Iontophoresis Of Acetylcholine Research Articles

Role of cyclooxygenase in the vascular response to locally delivered acetylcholine in Caucasian and African descent individuals

IntroductionIndividuals of African descent (AFD) are more susceptible to non-freezing cold injury (NFCI) compared with Caucasian individuals (CAU). Vasodilatation to acetylcholine (ACh) is lower in AFD compared with CAU in the non-glabrous foot and finger skin sites; the reason for this is unknown. Prostanoids are responsible, in part, for the vasodilator response to ACh, however it is not known whether the contribution differs between ethnicities. Methods12 CAU and 12 AFD males received iontophoresis of ACh (1 w/v%) on non-glabrous foot and finger skin sites following placebo and then aspirin (600mg, single blinded). Aspirin was utilised to inhibit prostanoid production by inhibiting the cyclooxygenase (COX) enzyme. Laser Doppler flowmetry was utilised to measure changes in skin blood flow. ResultsNot all participants could receive iontophoresis charge due to high skin resistance; these participants were therefore excluded from the analyses.Foot: ACh elicited greater maximal vasodilatation in CAU than AFD following placebo (P=0.003) and COX inhibition (COXib) (P<0.001). COXib did not affect blood flow responses in AFD, but caused a reduction in the area under the curve for CAU (P=0.031).Finger: ACh elicited a greater maximal vasodilatation in CAU than AFD following placebo (P=0.013) and COXib (P=0.001). COXib tended to reduce the area under the curve in AFD (P=0.053), but did not affect CAU. ConclusionsCAU have a greater endothelial reactivity than AFD in both foot and finger skin sites irrespective of COXib. It is concluded that the lower ACh-induced vasodilatation in AFD is not due to a compromised COX pathway.

Assessment of microvascular endothelial function in type 1 diabetes using laser speckle contrast imaging

ObjectiveTo test whether laser speckle contrast imaging (LSCI) coupled with physiological post-occlusive reactive hyperemia (PORH) and pharmacological iontophoresis of acetylcholine (ACh) as local vasodilator stimuli could distinguish between cutaneous microvascular responses of Type 1 Diabetes (T1DM)’s patients with endothelial dysfunction and that of healthy controls. MethodsPatients with T1DM aged ≥12years completed a clinical-epidemiological questionnaire. Data detailing patients' such as daily insulin dose, duration of diabetes, and use of pharmaceuticals such as antihypertensive drugs and statins that could interfere with endothelial function were obtained. Vascular reactivity was assessed in the forearm by LSCI and PORH at baseline and during iontophoresis of ACh using increasing anodic currents of 30, 60, 90, 120, 150 and 180μA in 10second intervals. ResultsThis study included 50 patients with T1DM and 30 control subjects. The mean resting flux did not differ between patients and control subjects. T1DM patients exhibited endothelial dysfunction upon challenge with physiological or pharmacological stimuli. The microvascular response to both ACh and PORH (i.e., maximum response at peak and amplitude) were significantly reduced in patients with diabetes compared with control subjects (p<0.001). ConclusionWe demonstrated that endothelium-dependent skin microvascular vasodilator responses are significantly impaired in patients with T1DM compared to healthy subjects investigated using LSCI coupled with ACh iontophoresis and PORH. Additionally, we find that LSCI is a promising methodology for studying physiological vascular reactivity in T1DM.

Cutaneous Autonomic Pilomotor Testing to Unveil the Role of Neuropathy Progression in Early Parkinson's Disease (CAPTURE PD): Protocol for a Multicenter Study.

In Parkinson's disease (PD), alpha-synuclein accumulation in cutaneous autonomic pilomotor and sudomotor nerve fibers has been linked to autonomic nervous system disturbances even in the early stages of the disease. This study aims to assess the association between alpha-synuclein-mediated structural autonomic nerve fiber damage and function in PD, elucidate the role of neuropathy progression during the early disease stages, and test reproducibility and external validity of pilomotor function assessment using quantitative pilomotor axon-reflex test and sudomotor function via quantitative direct and indirect test of sudomotor function. A prospective controlled study will be conducted at four study sites in Europe and the USA. Fifty-two male and female patients with idiopathic PD (Hoehn and Yahr 1-2) and 52 age- and sex-matched healthy controls will be recruited. Axon-reflex-mediated pilomotor erection will be induced by iontophoresis of phenylephrine on the dorsal forearm. Silicone impressions of the response will be obtained, scanned, and quantified for pilomotor muscle impressions by number, impression size, and area of axon-reflex spread. Axon-reflex-mediated sweating following acetylcholine iontophoresis will be quantified for number and size of droplets and axon-reflex spread. Sympathetic skin responses, autonomic and motor symptoms will be evaluated. Tests will be performed at baseline, after 2 weeks, 1, 2, and 3 years. Skin biopsies will be obtained at baseline and after 3 years and will be analyzed for nerve fiber density and alpha-synuclein accumulation. We anticipate that progression of autonomic nerve dysfunction assessed via pilomotor and sudomotor axon-reflex tests is related to progression of autonomic symptom severity and alpha-synuclein deposition. Potential applications of the techniques include interventional studies evaluating disease-modifying approaches and clinical assessment of autonomic dysfunction in patients with PD. TRN NCT03043768.

Fetal growth is associated with first-trimester maternal vascular function.

To investigate the relationship between maternal endothelial function in the first trimester, assessed in both the brachial artery and the forearm skin microcirculation, and fetal growth. Vascular function was assessed in 56 pregnant women during gestational weeks 11-14. Vascular reactivity in the brachial artery was evaluated by postischemic hyperemia-induced flow-mediated vasodilatation (FMD) and by vasodilatation following administration of sublingual glyceryl trinitrate (GTN). Forearm skin microcirculation was investigated by laser Doppler perfusion imaging during iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to assess endothelium-dependent and -independent microvascular vasodilatation, respectively. Fetal growth was measured at study inclusion and birth-weight centile was calculated after delivery. FMD and GTN-induced vasodilatation were both associated with birth-weight centile. On multivariate analysis (adjusted for brachial artery diameter at rest, blood pressure, maternal age and heart rate), for FMD β = 1.7 (95% CI, 0.06-3.34), r2 = 0.26 and P = 0.042, and for GTN-induced vasodilatation β = 2.6 (95% CI, 0.44-4.68), r2 = 0.15 and P = 0.02. Endothelium-dependent and -independent microvascular reactivity were also associated with birth-weight centile: for ACh β = 7.82 (95% CI, 1.81-13.83), r2 = 0.12 and P = 0.029, and for SNP β = 6.27 (95% CI, 1.20-11.34), r2 = 0.11 and P = 0.016. First-trimester maternal vascular dilatation capacity (rather than endothelial function alone) is associated with fetal growth. These findings were consistent in both the brachial artery and the forearm skin microcirculation. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

PP.12.06] PENILE MICROVASCULAR ENDOTHELIAL FUNCTION IN HYPERTENSIVE PATIENTS

Objective: The primary aim of this study was to test penile endothelial microvascular function in patients with treated arterial hypertension, compared to an age-matched group of normotensive subjects using laser speckle contrast imaging (LSCI). Additionally, we tested the acute penile microvascular effects induced by the oral administration of the phosphodiesterase type 5 inhibitor sildenafil citrate (SIL). Design and method: Endothelium-dependent penile microvascular reactivity of hypertensive patients (aged 58.8 ± 6.6 years, n = 34) and age-matched healthy volunteers (n = 33) was evaluated at rest and 60 minutes following oral administration of SIL (100 mg). LSCI was coupled with the cutaneous iontophoresis of acetylcholine (ACh) using increasing anodal currents. The measurements of skin blood flow (arbitrary perfusion units, APU) were divided by values of mean arterial pressure to give the cutaneous vascular conductance (CVC) in APU/mmHg. Results: Office systolic arterial pressure was 122.6 ± 8.8 and 136.7 ± 13.8 mmHg for control and hypertensive subjects, respectively (P < 0.0001); diastolic arterial pressure was 79.3 ± 6.6 and 86.7 ± 7.6 mmHg for control and hypertensive subjects, respectively (P < 0.0001). The basal values of skin microvascular flow (APU) in the penis before (P = 0.5808) and after SIL (P = 0.4256) were similar in the control and hypertensive subjects. Penile baseline microvascular flow was significantly increased after SIL in control (P = 0.0006) and also in hypertensive (P = 0.0038) subjects, compared to basal values before SIL. The basal values of CVC in the penis before (P = 0.0590) and after (P = 0.0857) SIL in the control and hypertensive participants were not significantly different. The peak values of CVC during iontophoresis of ACh in the penis before SIL were of 0.62 (0.44–0.91) and 0.50 (0.33–0.79) APU/mmHg in the control and hypertensive participants, respectively (P = 0.2052). After administration of SIL, the peak values of CVC during iontophoresis of ACh in the penis were of 0.88 (0.66–1.12) and 0.69 (0.56–0.84) APU/mmHg in the control and hypertensive participants, respectively (P = 0.0427). Conclusions: Penile endothelium-dependent microvascular function was similar in hypertensive patients and healthy controls. Nevertheless, the response to the acute administration of SIL was higher in the controls than in hypertensive patients.

F5. Skin microvascular dysfunction in preeclampsia persists to the postpartum period

Introduction: Preeclampsia is a multisystem disorder characterised by endothelial and microvascular dysfunction that develops in ∼10% of pregnancies. This study will characterise skin microvascular reactivity using laser Doppler flowmetry in women with preeclampsia compared to matched controls during pregnancy and early postpartum.Methods: Women were recruited and studied on the diagnosis of preeclampsia and followed up for 6-months during postpartum period. Controls were matched for age, gestation and comorbidities. Skin blood flow corrected for mean arterial pressure (cutaneous vascular conductance; CVC) was measured using laser Doppler flowmetry (Periflux5000, Perimed AB, Sweden) on the dominant forearm. We measured the vasodilatory response to iontophoresis of acetylcholine (ACh; endothelial dependent) and sodium nitroprusside (SNP; endothelial independent) as well as local heating (initial axon-reflex and secondary nitric oxide-mediated). Results were analysed using repeated measures ANOVA.Results: Fourteen women with preeclampsia and 15 controls were included in this analysis. Compared to controls, women with preeclampsia had significantly decreased baseline CVC during pregnancy, which persisted to the postpartum (p < 0.01). There was a significant increase in the ratio of maximum vasodilatory response to ACh and SNP at both time points (p < 0.01). There was a trend towards a higher initial axon-reflex response to heat (p = 0.05), but no difference in the secondary peak response.Conclusions: This study is the first to demonstrate a significantly increased response to ACh compared to SNP during pregnancy that persisted in the postpartum period. In addition, we demonstrated that the response to heat may not recover in the early postpartum period. These findings indicate persistent microvascular dysfunction in women with preeclampsia.

Does third generation left ventricular assist device alter heart failure-related microvascular dysfunction?

Background Left ventricular assist device (LVAD) is a promising new therapy in patients with advanced heart failure. Previous studies suggested that continuous blood flow impairs endothelial function. Whether the third-generation LVAD (HeartWareR, HeartWare Inc., Framingham, MA, USA) system affects endothelial regulation of microvascular flow, endothelial nitric oxide (NO) bioavailability and endothelial production of vWF is not known.Methods Fifteen LVAD-supported heart failure patients and 13 age/body mass index matched heart failure patients (HF) were included. The microvascular endothelial function of skin vessels was assessed with laser Doppler imager (LDI) using 3 different hyperaemic challenges: acetylcholine (Ach) iontophoresis, sodium nitroprusside (SNP) iontophoresis and local heating to 44°C. NO-mediated vasodilation was further evaluated by comparing heating hyperaemic response in skin area pretreated either by a saline solution (control) or a specific NO-synthase inhibitor (L-N-arginine-methyl-ester, L-NAME). vWF antigen was also measured in LVAD and HF patients.Results SNP-induced vasodilation did not differ between LVAD and HF patients, and we observed a trend towards an increased vasodilator response to Ach in LVAD patients (P =0.06). Compared to HF patients, skin thermal hyperaemia was increased in LVAD patients in both control and L-NAME pretreated skin (all P < 0.001). The hyperaemic reaction attributable to NO-mediated vasodilation correlated negatively with HF duration (r = –0.50, P < 0.01, n = 28), but did not differ between LVAD and HF patients. Both groups disclosed also similar vWF antigen serum levels.Conclusion This case-control study indicates that third-generation LVAD therapy does not alter skin microvascular endothelial function and vWF production of patients with HF

High-dose atorvastatin is associated with lower IGF-1 levels in patients with type 1 diabetes

IntroductionInsulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 (IGFBP-1) play an important role in vascular health. Many patients with type 1 diabetes are medicated with HMG-CoA reductase inhibitors, statins, in order to prevent vascular complications. Yet little is known about the effect of statins on the IGF-1/IGFBP-1 axis in these patients. ObjectivesThe aim of this study was to evaluate the effect of atorvastatin treatment on IGF-1 and IGFBP-1 with regards to microvascular function. DesignTwenty patients with type 1 diabetes received either placebo or 80mg atorvastatin for two months in a double-blinded cross-over study. IGF-1 and IGFBP-1 levels were assessed before and after each treatment period. Skin microcirculation was studied using Doppler perfusion imaging during iontophoresis of acetylcholine and sodium nitroprusside to assess endothelium-dependent and endothelium-independent microvascular reactivity, respectively. ResultsTreatment with high-dose atorvastatin was associated with a significant decrease in IGF-1 levels compared to placebo (p<0.05, ANOVA repeated measures), whereas no effect was seen on IGFBP-1 or the IGF-1/IGFBP-1 ratio. These variables did not correlate with measurements of skin microvascular reactivity. ConclusionsThe study found that treatment with high-dose atorvastatin was associated with reduced IGF-1 levels, which may indicate a potential negative effect on microvascular function and long-term risk of microangiopathy development.

0076 : Impact of a primary cardiovascular prevention program: evolution in microcirculatory endothelial function, clinical and functional parameters

Endothelial dysfunction appears early and is related to atherosclerosis and cardiovascular risk factors. Primary prevention through lifestyle changes is essential. The aim of our study was to evaluate the impact of a primary prevention program, on microcirculation (primary endpoint), clinical and functional parameters. Nine women and five men, mean age (54.1±11.4), with 2.9±1.8 cardiovascular risk factors, were included in a program based on one dietary and three physical activity sessions per week, for three months. Treatments didn’t change during the protocol. Skin blood flow was assessed by Laser Doppler (LD) flowmetry during post occlusive reactive hyperemia, and iontophoresis of acetylcholine and sodium nitroprusside, successively. LD, Heart rate, blood pressure, weight, waist circumference and functional tests involving stress test bike and 6-minute walk test, were performed before the program and at the end. No statistically significant effect is found on microcirculation vasoreactivity whatever the provocation test used. However clinical and functional parameters are statistically improved (table n°1). The program appears functionally effective. The lack of improvement in microcirculation could be explained by a short duration of the program. A further study over a longer period is needed. The measurement of VO2max would bring an approach to energy metabolism too. The author hereby declares no conflict of interest Table Improved parameters* p<0,05 Beginning End Resting heart rate (BPM) 72±3 68±2 * Blood Pressure (mmHg) Systolic 141.4±11.2 129.3±15.5 * Diastolic 81.4±7.7 76.1±8.8 * Mean 101.4±7.8 93.8±10.7 * Power reached on bicycle (Watts ) 114±5.8 137±5.8 * 6 minutes Walking Test Max Heart rate (BPM) 121±3 130±4 * Walking distance (m) 494±24 601±24 *

Accuracy of a Rapid and Non-Invasive Method for the Assessment of Small Fiber Neuropathy Based on Measurement of Electrochemical Skin Conductances.

Peripheral nerves (PN) consist of small and large fibers (1). The small fibers represent 80% of PN and are long, thin, with little or no myelin. They are, therefore, more fragile and the first to be damaged in many pathological processes (2–5). The current clinical diagnostic methods mainly assess large fibers (6). Similarly the gold standard neurophysiological tool, namely nerve conduction studies or NCS, is also limited to measuring large fiber function. These recommended methodologies, therefore, only examine 20% of PN, those that are largest and degenerate late or not at all in certain diseases. Small fibers can be sensory or autonomic and there are several methods to assess small fiber function or structure (7). Laser-evoked potentials assess A-delta fiber function (sensory nerves) but these instruments are not widely available (8). Quantitative sensory testing (QST) measures sensitivity to cold, heat, and vibration (sensory small and large fibers) and is more widely available but time-consuming and subjective for routine clinical practice (9). Skin biopsies can assess small fiber structure but are relatively invasive (3 mm in diameter, 1 month for full healing) and, thus, are ill suited for longitudinal assessments (10). Sudomotor function assessing small fibers of the sympathetic autonomic system can be evaluated by the quantitative sudomotor axon reflex test (QSART); though considered the reference method, QSART remains mostly limited to research centers due to the technical complexity and relative discomfort of the examination (11). Other sudomotor methodologies include the Neuropad, which is semi-quantitative and not highly sensitive (12), quantitative direct and indirect testing (QDIRT) and the dynamic sweat test (DST). QDIRT and DST both induce sweating with iontophoresis of acetylcholine or pilocarpine; they are relatively tedious and not particularly suited to the outpatient clinic and there are no data validating the diagnostic utility of these newer technologies (13, 14). Specific stains can be used to evaluate sweat gland nerve fiber density (SGNFD), but there is currently no standardized methodology or normative reference ranges for SGNFD (15). The SUDOSCAN® device was developed to allow the quantitative measurement of sweat gland function using a simple and rapid process (16, 17). Results are immediately available and expressed as electrochemical skin conductances (ESCs). This technique has been compared to reference neurological tests, is not operator dependent, and could be used in the follow-up of patients and in multi-center studies (18–21). The aim of this study was to assess repeatability and reproducibility of the method in healthy volunteers (HV) and diabetic patients with a range of glycemic control.

Seasonal acclimation in sudomotor function evaluated by QSART in healthy humans.

The quantitative sudomotor axon reflex testing (QSART) is a classic test of routine postganglionic sudomotor function. We investigated sudomotor function by QSART after summer (July 2012) and winter (January 2013) seasonal acclimation (SA) in the Republic of Korea. QSART with acetylcholine (ACh) iontophoresis were performed to determine directly activated (DIR) and axon reflex-mediated (AXR1, 2) sweating rate. Onset time of axon reflex, activated sweat gland density (ASGD), activated sweat gland output (ASGO), tympanic and skin temperatures (Tty, Tsk), basal metabolic rate (BMR), and evaporative loss volume changes were measured. Tympanic and mean body temperature (Tb; calculated from Tty, Tsk) were significantly lower after summer-SA than that of winter-SA. Sweat onset time was delayed during winter-SA compared to that after summer-SA. BMR, AXR(1), AXR(2), and DIR sweat rates, ASGD and ASGO, and evaporative loss volume were significantly diminished after winter-SA relative to after summer-SA. In conclusion, changes in sweating activity measured by QSART confirmed the involvement of the peripheral nervous system in variation of sudomotor activity in seasonal acclimation.

Distant changes in the assessment of the microcirculation with neuropathic and neuroischemic forms of diabetic foot syndrome

The endothelial dysfunction (ED) in diabetic foot syndrome (DFS) is manifested in the imbalance between the formation of vasodilating and vasoconstrictive substances, not only in the affected area (lower limb), but in the other areas of the peripheral circulation (skin of dorsum of the hand). The aim of this study was the comparative evaluation of endothelial function in patients with neuropathic and neuroischemic forms of DFS in the remote skin tissue, that is, skin. Laser Doppler flowmetry (LDF) was used to assess skin perfusion. The study was conducted in patients with neuropathic and neuroischemic forms of diabetic foot receiving standard hospital treatment at the surgical ward of complicated forms of diabetic foot syndrome in the St. Petersburg's City Hospital 14. Control group comprised patients with proven absence of manifestations of diabetes mellitus and cardiovascular disease. In patients with neuropathic and neuroischemic forms of DFS the significant decrease in microcirculation in the skin was observed. Assessment of the functional state of endothelium in patients with neuropathic and neuroischemic forms of DFS was conducted using functional tests (cold test and iontophoresis of acetylcholine or nitroglycerine). We found significant decrease in endothelium-dependent and endothelium-independent vasodilatation, which was more prominent in neuroischemic forms of DFS.

Paricalcitol, Microvascular and Endothelial Function in Non-Diabetic Chronic Kidney Disease: A Randomized Trial

Background: Vitamin D deficiency, sympathetic activation and endothelial dysfunction are associated with increased cardiovascular risk in patients with chronic kidney disease (CKD). Studies have so far failed to establish the role of vitamin D and vitamin D receptor activator (VDRA) treatment in moderate CKD. This trial was designed to assess whether VDRA treatment can ameliorate sympathetic activation and macro- and microvascular dysfunction in non-diabetic patients with moderate CKD. Methods: We conducted a randomized controlled double-blind trial using placebo, 1 or 2 μg of paricalcitol, a VDRA, for 3 months. We assessed muscle sympathetic nerve activity (MSNA) by microneurography, pulse wave velocity (PWV) by tonometry, flow mediated vasodilatation (FMD) by brachial ultrasound, skin microcirculation assessed by iontophoresis and capillary blood velocity (CBV) by videophotometric capillaroscopy. Results: Thirty-six patients with a mean age of 65 years and mean estimated glomerular filtration rate of 40 ml/min/1.73 m² were included. We found a significant decline in endothelial function after 3 months, except in the group receiving 2 μg of paricalcitol. The higher dose (2 μg) seemed to attenuate the decline in microvascular endothelial function, assessed by iontophoresis of acetylcholine (p = 0.06 for all groups, p = 0.65 for the 2 μg group) and for FMD (p = 0.006 for all groups, p = 0.54 for the 2 μg group). We found a borderline significance (p = 0.05) for improved CBV in the treated groups. We found no significant changes between treatments in MSNA, PWV or albuminuria. Conclusions: Endothelial function declined significantly over 3 months in patients with moderate CKD, and this decline could be ameliorated by VDRA treatment (NCT01204528).

O115. First trimester maternal vascular function is associated with fetal growth

Introduction It has been suggested that preeclampsia (PE) and intrauterine growth restriction arise from a maternal predisposition to endothelial dysfunction existing already before the pregnancy, and this contributes to an impaired placental implantation. The first trimester thus represents an interesting time window for research on the early mechanisms that influence fetal growth and the development of PE. Objective To investigate the relationship between first trimester endothelial function, assessed both in the brachial artery and in the forearm skin microcirculation, and fetal growth. Methods Vascular function was assessed in 58 pregnant women during gestational week 11–14. Vascular reactivity in the in the brachial artery was evaluated by post-ischemic hyperaemia induced flow mediated vasodilatation (FMD) and by administration of sublingual glyceryl trinatrate (GTN). Forearm skin microcirculation was investigated by laser Doppler perfusion imaging during iontophoresis of acetylcholine (Ach) and sodium nitroprusside (SNP) to assess endothelium-dependent and endothelium-independent microvascular vasodilatation, respectively. Fetal growth during pregnancy was measured in each trimester and birth weight centile was calculated. Results FMD and GTN were associated with birth weight centile. By multivariate analysis (adjusted for brachial artery diameter at rest, blood pressure, age and heart rate), β was 1.7 (95% CI 0.06–3.34), r 2 =0.26, p =0.043 for FMD. For GTN, β was 2.6 (95% CI 0.44–4.68) r 2 =0.15, p =0.020. Endothelium-dependent and independent microvascular reactivity was also associated with birth weight centile: β for Ach=7.8 (95% CI 1.8–13.8) r 2 =0.12 p =0.029 and β for SNP=6.2 (95%CI 1.2–11.3) r 2 0.11 p =0.016 respectively. These significant associations for FMD and ACh to birth weight centile were no longer retained when adjusted for responses to GTN and SNP, respectively. Conclusion Fetal growth is associated with first trimester maternal vascular dilative capacity, rather than to endothelial function specifically. These findings were consistent in, both in the brachial artery and the forearm skin microcirculation.

Retinal Vessel Tortuosity and Its Relation to Traditional and Novel Vascular Risk Markers in Persons with Diabetes

ABSTRACTPurpose/Aim: To investigate the association between retinal vascular tortuosity and traditional- and vascular-related risk factors in persons with diabetes.Methods: We recruited 224 diabetic patients. Retinal vascular tortuosity was measured from fundus photographs. Association of tortuosity with the following factors was assessed after adjusting for significant co-factors: diabetes duration, HbA1c, systolic blood pressure (SBP), cholesterol and body mass index (BMI), flicker-light induced retinal vasodilatation, and markers of endothelial function and inflammation (skin microvacular responses to acetylcholine iontophoresis, soluble e-selectin, inter-cellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelin-1, total nitrite, C-reactive protein).Results: Adjusting for age and gender, longer diabetes duration was associated with more tortuous retinal arterioles (mean difference in arteriolar tortuosity 5.85 × 10−5, 95% Confidence Interval 1.44–10.3 × 10−5; p = 0.016; ≤10 versus >10 years duration). Reduced flicker-light induced retinal vasodilatation was associated with tortuous arterioles and venules (mean difference in arteriolar tortuosity 5.62 × 10−5, 4.50–6.72 × 10−5; p < 0.001 and in venules 5.94 × 10−5, 3.33–8.55 × 10−5; p < 0.001; comparing highest versus lowest tertile of flicker-light vasodilatation). These associations remained after adjusting for co-factors. Diabetes duration explained about 36% and flicker-light vasodilatation 25% of the variation in retinal arteriolar tortuosity. No associations were found between retinal arteriolar or venular tortuosity and HBA1c, SBP, cholesterol, BMI and serum markers of endothelial function.Conclusions: Increased retinal arteriolar tortuosity was related to longer diabetes duration and reduced flicker-light induced vasodilatory response, suggesting that retinal vascular tortuosity in adults with diabetes may be influenced by multiple diabetes-related physio-pathological changes.

PP.41.10

Objective: The primary aim of this study was to evaluate the effectiveness of laser speckle contrast imaging (LSCI), coupled with the transdermal iontophoretic delivery of acetylcholine (ACh), in the assessment of penile microvascular function. Additionally, we tested systemic microvascular function using both LSCI and ACh iontophoresis in the forearm. Design and method: We assessed cutaneous endothelium-dependent microvascular reactivity in the penis and forearm of healthy volunteers (aged 56.6 ± 1.0 years, n = 26), at rest and 60 minutes following the oral administration of the phosphodiesterase type 5 inhibitor, sildenafil (SIL, 100 mg). LSCI was coupled with the iontophoresis of ACh, using increasing anodal currents of 30, 60, 90, 120, 150 and 180 μA, during 10 second intervals spaced 1 minute apart. Results: Basal skin microvascular flow in the penis increased significantly following SIL (P = 0.0014) administration. The endothelium-dependent skin microvascular vasodilator responses induced by ACh were also significantly enhanced following SIL administration for each of the following parameters: the peak values of cutaneous vascular conductance (CVC, P < 0.0001), the increases in CVC (P < 0.0001) and the area under the curve for ACh-induced vasodilation (P = 0.0094). Conclusions: LSCI appears to be a promising noninvasive technique in the evaluation of penile microvascular endothelial function. This methodology may be valuable in the evaluation of penile microvascular reactivity among patients with cardiovascular and metabolic diseases, as well as the effectiveness of drugs used to treat vasculogenic erectile dysfunction.

Abstract 557: Gene Polymorphisms in IL-10, INF-γ and TGF-β are Associated with Early-Onset Coronary Artery Disease and Microvascular Function.

The influence of genetics on atherosclerosis development remains unclear. Association of single-nucleotide polymorphisms (SNPs) with early-onset coronary artery disease (EOCAD), as well as with carotid intima-media thickness (CIMT), and systemic microvascular reactivity was examined in 52 patients with EOCAD (45 ±3 years old) and 35 age-matched controls. SNPs in ACE, TNF-α (-308G/A, -238 G/A), IFN-γ (+874 A/T), MMP-9 (-1562 C/T), IL-10 (-1082 A/G, -819 C/T, 592 C/A), NOS3 (894 G/T), ApoA1 (rs964184), and TGF-β (codon 10 T/C) genes were genotyped by automatic sequencing. CIMT was determined by ultrasound and capillary density by intravital video-microscopy. Microvascular reactivity was evaluated using laser speckle contrast imaging, cutaneous blood flow was assessed at rest and during post-occlusive reactive hyperemia (PORH), and acetylcholine (Ach) or sodium nitroprusside (SNP) iontophoresis. Genotype distribution was: ACE: 31 DD, 12 II, 43 DI; TNF-α: 56 GG, 20 GA, 3 AA at position -308, and 76 GG, 3 GA at position -238; IFN-γ: 8 subjects with high producer TT genotype; MMP-9: 62 CC, 23 CT; IL-10: 8 high producer haplotype, 35 intermediate, and 43 low; NOS3: 41 GG, 34 GT, 11 TT; ApoA1: 47 CC, 29 CG, 10 GG; TGF-β (cd 25): 75 GG, 10 GC; TGF-β (cd 10): 66 high producer genotype, 19 low producer. IFN-γ, IL-10 haplotype, and TGF-β were significantly related to EOCAD. CIMT was increased (0.93 ±0.02 mm, p&lt;0.0001), while capillary density (87 ±3 capillaries/mm2, p=0.029) was reduced in EOCAD. CC genotype of TGF-β showed higher CIMT (p=0.004) and lower capillary density (p=0.019) than TT. High IL-10 haplotype reduced vasodilator response after PORH (0.32 APU/mmHg, p=0.0316), while high IFN-γ genotype reduced the response induced by both Ach (0.19 APU/mmHg) and SNP (0.13 APU/mmHg) in relation to low producer (0.44, 0.31, and 0.24 APU/mmHg, respectively). TT genotype of TGF-β showed lower vasodilator response after SNP than CC. In conclusion, IFN-γ, IL-10 and TGF-β genotypes were associated with EOCAD, as well as with systemic microvascular response, CIMT, and capillary rarefaction. The results suggest that IFN-γ, IL-10 and TGF-β genotypes could influence EOCAD, affecting microvascular reactivity through endothelium-dependent and -independent pathways.

Different responses of the retinal and cutaneous microcirculation to transient dysmetabolic conditions

ObjectiveThis study evaluated the responses of the retinal and cutaneous microcirculation to acute hyperlipidemia and hyperhomocysteinemia. MethodsTwenty-five clinically healthy men (mean age 24 ± 2 years) were studied four times in a randomized order, with intervals of at least one week between the two dietary interventions always preceded by a day for baseline assessment. The two interventions consisted of either 0.1 g/kg l-methionine to induce hyperhomocysteinemia or of 500 ml whipping cream (30% fat) to induce hyperlipidemia. Microvascular vasodilator responses to flickering-light and to cutaneous acetylcholine iontophoresis were assessed by retinal vessel analysis and laser Doppler flowmetry respectively. ResultsThe fat load produced significant increases in triglycerides and total cholesterol which was accompanied by a reduction of the retinal arterial flicker response. Methionine administration induced a threefold increase in homocysteine levels and a concomitant decrease in retinal venous flicker response. Acute hyperlipidemia and hyperhomocysteinemia had no effect on cutaneous microvascular vasodilator responses to acetylcholine. The inter- and intra-subject reproducibility was higher for retinal vessel analysis as compared to laser Doppler flowmetry. ConclusionThe retinal microcirculation is more sensitive to metabolic changes than the cutaneous microcirculation and can be reliably assessed by retinal vessel analysis. Reproducibility of retinal vessel analysis may be enhanced by multi-vessel assessment.

The evaluation of penile microvascular endothelial function using laser speckle contrast imaging in healthy volunteers

ObjectiveThe primary aim of this study was to evaluate the effectiveness of laser speckle contrast imaging (LSCI) coupled with transdermal iontophoretic delivery of acetylcholine (ACh) for the assessment of penile microvascular function. Additionally, we tested systemic microvascular function using both LSCI and ACh iontophoresis on the forearm. MethodsWe assessed cutaneous, endothelium-dependent microvascular reactivity on the penis and forearm of healthy volunteers (aged 56.6±1.0years, n=26) at rest and 60min following the oral administration of the phosphodiesterase type 5 inhibitor (sildenafil: SIL, 100mg). LSCI was coupled with the iontophoresis of ACh using increasing anodal currents of 30, 60, 90, 120, 150 and 180μA during 10-second intervals spaced 1min apart. ResultsBasal skin microvascular flow in the penis increased significantly following SIL administration. The endothelium-dependent skin microvascular vasodilator responses induced by ACh were also significantly enhanced following SIL administration for each of the following parameters: peak values of cutaneous vascular conductance (CVC); increases in CVC; and the area under the curve for ACh-induced vasodilation. ACh-induced microvascular vasodilation in the forearm was not modified by SIL. Finally, the administration of electric current alone did not affect penile microvascular flow. ConclusionLSCI appears to be a promising non-invasive technique for the evaluation of penile microvascular endothelial function. This methodology may be valuable for the evaluation of penile microvascular reactivity among patients with cardiovascular and metabolic diseases and to test the effectiveness of drugs used to treat vasculogenic erectile dysfunction.

0175 : Acute sugary drink induces micro- and macrovascular dysfunction even in healthy young human: a randomized cross-over study

Overconsumption of sugary drinks has recently been implicated in the pathogenesis of cardiovascular disease. Our objective was to elucidate acute hemodynamic and nitric oxide (NO)- related micro- and macrovascular responses to the ingestion of a commercial sugary drink containing sucrose or tap water with or without sucrose at a similar concentration to that found in commercial soft drinks. In a randomized cross-over study design, 12 young healthy males ingested 600ml of the 1) commercial sugary drink (Solo Lemon®, Schweppes, Australia) containing 72,4g of sucrose (SD), 2) tap water with dissolved 72,4g of sucrose (TWS) and 3) tap water (TW). Blood glucose, blood pressure and heart rate were monitored during the protocol. Additionally, vascular endothelial function testing was performed during the blood glycaemia peak, 15min after drink ingestion, including NO microvascular (cutaneous blood flow measured by laser Speckle contrast imaging in response to iontophoresis of acetylcholine and sodium nitroprusside), and macrovascular reactivity (flow-mediated dilation and nitrate-mediated dilation). Blood glucose increased significantly and by a similar magnitude during SD and TWS compared with baseline measure and the TW trial. SD, TWS and TW did not increase blood pressure during the various trials, and heart rate did not change, except at the end of TWS testing. Micro- and macrovascular endothelial function after SD were compromised compared to TW. Unpredictably, TWS induced only macrovascular dysfunction, with no changes in microvascular function compared to SD. Smooth muscle cell function was unaltered, independent of drinks. Collectively, the results demonstrated that SD-induced acute hyperglycemia can lead to NO-related endothelial dysfunction in micro- as well as in macrovascular beds. However, since TW with the same dose of sucrose compared with SD induced only macrovascular dysfunction, the effects of other ingredients (food acids, preservative, flavor…) present in SD on microcirculation can be questioned.