Endothelial Cell Inflammation and Antioxidant Capacity are Associated With 6-Minute Walk Performance in Patients With Symptomatic Peripheral Artery Disease

Novel components in the nuclear factor-kappa B (NF-κB) signaling pathways of endothelial cells under hyperglycemic-ischemic conditions

Diabetes worsens the outcomes of a number of vascular disorders including peripheral arterial disease (PAD) at least in part through induction of chronic inflammation. However, in experimental PAD, recovery requires the nuclear factor-kappa B (NF-κB) activation. Previously we showed that individually, both ischemia and high glucose activate the canonical and non-canonical arms of the NF-κB pathway, but prolonged high glucose exposure specifically impairs ischemia-induced activation of the canonical NF-κB pathway through activation of protein kinase C beta (PKCβ). Although a cascade of phosphorylation events propels the NF-κB signaling, little is known about the impact of hyperglycemia on the canonical and non-canonical NF-κB pathway signaling. Moreover, signal upstream of PKCβ that lead to its activation in endothelial cells during hyperglycemia exposure have not been well defined. In this study, we used endothelial cells exposed to hyperglycemia and ischemia (HGI) and an array of approximately 250 antibodies to approximately 100 proteins and their phosphorylated forms to identify the NF-κB signaling pathway that is altered in ischemic EC that has been exposed to high glucose condition. Comparison of signals from hyperglycemic and ischemic cell lysates yielded a number of proteins whose phosphorylation was either increased or decreased under HGI conditions. Pathway analyses using bioinformatics tools implicated BLNK/BTK known for B cell antigen receptor (BCR)-coupled signaling. Inhibition of BLNK/BTK in endothelial cells by a specific pharmacological inhibitor terreic acid attenuated PKC activation and restored the IκBα degradation suggesting that these molecules play a critical role in hyperglycemic attenuation of the canonical NF-κB pathway. Thus, we have identified a potentially new component of the NF-κB pathway upstream of PKC in endothelial cells that contributes to the poor post ischemic adaptation during hyperglycemia.

Physiological responses during walking in men and women with intermittent claudication

BACKGROUND

Miyasato et al. show that peak oxygen consumption, walking economy, anaerobic threshold, and cardiovascular responses (heart rate, blood pressure, and rate pressure product) during walking were similar between men and women with peripheral artery disease and intermittent claudication. There were no differences in the physiological responses to walking between men and women with intermittent claudication. Sex per se is not a factor that demands changes in walking prescription for patients with intermittent claudication.

OBJECTIVE

Peak oxygen consumption (VO2peak), anaerobic threshold, walking economy, and cardiovascular responses during walking are used to guide and monitor walking training in patients with peripheral artery disease and intermittent claudication. Women with peripheral artery disease and intermittent claudication present greater impairments than men, and evaluating training markers according to sex for decisions regarding walking prescription in this population is important. This study aimed to compare VO2peak, walking economy, anaerobic threshold, and cardiovascular responses during walking in men and women with peripheral artery disease and intermittent claudication.

METHODS

Forty patients (20 men and 20 women with similar baseline characteristics) underwent a cardiopulmonary treadmill test (3.2km/h and 2% increase in slope every 2 minutes until maximal leg pain). The VO2 and rate-pressure product were assessed. Data from men and women were compared using t-tests.

RESULTS

There were no significant differences between men and women (VO2peak: 15.0±4.8 versus 13.9±2.9mL∙kg-1∙min-1, p=0.38; walking economy: 9.6±2.7 versus 8.4±1.6mL∙kg-1∙min-1, p=0.09; anaerobic threshold: 10.5±3.2 versus 10.5±2.2mL∙kg-1∙min-1, p=0.98; rate pressure product at 1st stage: 13,465± 2,910 versus 14,445±4,379bpm∙mmHg, p=0.41; and rate pressure product at anaerobic threshold:13,673±3,100 versus 16,390±5,870bpm∙mmHg, p=0.08 and rate pressure product at peak exercise: 21,253±6,141 versus 21,923±7,414bpm∙mmHg, p=0.76, respectively).

CONCLUSION

Men and women with peripheral artery disease and similar baseline characteristics presented similar responses to walking, suggesting that decisions regarding walking prescription and monitoring can be made regardless of sex in this specific population.

Natural Activators of Autophagy Increase Maximal Walking Distance and Reduce Oxidative Stress in Patients with Peripheral Artery Disease: A Pilot Study

Trehalose, spermidine, nicotinamide, and polyphenols have been shown to display pro-autophagic and antioxidant properties, eventually reducing cardiovascular and ischemic complications. This study aimed to investigate whether a mixture of these components improves maximal walking distance (MWD) in peripheral artery disease (PAD) patients. Nitrite/nitrate (NOx), endothelin-1, sNOX2-dp, H2O2 production, H2O2 break-down activity (HBA), ATG5 and P62 levels, flow-mediated dilation (FMD), and MWD were evaluated in 20 PAD patients randomly allocated to 10.5 g of mixture or no-treatment in a single-blind study. The above variables were assessed at baseline and 60 days after mixture ingestion. Compared with baseline, mixture intake significantly increased MWD (+91%; p < 0.01) and serum NOx (+96%; p < 0.001), whereas it significantly reduced endothelin-1 levels (−30%, p < 0.01). Moreover, mixture intake led to a remarkable reduction in sNOX2dp (−31%, p < 0.05) and H2O2 (−40%, p < 0.001) and potentiated antioxidant power (+110%, p < 0.001). Finally, mixture ingestion restored autophagy by increasing ATG5 (+43%, p < 0.01) and decreasing P62 (−29%, p < 0.05). No changes in the above-mentioned variables were observed in the no-treatment group. The treatment with a mixture of trehalose, spermidine, nicotinamide, and polyphenols improves MWD in PAD patients, with a mechanism possibly related to NOX2-mediated oxidative stress downregulation and autophagic flux upregulation. Clinical Trial Registration unique identifier: NCT04061070.

Influence of Peripheral Transluminal Angioplasty Alongside Exercise Training on Oxidative Stress and Inflammation in Patients with Peripheral Arterial Disease

In patients with intermittent claudication, exercise training ameliorates inflammation by reducing oxidative stress. A total of 41 patients with intermittent claudication (Rutherford 3) were included in the study (with 21 patients treated by endovascular revascularization (ER), and 20 patients without ER). All patients were referred to home-based exercise training. Absolute and initial claudication distance (ACD, ICD) and ABI (ankle–brachial index) were measured. ROS (reactive oxygen species) formation was measured using the luminol analogue L-012. Follow-up was performed after 3 months. ROS production after NOX2 (NAPDH oxidase 2) stimulation showed a significant reduction in both groups at follow-up (PTA group: p = 0.002, control group: p = 0.019), with a higher relative reduction in ROS in the PTA group than in the control group (p = 0.014). ABI measurements showed a significant increase in the PTA (peripheral transluminal angioplasty) group (p = 0.001), but not in the control group (p = 0.127). Comparing both groups at follow-up, ABI was higher in the PTA group (p = 0.047). Both groups showed a significant increas ACD and ICD at follow-up (PTA group: ACD: p = 0.001, ICD: p < 0.0001; control group: ACD: p = 0.041, ICD: p = 0.002). There was no significant difference between both groups at follow-up (ACD: p = 0.421, ICD: p = 0.839). Endovascular therapy in combination with exercise training leads to a lower leukocyte activation state with a reduced NOX2-derived ROS production paralleled by an improved ABI, ACD and ICD. Our data support the strategy to combine exercise training with preceding endovascular therapy.

Principles of brain aging: Status and challenges of modeling human molecular changes in mice

Due to the extension of human life expectancy, the prevalence of cognitive impairment is rising in the older portion of society. Developing new strategies to delay or attenuate cognitive decline is vital. For this purpose, it is imperative to understand the cellular and molecular events at the basis of brain aging. While several organs are directly accessible to molecular analysis through biopsies, the brain constitutes a notable exception. Most of the molecular studies are performed on postmortem tissues, where cell death and tissue damage have already occurred. Hence, the study of the molecular aspects of cognitive decline largely relies on animal models and in particular on small mammals such as mice. What have we learned from these models? Do these animals recapitulate the changes observed in humans? What should we expect from future mouse studies? In this review we answer these questions by summarizing the state of the research that has addressed cognitive decline in mice from several perspectives, including genetic manipulation and omics strategies. We conclude that, while extremely valuable, mouse models have limitations that can be addressed by the optimal design of future studies and by ensuring that results are cross-validated in the human context.

Acute effects of leg heat therapy on walking performance and cardiovascular and inflammatory responses to exercise in patients with peripheral artery disease

Lower-extremity peripheral artery disease (PAD) is associated with increased risk of cardiovascular events and impaired exercise tolerance. We have previously reported that leg heat therapy (HT) applied using liquid-circulating trousers perfused with warm water increases leg blood flow and reduces blood pressure (BP) and the circulating levels of endothelin-1 (ET-1) in patients with symptomatic PAD. In this sham-controlled, randomized, crossover study, sixteen patients with symptomatic PAD (age 65 ± 5.7 years and ankle-brachial index: 0.69 ± 0.1) underwent a single 90-min session of HT or a sham treatment prior to a symptom-limited, graded cardiopulmonary exercise test on the treadmill. The primary outcome was the peak walking time (PWT) during the exercise test. Secondary outcomes included the claudication onset time (COT), resting and exercise BP, calf muscle oxygenation, pulmonary oxygen uptake (V̇O2 ), and plasma levels of ET-1, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Systolic, but not diastolic BP, was significantly lower (~7 mmHg, p < .05) during HT when compared to the sham treatment. There was also a trend for lower SBP throughout the exercise and the recovery period following HT (p = .057). While COT did not differ between treatments (p = .77), PWT tended to increase following HT (CON: 911 ± 69 s, HT: 954 ± 77 s, p = .059). Post-exercise plasma levels of ET-1 were also lower in the HT session (CON: 2.0 ± 0.1, HT: 1.7 ± 0.1, p = .02). Calf muscle oxygenation, V̇O2 , COT, IL-6, and TNF-α did not differ between treatments. A single session of leg HT lowers BP and post-exercise circulating levels of ET-1 and may enhance treadmill walking performance in symptomatic PAD patients.