.

Conclusions

These results suggest that LPA signaling may modulate a MYO5B‐independent trafficking mechanism for some brush border proteins in the small intestine, demonstrating a therapeutic potential for LPA in the treatment of MVID.

Support or Funding Information

Supported by The Christine Volpe Foundation

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Acute Effect of a Ketone Monoester Supplement on Metabolic Control in Individuals with Obesity
Authors: Myette‐Côté Etienne , Caldwell Hannah , Clarke Kieran , Little Jonathan P.
Published: June 2021

OBJECTIVES

To determine whether acute ingestion of ketone monoester (KE; (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate) impacts plasma glucose and free fatty acid levels during a standard 75‐gram oral glucose tolerance test (OGTT) in individuals with obesity.

METHODS

Fifteen participants (age = 47±10 years) with a body mass index > 27 kg/m2 and a waist circumference >88 cm (female) or >102 cm (male) took part in a randomized crossover study. After an overnight fast, participants consumed a KE supplement (DeltaG®; 0.45 ml/kg body weight) or taste‐matched placebo 30 minutes before completing a 2‐hour OGTT with blood samples collected every 15–30 minutes. Participants and study personnel performing laboratory analyses were blinded to condition.

RESULTS

KE acutely raised blood D‐beta‐hydroxybutyrate to an average concentration of 2.4±1.2 mM within 30 minutes with levels remaining elevated throughout the entire OGTT. Compared to placebo, KE significantly decreased glucose area under the curve (AUC; −11%, P = 0.002), glucose incremental area under the curve (AUC; −23%, P = 0.008) and non‐esterified fatty acid (AUC; −21%, P = 0.009). Insulin and C‐peptide levels increased significantly over the 30 minutes period prior to the OGTT (P = 0.001 and 0.003 respectively) but no differences in total AUCs were observed as compared to placebo. No significant changes in lactate or triglycerides were observed.

CONCLUSION

In conclusion, a KE supplement that acutely increased D‐beta‐hydroxybutyrate levels attenuated the glycemic response to an OGTT in individuals with obesity. The reduction in glycemic response was accompanied by a reduction in non‐esterified fatty acids. These results suggest that ketone ester supplements could have therapeutic potential in the management and prevention of metabolic diseases.

Support or Funding Information

This project was funded by a Heart and Stroke Foundation of Canada Grant‐in‐Aid. JPL is supported by a Canadian Institutes of Health Research (CIHR) New Investigator Salary Award (MSH‐141980) and a Michael Smith Foundation for Health Research (MSFHR) Scholar Award (16890).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Suppression of Copper Metabolism MURR Domain 1 (COMMD1) Prevents Myocardial Ischemic Injury in Mice
Authors: Li Chen , Wang Tao , Meng Xia , Li Kui , Peng Hongxu , Kang Y. James
Published: June 2021

Previous studies demonstrated that myocardial ischemia causes copper (Cu) reduction and Cu metabolism MURR domain 1 (COMMD1) protein accumulation in the ischemic infarct myocardium. Since COMMD1 is involved in the export of Cu from several types of cells, the present study was undertaken to test the hypothesis that the accumulation of COMMD1 is responsible for Cu reduction in the ischemic heart, thus worsening myocardial ischemic injury. We generated a tamoxifen‐induced, cardiac‐specific COMMD1 knockout mouse model (Myh6‐creER COMMD1flox/flox) to examine the alterations in Cu status and myocardial function in mice subjected to ischemic insult. Six‐week‐old, male Myh6‐creER COMMD1flox/flox and littermate control mice were injected intraperitoneally with tamoxifen for two weeks and subsequently subjected to left anterior descending (LAD) coronary artery ligation or sham operation. Cardiac function was determined by echocardiography on the seventh day after the operation. Histological examinations including hematoxylin and eosin stain (HE) and sirius red (SR) staining were performed to visualize the differences in infracted area, myocardial cell death, and fibrosis. The results showed that in the absence of COMMD1, ischemia‐induced reduction of Cu concentrations in the heart was alleviated, and the declines in both ejection fraction (EF) and fractional shortening (FS) were significantly suppressed. These changes were accompanied by the reduction in the infarct size, cell death, and fibrosis in the COMMD1‐deficient heart. These results thus suggest that COMMD1 plays a critical role in the pathogenesis of ischemic heart disease, and deletion of COMMD1 leads to suppression of myocardial ischemic injury.

Support or Funding Information

Scientific research funds of West China Hospital of Sichuan University

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Iron Deficiency Induces Faster Sickling Kinetics in Transgenic Sickle Mice
Authors: Almashjary Majed , Brooks Steven , Dunkelberger Emily , Castro Oswaldo , Eaton William , Ackerman Hans
Published: June 2021

Sickle cell disease (SCD) is caused by polymerization of deoxygenated hemoglobin‐S (HbS) within the red blood cell (RBC). The kinetics of hemoglobin polymerization are dependent on the intra‐erythrocytic concentration of HbS; specifically, the time from deoxygenation to polymerization is inversely related to HbS concentration30. We hypothesized that iron‐deficient erythropoiesis would produce RBCs with decreased intracellular Hb concentration and prolonged sickling times which would reduce the severity of SCD.

To interrogate this hypothesis, we studied Townes mice that express humanized alpha globin, gamma globin, and either beta‐S (Townes‐SCD) or normal beta globin (Townes‐Control). RBCs from these Townes‐SCD mice have similar sickling kinetics to RBCs from human volunteers with SCD. To induce iron deficiency, we fed mice either an iron‐restricted diet (3 ppm iron) or iron‐normal diet (48 ppm iron) introduced at the time of weaning. After two months on the experimental diets, we measured RBC parameters using an Advia 2120 hematology analyzer and measured in vitro RBC sickling kinetics at 3% oxygen. Analysis of RBC parameters revealed that SCD mice on the iron‐restricted diet had lower hematocrit (32% vs 42.2%, P <0.0001), and there were trends toward lower hemoglobin, mean corpuscular volume, mean cell hemoglobin, and mean corpuscular hemoglobin concentration. Surprisingly, the in vitro sickling kinetic assay showed a significantly shortened time to 50% sickled in the Iron Restricted group (t50: 96.6 vs 136.5 min., p<0.0001).

At this two‐month time point, this study provides insights into the hematologic changes that occur during the initial onset of iron deficiency anemia in Townes‐SCD mice. We were surprised to find that the rate of sickling increased in the iron‐restricted mice; however, at two months of iron deficient diet, we have yet to see a substantial fall in the MCHC, a major determinant of the sickling delay time. Furthermore, these mice may have experienced compensatory changes in the red cell that adversely affected sickling such as a decrease in hemoglobin F levels, or a shift in the Hb‐ O2 dissociation curve that favors releasing oxygen at lower partial pressures. To address these questions, we will investigate the hemoglobin composition and the oxygen dissociation curve at the remaining four‐ and six‐month timepoints. We aim to determine the intermediate and long‐term potential of iron deficiency to delay sickling and reduce the severity of organ damage in the context of SCD. This may inform a strategy of optimizing iron intake as a potential treatment for SCD.

Support or Funding Information

Support from NIAID Intramural funding and NIH Division of Veterinary Resources

Scholarship Award from the Saudi Arabian Cultural Mission (SACM)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Chromatin Regulation of Tumor Responses to Immune Checkpoint Blockade
Authors: Shi Yang
Published: June 2021

Recent studies have shown that chromatin regulators impact tumor cell immunogenicity and immune cell functions, thus impacting responses of tumors to the immune system. We have been using genetic tools to identify chromatin regulators that control tumor responses to the immune system, with the ultimate goal of identifying small molecules which would work together with checkpoint inhibitors to curtail cancers.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Connecting variation in the gut microbiome with susceptibility to vascular disease
Authors: Rey Federico
Published: June 2021

The human distal gut harbors complex, diverse and dynamic microbial communities that are shaped by diet and host factors. These communities provide the host with a vast range of functions such as digestion of complex dietary components, production of vitamins, and maturation of the immune system. Dietary components such as complex plant polysaccharides (e.g., fiber) which are not absorbed in the proximal intestine reach the distal gut where they boost the growth of many intestinal bacteria, which in turn release metabolites that modulate host epigenetic programing and health. Because of the large variation in gut microbiota composition among individuals these microbial communities represent an important and differential factor that can modulate the nutritional value of food., with increased representation of butyrate‐producing microbes proposed as one of the potential mediators. I will illustrate approaches focusing on our recent studies aimed at defining the interrelationships between diet, gut microbiome variation, host epigenetic regulation and atherosclerosis.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Rare Bilateral Variation of the Posterior Intercostal Arteries
Authors: Sehi Daniel , Wallace Nolan , Daly Daniel , Martin John , Tan Yun
Published: June 2021

Background

The thoracic aorta usually gives off the 3rd to 11th pairs of posterior intercostal arteries (PIA) and 1 pair of subcostal arteries. The first two pairs of PIA typically originate via the highest intercostal artery via the costocervical trunk of the subclavian artery. The PIA supply blood to the intercostal spaces, spinal cord and spinal nerve roots.

A bilateral branching anomaly in multiple PIA were observed in an 81 year‐old male cadaver during routine dissection. The thoracic aorta gave rise to asymmetrical common PIA trunks at different levels on both sides. Five common PIA trunks were found arising from the thoracic aorta and a descending branch of the right vertebral artery was also observed. Two common PIA trunks were observed on the right side branching from the thoracic aorta. The first common PIA trunk supplied the 4th through 7th intercostal spaces while the second common PIA supplied the 10th and 11th intercostal spaces. The 8th and 9th PIAs were direct branches off the thoracic aorta as normal. Three common PIA trunks were observed on the left side originating from the thoracic aorta. The first common trunk supplied the 3rd through 5th intercostal spaces. The second supplied the 6th and 7th intercostal spaces. The third trunk was observed to supply the 11th intercostal space as well as the subcostal region. Another vascular variation observed included a branch from the right vertebral artery that descended inferiorly and dorsally toward the first four ribs through the right costotransverse foramen. This descending branch of the vertebral artery gave off branches to supply the second, third, and fourth intercostal spaces on the right side. While common trunks of PIA have been reported to be highly prevalent, there are normally 1–2 common trunks found in a typical thorax. Thus, a cadaver that displays up to 5 common trunks of PIA in a singular thorax is a rare occurrence. Also anomalous is the presentation of a direct branch of the vertebral artery that courses dorsal to ribs while supplying several intercostal spaces. Understanding such anomalies has important clinical implications to interventional radiologists during thoracic cavity procedures as well as spine and thoracic surgeries.

Support or Funding Information

Center for Anatomical Science and Education, Department of Surgery, Saint Louis University School of Medicine

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Estimation of Stature from the Sternal Length in American White Population Using Linear Regression Equation: A Preliminary Cadaveric Study
Authors: Zavurov Gabriel , Malhis Camillia , Sims Taylor , Gupta Anupam , Walia Jasmit , Khalid Kanza , Ambati Sudhir , Lobo Stany
Published: June 2021

Objective

To estimate stature from the sternal length in American white population using linear regression equation.

Rationale

There is an extensive study to correlate the stature from long bones and sternum in the literature in the Asian continent population. However these studies are sporadic for white and Hispanic American population. In this study we used regression analysis to address the reliability of sternal length for estimation of stature in White American population.

Material and Methods

This preliminary research project was conducted at Touro College of Osteopathic Medicine during the academic year 2018–2019 and 21 female and 14 male cadavers from the Department of Anatomy were used for the study. The research project was approved by the Institutional research committee. Cadavers with any noticeable physical anomaly affecting the stature were excluded from the study. The age and ethnicity of the cadavers were obtained by the departmental records. Stature was measured using a steel tape from Heel to Vertex. After the reflexion of the skin, the length of the sternum was measured from incisura angularis to mesoxiphoid point using a digital Vernier Caliper. Regression equations were derived using SPSS statistical software.

Results

Regression equation for female: Y= 135.039 + (0.146) X where Y= stature and X= length of the sternum. Regression equation for male: Y=141.603 + (0.17) X where Y= stature and X= length of the sternum. The SD was 13.88, 16.21 and P value was 0.18, 0.12 respectively for females and males.

Conclusion

Based on the calculations and the P value, we concluded that the length of the sternum is not a reliable factor for stature estimation for American white population. Forensic importance of these findings and its comparison with existing literature will be discussed.

Support or Funding Information

NA

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Environmental Radio‐Toxins as Possible Radio‐biomarkers for Diseases of the CNS
Authors: Lykken Glenn I. , Momcilovic Berislav , Traudt Jon , Ward Thomas E.
Published: June 2021

A hypothesis is presented identifying environmental radon (EnRn) progeny as a radio‐biomarker of use in studies of the brain and central nervous system (CNS) diseases such as Alzheimer's (AD) and Parkinson's (PD). The long‐lived environmental radon progeny, Pb‐210/Po‐210, in air and soil is a common radio‐biomarker in plants and animals. Hydrocarbon combustion in power plants and internal combustion engines produce copious quantities of ultrafine carbon particles that entrain heavy metals such as Pb‐210 found in air of the combustion process. The UFP's laden with Pb‐210 are readily taken up in the lungs and transported by the blood throughout the body including the brain and CNS. The more numerous small UFP's (<10nm) can be transferred across the blood‐brain and cellular barriers into cells where Pb‐210 is permanently deposited. The Pb+2 ions can mimic Ca+2 in brain and CNS cellular action potential systems providing a pathway into the cells and producing deleterious biochemical effects, additionally with radioactive Pb‐210 there are cellular radiation effects. Within the context of the proposed hypothesis data of diseased brain tissues containing Pb‐210/Po‐210 showed selective deposition in the brain proteins in AD and brain lipids in PD, with increased Po‐210 in MS colon tissue

Support or Funding Information

This abstract is an end result of over 40 years of collaborative studies of environment radon progeny in humans. Collaboration among scientists from academia, government and private industry is noted.

The support programs are too numerous to mention, but have been recognized in peer‐reviewed publications associated with the work.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cortical and trabecular bone density distribution in primate and felid limb epiphyses
Authors: Perry Taylor A , Chirchir Habiba
Published: June 2021

Studies show that cortical and trabecular bone are responsive to mechanical loading, albeit in different ways. Increased loading results in an increase in trabecular bone density in epiphyses, whereas articular cortical bone is conserved to maintain joint congruity. However, the co‐distribution of articular cortical and trabecular bone density in joints has not been reported within a mechanical loading context, and in reference to locomotor behavior. This study analyzes cortical and trabecular bone density co‐distribution based on habitual loading in multiple limb elements across taxa with different locomotor behaviors (bipeds, terrestrial quadrupeds and arboreal quadrupeds). We predict that joints subjected to greater loading during locomotion will have an increased ratio of trabecular bone density to cortical bone than those that experience reduced loading. Specifically, we predict that non‐primate quadrupeds known to experience greater substrate reaction forces on the forelimb than hindlimb will exhibit greater trabecular to cortical bone density ratio in the forelimb epiphyses than the primate quadrupeds. We test this prediction using peripheral quantitative computed tomography (pQCT) measuring trabecular and cortical bone density in primates and felids. Results from one‐way ANOVA with Tukey post‐hoc corrections show that the femoral head in all locomotor groups studied display the least ratio between trabecular and cortical bone density in comparison to other limb elements. Additionally, other elements did not follow predicted patterns of bone density distribution based on locomotor behavior. Instead, they vary according to phylogeny. The results indicate that the femoral head, a relatively large epiphyseal element, displays greater density ‐ both cortical and trabecular ‐ regardless of locomotor repertoire. This suggests there are potentially non‐loading factors influencing observed bone distribution patterns. Furthermore, this study correlates bone density, fracture susceptibility, and injury risk, which have significant clinical applications.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.