Forearm vasoreactivity in type 1diabetic subjects

Early Endothelial Dysfunction in Type 1 Diabetes Is Accompanied by an Impairment of Vascular Smooth Muscle Function: A Meta-Analysis

Background: A large yet heterogeneous body of literature exists suggesting that endothelial dysfunction appears early in type 1 diabetes, due to hyperglycemia-induced oxidative stress. The latter may also affect vascular smooth muscles (VSM) function, a layer albeit less frequently considered in that pathology. This meta-analysis aims at evaluating the extent, and the contributing risk factors, of early endothelial dysfunction, and of the possible concomitant VSM dysfunction, in type 1 diabetes. Methods: PubMed, Web of Sciences, Cochrane Library databases were screened from their respective inceptions until October 2019. We included studies comparing vasodilatory capacity depending or not on endothelium (i.e., endothelial function or VSM function, respectively) in patients with uncomplicated type 1 diabetes and healthy controls. Results: Fifty-eight articles studying endothelium-dependent function, among which 21 studies also assessed VSM, were included. Global analyses revealed an impairment of standardized mean difference (SMD) (Cohen's d) of endothelial function: -0.61 (95% CI: -0.79, -0.44) but also of VSM SMD: -0.32 (95% CI: -0.57, -0.07). The type of stimuli used (i.e., exercise, occlusion-reperfusion, pharmacological substances, heat) did not influence the impairment of the vasodilatory capacity. Endothelial dysfunction appeared more pronounced within macrovascular than microvascular beds. The latter was particularly altered in cases of poor glycemic control [HbA_1c > 67 mmol/mol (8.3%)]. Conclusions: This meta-analysis not only corroborates the presence of an early impairment of endothelial function, even in response to physiological stimuli like exercise, but also highlights a VSM dysfunction in children and adults with type 1 diabetes. Endothelial dysfunction seems to be more pronounced in large than small vessels, fostering the debate on their relative temporal appearance.

Cardiovascular function is related to neuromuscular performance in Parkinson's disease

Aim: The current study examined the relationship of handgrip, leg and arm neuromuscular performance with cardiovascular function in patients with Parkinson's disease (PD). Materials & methods: Blood pressure, vascular measures and handgrip, shoulder and leg neuromuscular performance were obtained in PD persons and healthy controls. Results: The data reveal that muscular and cardiovascular functions are altered (p < 0.05) in PD. Most importantly, regression indicates that altered central and peripheral cardiovascular function measures demonstrate a moderately strong relationship (p < 0.05) with deteriorated handgrip (R2-range = 0.196–0.257), shoulder (R2-range = 0.146–0.289) and leg (R2-range = 0.19–0.35) neuromuscular performance in PD. Conclusion: These results suggest that deteriorated neuromuscular performance and cardiovascular function are related in PD. Future studies are needed to determine that developing muscular strength might contribute to improving cardiovascular function in PD.

Altered cardiovascular function is related to reduced BDNF in Parkinson's disease

Brain-derived neurotrophic factor (BDNF) has been linked to cardiovascular health and function, however, the exact role is yet to be understood. The current study examined the relationship of circulatory BDNF with vascular function in Parkinson's disease (PD). ELISA was used to determine plasma BDNF in PD patients and healthy control (CT). Additionally, forearm resting blood flow (RBf), vascular resistance (RVr), venous capacitance (RVc), and venous outflow (RVo) as well as post occlusion blood flow (OcBf), vascular resistance (OcVr), venous capacitance (OcVc), and venous outflow (OcVo) were obtained using strain-gauge plethysmography. Simple linear regression showed that being PD patient can predict (p < 0.05) 12.9% of BDNF, 16.8% of RVc, 15.0% of OcVc, and 13.6% of OcVo. Subsequent stepwise regression included BDNF, RVc, OcVc, and OcVo, showed that being PD patient predicted (p < 0.05) 58.0% of BDNF, 47.7% of OcVo, and 15.1% of OcVc. Another simple linear regression demonstrated that BDNF predicted (p < 0.05) 18.5% of OcBf, 22.0% of OcVr, and 24.1% of OcVc in PD. In a subsequent stepwise linear regression, BDNF explained 26% ofOcVr (p = 0.008) and 42% of OcVc (p = 0.002) in PD. The study showed that BDNF is reduced and related to altered vascular function in PD. The results suggest that BDNF might contribute to preserving and maybe improving vascular function in PD.

Dysregulated metabolism contributes to oncogenesis

Cancer is a disease characterized by unrestrained cellular proliferation. In order to sustain growth, cancer cells undergo a complex metabolic rearrangement characterized by changes in metabolic pathways involved in energy production and biosynthetic processes. The relevance of the metabolic transformation of cancer cells has been recently included in the updated version of the review "Hallmarks of Cancer", where dysregulation of cellular metabolism was included as an emerging hallmark. While several lines of evidence suggest that metabolic rewiring is orchestrated by the concerted action of oncogenes and tumor suppressor genes, in some circumstances altered metabolism can play a primary role in oncogenesis. Recently, mutations of cytosolic and mitochondrial enzymes involved in key metabolic pathways have been associated with hereditary and sporadic forms of cancer. Together, these results demonstrate that aberrant metabolism, once seen just as an epiphenomenon of oncogenic reprogramming, plays a key role in oncogenesis with the power to control both genetic and epigenetic events in cells. In this review, we discuss the relationship between metabolism and cancer, as part of a larger effort to identify a broad-spectrum of therapeutic approaches. We focus on major alterations in nutrient metabolism and the emerging link between metabolism and epigenetics. Finally, we discuss potential strategies to manipulate metabolism in cancer and tradeoffs that should be considered. More research on the suite of metabolic alterations in cancer holds the potential to discover novel approaches to treat it.

Modulation of circulating angiogenic factors and tumor biology by aerobic training in breast cancer patients receiving neoadjuvant chemotherapy

Aerobic exercise training (AET) is an effective adjunct therapy to attenuate the adverse side-effects of adjuvant chemotherapy in women with early breast cancer. Whether AET interacts with the antitumor efficacy of chemotherapy has received scant attention. We carried out a pilot study to explore the effects of AET in combination with neoadjuvant doxorubicin-cyclophosphamide (AC+AET), relative to AC alone, on: (i) host physiology [exercise capacity (VO2 peak), brachial artery flow-mediated dilation (BA-FMD)], (ii) host-related circulating factors [circulating endothelial progenitor cells (CEP) cytokines and angiogenic factors (CAF)], and (iii) tumor phenotype [tumor blood flow ((15)O-water PET), tissue markers (hypoxia and proliferation), and gene expression] in 20 women with operable breast cancer. AET consisted of three supervised cycle ergometry sessions/week at 60% to 100% of VO2 peak, 30 to 45 min/session, for 12 weeks. There was significant time × group interactions for VO2 peak and BA-FMD, favoring the AC+AET group (P < 0.001 and P = 0.07, respectively). These changes were accompanied by significant time × group interactions in CEPs and select CAFs [placenta growth factor, interleukin (IL)-1β, and IL-2], also favoring the AC+AET group (P < 0.05). (15)O-water positron emission tomography (PET) imaging revealed a 38% decrease in tumor blood flow in the AC+AET group. There were no differences in any tumor tissue markers (P > 0.05). Whole-genome microarray tumor analysis revealed significant differential modulation of 57 pathways (P < 0.01), including many that converge on NF-κB. Data from this exploratory study provide initial evidence that AET can modulate several host- and tumor-related pathways during standard chemotherapy. The biologic and clinical implications remain to be determined.

Vascular function and handgrip strength in rheumatoid arthritis patients

OBJECTIVE

To examine the relationship of handgrip strength with forearm blood flow (BF) and vascular resistance (VR) in rheumatoid arthritis (RA) patients.

METHODS

Forearm BF at rest (RBF) and after upper arm occlusion (RHBF), and handgrip strength were examined in 78 individuals (RA = 42 and controls (CT) = 36). Subsequently, VR at rest (RVR) and after occlusion (RHVR) were calculated.

RESULTS

The patients' RBF (P = 0.02) and RHBF (P = 0.0001) were less, whereas RVR (P = 0.002) and RHVR (P = 0.0001) were greater as compared to the CTs. Similarly, handgrip strength was lower in the RAs (P = 0.0001). Finally, handgrip strength was directly associated with RBF (r = 0.43; P = 0.0001), and RHBF (r = 0.5; P = 0.0001), and inversely related to RVR (r = -0.3; P = 0.009) and RHVR (r = -0.3; P = 0.007).

CONCLUSION

The present study uniquely identifies an association between regional measures of forearm blood flow and handgrip strength in patients and healthy control. In addition, this study confirms the presence of vascular and muscle dysfunction in patients with rheumatoid arthritis, as evidenced by lower forearm blood flow indices, at rest and following occlusion, and lower handgrip strength as compared to healthy individuals.

Forearm vasoconstrictor response in uncomplicated type 1 diabetes mellitus

BACKGROUND

According to the 'haemodynamic hypothesis', increased tissue perfusion predisposes to microangiopathy in diabetic patients. We hypothesized that the typical haemodynamic changes underlying the increased tissue perfusion can be explained by a decreased sympathetic nerve activity caused by chronic hyperglycaemia. In this study we investigated sympathetic activity in patients with uncomplicated type 1 diabetes mellitus (DM).

MATERIALS AND METHODS

In 15 DM patients (DM duration 6.3 +/- 3.8 year; HbA1c 7.9 +/- 1.3%) and 16 age- and sex-matched healthy volunteers (Control), sympathetic nervous system activity was measured at rest (baseline) and during sympathoneural stimulation (lower body negative pressure (LBNP)) by means of interstitial and plasma noradrenaline (NA) sampling and power spectral analysis. Muscle sympathetic nerve activity (MSNA) was measured before (baseline) and during a cold pressure test. Forearm blood flow was measured during forearm vascular alpha- and beta-adrenergic receptor blockade.

RESULTS

At baseline, forearm vascular resistance (FVR), plasma NA concentrations, MSNA and heart rate variability were similar in both groups. LBNP-induced vasoconstriction was significantly attenuated in the DM group compared with the Control group (DeltaFVR: 12 +/- 4 vs. 19 +/- 3 arbitrary units, P < 0.05). The responses of plasma NA and heart rate variability did not differ.

CONCLUSIONS

Baseline FVR and sympathetic nerve activity are normal in patients with uncomplicated type 1 diabetes. However, the forearm vasoconstrictor response to sympathetic stimulation is attenuated, which cannot be attributed to an impaired sympathetic responsiveness.

Influence of venous function on exercise tolerance in chronic heart failure

PURPOSE

The clinical phase of chronic heart failure (HF) includes a marked decline in exercise tolerance, in part due to impaired skeletal muscle blood flow delivery. Interestingly, the role of the venous system on exercise tolerance in patients with HF has not received much attention, despite evidence of changes in venous structure and function. The purpose of this study was to examine the relationship between forearm arterial and venous function, and exercise tolerance in patients with HF and age-matched controls.

METHODS

Vascular function and exercise tolerance was examined in 20 patients with HF (age 59 +/- 13 years) and 10 control subjects (age 51 +/- 16 years). Nondominant forearm arterial inflow, vascular resistance, venous capacitance, and venous outflow were evaluated at rest and after 5 minutes of upper arm occlusion, using strain gauge plethysmography. Exercise tolerance was measured as the maximum walking distance achieved on a 6-minute walking test.

RESULTS

Maximum walking distance (HF: 178 +/- 65 m; controls: 562 +/- 136 m, P=.0001), and forearm vascular function after occlusion were significantly different between groups (forearm arterial inflow: HF 15.3 +/- 6; controls 22 +/- 6.7; forearm venous capacitance: HF 1.4 +/- 0.5; controls 2.0 +/- 0.4; forearm venous outflow: HF 24.5 +/- 9.4; controls: 33 +/- 10 mL x 100 mL tissue(-1) x min(-1); and forearm vascular resistance: HF 7.8 +/- 3; controls 4.6 +/- 1.4 U). Correlation analysis revealed significant associations between all forearm vascular measurements after occlusion and maximum walking distance.

CONCLUSION

These data confirm previous studies indicating the importance of arterial reactivity on exercise tolerance in patients with HF. Additionally, the results suggest the importance of venous function as a contributing factor to exercise performance.