Navigating a Complex Case of Mycobacterium Xenopi in a Patient with Blue Rubber Bleb Nevus Syndrome.

Introduction: Blue rubber bleb nevus syndrome is a rare disorder of venous malformations, with around 200 cases reported. We present a case of Mycobacterium xenopi infection in a patient with blue rubber bleb nevus syndrome. Case Description: A 40-year-old female with blue rubber bleb nevus syndrome, asthma, and bronchiectasis came to the pulmonology clinic with shortness of breath and a cough. She was recently admitted for a bronchiectasis exacerbation but continued to have a worsening productive cough and fevers. The most recent CT scan of the chest showed interval stable right upper lobe fibrocavitary disease, demonstrating gradual progression over two years. She had occasional positive cultures for Mycobacterium Avium Complex and M. xenopi one year previously, assumed to be a colonizer and not treated. Most recent hospital cultures were negative for bacteria and an acid-fast bacilli smear. She was sent to the emergency department for bronchiectasis exacerbation and returned to the clinic six weeks later with two sputum cultures growing M. xenopi. It was decided to treat M. xenopi as this was likely the cause of her cavitary lung lesion and frequent infections. Azithromycin, rifampin, and sulfamethoxazole/trimethoprim were initiated. Intravenous amikacin was added later on. She finally had a right partial lung resection done after one year at an outside hospital. She was on and off antibiotics for M. xenopi for approximately three years with negative repeat cultures for non-tuberculous mycobacteria. Conclusion: Due to the high mortality of M. xenopi infections (which can be as high as 69%), treatment of at least twelve months is recommended. To our knowledge, this is the first reported case of M. xenopi in a patient with blue rubber bleb nevus syndrome. LEARNING POINTS: The decision to initiate treatment for non-tuberculous mycobacterium infections is often challenging with prolonged treatment.Lifetime monitoring is required in patients with blue rubber bleb nevus syndrome, which can have pulmonary complications.M. xenopi has the highest mortality among non-tuberculous mycobacterium infections and requires at least 12 months of treatment.

Effect of glycocalyx-targeted therapy on vascular function in older adults: a randomized controlled trial.

Advancing age increases cardiovascular disease risk, in part, because of impaired glycocalyx thickness and endothelial dysfunction. Glycocalyx-targeted therapies, such as Endocalyx Pro, could improve both glycocalyx thickness and endothelial function in older adults; however, this has yet to be tested. We hypothesized that Endocalyx Pro supplementation would increase glycocalyx thickness and endothelial function in older adults. Twenty-three older adults aged 66 ± 7 yr (52% female) were enrolled in a randomized, double-blind, placebo-controlled, parallel-arms study to investigate the effect of 12-wk Endocalyx Pro supplementation (3,712 mg/day) on glycocalyx thickness and endothelial function. Glycocalyx thickness was assessed using the GlycoCheck, and endothelial function was determined via brachial artery flow-mediated dilation (FMD). Between-group comparisons revealed Endocalyx Pro did not increase glycocalyx thickness in microvessels 4-25 µm (P = 0.33), 4-7 µm (P = 0.07), or 10-25 µm (P = 0.47) in diameter when compared with placebo. In addition, Endocalyx Pro did not significantly improve FMD [mean ratio (95%) confidence interval [CI]) for between-group comparisons, 1.16 (0.77-1.74); P = 0.48]. However, Endocalyx Pro improved FMD normalized to shear rate (SR) area under the curve [mean ratio (95% CI) for between-group comparisons, 2.41 (1.14,4.13); P = 0.001]. Moreover, Endocalyx Pro increased capillary glycocalyx thickness more than placebo in individuals not taking antihypertensive medication [mean difference (95% CI) for between-group comparison, -0.08 (-0.15, -0.01); P = 0.02]. Our pilot study suggests that Endocalyx Pro supplementation is feasible in older adults but has no measurable effect on overall glycocalyx thickness and FMD. However, Endocalyx Pro may have select effects on capillary glycocalyx thickness and FMD normalized to shear rate among older adults, but further investigation is warranted.NEW & NOTEWORTHY Endothelial glycocalyx thickness and vascular endothelial function decline with advancing age. Endocalyx Pro is a glycocalyx-targeted therapy that may improve endothelial glycocalyx thickness and vascular endothelial function in older adults. This study demonstrated that 12-wk Endocalyx Pro supplementation did not improve overall endothelial glycocalyx thickness or flow-mediated dilation in older adults; however, Endocalyx Pro did increase capillary glycocalyx thickness in individuals not taking antihypertensive medication and improve flow-mediated dilation normalized to the shear stimulus.

Clinical pharmacology and tolerability of REC-994, a redox-cycling nitroxide compound, in randomized phase 1 dose-finding studies.

Cerebral cavernous malformation (CCM) has variable clinical symptoms, including potentially fatal hemorrhagic stroke. Treatment options are very limited, presenting a large unmet need. REC-994 (also known as tempol), identified as a potential treatment through an unbiased drug discovery platform, is hypothesized to treat CCMs through a reduction in superoxide, a reactive oxygen species. We investigated the safety, tolerability, and pharmacokinetic profile of REC-994 in healthy volunteers. Single- and multiple-ascending dose (SAD and MAD, respectively) studies were conducted in adult volunteers (ages 18-55). SAD study participants received an oral dose of REC-994 or placebo. MAD study participants were randomized 3:1 to oral doses of REC-994 or matching placebo, once daily for 10 days. Thirty-two healthy volunteers participated in the SAD study and 52 in the MAD study. Systemic exposure increased in proportion to REC-994 dose after single doses of 50-800 mg and after 10 days of dosing over the 16-fold dose range of 50-800 mg. Median Tmax and mean t1/2 were independent of dose in both studies, and the solution formulation was more rapidly absorbed. REC-994 was well tolerated. Treatment-emergent adverse effects across both studies were mild and transient and resolved by the end of the study. REC-994 has a favorable safety profile and was well tolerated in single and multiple doses up to 800 mg with no dose-limiting adverse effects identified. Data support conducting a phase 2 clinical trial in patients with symptomatic CCM.

Unveiling the Chameleon: A Case Report on Acute Intermittent Porphyria.

Acute intermittent porphyria (AIP) is a rare autosomal dominant metabolic disorder with low penetrance, often presenting with a broad spectrum of clinical manifestations. Acute neurovisceral attacks commonly occur in young women, mimicking signs and symptoms of other medical and psychiatric conditions, thus delaying the diagnosis. We present the case of an 18-year-old female college student with recurrent hospitalizations for intractable abdominal pain, now again with pain and new subjective hematuria. The patient had previously undergone an endoscopy/colonoscopy with negative biopsies and serologies for acute pathology, including celiac disease. Celiac studies were repeated, given the possibility of inadvertent gluten exposure before the onset of the latest symptoms, but were negative. Basic labs and repeat imaging, including contrast-enhanced CT, MRI, and magnetic resonance (MR) enterography of the abdomen, continued to be unremarkable, and the patient's symptoms were felt to be functional in etiology. The patient's urinalysis was normal, and pregnancy was also ruled out. The patient continued to have pain despite receiving opiate analgesics, thus prompting a psychiatry consultation. She was diagnosed with acute adjustment disorder with anxiety and was started on hydroxyzine. Due to persistent symptoms, serum and urine samples were sent, revealing low levels of porphobilinogen deaminase (PBGD) and hydroxymethylbilane synthase (HMBS) gene mutation, confirming the diagnosis of AIP. She was treated with oral glucose and outpatient IV hemin infusions with the resolution of symptoms. AIP presents a nonspecific and highly variable clinical picture, often making it a challenging diagnosis due to such a broad differential. While our patient was thought to have acute adjustment disorder due to an unremarkable initial workup, further testing revealed otherwise. This case demonstrates how clinicians must have a high suspicion of AIP when caring for young females, manifesting with neurovisceral and psychiatric signs and symptoms. Timely diagnosis improves a patient's quality of life and can decrease overutilization of healthcare resources.

Endothelial-Specific Reduction in Arf6 Impairs Insulin-Stimulated Vasodilation and Skeletal Muscle Blood Flow Resulting in Systemic Insulin Resistance in Mice.

BACKGROUND: Much of what we know about insulin resistance is based on studies from metabolically active tissues such as the liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance; however, the underlying mechanisms remain incompletely understood. Arf6 (ADP ribosylation factor 6) is a small GTPase that plays a critical role in endothelial cell function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance. METHODS: We used mouse models of constitutive endothelial cell-specific Arf6 deletion (Arf6f/- Tie2Cre+) and tamoxifen-inducible Arf6 knockout (Arf6f/f Cdh5CreER+). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose and insulin tolerance tests and hyperinsulinemic-euglycemic clamps. We used a fluorescence microsphere-based technique to measure tissue blood flow. Skeletal muscle capillary density was assessed using intravital microscopy. RESULTS: Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide bioavailability but independent of altered acetylcholine-mediated or sodium nitroprusside-mediated vasodilation. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow-fed mice and glucose intolerance in high-fat diet-fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability. CONCLUSIONS: Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.

Physiological determinants of mechanical efficiency during advanced ageing and disuse.

This study aimed to determine which physiological factors impact net efficiency (ηnet) in oldest-old individuals at different stages of skeletal muscle disuse. To this aim, we examined ηnet, central haemodynamics, peripheral circulation, and peripheral factors (skeletal muscle fibre type, capillarization and concentration of mitochondrial DNA [mtDNA]). Twelve young (YG; 25 ± 2 years), 12 oldest-old mobile (OM; 87 ± 3 years), and 12 oldest-old immobile (OI; 88 ± 4 years) subjects performed dynamic knee extensor (KE) and elbow flexors (EF) exercise. Pulmonary oxygen uptake, photoplethysmography, Doppler ultrasound and muscle biopsies of the vastus lateralis and biceps brachii were used to assess central and peripheral adaptations to advanced ageing and disuse. Compared to the YG (12.1 ± 2.4%), the ηnet of lower-limb muscle was higher in the OM (17.6 ± 3.5%, P < 0.001), and lower in the OI (8.9 ± 1.9%, P < 0.001). These changes in ηnet during KE were coupled with significant peripheral adaptations, revealing strong correlations between ηnet and the proportion of type I muscle fibres (r = 0.82), as well as [mtDNA] (r = 0.77). No differences in ηnet were evident in the upper-limb muscles between YG, OM and OI. In view of the differences in limb-specific activity across the lifespan, these findings suggest that ηnet is reduced by skeletal muscle inactivity and not by chronological age, per se. Likewise, this study revealed that the age-related changes in ηnet are not a consequence of central or peripheral haemodynamic adaptations, but are likely a product of peripheral changes related to skeletal muscle fibre type and mitochondrial density. KEY POINTS: Although the effects of ageing and muscle disuse deeply impact the cardiovascular and skeletal muscle function, the combination of these factors on the mechanical efficiency are still a matter of debate. By measuring both upper- and lower-limb muscle function, which experience differing levels of disuse, we examined the influence of central and peripheral haemodynamics, and skeletal muscle factors linked to mechanical efficiency. Across the ages and degree of disuse, upper-limb muscles exhibited a preserved work economy. In the legs the oldest-old without mobility limitations exhibited an augmented mechanical efficiency, which was reduced in those with an impairment in ambulation. These changes in mechanical efficiency were associated with the proportion of type I muscle fibres. Recognition that the mechanical efficiency is not simply age-dependent, but the consequence of inactivity and subsequent skeletal muscle changes, highlights the importance of maintaining physical activity across the lifespan.

Endothelial cell-specific reduction in mTOR ameliorates age-related arterial and metabolic dysfunction.

Systemic inhibition of the mammalian target of rapamycin (mTOR) delays aging and many age-related conditions including arterial and metabolic dysfunction. However, the mechanisms and tissues involved in these beneficial effects remain largely unknown. Here, we demonstrate that activation of S6K, a downstream target of mTOR, is increased in arteries with advancing age, and that this occurs preferentially in the endothelium compared with the vascular smooth muscle. Induced endothelial cell-specific deletion of mTOR reduced protein expression by 60-70%. Although this did not significantly alter arterial and metabolic function in young mice, endothelial mTOR reduction reversed arterial stiffening and improved endothelium-dependent dilation (EDD) in old mice, indicating an improvement in age-related arterial dysfunction. Improvement in arterial function in old mice was concomitant with reductions in arterial cellular senescence, inflammation, and oxidative stress. The reduction in endothelial mTOR also improved glucose tolerance in old mice, and this was associated with attenuated hepatic gluconeogenesis and improved lipid tolerance, but was independent of alterations in peripheral insulin sensitivity, pancreatic beta cell function, or fasted plasma lipids in old mice. Lastly, we found that endothelial mTOR reduction suppressed gene expression of senescence and inflammatory markers in endothelial-rich (i.e., lung) and metabolically active organs (i.e., liver and adipose tissue), which may have contributed to the improvement in metabolic function in old mice. This is the first evidence demonstrating that reducing endothelial mTOR in old age improves arterial and metabolic function. These findings have implications for future drug development.

Effect of acute heparin administration on glycocalyx thickness and endothelial function in healthy younger adults.

The endothelial glycocalyx is a dynamic, gel-like layer that is critical to normal vascular endothelial function. Heparin impairs the endothelial glycocalyx and reduces vascular endothelial function in a murine model; however, this has yet to be tested in healthy humans. We hypothesized that a single bolus dose of heparin would increase circulating glycocalyx components and decrease endothelial glycocalyx thickness resulting in blunted brachial artery vasodilation in healthy younger adults. Healthy adults (n = 19, aged 18-39 yr, 53% female) underwent measurements of the endothelial glycocalyx and vascular endothelial function at baseline and after a single bolus 5,000 U dose of heparin. The glycocalyx components syndecan-1 and heparan sulfate were measured from plasma samples using enzyme-linked immunosorbent assays. Glycocalyx thickness was determined as perfused boundary region (PBR) in sublingual microvessels using the GlycoCheck. Endothelial function was measured via ultrasonography and quantified as brachial artery flow-mediated dilation (FMD). Following acute heparin administration, there was no increase in syndecan-1 or heparan sulfate (P = 0.90 and P = 0.49, respectively). In addition, there was no change in PBR 4-7 µm (P = 0.55), PBR 10-25 µm (P = 0.63), or 4-25 µm (P = 0.49) after heparin treatment. Furthermore, we did not observe a change in FMDmm (P = 0.23), FMD% (P = 0.35), or plasma nitrite concentrations (P = 0.10) in response to heparin. Finally, time to peak dilation and peak FMD normalized to shear stress were unchanged following heparin (P = 0.59 and P = 0.21, respectively). Our pilot study suggests that a single bolus intravenous dose of heparin does not result in endothelial glycocalyx degradation or vascular endothelial dysfunction in healthy younger adults.NEW & NOTEWORTHY The endothelial glycocalyx's role in modulating vascular endothelial dysfunction with aging and disease is becoming increasingly recognized. This study presents novel findings that acute heparin administration is not a feasible method to experimentally degrade the endothelial glycocalyx and measure concurrent changes in vascular endothelial function in healthy humans. Alternative approaches will be needed to translate findings from preclinical studies and test the effects of acute endothelial glycocalyx degradation on vascular endothelial function in humans.

Reduction of double-strand DNA break repair exacerbates vascular aging.

Advanced age is the greatest risk factor for cardiovascular disease (CVD), the leading cause of death. Arterial function is impaired in advanced age which contributes to the development of CVD. One underexplored hypothesis is that DNA damage within arteries leads to this dysfunction, yet evidence demonstrating the incidence and physiological consequences of DNA damage in arteries, and in particular, in the microvasculature, in advanced age is limited. In the present study, we began by assessing the abundance of DNA damage in human and mouse lung microvascular endothelial cells and found that aging increases the percentage of cells with DNA damage. To explore the physiological consequences of increases in arterial DNA damage, we evaluated measures of endothelial function, microvascular and glycocalyx properties, and arterial stiffness in mice that were lacking or heterozygous for the double-strand DNA break repair protein ATM kinase. Surprisingly, in young mice, vascular function remained unchanged which led us to rationalize that perhaps aging is required to accumulate DNA damage. Indeed, in comparison to wild type littermate controls, mice heterozygous for ATM that were aged to ~18 mo (Old ATM +/-) displayed an accelerated vascular aging phenotype characterized by increases in arterial DNA damage, senescence signaling, and impairments in endothelium-dependent dilation due to elevated oxidative stress. Furthermore, old ATM +/- mice had reduced microvascular density and glycocalyx thickness as well as increased arterial stiffness. Collectively, these data demonstrate that DNA damage that accumulates in arteries in advanced age contributes to arterial dysfunction that is known to drive CVD.

Therapeutic strategies targeting the endothelial glycocalyx.

PURPOSE OF REVIEW: This review will highlight recent studies that have examined the endothelial glycocalyx in a variety of health conditions, as well as potential glycocalyx-targeted therapies. RECENT FINDINGS: A degraded glycocalyx is present in individuals that consume high sodium diet or have kidney disease, diabetes, preeclampsia, coronavirus disease 2019 (COVID-19), or sepsis. Specifically, these conditions are accompanied by elevated glycocalyx components in the blood, such as syndecan-1, syndecans-4, heparin sulfate, and enhanced heparinase activity. Impaired glycocalyx barrier function is accompanied by decreased nitric oxide bioavailability, increased leukocyte adhesion to endothelial cells, and vascular permeability. Glycocalyx degradation appears to play a key role in the progression of cardiovascular complications. However, studies that have used glycocalyx-targeted therapies to treat these conditions are scarce. Various therapeutics can restore the glycocalyx in kidney disease, diabetes, COVID-19, and sepsis. Exposing endothelial cells to glycocalyx components, such as heparin sulfate and hyaluronan protects the glycocalyx. SUMMARY: We conclude that the glycocalyx is degraded in a variety of health conditions, although it remains to be determined whether glycocalyx degradation plays a causal role in disease progression and severity, and whether glycocalyx-targeted therapies improve patient health outcomes. Future studies are warranted to investigate therapeutic strategies that target the endothelial glycocalyx.

Endothelial cell telomere dysfunction induces senescence and results in vascular and metabolic impairments.

In advanced age, increases in oxidative stress and inflammation impair endothelial function, which contributes to the development of cardiovascular disease (CVD). One plausible source of this oxidative stress and inflammation is an increase in the abundance of senescent endothelial cells. Cellular senescence is a cell cycle arrest that occurs in response to various damaging stimuli. In the present study, we tested the hypothesis that advanced age results in endothelial cell telomere dysfunction that induces senescence. In both human and mouse endothelial cells, advanced age resulted in an increased abundance of dysfunctional telomeres, characterized by activation of DNA damage signaling at telomeric DNA. To test whether this results in senescence, we selectively reduced the telomere shelterin protein telomere repeat binding factor 2 (Trf2) from endothelial cells of young mice. Trf2 reduction increased endothelial cell telomere dysfunction and resulted in cellular senescence. Furthermore, induction of endothelial cell telomere dysfunction increased inflammatory signaling and oxidative stress, resulting in impairments in endothelial function. Finally, we demonstrate that endothelial cell telomere dysfunction-induced senescence impairs glucose tolerance. This likely occurs through increases in inflammatory signaling in the liver and adipose tissue, as well as reductions in microvascular density and vasodilation to metabolic stimuli. Cumulatively, the findings of the present study identify age-related telomere dysfunction as a mechanism that leads to endothelial cell senescence. Furthermore, these data provide compelling evidence that senescent endothelial cells contribute to age-related increases in oxidative stress and inflammation that impair arterial and metabolic function.

Endothelial specific reduction in Arf6 impairs insulin-stimulated vasodilation and skeletal muscle blood flow resulting in systemic insulin resistance.

Background: Much of what we know about insulin resistance is based on studies from metabolically active tissues such as liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance, however, the underlying mechanisms remain incompletely understood. ADP ribosylation factor 6 (Arf6) is a small GTPase that plays a critical role in endothelial cell (EC) function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance. Methods: We used mouse models of constitutive EC-specific Arf6 deletion (Arf6 f/- Tie2Cre) and tamoxifen inducible Arf6 knockout (Arf6 f/f Cdh5Cre). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose- and insulin-tolerance tests and hyperinsulinemic-euglycemic clamps. A fluorescence microsphere-based technique was used to measure tissue blood flow. Intravital microscopy was used to assess skeletal muscle capillary density. Results: Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue (WAT) and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide (NO) bioavailability but independent of altered acetylcholine- or sodium nitroprusside-mediated vasodilation. In vitro Arf6 inhibition resulted in suppressed insulin stimulated phosphorylation of Akt and endothelial NO synthase. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow fed mice and glucose intolerance in high fat diet fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability. Conclusion: Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.

Constrictive Pericarditis from an Atraumatic Hemopericardium After Systemic Thrombolysis for a Massive Pulmonary Embolism.

Constrictive pericarditis most commonly results from fibrosis and adhesions of the parietal and visceral pericardium due to long-standing inflammation. Common etiologies include idiopathic, post-surgical, radiation injury and infectious etiologies including tuberculosis. Traumatic hemopericardium is a rare cause of constrictive pericarditis but atraumatic hemopericardium causing constrictive pericarditis has not been reported in the literature to date. We present a case of constrictive pericarditis from an atraumatic hemopericardium after systemic thrombolysis for a massive pulmonary embolism.

Heterozygosity for ADP-ribosylation factor 6 suppresses the burden and severity of atherosclerosis.

Atherosclerosis is the root cause of major cardiovascular diseases (CVD) such as myocardial infarction and stroke. ADP-ribosylation factor 6 (Arf6) is a ubiquitously expressed GTPase known to be involved in inflammation, vascular permeability and is sensitive to changes in shear stress. Here, using atheroprone, ApoE-/- mice, with a single allele deletion of Arf6 (HET) or wildtype Arf6 (WT), we demonstrate that reduction in Arf6 attenuates atherosclerotic plaque burden and severity. We found that plaque burden in the descending aorta was lower in HET compared to WT mice (p˂0.001) after the consumption of an atherogenic Paigen diet for 5 weeks. Likewise, luminal occlusion, necrotic core size, plaque grade, elastic lamina breaks, and matrix deposition were lower in the aortic root atheromas of HET compared to WT mice (all p≤0.05). We also induced advanced human-like complex atherosclerotic plaque in the left carotid artery using partial carotid ligation surgery and found that atheroma area, plaque grade, intimal necrosis, intraplaque hemorrhage, thrombosis, and calcification were lower in HET compared to WT mice (all p≤0.04). Our findings suggest that the atheroprotection afforded by Arf6 heterozygosity may result from reduced immune cell migration (all p≤0.005) as well as endothelial and vascular smooth muscle cell proliferation (both p≤0.001) but independent of changes in circulating lipids (all p≥0.40). These findings demonstrate a critical role for Arf6 in the development and severity of atherosclerosis and suggest that Arf6 inhibition can be explored as a novel therapeutic strategy for the treatment of atherosclerotic CVD.

The role of hyaluronan in endothelial glycocalyx and potential preventative lifestyle strategy with advancing age.

The endothelial glycocalyx (EG) is a gel-like structure that forms a layer in between the surface of the endothelium and lumen. EG was once thought to be merely a structural support for the endothelium. However, in recent years, the importance of EG as a first line of defense and a key regulator to endothelial integrity has been illuminated. With advanced age, EG deterioration becomes more noticeable and at least partially associated with endothelial dysfunction. Hyaluronan (HA), one of the critical components of the EG, has distinct properties and roles to the maintenance of EG and endothelial function. Therefore, given the intimate relationship between the EG and endothelium during the aging process, HA may serve as a promising therapeutic target to prevent endothelial dysfunction.

Sex differences in atrial fibrillation ablation in-hospital outcomes from the National Inpatient Sample database 2016-2019.

Background: Research has shown mixed results when comparing in-hospital complications following atrial fibrillation ablation in women compared to men. Objectives: To better quantify sex differences and in-hospital outcomes in atrial fibrillation ablation procedures and identify factors associated with poorer outcomes. Methods: We queried the NIS database from 2016 to 2019 for hospitalizations with a primary diagnosis of atrial fibrillation ablation and excluded patients with any other arrhythmias, ICD/pacemaker placement. We assessed demographics, in-hospital mortality, and complications of women compared to men. Results: Admissions for atrial fibrillation were more common in females than males (849 050 vs. 815 665; p < .001). However, females were less likely to receive ablation (1.65% vs. 2.71%, OR: 0.60; 95% confidence interval: 0.57-0.64, p < .001), which persisted after adjusting for cardiomyopathy (adjusted OR: 0.61; 95% confidence interval: 0.58-0.65, p < .001). The primary outcome of in-hospital mortality was not statistically different in univariate analysis (0.39% vs. 0.36%, OR: 1.09, 95% CI: 0.44-2.72, p = .84), finding that did not change when adjusted for comorbidities (adjusted OR: 0.94, 95% CI: 0.36-2.49). The complication rate in hospitalized patients following ablation was 8.08%. The total unadjusted complication rate was higher for females than males (9.58% vs. 7.09%, p = .001); however, it was not significant when adjusted for risks (adjusted OR: 1.23, 95% CI: 0.99-1.53, p = .06). Conclusion: Female sex is not associated with increased complications or death in a real-world study of catheter ablation when results are adjusted for risks. However, females admitted with atrial fibrillation receive ablation less often than males during hospital admission.

Glycocalyx-targeted therapy ameliorates age-related arterial dysfunction.

Advanced age is accompanied by arterial dysfunction, as well as a diminished glycocalyx, which may be linked to reduced high molecular weight-hyaluronan (HMW-HA) synthesis. However, the impact of glycocalyx deterioration in age-related arterial dysfunction is unknown. We sought to determine if manipulations in glycocalyx properties would alter arterial function. Tamoxifen-induced hyaluronan synthase 2 (Has2) reduction was used to decrease glycocalyx properties. Three weeks post-tamoxifen treatment, glycocalyx thickness was lower in Has2 knockout compared to wild-type mice (P<0.05). Has2 reduction induced arterial dysfunction, demonstrated by impaired endothelium-dependent dilation (EDD) and elevated aortic stiffness (P<0.05). To augment glycocalyx properties, old mice received 10 weeks of a glycocalyx-targeted therapy via Endocalyx™ (old+ECX), which contains HMW-HA and other glycocalyx components. Compared to old control mice, glycocalyx properties and EDD were augmented, and aortic stiffness decreased in old+ECX mice (P<0.05). Old+ECX mice had a more youthful aortic phenotype, demonstrated by lower collagen content and higher elastin content than old control mice (P<0.05). Functional outcomes were repeated in old mice that underwent a diet supplemented solely with HMW-HA (old+HA). Compared to old controls, glycocalyx properties and EDD were augmented, and aortic stiffness was lower in old+HA mice (P<0.05). We did not observe any differences between old+HA and old+ECX mice (P>0.05). Has2 reduction phenocopies age-related arterial dysfunction, while 10 weeks of glycocalyx-targeted therapy that restores the glycocalyx also ameliorates age-related arterial dysfunction. These findings suggest that the glycocalyx may be a viable therapeutic target to ameliorate age-related arterial dysfunction.

In type 2 diabetes, glargine and liraglutide each improved glycemic outcomes at 5 y vs. glimepiride or sitagliptin.

SOURCE CITATION: GRADE Study Research Group; Nathan DM, Lachin JM, Balasubramanyam A, et al. Glycemia reduction in type 2 diabetes-glycemic outcomes. N Engl J Med. 2022;387:1063-74. 36129996.

In type 2 diabetes, liraglutide reduced CV events at 5 y vs. glargine, glimepiride, or sitagliptin.

SOURCE CITATION: GRADE Study Research Group; Nathan DM, Lachin JM, Buse JB, et al. Glycemia reduction in type 2 diabetes-microvascular and cardiovascular outcomes. N Engl J Med. 2022;387:1075-88. 36129997.

Senolytic drugs, dasatinib and quercetin, attenuate adipose tissue inflammation, and ameliorate metabolic function in old age.

Aging results in an elevated burden of senescent cells, senescence-associated secretory phenotype (SASP), and tissue infiltration of immune cells contributing to chronic low-grade inflammation and a host of age-related diseases. Recent evidence suggests that the clearance of senescent cells alleviates chronic inflammation and its associated dysfunction and diseases. However, the effect of this intervention on metabolic function in old age remains poorly understood. Here, we demonstrate that dasatinib and quercetin (D&Q) have senolytic effects, reducing age-related increase in senescence-associated ß-galactosidase, expression of p16 and p21 gene and P16 protein in perigonadal white adipose tissue (pgWAT; all p ≤ 0.04). This treatment also suppressed age-related increase in the expression of a subset of pro-inflammatory SASP genes (mcp1, tnf-α, il-1α, il-1ß, il-6, cxcl2, and cxcl10), crown-like structures, abundance of T cells and macrophages in pgWAT (all p ≤ 0.04). In the liver and skeletal muscle, we did not find a robust effect of D&Q on senescence and inflammatory SASP markers. Although we did not observe an age-related difference in glucose tolerance, D&Q treatment improved fasting blood glucose (p = 0.001) and glucose tolerance (p = 0.007) in old mice that was concomitant with lower hepatic gluconeogenesis. Additionally, D&Q improved insulin-stimulated suppression of plasma NEFAs (p = 0.01), reduced fed and fasted plasma triglycerides (both p ≤ 0.04), and improved systemic lipid tolerance (p = 0.006). Collectively, results from this study suggest that D&Q attenuates adipose tissue inflammation and improves systemic metabolic function in old age. These findings have implications for the development of therapeutic agents to combat metabolic dysfunction and diseases in old age.