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Pathogenesis of Irritable Bowel Syndrome (IBS) is multifactorial, and gut microbes are sought to play a role in development and progression of disease. In this study we examined how constipation‐predominant Irritable Bowel Syndrome (IBS‐C) microbiota affect host intestinal transit and signaling pathways. To determine IBS‐C dysbiosis effects on the host, we introduced fecal microbiota from constipated mice to germ‐free recipients. Recipient mice of IBS‐C microbiota developed delayed GI transit time when compared to controls. Bacterial DNA analysis by HiSeq sequencing showed significant increase in Bacteroides uniformis , Bacteroides ovatus and Parabacteroides distasonis species from Bacteroidetes phylum in constipated mice. Fecal microbiota metabolic potential was measured with tetrazolium dye assay and showed significant differences between recipients of control and IBS‐C microbiota. Microbial metabolites such as short chain fatty acids (SCFA) are known to alter intestinal transit. SCFA levels in cecal contents of recipeints were measured by GC‐MS, and showed lower butyrate, propionate and acetate concentration in IBS‐C mice when compared to controls. To determine contractile properties of intestine after introduction of control and IBS‐C microbiota, we stimulated colonic rings with carbachol and KCl, and observed hypercontractility in IBS‐C microbiota recipients. To determine mechanism for delayed GI transit we analyzed colon tissues in fecal microbiota recipients by qRT‐PCR, and determined dysregulated neuromediator pathways. Overall, these results suggest that IBS‐C dysbiosis contributes to development of delayed transit time through microbial metabolite production and changes in colonic contractile properties. Support or Funding Information R01 DK097268 and T32 DK007074

In pathologies of the heart, blood vessels, and airways, and in cancer as well, the ultimate therapeutic target is often modulation of cellular contractile force. For discovering new therapies, drug screening technologies typically use biochemical or structural surrogates for contractile force rather than contractile force itself. Because such approaches are indirect, some hits are false while other potential hits could be missed. To fill this gap, we developed a new high‐throughput method that utilizes cellular contractile force directly as the reporter ‐‐called contractile force screening (CFS)‐‐ and established feasibility of CFS in the context of drug discovery in asthma. During an acute asthma attack, contractile forces generated by airway smooth muscle cells act to constrict the airway and thus obstruct airflow. To dilate constricted airways, asthma patients use bronchodilators to reduce these contractile forces and thus allow the airway to open more fully, but currently available bronchodilator medications often fail to relax that muscle sufficiently, especially in severe asthma. To address this unmet need for more effective bronchodilator medications, we implemented CFS to evaluate 10,000 small molecule compounds selected randomly from the Chembridge DIVERset® library. Acrylamide gels were made in 96‐well plates and fluorescent markers and collagen were coated onto gel surfaces. Upon each gel we cultured primary human airway smooth muscle (HASM) cells to near confluence. Drug effects were quantified as the ‘force response ratio’, namely, the ratio of the contractile forces before and after drug addition. By screening mixtures of 8 compounds simultaneously, we were able to evaluate 2000 compounds per week in quadruplicate. After retesting individual compounds from initially positives, we identified 2 individual compounds that relaxed HASM cells in a dose‐dependent and a non‐toxic manner. The mechanism of action is still under investigation but we found that these compounds work independent of cAMP. CFS provides a convenient, rapid, and inexpensive platform for drug discovery based upon a physiological endpoint, namely, cell contractile force. Furthermore, CFS technology has the potential to become a new high‐content assay for drug discovery in any disease process in which cellular contractile force plays a central role. Support or Funding Information NIH P50HL107171 (CADET phase I), R01EY019696 (Eye BRP), NRF GRN (NRF‐2013S1A2A2035518)

Background Individuals with sleep apnea experience repeated intermittent hypoxic exposures during sleep. Previous work in sleep apnea showed patients have an increased heart rate (HR), corrected QT interval (QTc), QTc dispersion and P‐wave maximum duration and dispersion (max‐min P‐wave duration). Such changes have been linked to increased risk of cardiovascular disease and sudden cardiac death. Unfortunately, the mechanisms contributing to these changes are not completely understood. Given that individuals with sleep apnea experience repeated intermittent hypoxic exposures during sleep, we tested the hypothesis that exposure to intermittent hypoxia (IH) in young healthy adults would result in similar ECG changes to those seen in patients with sleep apnea. Methods To test this hypothesis, we completed ECG analysis of 7 healthy humans (6M/1F, Age=29±5 years, BMI=24±4kg/m 2 ) without sleep apnea before and after 3‐hours of exposure to IH. Subjects were exposed to hypoxic gas (0.05 FiO2) for 25‐seconds separated by 2‐minutes of room air breathing. This resulted in 25 hypoxic events per hour in which oxygen saturation was significantly reduced (Normoxia: 97%, Hypoxia: 89%, p<0.01). ECG analysis was completed in Lab Chart 7 software and consisted of measurement of intervals (RR, PR, QT), durations (P, QRS), and amplitudes (P, Q, R, S, T) during 10 minutes of normoxic quiet rest before and after IH exposure. QTc was calculated using Bazett's formula (QT duration/√HR). Dispersion of QTc and P waves were calculated as max duration ‐min duration. Results HR was significantly increased following IH (60±8 vs. 66±8 beats/min, baseline vs. post‐IH, respectively, p<0.05). There was no significant change in P‐wave maximum duration or dispersion following IH. QT interval was significantly decreased and QTc was significantly increased following IH (QT interval: 377±13 vs. 368±8ms, QTc: 377±22 vs 384±22ms, baseline vs. post‐IH, p<0.05 for both). QTc dispersion was not significantly different from baseline following IH. Conclusions We found that 3 hours of experimentally‐induced IH in young healthy individuals resulted in increased HR, decreased QT interval, and increased QTc. These data suggest that IH exposure experienced by patients with sleep apnea may contribute to ECG changes commonly observed in this population and subsequent increases in cardiovascular morbidity and mortality. Support or Funding Information Funding : DK90541 (MJJ), HL120570 (JKL)

Background We have previously shown that the carotid body chemoreceptors play an important role in glucoregulation. When the carotid bodies are experimentally desensitized in humans, counterregulatory responses to hypoglycemia are attenuated. Whether carotid body activation conversely increases circulating glucose levels was previously unexamined. We hypothesize plasma glucose levels would be increased in young healthy adults after carotid body activation via acute intermittent hypoxia. Methods Seven (6M/1F, 21–34 years) healthy, non‐obese, non‐diabetic, subjects without sleep apnea completed 2 visits randomized to 3‐hours of intermittent hypoxia or continuous normoxia. Oxygen saturation and ventilation (turbine ventilation flow transducer) were measured continuously. Plasma glucose levels and carotid body chemosensitivity (hypoxic ventilatory response, HVR) were measured before and after the 3‐hour protocol. Intermittent hypoxia consisted of 25‐s exposures to hypoxic gas (0.05 FiO 2 ) separated by 2‐min of room air breathing, resulting in 25‐events per hour in which oxygen saturation was significantly reduced (Normoxia: 97%, Hypoxia: 89%, p<0.01). Results No changes in plasma glucose (93 vs 93 mg/dL, p=0.92) or HVR (−0.35 vs. −0.39 L/min/%SpO 2, p=0.56) were observed after 3‐hours of continuous normoxia. In contrast, circulating glucose levels and chemosensitivity increased after intermittent hypoxia when compared to baseline (92 vs 97 mg/dL, p<0.01) and (−0.39 vs −0.60 L/min/%SpO 2 , p=0.04), respectively. Additionally, the rise in glucose was significantly correlated with the rise in carotid body chemosensitivity (R=0.38, p=0.05). Conclusion Circulating glucose levels increased after 3‐hours of intermittent hypoxia. The significant relationship between HVR and circulating glucose suggests that the carotid bodies may play a role in altered glucose handling. These findings may have important implications for the high prevalence of diabetes in patients with sleep apnea. Support or Funding Information DK90541, HL120570

Women who have experienced hypertensive pregnancy disorders (HPD) are at an increased risk for developing cardiovascular disease later in life, including fatal and non‐fatal stroke. Cerebrovascular reactivity is related to stroke in individuals with carotid artery disease, and it is possible that this measure may be altered in women with a history of HPD prior to overt cerebrovascular disease. It is unknown if cerebrovascular reactivity is altered in postmenopausal women decades after experiencing a hypertensive pregnancy. Therefore, the goal of this study was to determine if cerebral blood flow velocity and cerebrovascular reactivity are altered in women with a history of HPD in comparison to women with no history of HPD. We studied a cohort of postmenopausal women approximately 35 years after they experienced an HPD (n=27, age at testing: 58±1) and a group of age‐ and parity‐matched women with no history of HPD (n=30, age at testing: 59±1). We measured middle cerebral artery velocity (MCAv, via transcranial Doppler), continuous blood pressure (finger photoplethysmography), and end‐tidal CO 2 (nasal cannula) in these women at baseline (room air) and during stepped hypercapnia at 2, 4, and 6% inhaled CO 2 for 3 minutes at each condition. Women with a history of HPD had a higher body mass index than women without a history of HPD (29±1 vs. 26±1 kg/m 2 , respectively; p<0.05). At baseline and during 6% CO 2 , MCAv was lower in women with a history of HPD (baseline: 60±4 vs. 71±3 cm/s, respectively; 6% CO 2 : 82±6 vs. 99±5 cm/s, respectively; p<0.05 for both conditions) compared to women without a history of HPD. Cerebrovascular reactivity, the slope defining the association between MCAv and end‐tidal CO 2 across the entire breathing trial, was also lower in women with a history of HPD (2.0±0.2 vs. 2.7±0.2 cm/s/mmHg, respectively; p<0.05). Body mass index was not correlated with MCAv or cerebrovascular reactivity in either group (p>0.05). In conclusion, resting MCAv and cerebrovascular reactivity to CO 2 is lower in women with a history of HPD in comparison with women who have never experienced HPD. Our findings suggest that HPD may have long‐term effects on cerebrovascular regulation in women who have suffered from these conditions. Support or Funding Information NIH HL083947, NIA 1P50AG044170‐01, and CTSA UL1TR000135

The proximal tubule electrogenic, sodium‐coupled bicarbonate transporter, NBCe1, has a critical role in two proximal tubule acid‐base functions, bicarbonate reabsorption and ammonia metabolism. A third component of acid‐base homeostasis involves organic anion metabolism. The purpose of the current study was to determine NBCe1's role in organic anion metabolism by comparing mice with NBCe1 deletion to wild‐type (WT) littermates. Because NBCe1 KO causes early post‐natal mortality, we studied mice at day 8±1. Also, because NBCe1 deletion causes metabolic acidosis, we compared effects of NBCe1 deletion to that of experimental metabolic acidosis in adult WT mice. Both NBCe1 knockout (KO) and acidosis decreased citrate excretion, but their effect on proximal tubule citrate transporters differed. NaDC‐1 is the primary apical citrate transporter, and NBCe1 KO decreased NaDC‐1 mRNA expression and it decreased proximal tubule apical immunolabel. In contrast, acidosis in WT mice increased NaDC‐1 mRNA increased and proximal tubule apical immunolabel. The basolateral citrate transporter is NaDC‐3. NBCe1 deletion decreased NaDC‐3 expression whereas metabolic acidosis increased expression. A second key urinary organic anion is 2‐oxoglutarate. NBCe1 KO increased 2‐oxoglutarate excretion ~15‐fold, whereas metabolic acidosis decreased excretion by ~85%. NBCe1 deletion did not alter expression of the enzyme involved in 2‐oxoglutarate generation (Glud1), whereas metabolic acidosis increased it. There were no substantial changes in expression of the 2‐oxoglutarate dehydrogenase complex components, Ogdh, Dlst or Dld, with either NBCe1 KO or acidosis. Expression of the putative apical 2‐oxoglutarate transporter, OAT10, was decreased similarly by NBCe1 KO and by acidosis. Thus, effects of NBCe1 KO on 2‐oxoglutarate excretion did not correlate with changes in proteins involved in production, metabolism, basolateral transport (NaDC‐3) or its putative apical transporter (OAT10). 2‐oxoglutarate is proposed to stimulate urine alkalinization by activating the Oxgr1 receptor in pendrin‐positive intercalated cells. However, NBCe1 KO causes a urine pH of ~4.2 despite increased 2‐oxoglutarate excretion. Pendrin, the primary mechanism of collecting duct bicarbonate secretion, exhibited significantly decreased expression with NBCe1 KO. Expression of the 2‐oxoglutarate receptor, Oxgr1, was unaffected by NBCe1 KO, whereas it was decreased by metabolic acidosis. In summary: 1) NBCe1 is necessary for normal expression of the proximal tubule citrate transporters, NaDC‐1 and NaDC‐3; 2) NBCe1 is necessary for normal 2‐oxoglutarate metabolism through mechanisms independent of expression of known transport and metabolic pathways; and, 3) the lack of 2‐oxoglutarate urinary alkalinization in NBCe1 KO mice likely results from decreased expression of its target transporter, pendrin. Thus, NBCe1 expression is necessary for normal renal metabolism of the key organic acids, citrate and 2‐oxoglutarate. We conclude that NBCe1 expression is necessary for normal regulation of each of the three major components of proximal tubule acid‐base homeostasis, filtered bicarbonate reabsorption, ammonia metabolism and organic anion transport. Support or Funding Information Funds from the NIH (R01–DK045788 to IDW, R01‐EY017732 to MFR and R01‐DK095879 to KHS) and from the Department of Veterans Affairs (1I01BX000818 to IDW) supported these studies.

Background Obstructive sleep apnea (OSA) increases the risk for metabolic and cardiovascular disease. Telomere shortening has been linked to hypertension, diabetes mellitus, and cardiovascular diseases such as stroke and myocardial infarction. Because these conditions are highly prevalent in sleep apnea, we hypothesized that telomere length (TL) would be reduced in patients with OSA. Methods Genomic DNA was isolated from circulating leukocytes in 176 subjects (42.8 ± 13.8 years, 22.7 % women) who had undergone overnight polysomnographic evaluation. Of these individuals, 92 subjects had an Apnea Hypopnea Index (AHI) >5 events/hour and were classified as OSA patients. TL was measured using a quantitative PCR where a telomere to single copy gene ratio is determined and represented as number of base pairs (bp). The effect of OSA on TL was determined by comparing a control group (no OSA) (AHI<5, n=92) with patients with mild OSA (≥ 5 AHI <15, n=25), and those with moderate to severe OSA (AHI ≥15, n=59) in unadjusted and age‐adjusted models. Results Compared to control subjects, mild and moderate to severe OSA subjects were older: 48.9 ± 11.2 vs. 36.0 ± 11.2 years (p<0.001) and 50.8 ± 13.1 vs. 36.0 ± 11.2 years (p<0.001), respectively. Statistical models examining the effects of OSA severity on TL showed a J‐shaped curve : longer TL in moderate to severe OSA (4867 ± 221 bp) and controls (4820 ± 160 bp), and the shortest TL in mild OSA (4742 ± 155 bp). The mean TL in moderate to severe OSA was significantly longer than in mild OSA (p=0.0048). These effects were more pronounced after adjustment for age, when we observed significant differences in mean TL between moderate to severe OSA and mild OSA (p=0.0036) and between moderate to severe OSA and the control group (p=0.0379) (). However, the mean TL between control subjects and subjects with mild OSA was not different. Conclusion Moderate to severe OSA patients had longer TL compared with mild OSA and control group. This association was independent of age. Even though OSA is associated with increased cardiovascular risk, telomere lengthening in subjects with moderate to severe OSA suggests the presence of protective compensatory mechanisms to prevent telomere shortening in OSA. On the other hand, the existence of longer telomere in subjects with moderate and severe OSA may also indicate triggering of molecular mechanisms which may contribute to cancer development. Further studies are needed to explain the role of hypoxia in telomere dynamics in OSA, and the interactions between telomere length and increased longevity reported in older patients with OSA. Support or Funding Information NIH R01 grant (#HL65176); Singh P. is supported by AHA scientist development grant (11SDG7260046). Becari C. is supported by grant from CNPq‐Brazil (# 203802/2014‐4).

Doxorubicin (DOX) is a highly effective chemotherapy agent. Its use is hampered however owing to severe dose‐dependent cardiovascular toxicity in cancer survivors. Multiple mechanisms have been implicated in the pathogenesis of DOX cardiotoxicity, one of which involves inflammation mediated by activation of the NFκB/TLR4/COX‐2 pathway in the heart. Knowledge regarding the toxic effects of DOX‐induced inflammation in other organ systems such as the brain has not been thoroughly investigated. Therefore, we explored the inflammatory potential of DOX by assessing TLR4 and COX‐2 levels in cortex and pial arteries isolated from ovariectomized (OVX) female Sprague‐Dawley rats. We hypothesized that DOX would promote inflammation by increasing COX‐2 expression along with expression of its upstream innate immune receptor, TLR4, both of which are under the transcriptional regulation of NFκB. OVX rats were treated with three, bi‐weekly, i.p. injections of DOX (4 mg/kg; cumulative dose 12 mg/kg) or vehicle (saline) and euthanized 5 days after the last dose. Tissues were isolated, snap frozen, homogenized, and analyzed for COX‐2, TLR4 and NFκBp65 levels using standard western blotting. Although COX‐2 is typically considered an inducible enzyme, it has been shown to be expressed under basal conditions. In cortex and pial arteries from vehicle‐treated rats, measurable levels of COX‐2 and TLR4 protein were detected. However, contrary to our hypothesis, levels of COX‐2 and TLR4 were decreased following DOX. In pial arteries, DOX elicited a reduction in both the COX‐2 72 kDa band 74 kDa band with the greatest reduction observed in the 72 kDa. The 72 kDa band corresponds to the partially glycosylated inactive form of enzyme, while the 74 kDa band has been shown to represent the fully glycosylated active form. Cytosolic levels of NFκBp65 levels were detected in brain and pial vessel lysate, however levels were not altered by DOX. Similar to brain and pial arteries, basal expression of COX‐2 and TLR4 were detected in left ventricle and DOX treatment attenuated expression. In conclusion, although others have suggested the involvement of the NFκB pathway during the development and progression of DOX‐induced cardiomyopathy, our studies demonstrate a possible novel action for the anticancer agent implicating anti‐inflammatory mechanisms, particularly in female cohorts with low circulating levels of gonadal hormones. Support or Funding Information Arizona State University Intramural Funds (SA and JD), Midwestern University Intramural Funds (CC), Sarver Heart Center (RG)

The disruption of the cerebral microvascular endothelium and increases in capillary permeability are characteristic of many brain pathologies, including Alzheimer's disease, small vessel disease, ischemia/hypoxia, and hemorrhagic stroke. This study was designed to investigate whether microvesicles (MVs) released from activated human brain microvascular endothelial cells (HBMECs) alter permeability of endothelial monolayers. Male donor HBMECs were cultured to confluence in flasks, then treated for 24 hrs with medium alone (control) or with medium plus either tumor necrosis factor (TNF a , 20 ng/ml), thrombin (THR, 2 U/ml), angiotensin II (AngII, 10 nM), or hydrogen peroxide (H 2 O 2 , 0.8 mM). MVs released into the medium were isolated by differential centrifugation, labeled with annex in V plus antibodies against endothelial adhesion molecules which have modified expression during inflammation (PECAM‐1, ICAM‐1, E‐select in, integrin aV, or MCAM); and then analyzed by FACS. Total number of MVs released (MVs/ml) by each of the agonists (TNF a , 615.8±13.9 MV/μL; THR, 113.8±4.8 MV/μL; and H 2 O 2, 152.8±23.5 MV/μL) were significantly greater (P<0.05) compared the number released from cells treated medium alone (82.2±5.4 MV/μL). Each agonist treatment released distinct types of MV identified by FACS. Permeability (% control) of the HBMEC monolayer assessed using FITC‐dextran transport across the monolayers increased after 90 minute exposure to all agonist treatments: 199.5%, 234.1%, 126.8%, and 588.3% for TNF a , THR, AngII, and H 2 O 2 , respectively. MV derived from the treated cells were labeled with PKH67 and applied to monolayers of (control) HBMECs cultures. Within 30 minutes of exposure punctate structures with PKH67 labeling were observed within the cytoplasm, and after 60 min, similar structures also associated with nuclei and some of which were co‐labeled with the lysosome marker lysotracker red. Co‐localization of labeled MVs with early endosomes, (labeled with anti‐EEA‐1 Ab/Alexa Fluor 647) was absent at these time points. Within these parameters, no differences in vesicle‐trafficking were observed between MVs generated from cells exposed to either medium, TNF a , or H 2 O 2 . These results suggest that treatment of HBMECs with agonists associated with inflammation and thrombosis increase release of distinct MVs which in turn increase paracellular permeability. Capillary endothelial permeability may be disturbed by populations of MVs released from proximal activated cells or MV derived from activated cells and carried in the blood. Support or Funding Information Supported by the Aurora Fnd, NIH HL88988 and Mayo Clinic

Substantial evidence indicates that red blood cells (RBCs) can act as a ‘sensor’ for oxygen demand in addition to their traditional role as an oxygen ‘carrier’, in that they are able to stimulate vasodilation and increase oxygen delivery to the tissue through the release of ATP in direct proportion to the degree of hemoglobin (Hb) deoxygenation. However, RBCs from older adults have an impaired ability to release ATP in response to Hb deoxygenation compared to RBCs from young adults, yet the underlying cause of this remains unknown. RBC membrane deformability has been shown to decrease with advancing donor age, thus we hypothesized that increasing membrane deformability (via the Rho‐kinase inhibitor Y‐27632) would restore ATP release from RBCs of older adults, while decreasing membrane deformability (via the cell‐stiffening agent diamide) would impair ATP release from RBCs of young adults. Isolated RBC ATP release in response to normoxic (PO 2 ~110 mmHg) and hypoxic (PO 2 ~20 mmHg) stimuli was quantified in RBCs from young (23 ± 3 years; n = 11 for Y‐27632 and diamide) and older (68 ± 7 years; n = 11 and 6 for Y‐27632 and diamide, respectively) adults using the luciferin‐luciferase technique following RBC incubation with either saline (control), Y‐27632, or diamide. The relative change in ATP release from normoxia to hypoxia in saline control conditions was impaired in RBCs from older (41.5 ± 12.1% and 63.5 ± 18.5%) vs. young (110.4 ±12.7% and 146.0 ± 29.3%) adults (P < 0.05; control trials for Y‐27632 and diamide, respectively). Y‐27632 improved RBC ATP release in older adults (98.8 ± 19.8%) such that it was not different from the young control (P > 0.05), whereas diamide decreased RBC ATP release in young adults (57.4 ± 8.4%) such that it was not different from the older control (P > 0.05). Preliminary data from our laboratory indicate that these drugs affected RBC membrane deformability as expected based on other reports of the effects of Y‐27632 and diamide on RBC membrane deformability. We conclude that decreased membrane deformability contributes to the impaired ability of RBCs from older adults to release ATP in response to Hb deoxygenation, and that this may have implications for impaired vascular control with advancing age. Support or Funding Information HL095573, HL119337, F31HL126377