bluuebunny/crossref_metadata_2025 huggingface dataset:
Peripheral Serotonin Deficiency May Assist Early Lactation Outcomes in Mice Fed a High‐Fat Diet
Authors: Cheng Adrienne A. , Hernandez Laura L
Published: November 2023

Breastfeeding benefits both the mother and infant. Breastfed children have a lower incidence of type 1 and type 2 diabetes, childhood obesity, and gastroenteritis than those fed formula. Breastfeeding in the United States is much lower than ideal, with only 43.5% of mothers breastfeeding at 6 months. One of the factors is increasing prevalence of maternal obesity. As of 2009, 20.5% of women in the US are obese upon entering pregnancy. Obese women are less likely to initiate breastfeeding than their non‐obese counterparts, making their children more susceptible to health problems later in life. Decreased breastfeeding in obese women is attributed to a delay in lactation onset. Although the molecular mechanisms behind this are unknown, recent work in our lab suggests a role for peripheral serotonin deficiency in the lactating mammary gland. This study utilizes four different genotypes: wild‐type (WT), Tph1 knockout (Tph1 KO), low density lipoprotein receptor knockout (Ldlr KO), and a Tph1/Ldlr double knockout. Female mice were enrolled at 3wk and bred at 7wk. Vaginal plugs were checked daily, and the day of plug was denoted as embryonic day 0 (E0). A portion of WT and Ldlr KO mice were given their respective chow and HFD with added Tph1 inhibitor starting from E0 through their sacrifice date to assess the effect of a pharmacologic intervention in lactation outcomes. This study consists of three time points: baseline (7wk of age), lactation day 2 (L2; early lactation), and L10 (peak lactation). On L2 and L10, dams were anesthetized with isofluorane and given an i.m. injection of 0.2mL of oxytocin. Milk was collected and frozen for further protein and fatty acid analysis. Weigh‐suckle‐weigh was used to estimate total milk yield in one bout of nursing. As expected, WT and Ldlr KO mice on a HFD had increased pup mortality compared to their chow counterparts (P<0.05). At L2, these mice also exhibited difficulty lactating upon milking. However, upon the addition of the Tph1 inhibitor to the diet, WT and Ldlr KO mice have increased pup survival and restored lactation function. Previous studies in our lab have shown that mice that were fed a high fat diet (HFD) prior to and during pregnancy exhibited increased inflammatory markers in their mammary glands, similar to the inflammatory signature seen during mammary gland involution (lactation cessation). However, genetic ablation of tryptophan hydroxylase‐1 (Tph1), the rate limiting step in serotonin synthesis was able to reverse these effects. This study will further delve into how a HFD can induce inflammation in the mammary gland and whether a pharmacologic Tph1 inhibitor can be used to reverse these effects. These studies are crucial in understanding how the serotonergic system can be used clinically to improve lactation onset in obese women.

Support or Funding Information

Hatch funding: 142PRJ74RH
Trends in Breastfeeding in the State of Georgia, 2004–2013
Authors: Anderson Alex Kojo , Kanu Florence Adanma , Mwaura Mumbi , Ward Trina Salm
Published: November 2023

Background

National data suggest upward trends in breastfeeding initiation, exclusivity and duration across the United States but disparities between states still exist. The objective of this study is to describe trends in breastfeeding initiation and exclusivity in the state of Georgia.

Method

Georgia Pregnancy Risk Assessment Monitoring System (PRAMS) data 2004–2013 were analyzed. Participants were included in analyses if infant was born full‐term, normal weight, no birth defect, ≥ 6 months of age at time of data collection and living with the biological mother. SAS statistical software package was used for analyses.

Results

Of the 4,643 mothers included, 50.4% were White, 10.3% < 20 years, 17.9% < high school education, 60.1% married, 50.6% used Medicaid, 40.3% primiparous and 71.4% lived in an urban area. A little more than half (53.2%) reported their pregnancy was intended and 50.3% of the infants were male. 74.2% initiated breastfeeding with only 28.2% breastfeeding exclusively. There was an overall decreasing trend in breastfeeding initiation and an increasing trend for exclusive breastfeeding between 2004 and 2013 from 73.4%–70.6% and 11.9%–48.8%, respectively. Breastfeeding initiation increased only among Hispanics, 25–34 year olds, and college graduates, while exclusive breastfeeding increased among non‐Hispanic whites, Hispanics, 25–34 year olds, and across all levels of education. Despite the continued recommendations for breastfeeding by the American Academy of Pediatrics, Centers of Disease Control and Prevention and others, initiation rates in Georgia are decreasing, suggesting the need for timely education around the benefits of breastfeeding. Interestingly, there is an increasing trend for exclusive breastfeeding rate for those who initiated breastfeeding across the survey waves, which is encouraging news in the right direction.

Conclusion

Trends in breastfeeding initiation and exclusivity at the state level provide valuable information for state‐level public health professionals and policy makers as well as breastfeeding advocates about the challenge to meet the Healthy People 2020 objective for breastfeeding.

Support or Funding Information

Georgia Agricultural Experimental Station (HATCH # GEO00820)
Stem‐Like Cells in Breastmilk for Hospitalized Preterm Infants
Authors: Briere Carrie‐Ellen , Jensen Todd , McGrath Jacqueline M , Finck Christine
Published: November 2023

Breastmilk stem cells are a relatively new discovery in the scientific community. There are still many unknowns about their specific mechanisms of interaction; however, it has been hypothesized that their presence contributes to growth and development of the breastfed infant. Our research team is the first known team to enroll mothers of hospitalized preterm infants during the first few weeks of lactation and compare stem cell phenotypes and expression to mothers of healthy full‐term infants. The purpose of this study was to evaluate the feasibility of NICU breastmilk collection and the comparison of preterm and full‐term breastmilk cells. We enrolled mothers of preterm infants (n=7; range 26 4/7 – 34 5/7 weeks gestational age at birth) and mothers of healthy full‐term infants (n=4; range 39 5/7–40 5/7 weeks gestational age at birth). Flow cytometry and qRT‐PCR analysis were used to assess the prevalence of a variety of pluripotent and mesenchymal stem cell markers. Overall, cells with stem‐like characteristics were identified in both preterm and full‐term breastmilk samples. There was large variability among the amount of each stem cell phenotype present, as well as in the expression of specific markers. Preliminary results indicate that gene expression in the majority of the tested markers were significantly different between the preterm sample and the full‐term sample. In conclusion, there are individual differences in the cellular composition of breastmilk, and this variation results in differential expression of phenotypic markers and gene expression of breastmilk cells with multipotent and pluripotent characteristics. The science of breastmilk stem cells is new and there is future potential to use these easily accessible stem cells in regenerative medicine. Future studies will explore the relationship of breastmilk stem cell characteristics to neonatal health, most notably their regenerative and protective potential.

Support or Funding Information

National Association of Neonatal Nurses and Foundation for Neonatal Research and Education
Endothelial Mitochondria Regulate Local Calcium Signalling in Mesenteric Arteries From Mice
Authors: Toussaint Fanny , Béziau Delphine , Charbel Chimène , Blanchette Alexandre , Mayer Gaetan , Comtois Philippe , Ledoux Jonathan
Published: November 2023

Local calcium (Ca2+) signals are crucial for endothelial functions, including regulation of underlying smooth muscle cell contractility. Ca2+ pulsar is an endothelial IP3R‐dependent Ca2+ signal restricted to myoendothelial projections (MEP). Targets for this spatially‐discrete Ca2+ signal such as KCa3.1 channels, NOS3 and CaMKII have been previously described. However, determinants for Ca2+ pulsar kinetics and stochasticity remains poorly understood. Mitochondria are an important regulator of intracellular Ca2+ dynamics in several cell types such as pancreatic acinar cells. It has thus been hypothesized that mitochondria are an important modulator of Ca2+ pulsar. Mitochondrial influence on Ca2+ pulsar was explored on cut‐opened mesenteric resistance arteries using a high‐speed confocal microscope. Inhibition of mitochondrial uniporter‐dependent Ca2+ uptake (Ru360) increased the surface covered by a Ca2+ pulsar (+30%). Conversely, stimulation of mitochondrial Ca2+ uptake (kaempferol) reduced Ca2+ pulsar's spreading (−20%), suggesting that mitochondria could limit Ca2+ pulsars propagation. Interestingly, inhibition of mitochondrial Ca2+ efflux (CsA for mPTP; CGP37157 for NCLX) had little if any effect on spatial dispersion of a Ca2+ pulsar. However, de novo Ca2+ pulsar sites were observed following exposure to CsA/CGP. Mitochondria might thus control subcellular Ca2+ levels within MEP to modulate IP3R activity. Electron microscopy showed clustering of mitochondrial distribution near the MEP. These results suggest that mitochondria might play a significant role in regulating local endothelial Ca2+ signalling and then, modulate vascular tone.

Support or Funding Information

FRQS, CFI, SQHA and CIHR
Estradiol Deficiency Leads to High miR‐21 Level in Skeletal Muscle of Ovariectomized Mice
Authors: Karvinen Sira M , Laakkonen Eija , Le Gengyun , Collins Brittany C , Mader Tara L , Lowe Dawn A
Published: November 2023

The loss of skeletal muscle strength is a consequence of aging. In women, there is an even greater loss of muscle strength due to reduced ovarian hormones that occurs during menopause. Estradiol (E2) has been shown to mitigate the detrimental effects on muscle strength in females. However, the underlying molecular mechanisms of estradiol's beneficial effects are not completely understood. Here we have focused on signaling by microRNAs (miRs) which are known to be potential biomarkers for disease (1). miRs are small RNA molecules that work as post‐transcriptional regulators by blocking translation. Previously we have shown in women that there are several E2 responsive miRs in skeletal muscle (2). MiR‐21 is a specific miRNA that is frequently up‐regulated in cancer and has a key role in apoptosis. Apoptosis signaling has a potential role in muscle atrophy contributing to loss of muscle strength with aging.

METHODS

Adult C57BL/6 mice were either sham operated (ovary‐intact) or ovariectomized (OVX) under isoflurane anesthesia. Four weeks later, extensor digitorum longus (EDL) muscles from the OVX mice were isolated and underwent a series of repetitive maximal isometric tetanic contractions in the presence or absence of E2 in the bathing medium, after which muscles were snap frozen and analyzed for miR‐21. Gastrocnemius muscles and blood serum were also collected for miR‐21 analysis.

RESULTS

OVX mice had 11‐fold higher miR‐21 levels in gastrocnemius muscles (p < 0.01) compared to sham mice, but serum levels did not differ (p = 0.18). Electrically stimulated muscle contractions in vitro increased the expression of miR‐21 in EDL muscles, whereas acute E2 exposure diminished the contraction‐induced upregulation of miR‐21 in OVX mice.

CONCLUSION

Our preliminary results show that E2 deficiency via OVX leads to high miR‐21 levels in skeletal muscle and that a short term exposure of muscle to E2 can blunt muscle contraction‐induced upregulation of miR‐21. More studies are needed to find out mechanisms through which E2 affects miR‐21 levels.

Support or Funding Information

This study is supported by NIH grant R01‐AG031743.
ANNONA SENEGALENSIS SHOWS POTENT ANTI‐DIABETIC ACTIVITY BY ATTENUATING DNA FRAGMENTATION IN OXIDATIVE INJURY AND INHIBITING KEY‐ENZYMES LINKED TO TYPE 2 DIABETES
Authors: Erukainure Ochuko L. , Islam Shahidul
Published: November 2023

The leaves and stem bark of Annona senegalensis were investigated for their anti‐oxidative vis‐à‐vis anti‐diabetic potentials in vitro. Extracts from sequential extraction with solvents of increasing polarity (n‐hexane, ethyl acetate, ethanol and aqueous) of the leaves and stem barks were subjected to in vitro antioxidant assays using the 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging and Ferric reducing antioxidant power (FRAP) protocols respectively. Their inhibitory effects were investigated on intestinal α‐glucosidase, hepatic and pancreatic lipases, glucose‐6‐phospatase and pancreatic ATPase activities. Their antioxidant and anti‐apoptotic effects on Fe2+ ‐ induced oxidative injuries in pancreatic and hepatic tissues were also investigated ex vivo. The extracts showed potent free radical scavenging activity and significantly (p<0.05) inhibited all studied enzymes, with the stem bark extract showing better activity. Superoxide Dismutase (SOD) and Catalase activities were significantly (p<0.05) increased in both pancreatic and hepatic tissues with concomitant elevation of reduced glutathione (GSH) levels as well as reduced levels of malondialdehyde (MDA). The extracts significantly inhibited DNA fragmentation in both tissues. These activities were dose – dependent. These results indicate the anti‐oxidative, anti‐diabetic and anti‐obesogenic potentials of A. senegalensis, with the ethanolic extract of stem bark showing the best activity. Thus, giving credence to its antidiabetic folkloric claims

Support or Funding Information

University of KwaZulu‐Natal, Durban 4000, South Africa
Dietary and Lifestyle Determinants of Vitamin D Status in Filipino Women Living in Korea: FiLWHEL Study
Authors: Kim Soonji , Abris Grace , Provido Sherlyn Mae , Shin Wookyoung , Hong Sangmo , Yu Sung Hoon , Lee Chang Beom , Lee Jung Eun
Published: November 2023

Objective

We aimed to assess vitamin D status and to identify dietary and lifestyle determinants for vitamin D status among Filipino women living in Korea of the Filipino Women's Diet and Health Study (FiLWHEL).

Methods

Filipino women who have been married to Korean men were recruited from March 2014 to April 2016. We included a total of 486 Filipino women aged 20–55 years old in our analysis. Serum levels of 25 hydroxyvitamin D (25(OH)D) were measured using electrochemiluuminescence immunoassay. We asked participants about demographic and lifestyle factors through face‐to‐face interview and assessed anthropometric measures using bioimpedance method. We identified dietary, demographic, anthropometric, and lifestyle factors associated with circulating 25(OH)D levels using the linear regression model. We included variables of which significance levels were under 0.1 in the univariate model and examined whether these variables were statistically significant at an alpha of 0.05 in the multivariate model.

Results

Mean serum 25(OH)D level was 15.4 ng/mL (SD= 6.4). The prevalences of severe deficiency (<10 ng/mL), mild to moderate deficiency (10–<20 ng/mL), and insufficiency (20–<30 ng/mL) of vitamin D in this population were as follows; 17.5%, 63.6%, and 16.5%. Vitamin D intake from food and supplements (β=2.56, p=0.008), season of blood draw (fall vs. spring; β=0.22, p<.0001), skin change in summer sun (a sunburn skin without blisters vs. a mild sunburn that becomes a tan; β=−0.14, p=0.023), and oral contraceptive use (use vs. nonuse; β=0.15, p=0.002) were significantly associated with circulating 25(OH)D levels.

Conclusions

We found that immigrant Filipino women in Korea had high prevalence of deficiency and insufficiency of vitamin D and vitamin D intake, season, skin change and oral contraceptive use were associated with vitamin D status.
Activation of Adrenergic Receptor Subtypes Differentially Regulate Expression of Metabolic Genes in Porcine Adipocytes
Authors: Shin Sunhye , Ajuwon Kolapo M
Published: November 2023

Pigs adipocytes express mostly the β1 and β2 adrenergic receptors (AR), with limited expression of the β3 adrenergic receptor subtype. However, there is limited understanding of the relative contribution of these receptors to the regulation of important metabolic genes in pig adipocytes. Therefore, this study was conducted with the objective of determining the effect of agonists of β1(dobutamine), β2 (bambuterol), β3 (CGP‐12177‐Hydrochloride) AR and that of α AR (UK14,304). Norepinephrine (NOR) treatment was used to represent non‐specific adrenergic receptor activation. Markers of metabolic activation used include carnitine palmitoyl transferase 1 (CPT1), PPARg coactivator 1a (PGC1a) and deiodinase 2 (DIO2). Significant induction (at least two fold) of expression of these genes was observed with NOR and the b1 agonist, whereas the β2 agonist inconsistently induced these genes. However, the β3 and α AR agonists were ineffective. We further investigated effect of adrenergic receptor blockage with propranolol and inhibition of PKA with H‐89. Both inhibitors blocked NOR and dobutamine effect. These results indicate that pig adipocytes have an inducible, but selective, response to β AR agonists, but are not responsive to α AR agonists. This might indicate the relative importance of these AR subtypes in the regulation of adipocyte metabolism and phenotype in the pig.

Support or Funding Information

Funding was received from the Department of Animal Sciences, Purdue University
Positive association between reduced GSH and inadequacy/deficiency of 25‐hydroxy‐vitamin D in obese children
Authors: Jain Sushil K. , Parsanathan Rajesh , Achari Arunkumar E
Published: November 2023

The deficiency of 25‐hydroxy‐vitamin D [25(OH) VD] has become a world‐wide epidemic. Genetic studies in humans show that the blood levels of 25(OH) VD in response to VD supplements is modulated by the VD regulatory genes. Recent studies report that supplementation with L‐cysteine (LC), a precursor of glutathione (GSH) can upregulate VD regulatory genes [vitamin D binding protein (VDBP), VD‐25‐hydroxylase and vitamin D‐receptor (VDR)]. This study examined the hypothesis that VD deficiency is associated with reduced GSH levels in obese children. Fasting blood was collected from normal subjects enrolled after prior IRB approval. We measured GSH levels by HPLC; 25(OH) VD, insulin and TNF‐α levels using ELISA kits, and glucose using glucose oxidase method. Table shows blood levels of 25(OH) VD and GSH were significantly lower in obese (BMI>30) compared with lean (≤25 BMI) or overweight (≤30 BMI) children. HOMA‐Insulin resistance (IR) and TNF‐α were significantly higher in obese compared with lean or overweight. There was a significant positive correlation between 25(OH) VD and GSH (r=0.24, p=0.04, n=74); IR showed negative association with 25(OH) VD (r=−0.24, p=0.04) and positive association with TNF‐α (r=0.30, p=0.02). GSH‐deficiency induced by glutamate‐cysteine ligase (GCLC) KD, caused down‐regulation of VDBP, VD 25‐hydroxylase and VDR; and pretreatment with LC, a precursor of GSH, and prevented the down‐regulation of VDBP, VD‐25‐hydroxylase and VDR in (FL83B) hepatocytes. Treatment with exogenous TNF‐α (0.2 ng/ml), or GCLC KD caused down regulation of GLUT4 and increase in TNF‐α secretion, which was reversed by LC, in (3T3‐L1) adipocytes. This suggests that deficiency of GSH down‐regulates VD regulatory genes and GLUT4 and thereby reduces circulating 25(OH) VD and induces IR in obesity. Thus, improvement in GSH level represent a novel therapeutic target in preventing/treating 25(OH) vitamin D deficiency and IR in a population at risk for 25(OH) VD‐deficiency (supported by NCCIH RO1 AT007442).

Support or Funding Information

supported by NCCIH RO1 AT007442
Solute Carrier Family 2 Member 4 Regulates TRIM24‐DDX58 Axis to Promote Head and Neck Cancer Metastasis
Authors: Chang Yu‐Chan , Hsiao Michael
Published: November 2023

Metabolic reprogramming and aerobic glycolysis has been observed in head and neck squamous cell carcinoma (HNSCC) involved tumor metastasis and tumorigenesis. Solute carrier family (SLC) members present as a major hub in glycolysis pathway by accelerated metabolic rate. However, solute carrier family 2 member 4's (SLC2A4) role in HNSCC has not been fully investigated. In this study, we identified the SLC2A4 had most significant value and ranking associated with HNSCC survival rate and metastasis status than other family members via in silico database analysis. Furthermore, immunohistochemistry analysis also showed consistency result that SLC2A4 is positive correlated with N status. In addition, our clinicopathologic analysis showed that an increased SLC2A4 expression in HNSCC patients was associated with a significant poor overall survival (OS, p=0.035) and recurrence‐free survival (RFS, P = 0.001). Two‐way complementary models including overexpression or knockdown of SLC2A4 were preformed and identified SLC2A4 overexpression promoted HNSCC migration and invasion in vitro and in vivo. SLC2A4‐overexpressed FaDu cell line was used to perform gene expression microarray to determine the underneath molecular mechanisms. Ingenuity Pathway Analysis (IPA) software was utilized and identified tripartite motif‐containing 24 (TRIM24) transcription factor was a leading downstream regulator of SLC2A4. DDX58 was further confirmed to be the main downstream target of TRIM24 whose down‐regulation was found essential for the migratory phenotype induced by SLC2A4‐TRIM24 activation in our model. Finally, combined SLC2A4 with DDX58 could be used as a strong independent prognosis marker that is significantly correlated with poor survival rate in HNSCC patients. This novel signaling axis may be used for therapeutics development of HNSCC in the near future.
Aged Microvascular Networks Display Increased Pericyte Coverage along Capillaries
Authors: Suarez‐Martinez Ariana Diandra , Lane James Hayden , Murfee Walter Lee
Published: November 2023

While a common characteristic of aging is impaired angiogenesis, defined as the sprouting of capillaries from existing blood vessels, the altered mechanisms remain understudied. An opportunity exists to identify potential mechanisms by comparing cellular characteristics of aged versus adult microvascular networks. A critical cell type involved in capillary sprouting is the vascular pericyte with pericyte‐endothelial cell interactions playing both vessel stabilization (anti‐angiogenic) and angiogenic roles. However, little is known regarding whether pericyte presence is altered in aged tissues. The objective of this study was to compare pericyte coverage along capillaries in adult and aged microvascular networks. Mesentery tissues from adult (9 months) and aged (24 months) male Fischer 344 rats were harvested and immunohistochemically labeled for platelet endothelial cell adhesion molecule (PECAM), and pericyte markers, α‐smooth muscle actin (α‐SMA) or neuron‐glial antigen 2 (NG2). PECAM labeling identified endothelial cells along arterioles, venules, and capillaries across the hierarchy of networks. The percentage of capillaries (diameter <7 mm) with observable SMA positive pericyte labelling in aged networks was significantly increased compared to adult networks (Aged = 90.9% vs. Adult = 78.1%; p<0.05). Similarly, NG2 coverage of capillaries was also significantly increased in aged networks compared to adult networks (Aged = 94.9% vs. Adult = 76.6%; p<0.005). These results suggest that aged microvascular networks are characterized by increased pericyte coverage and motivate a new hypothesis for aging research that impaired angiogenesis in aged tissues is associated with increased vessel stabilization by vascular pericytes.

Support or Funding Information

NIH R01AG049821, NIH P20GM103629
Myocardial Vascular Protection in Hibernating Woodchucks
Authors: Zhang Jie , Vatner Dorothy E. , Guers John , Vatner Stephen F
Published: November 2023

True mammalian hibernation is a remarkable and natural mechanism to change the body's metabolism to meet the ravages of winter, when the animals do not eat or drink. At one point it was thought that these protective mechanisms related only to metabolism of fat and muscle including thermogenic protection. The goal of this study was to elucidate how the novel mechanisms elicited in hibernation can protect the heart from myocardial ischemia in an animal model with no coronary artery disease. Accordingly we compared the effects of myocardial infarction (MI) induced by permanent coronary artery occlusion (CAO) for 2 months in woodchucks in summer, when they were not hibernating, and in winter when they were. During hibernation they were markedly protected, p<0.05, from myocardial ischemia with reduced infarct size (37± 2.3% in winter, vs 47±3.1% in summer) and mortality (14% in winter vs 52% in summer) and preserved cardiac function as assessed by left ventricular ejection fraction (58±3.3% in winter, vs 42±3.3% in summer). The only way this might be possible in the face of permanent CAO would be if angiogenesis/arteriogenesis developed in the hibernating hearts following CAO. Indeed this is what was observed and determined by Ki67 + endothelial cell staining (0.60± 0.13% in winter vs 0.09±0.02% in summer). We then identified the vascular growth factors (VEGF, cTGF, PDGF, and EGR1) that were upregulated in the hibernating woodchuck heart, including nitric oxide synthase and CREB. Thus, natural mammalian hibernation induces marked cardioprotection through induction of angiogenesis/arteriogenesis.

Support or Funding Information

This study was supported by NIH funding R01HL130848.
Taurine Supplementation Improves Arterial Pressure Control Function after Cardiac Ischemia/Reperfusion via Systemic Inhibition of the Renin‐Angiotensin System in Adult Female Rats Perinatally Depleted of Taurine and Supplemented with High Sugar
Authors: Roysommuti Sanya , Kulthinee Supaporn , Wyss James Michael
Published: November 2023

Perinatal taurine depletion followed by a high sugar diet exacerbates cardiac injury and arterial pressure dysregulation after ischemia/reperfusion (IR), and this effect is blunted by taurine supplementation or inhibition of renin‐angiotensin system. This study tests the hypothesis that taurine supplementation improves arterial pressure control in this model via systemic inhibition of renin‐angiotensin system overactivity. Female Sprague‐Dawley rats were fed normal rat chow with tap water alone (control, C) or tap water containing 3% beta‐alanine (taurine depletion, TD) from conception to weaning. Female offspring were fed the normal rat chow and drank 5% glucose in tap water (CG and TDG) or tap water alone (CW and TDW) throughout the study. One week before surgery, half of rats in each treatment were supplemented with 3% taurine in tap water (CW+T, CG+T, TDW+T, and TDG+T). At 7–8 weeks of age, blood chemistry and hemodynamic parameters were studied in conscious and anesthetized rats after cardiac IR induction and in untreated Sham control rats. Body and heart weights, plasma electrolytes, plasma creatinine, and blood urea nitrogen were not significantly different among the nine groups. However, plasma angiotensin II concentrations were markedly and significantly elevated in TDG compared to all other groups (Sham, 33.9 ± 4.4 pg/ml; CW, 20.2 ± 2.3 pg/ml; CW+T, 24.4 ± 4.3 pg/ml, CG, 20.8 ± 2.9 pg/ml; CG+T, 20.2 ± 2.3 pg/ml; TDW, 22.6 ± 2.5 pg/ml; TDW+T, 15.1 ± 1.0 pg/ml; TDG, 61.1 ± 7.6 pg/ml (p < 0.05 to all other groups); TDG+T, 32.8 ± 4.7 pg/ml). After cardiac IR, mean arterial pressure significantly increased in all IR groups, compared to their corresponding values before IR. Further, in the TDG compared to all other groups, baroreflex sensitivity was markedly and significantly depressed and sympathetic nerve activity was significantly increased. Power spectral analysis of renal nerve activity indicated a significant increase in renal renin release only in the TDG compared to all other groups, though renal firing frequency increased in CG, TDW, TDW+T, TDG, and TDG+T groups. The adverse effects of cardiac IR on arterial pressure control, renin release, and plasma angiotensin II were improved by short‐term taurine supplementation. The present study demonstrates that in adult female rats perinatally depleted of taurine followed by a high sugar diet, taurine supplementation improves the adverse effects of cardiac IR on arterial pressure control via inhibition of systemic renin‐angiotensin system overactivity.

Support or Funding Information

This work was supported by Khon Kaen University, Khon Kaen, Thailand.
Elevated Sympathetic Nerve Activity Mediates Increases in Large Central Elastic Artery Stiffness Independent of Changes in Blood Pressure in Humans
Authors: Holwerda Seth William , Credeur Daniel P. , DuBose Lyndsey E. , Luehrs Rachel E. , Schwartz Christopher E. , Fadel Paul J. , Pierce Gary L.
Published: November 2023

Recent evidence suggests that elevated sympathetic nerve activity (SNA) may increase large central elastic artery stiffness (i.e., carotid, aorta), a robust independent predictor of cardiovascular disease. However, experimental manipulations involving increased (e.g., handgrip exercise) or decreased (e.g., ganglionic blockade) SNA in humans have also evoked concomitant changes in arterial blood pressure (BP) making interpretation difficult. Therefore, we tested the hypothesis that acute elevations in SNA increase central artery stiffness independent of BP. First, in 7 young healthy men (20 ± 1 yrs; 26 ± 1 kg/m2), carotid artery compliance was assessed at baseline and during a moderate level of lower body negative pressure (LBNP, −45mmHg), a stimulus known to significantly increase SNA without major changes in BP. Next, carotid‐femoral pulse wave velocity (PWV), the gold standard assessment of aortic stiffness, and resting muscle SNA (MSNA) were assessed in a larger sample of healthy individuals (n=30; 37 ± 3 yrs; 11 women) and correlated. During LBNP, baroreflex‐mediated increases in heart rate were observed (BL: 59 ± 3 vs. LBNP: 80 ± 5 bpm, P<0.05), but mean BP was unchanged (BL: 79 ± 1 vs. LBNP: 81 ± 1 mmHg, P>0.05). Carotid artery compliance was significantly reduced during LBNP compared with baseline (BL: 1.15 ± 0.11 vs. LBNP: 0.71 ± 0.1 mm2/mmHg×10−2, P<0.05) in addition to reductions in brachial artery compliance (BL: 0.1 ± 0.03 vs. LBNP: 0.07 ± 0.02 mm2/mmHg×10−2, P<0.05). In the larger sample, carotid artery compliance was moderately associated with resting MSNA (R=−0.374, P=0.055); however, there was a stronger association between carotid‐femoral PWV and resting MSNA (R=0.583, P<0.01) that persisted after adjusting for BP and sex (R=0.471, P<0.01). Together, these preliminary data suggest that SNA acutely increases large central elastic artery stiffness in humans independent of changes in BP, and that tonically elevated resting SNA may contribute to higher large central elastic artery stiffness.

Support or Funding Information

NIH T32 HL007121, P01HL014388, U54TR001356 and American Heart Association 13SDG143400012
Inhibition of mTORC1 signaling pathway attenuates the salt‐induced hypertension in Dahl SS rats
Authors: Kumar Vikash , Cowley Allen W
Published: November 2023

The kidney plays a key role in blood pressure regulation and can be significantly compromised by oxidative stress. In the Dahl SS rat model, high salt intake leads to an increase in the production of ROS including superoxide O·2 and H2O2 in the kidney by stimulating NADPH oxidase. Over the last decade, the mammalian target of rapamycin (mTOR) signaling pathway has emerged as a key regulator in a wide range of cellular processes such as cell cycle progression, hypertrophy, cell survival and Na+ reabsorption. The ability of mTOR signaling to sense and integrate various signals including H2O2 raises the possibility that mTOR may serve as a “molecular hub” that allows nephron segments to integrate various inputs for the development of salt‐sensitive hypertension, Na+ homeostasis and kidney injury. Remarkably, little is known about the association of the mTOR pathway to the pathophysiology of hypertension. The goal of the present study is to explore the inhibition of elevations of renal perfusion pressure (RPP) upon H2O2 mediated upregulation of mTORC1 attenuates the salt‐induced hypertension by inhibiting immune cells infiltration/proliferation, hypertrophy and kidney injury. We observed significant upregulation of pS6/S6 which is readout for mTORC1 activity in renal cortex and pAKT/AKT which is readout of mTORC2 activity in renal outer medulla of SS rats fed a 4.0% NaCl diet for 21 days. Our in vitro data suggested that isolated nephron segments treated with H2O2 can upregulate the mTOR signaling pathway. An FDA approved drug rapamycin (1.5 mg/Kg per day, ip) which specifically binds and inhibits mTORC1, administrated daily to 10 weeks old SS rats fed a 4.0% NaCl diet for 21 days significantly reduced mean arterial blood pressure (from 176 ± 9 to 153 ± 12 mmHg) and urine albumin/creatinine ratio (from 13.42 ± 6.47 to 4.13 ± 1.09) compared to vehicle treated SS rats. Rapamycin treated rats also exhibited significantly reduced hypertrophy index (kidney wt/body wt), proliferating cells (Ki67 positive cells) without increasing the apoptotic cells, T lymphocytes (CD3+/mm2 from 191.64 ± 77.83 to 80.39 ± 14.34 and 236.87 ± 70.40 to 71.02 ± 15.81 in renal cortex and outer medulla, respectively) and macrophages (ED1+/mm2 from 605.40 ± 149.94 to 253.65 ± 82.96 and 483.60 ± 275.33 to 204.43 ± 85.13 in renal cortex and outer medulla, respectively). These results demonstrate that the inhibition of mTORC1 attenuates the salt‐induced hypertension and infiltration of immune cells into the kidney. This study for the first time demonstrated that the mTOR inhibitor could be a potential therapeutic agent to attenuate salt‐induced hypertension.
Sex Differences in Blood Pressure and mRNA expression of Renal Sodium Transporters in Mice Under Normal Sodium Diet
Authors: Waturuocha Chiedozie , Fan Liming , Kudo Lucia , Gilbert Willie , Rouch Al
Published: November 2023

We previously reported sex differences in blood pressure and the renal handling of sodium in mice consuming high salt diet (Fan L., et al FASEB J. 30, 731.6, 2016). The purpose of this study was to determine sex differences in blood pressure and mRNA expression of key renal sodium transporters in mice consuming normal chow and water for six weeks. Four‐week old intact male and female CD‐1 mice were purchased from Harlan, Inc. (ENVIGO) (Indianapolis, IN). Female and male mice (n = 5/group) were placed in metabolic cages and consumed normal chow (Harlan Teklad 2019) and water ad libitum for six weeks. Blood pressure in these mice was measured 5 days/week via the tail‐cuff technique (Kent Scientific CODA device). Separate mice in bins were maintained on the same dietary regimen and used for mRNA analysis of renal sodium transporters. Four mice in each group were sacrificed at the end of the first, third, fifth, and sixth weeks. Kidneys were removed, total RNA was extracted from renal cortical tissue and measured for quantity and quality, and this was followed by first‐strand cDNA synthesis. Real time qt‐PCR was performed using Sybr green and the RT2 Profiler™ PCR Custom Array system from SABiosciences (QIAGEN). Arrays contain primers of the following renal transporters ENaC (a, b, g subunits), NKCC2, NCC, NHE2, NHE3, SGLT, Agtr1a, and Atp1a1. Mean blood pressure (MBP, mmHg) averaged weekly was analyzed via two‐way ANOVA with repeated measures. Real time data was determined via ΔΔCt method and analyzed via RT2 Profiler™ PCR Array Data Analysis (Version 3.5) by SABiosciences. Results indicated that female kidneys expressed significantly higher mRNA levels of ENaC (b), NCC, Agtr1a, NHE2, and NHE3 in all four measured periods, higher levels of ENaC (a & g) and SGLT in three of the four periods, and higher NKCC2 levels in one period. Most expression levels were 2 fold or higher in female kidneys. Males had significantly higher MBP than females in week two (82.3 ± 3.5 vs 69.5 ± 2.0, respectively, p < 0.02) and had non‐significantly higher MBP in all other weeks. Both sexes showed increased MBP from week one to week six (female: 72.3 ± 1.1 to 82.2 ± 1.7, p < 0.07; and male: 79.9 ± 3.2 to 88.6 ± 3.2, p < 0.05). We conclude that female mice express higher mRNA levels of renal sodium transporters than male mice and maintain lower MBP than male mice. We suggest that both estrogen and testosterone play important roles in the sex differences in mRNA expression and blood pressure.

Support or Funding Information

Research supported by Oklahoma INBRE 8P20GM103447 Summer Research Program.
The role of Atrial Natriuretic Peptide in the development of renal and cardiac damage in a Dahl SS rat model
Authors: Ilatovskaya Daria , Winsor Kristen , Levchenko Vladislav , Prudnikov Oleh , Blass Gregory , Kriegel Alison , Staruschenko Alexander
Published: November 2023

Atrial natriuretic peptide (ANP), encoded by the Nppa gene, is an osmoregulatory hormone that promotes salt excretion. A GWAS identified ANP as a causative factor of blood pressure development, and in humans ANP levels are suggested as an indicator of salt‐sensitivity. Recently, Flister et al. (Genome Res, 2013) generated a knockout of Nppa in the Dahl Salt‐Sensitive (SS) rat background (further referred to as the SSNPPA−/− rat). The aim of the current study was to provide mechanistic insights into the effects of ANP deficiency on renal and cardiac function in the Dahl SS rats.

In this study hypertension was induced in SSNPPA−/− and control Dahl SS rats by placing them on a high salt diet (HS, 4% NaCl) for 21 days. A combination of in vivo techniques (blood pressure monitoring and GFR measurements) with ex vivo imaging, electrophysiological, and biochemical methods were used to test the role of ANP deficiency in the development of SS hypertension. Immunohistochemical analysis was employed to assess renal and cardiac damage.

Chronic i.v. infusion of ANP in wild type SS rats (100 ng/kg/day) attenuated the salt‐induced increase in blood pressure in the wild type SS rats, whereas SSNPPA−/− rats demonstrated a significantly higher mean arterial pressure compared to SS controls when the rats were fed a HS diet: on day 21 of diet MAP was 185.8 ± 9 mmHg in SSNPPA−/− rats compared to 144.6 ± 4 mmHg in SS controls. Additionally, SSNPPA−/− rats showed exacerbated kidney damage as revealed by intensified kidney hypertrophy, higher glomerular injury scores, and increased renal arterial hypertrophy. GFR was found to be reduced in the control SS rats fed a HS diet compared to LS diet, however significance was not reached in the SSNPPA−/− group. SSNPPA−/− rats did exhibit reduced diuresis, as well as a trend for lower sodium and chloride excretion when fed a HS diet. The activity of Epithelial Sodium Channel (an important contributor to the development of SS hypertension) was found to be increased in the cortical collecting ducts of the SSNPPA−/− rats. Additionally, SSNPPA−/− rats fed a HS diet showed intensified cardiac damage compared to SS controls, as demonstrated by higher heart to body weight ratio, and a dramatically elevated interstitial fibrosis. However, ultrasound echocardiography revealed that although SSNPPA−/− rats have cardiac remodeling, they do not exhibit heart failure.

Therefore, ANP is major regulator in the development of SS hypertension, and its deficiency leads to more severe cardiac and kidney damage. Further work will be devoted to discovering specific ANP‐associated molecular pathways that mediate its effects in SS hypertension, and assessing the therapeutic benefits of ANP for treating cardiovascular diseases.

Support or Funding Information

MCW RAC Pilot Grant (DVI) and NIH HL10880 (AS)
Alpha‐ketoglutarate stimulates Cl− absorption in the mouse CCD through a mechanism dependent on pendrin and protein kinase C
Authors: Fernandez Yoskaly Lazo , Welling Paul A , Wall Susan M
Published: November 2023

Alpha‐ketoglutarate (aKG) is an intermediary of the citric acid cycle that binds to its G‐protein coupled receptor, OXGR1, in the apical membrane of the kidney type B and non‐A‐non‐B intercalated cells of the cortical collecting duct (CCD) which increases Cl−/HCO3− exchange in the CCD. To determine the intracellular signaling pathways by which aKG stimulates Cl− absorption, we examined aKG‐stimulated Cl− absorption in CCDs perfused in vitro that were taken from mice eating a standard rodent diet. Since pendrin is the major mechanism of apical Cl−/HCO3− exchange in type B intercalated cells, we asked if aKG‐stimulated Cl− absorption is pendrin‐dependent. To do so, we compared the effect of aKG on Cl− absorption in CCDs from pendrin null mice and their wild type littermates. aKG increased Cl− absorption in CCDs from wild type mice without changing transepithelial voltage, VT. However aKG had no effect on Cl− absorption in CCDs from pendrin KO mice. Because aKG's receptor in the type B IC, OXGR1, acts through a Gq‐mediated pathway, we asked if aKG stimulates Cl− absorption through PKC‐dependent signaling. To do so, we examined the effect of aKG on Cl− absorption in the presence of two structurally distinct PKC inhibitors (2.5 mM GF 109203X and 20 nM Calphostin C) or their vehicle. We observed that PKC inhibitor application to the bath solution eliminated aKG‐stimulated Cl− absorption. Moreover, PKCa gene ablation eliminated aKG‐stimulated Cl− absorption. To determine if aKG stimulates Cl− absorption through a Ca2+‐dependent mechanism, we examined the effect of aKG on Cl− absorption with the Ca2+‐chelator bapta (20 μM) or vehicle in the bath solution. We observed that this Ca2+ chelator eliminated the increment in Cl− absorption observed with aKG application. We conclude that aKG stimulates pendrin‐dependent Cl−/HCO3− exchange through a PKC‐ and Ca2+‐dependent mechanism that involves, at least in part, the PKCa isoform.

Support or Funding Information

This study was supported by National Institute of Diabetes and Digestive and Kidney Diseases grants DK‐46493 (to S. M. Wall and T32 DK‐07656 to Y. Lazo‐Fernandez.
Discoverable, Reproducible, and Reusable Biosimulation Models
Authors: Nickerson David , Hunter Peter
Published: November 2023

Computational models of the heart, arguably the most advanced organ model, have evolved substantially since Denis Noble published his original 1962 modification of the Hodgkin & Huxley equations applicable to Purkinje fibre action and pacemaker potentials. As available computational power has grown the range of cardiac physiology and anatomy able to be represented by the mathematical models and numerical simulations has rapidly increased, to the point where we are now able to make use of multiscale and multiphysics cardiac models in scientific investigations. Similarly, detailed biosimulation models for other organ systems have evolved covering an equally wide range of spatial and temporal scales as well as the required types of physics. Often such models are parameterised for a given scenario, including details such as a specific environment or species. The Virtual Physiological Rat Project (www.virtualrat.org), for example, provided a platform for the consistent parameterisation of a range of biosimulation models for one of the most common laboratory animals.

While recent biosimulation models can be very detailed biophysically and anatomically, scientists face many challenges when attempting to reproduce the results of a given study ‐ often as the first exploration step in a desire to reuse an existing model. For instance, cardiac cellular models consisting of large systems of ordinary differential equations are frequently impossible to implement from the published paper alone. To address this problem, the Physiome and Virtual Physiological Human communities have developed standards for encoding model and simulation descriptions which enable scientists to archive and exchange their models in a reproducible manner.

The encoded model and simulations alone, however, are often not sufficient to enable scientists to discover suitable existing models or to comprehend a model once it is discovered to enable reuse. Here we will present recent developments aimed at improving the discoverability and reusability of cardiac models. Future work to encourage scientists to make use of these developments will also be presented.

Support or Funding Information

Supported by the Virtual Physiological Rat Project, NIH grant [P50‐GM094503]
Autonomic dysfunction precede hemodynamic and metabolic changes in an experimental model of hypertension submitted to fructose overload
Authors: dos Santos Camila Paixão , Bernardes Nathalia , Da Silva Dias Danielle , Conti Filipe Fernandes , Santos Fernando , De Angelis Kátia
Published: November 2023

The aim this study was to evaluate the effects of 7 days of fructose overload on metabolic, hemodynamic and autonomic parameters in spontaneous hypertensive rats. Male Wistar rats and SHR rats were divided into control (C), hypertensive (H) and hypertensive submitted to fructose overload (HF). The fructose overload (100g/L in drinking water) was started with 30 days of life of the animals. Arterial pressure (AP) signals were directly recorded. Cardiovascular autonomic modulation was evaluated by spectral analysis. Regarding metabolic evaluations, the glucose, insulin resistance and triglycerides were similar between studied groups. The mean arterial pressure, systolic AP and diastolic arterial pressure were higher in hypertensive animals (mean AP, H: 124±2 and HF: 123±3 mmHg) compared to the C group (mean AP: 95±2 mmHg). There was no difference in heart rate among groups. However, the HF group showed lower vagal modulation than C group, evidenced by a reduction in variance of pulse interval (HF: 12±2 vs. C: 37±8 ms2) and RMSSD index (HF: 5.9±0.7 vs. C: 3.3±0.3 ms). Additionally, the HF group showed increase in variance of systolic arterial pressure compared to the C and H group (28 ± 4 vs. C: 13 ± 1 and H: 18 ± 2 mmHg2). In conclusion, only 7 days of fructose overload was able to induce impairment in cardiac vagal modulation and vascular sympathetic modulation with no alteration on metabolic or hemodynamic parameters, suggesting that autonomic modulation dysfunction precede cardiometabolic changes in this experimental model of metabolic syndrome.

Support or Funding Information

FAPESP ‐ 2015/11223‐6; CAPES‐PROSUP – 1277269; UNINOVE, CNPq.