Cortisol level after dexamethasone suppression test in patients with non-functioning adrenal incidentaloma is positively associated with the duration of reactive hyperemia response on microvascular bed.

PURPOSE: Data on endothelial derangements in patients with non-functioning adrenal incidentaloma (NFAI) are scarce. METHODS: We investigated if NFAI patients present clinical, biochemical and endothelial alterations compared to individuals without an adrenal lesion and also the associations among these variables. Forty-two NFAI and 40 controls were evaluated. NFAI diagnosis and controls were defined according to the current guidelines and based on a normal adrenal imaging exam, respectively. Body composition was evaluated by dual emission X-ray absorptiometry. Endothelial reactivity was assessed by two methods: tonometry (Endo-PAT®) and laser speckle contrast imaging (LSCI). RESULTS: There were no differences between groups regarding age, gender, ethnicity, smoking status, and statin use. The frequency of metabolic syndrome according to the International Diabetes Federation criteria was 69% and 57.9%, respectively in NFAI and controls (p = 0.36), whereas the atherosclerotic cardiovascular disease (ASCVD) risk was 63.4% and 66.7% (p = 0.81). The clinical, laboratory, and anthropometric characteristics, as well as body composition, were similar between the groups. Additionally, any differences between groups were observed on endothelial reactivity tests. Nevertheless, we noted an association between cortisol levels after 1 mg-dexamethosone suppression test (1 mg-DST) and the duration of post-occlusive reactive hyperemia tested on microcirculation (r = 0.30; p = 0.03). NFAI patients require more antihypertensive drugs to achieve blood pressure control (p = 0.04). The number of antihypertensive drugs used to control blood pressure correlated with cortisol levels after 1 mg-DST (r = 0.29; p = 0.03). CONCLUSIONS: Since both groups herein investigated had a high frequency of metabolic syndrome and ASCVD risk, it might explain similarities observed on endothelial reactivity. Nevertheless, prolonged reactive hyperemia response on microcirculation was correlated with cortisol levels under suppression.

Oxygen uptake, respiratory exchange ratio, or total distance: a comparison of methods to equalize exercise volume in Wistar rats.

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Oxygen uptake, respiratory exchange ratio, or total distance: a comparison of methods to equalize exercise volume in Wistar rats

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Can Heart Rate Variability be used to Estimate Gas Exchange Threshold in Obese Adolescents?

This study investigated the agreement and reliability of oxygen uptake (V̇O2), V̇O2 reserve (V̇O2 R), heart rate (HR) and power output at intensities corresponding to the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) in obese and eutrophic adolescents. A further aim was to establish whether the HRVT was able to detect changes in cardio-respiratory fitness in obese adolescents after 3 months of recreational soccer practice. First, 25 obese and 10 eutrophic adolescents (ages 12-17) visited the laboratory twice to perform cycling CPET to test the reliability of CPET outcomes at GET and HRVT. Furthermore, the level of agreement between GET and HRVT was determined for a subgroup of 10 obese adolescents after performing a 3-month recreational soccer program. No significant difference was found for V̇O2, %V̇O2 R, HR and power output at the GET and HRVT (P>0.05), which were equally able to detect improvements in aerobic fitness after the soccer intervention. Correlations between GET and HRVT for V̇O2 and %V̇O2 R ranged from 0.89 to 0.95 (P<0.001) and test-retest reliability ranged from 0.59 to 0.82 (P<0.006). Overall, HRVT seems to be a reliable alternative for prescribing aerobic exercise intensity in obese adolescents.

In elderly women moderate hypercholesterolemia is associated to endothelial and microcirculatory impairments.

How cholesterol influences the microcirculation on aging subjects is not well known. This study evaluated moderate hypercholesterolemia effects in, treated or not, lean elderly women on brachial artery reactivity and microcirculatory function using venous occlusion plethysmography (VOP) and nailfold videocapillaroscopy (NVC). Patients (mean age 73 years) were divided into healthy elderly (HE, n=15), treated dyslipidemia with statins during at least 6 months (TDL, n=9) and dyslipidemia (DL, n=9, cholesterol, 257±11 and LDL-cholesterol, 157±24 mg/dl). Young, mean age 23 years, women (YC, n=24), served as controls. Laboratory and anthropometrical analysis, VOP peak forearm blood flow (FBF) during the reactive hyperemia response/baseline FBF (%HYPER) and peak FBF after 0.4 mg sublingual nitroglycerin/baseline FBF (%NITRO) were assessed. NVC capillary density and diameters, maximum red blood cell velocity (RBCV(max)) during reactive hyperemia/baseline RBCV and time to reach RBCV(max) were evaluated. Correlations between %HYPER, %NITRO and plasma cholesterol fractions were performed. Total and LDL-cholesterol were increased only in DL group. Capillary diameters were larger in elderly groups than YC. RBCV(max)/baseline RBCV was reduced in the DL group compared to HE, TDL and YC. %HYPER was lower in DL and normalized in TDL group. YC %HYPER was double of HE. %NITRO decreased from (HE=YC) to TDL and DL groups. There was a significant inverse correlation between LDL-cholesterol, non-HDL-cholesterol and %HYPER/% Nitro. In conclusion, moderate hypercholesterolemia reversibly impaired the vasodilatatory response in the microcirculation but the endothelial-independent vasodilator response to nitroglycerine remained irreversibly lower in healthy aged women.

Effects of resistance training on cytokines.

It is speculated that exercise training decreases resting levels of tumor necrosis factor alpha (TNF-alpha) and C-reactive protein (CRP); reduces body mass and leptin (LP); and increases adiponectin (AD) and insulin sensitivity. This systematic review analyzed the effectiveness of resistance training (RT) longitudinal clinical studies on AD, LP, CRP and TNF-alpha. Seventeen studies were included and the majority of randomized controlled trials support that RT produces increases in AD, and decreases in both LP and CRP. Greater responses in AD and LP were evident in overweight and obese individuals; while RT appeared to be effective in reducing CRP in obese individuals, and older adults. Additionally, women may be more responsive to RT effects on AD, LP and CRP. Training duration and intensity may affect the response of AD and CRP with greater responses shown with 16 weeks or more of training and/or with intensities greater than 80% of one repetition maximum. No response to RT of TNF-alpha levels was apparent. Although based on a limited number of studies, some of which are uncontrolled non-randomized in design, our review suggests some positive effects of RT programs on cytokine levels, but specifics of the responses in different populations need further elucidation.

Rosiglitazone decreases intra- to extramyocellular fat ratio in obese non-diabetic adults with metabolic syndrome.

BACKGROUND: Insulin resistance is intrinsically related to intramyocellular (IMCL) rather than extramyocellular (EMCL) triglyceride content. Conflicting results have been reported on the ability of insulin sensitizer agents, such as thiazolidinediones, to modify muscle fat distribution. The aim of this study was to investigate the role of rosiglitazone on muscle fat compartment distribution in an adult population of obese non-diabetic metabolic syndrome patients. PATIENTS AND METHODS: Fifteen obese, non-diabetic, metabolic syndrome patients were studied by means of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy before and after treatment with rosiglitazone 8 mg/day for 6 months. Anthropometrical and metabolic variables were assessed. RESULTS: After rosiglitazone, body weight and hip circumference increased [100.9 (91.12-138.7) vs. 107.0 (79.6-142.8) kg and 118 (107-126) vs. 122 (110-131) cm]; while waist-hip ratio (WHR) decreased from 0.93 (0.87-1.00) to 0.89 (0.82-0.97) (P < 0.001 for all). Additionally, fasting plasma glucose, insulin and homeostatis model assessment of insulin resistance (HOMA-IR) significantly decreased while adiponectin increased over threefold [9.7 (3.7-17.7) vs. 38.0 (19.3-42.4) microg/ml] without any changes in resistin. Finally, the IMCL did not change [267.54 (213.94-297.94) vs. 305.75 (230.80-424.75) arbitrary units (AU), P = 0.15] while the EMCL increased [275.53 (210.39-436.66) vs. 411.39 (279.92-556.59) AU; P < 0.01] therefore decreasing the IMCL-to-EMCL (IMCL/EMCL) ratio [1.07 (0.78-1.23) vs. 0.71 (0.53-0.96); P < 0.01]. CONCLUSION: Rosiglitazone treatment increased body weight and hip circumference and decreased WHR. More importantly, it decreased the IMCL/EMCL ratio by increasing the EMCL without any significant change on the IMCL.

Adiponectin is related to intramyocellular lipid content in non-diabetic adults.

OBJECTIVE: Insulin resistance (IR) is associated with intramyocellular lipid (IMCL) content and low serum adiponectin (ADP) levels and ADP is also involved in muscle fat oxidation. However, the relationship between ADP and IMCL content is still controversial and in this study we explored it further in non-diabetic adults. DESIGN: Cross-sectional clinical study. SUBJECTS: Thirty-three adult subjects, 24 obese non-diabetic patients with metabolic syndrome (MS) and 9 lean healthy controls. MEASUREMENTS: Proton nuclear magnetic resonance spectroscopy (1H-NMRS) was performed to quantify IMCL content. The latter plus serum ADP, anthropometrics and biochemical parameters were evaluated and compared in these 2 groups. RESULTS: MS patients had higher body mass index, waist, waist-to- hip ratio, glucose, insulin, and triglycerides and lower HDL cholesterol (HDLc) compared to controls. Homeostasis model assessment of IR (HOMA-IR) [3.25 (2.58-4.13) vs 1.02 (0.73- 1.29); p<0.0001] and IMCL content [266.1 (189.9-296.3) vs 72.85 (55.3-109.4) AU, p<0.0001] were higher, and quantitative insulin-sensitivity check index (QUICKI) [0.32 (0.31-0.33) vs 0.38 (0.37-0.40); p<0.0001] and ADP [8.6 (4.05-15.95) vs 21.1 (12.9- 24.4) microg/ml; p=0.02] were lower in MS subjects compared to controls. IMCL content was directly associated to glucose, insulin, triglycerides, and HOMA-IR and inversely to HDLc, QUICKI and, more importantly, to ADP (r=-0.41; p<0.05). Only in the MS group, ADP partially influenced IMCL content. CONCLUSION: ADP is inversely related to IMCL content in non-diabetic adults. This finding has possible implications for the role of ADP in muscle fat oxidation, IR, and MS.

Microvascular dysfunction: a direct link among BMI, waist circumference and glucose homeostasis in young overweight/obese normoglycemic women?

OBJECTIVE: Capillary recruitment is impaired in obesity (OB), possibly worsening glucose and insulin availability to target organs. In this study, we investigated whether functional microvascular parameters were correlated with clinical-anthropometrical data and whether these parameters would influence OB-related metabolic disorders, especially glucose homeostasis, in young overweight (OW)/obese women. DESIGN: Cross-sectional clinical study of microvascular reactivity in young OW/obese women. SUBJECTS AND METHODS: A total of 10 lean (23.1 + or - 3.2 years, body mass index (BMI) 22.3 + or - 1.6 kg m(-2)) and 42 OW/obese (24.9 + or - 3.5 years; BMI 34.5 + or - 5.7 (25.7-46.5) kg m(-2)) sedentary non-smoking women were evaluated. Lipid profile, fasting plasma glucose (PG), post-load PG (75 g-2 h), insulin, C-reactive protein, HOMA-IR (homeostasis model assessment for insulin resistance) index and anthropometric variables (weight, BMI, waist and hip circumferences, waist-to-hip ratio and blood pressure (BP)) were determined. Functional microvascular parameters (functional capillary density, red blood cell velocity at baseline and peak (RBCV(max)), and time taken to reach RBCV(max) (TRBCV(max)) during post-occlusive reactive hyperemia after 1 min arterial occlusion) were evaluated by nailfold videocapillaroscopy. RESULTS: The time taken to reach RBCV(max) was significantly longer in OW/obese patients compared with control subjects (8.6 + or - 2.4 versus 5.7 + or - 1.1 s, P<0.001), and its delay was directly associated with adiposity levels, systolic BP and insulin resistance, and inversely related to high-density lipoprotein-cholesterol. Post-load PG could be correlated with TRBCV(max) (R = 0.48, P<0.05) and RBCV(max) (R = -0.29, P<0.05), and it was influenced by weight, waist circumference and TRBCV(max) (adjusted R(2) = 24%) as well. CONCLUSIONS: In the investigated group of young OW/obese women, the direct correlation between post-load PG and TRBCV(max) links microvascular parameters with metabolic variables and suggests a key role for microcirculation in OB-related metabolic disorders.

Changes on venous diameter and leg perimeter with different clinical treatments for moderate chronic venous disease: evaluation using Duplex scanning and perimeter measurements.

AIM: To evaluate changes on venous diameter and perimeter of lower limbs in chronic venous disorder (CVD) patients after different clinical treatments for four weeks. METHODS: Fifty-two female patients classified as C2,s or C2,3,s (CEAP classification) were allocated consecutively in three groups: Cirkan (40 mg of the root extract of Ruscus aculeatus + 100 mg of flavonoid hesperidine methylchalcone + 200 mg of vitamin C per pill); elastic compression stockings (ECS) and no treatment (NT). Diameters were determined by duplex ultrasound and perimeter with Leg-O-Meter. RESULTS: After treatment, Cirkan significantly decreased popliteal vein and great saphenous vein (GSV) diameters bilaterally and ECS decreased popliteal vein diameter bilaterally and GSV and varices only on the left limb. Perimeters changed only with ECS. Clinical scores changed between Cirkan x NT and ECS x Cirkan. Disability score varied for ECS x NT and Cirkan x NT. chi2 test detected different distribution frequency for C3 and C2 classes according to treatment: ECS (both limbs) and Cirkan (only left limb). Varices and anatomical scores did not change. CONCLUSIONS: ECS emerges as the most effective clinical treatment tested but improvements with Cirkan on vein diameter and CEAP class were also observed. Clinical scores improved due to pain relief and edema reduction (ECS). These findings point to a positive effect of Cirkan, suggesting that venotonic drugs should be taken into account in the treatment of CVD.

Metformin improves skin capillary reactivity in normoglycaemic subjects with the metabolic syndrome.

AIMS: Insulin resistance and a parental history of diabetes mellitus are independently associated with endothelial dysfunction. Oxidative stress has a pivotal role in the pathophysiology of vascular injury. Metformin, in addition to its glucose-lowering properties, has vasculoprotective effects. We investigated whether metformin has beneficial effects on the nutritive skin capillary circulation and deceases oxidative stress in a group at high risk for Type 2 diabetes mellitus (T2DM) and cardiovascular disease. METHODS: Thirty normoglycaemic subjects with the metabolic syndrome (MS),who had first-degree relatives with T2DM, participated. The mean age was 39.1 +/- 8.4 years and body mass index (BMI) 35.7 +/- 4.8 kg/m2 (mean +/- SD). SUBJECTS: were randomized 1 : 1 to receive placebo (n=14) or metformin (n=16; 1700 mg/day) in a double-blind study. At baseline and post treatment, blood and urine samples were collected for biochemical and 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha) analysis, respectively. Microcirculation was assessed by nailfold videocapillaroscopy, analysing afferent (AF), efferent (EF) and apical (AP) diameters of capillary loops, functional capillary density (FCD), red blood cell velocity at rest (RBCV), after 1 min arterial occlusion (RBCVmax) and time (TRBCVmax)taken to reach it. RESULTS: Groups did not differ significantly in anthropometric, clinical, laboratory or microvascular measurements at baseline. In the metformin group, weight,BMI, systolic blood pressure and fasting plasma glucose fell, and lipid profile and microcirculatory parameters FCD, AF, EF, AP, RBCVmaxand TRBCVmax improved (all P<0.01). No relationship between clinico-laboratory parameters and microvascular reactivity was observed, except for changes in total and low density lipoprotein-cholesterol and RBCVmax* 8-epi-PGF2alpha did not change significantly in either group. CONCLUSIONS: Metformin improved skin capillary reactivity in normoglycaemic MS subjects independently of significant changes in 8-epi-PGF2alpha levels.

Characterization of cardiopulmonary function and cardiac muscarinic and adrenergic receptor density adaptation in C57BL/6 mice with chronic Trypanosoma cruzi infection.

Circulating antibodies in chagasic patients interact with myocardial beta adrenergic and muscarinic cholinergic receptors, triggering intracellular signals that alter cardiac function along the course of the disease. However, until now, experimental data in models of chronically infected chagasic mice linking the effects on myocardial beta adrenergic and muscarinic receptors to cardiopulmonary dysfunction is lacking. Thus, we studied C57BL/6 mice 8 months after intraperitoneal injection of 100 trypomastigote forms of the Colombian strain of T. cruzi. Uninfected mice, matched in age, were used as controls. Histopathological analyses (inflammation and fibrosis) and radio-ligand binding assays for estimation of muscarinic and adrenergic receptor density were performed in myocardium tissue samples. When compared to controls, infected mice had electrical conduction disturbances, diastolic dysfunction, lower O2 consumption and anaerobic threshold. In addition, hearts of chronic chagasic mice had intense inflammation and fibrosis, and decreased beta adrenergic and increased muscarinic receptor densities than normal controls. Our data suggest that chronic T. cruzi infection causes alterations in cardiac receptor density and fibrosis deposition which can be associated with cardiac conduction abnormalities, diastolic dysfunction and lower exercise capacity, associating for the first time all these functional and histopathological alterations in chagasic mice.

Nailfold videocapillaroscopy in patients with systemic lupus erythematosus.

Nailfold videocapillaroscopy was performed in 21 controls (C) and 21 patients (P) with systemic lupus erythematosus (SLE) classified according to the American College of Rheumatology, with, at least, 1 year of diagnosed disease and having low activity (MEX-SLEDAI) and sequel (SLICC) indexes at the time of the examination, paired by sex and age. Red blood cell velocity (RBCV, mm/s) at rest and after the release of 60s arterial occlusion (RBCVmax, mm/s), time to reach it (TRBCVmax, s), functional capillary density (FCD, number of capillaries /mm2), afferent, apical and efferent capillary diameters (microm) (DAF, DAP and DEF, respectively) were obtained from videotapes analyzed by the CapImage software. The results did not show any significant difference between the groups that were analyzed, suggesting that morphological (capillary diameters) and functional (RBCV, RBCVmax, TRBCVmax and FCD) parameters are not affected by SLE when low activity and sequel indexes of the disease are present.

Nailfold videocapillaroscopy in primary antiphospholipid syndrome (PAPS).

OBJECTIVES: To evaluate microcirculatory changes (functional and morphological) in primary antiphospholipid syndrome (PAPS) patients. METHODS: Thirty-one patients were examined using nailfold videocapillaroscopy (18 PAPS patients and 13 healthy subjects). The patients were subdivided into two subgroups, with lupus anticoagulant (n = 8) and with anticardiolipin (n = 10) antibodies. Capillary morphology was determined; diameters ( micro m) and functional capillary density (FCD, number capillaries/mm2) were measured in control conditions. Blood flow velocity (CBFV, mm/s) was also evaluated at rest and after release of 60 s arterial occlusion. RESULTS: The percentage of subjects with at least one morphological alteration in the observed capillaries was 77.8% for patients and 21.3% for healthy subjects. Capillary diameters ( microm) [afferent (AD), apical (APD) and efferent (ED)] were significantly smaller (mean +/- s.d.: AD-PAPS, 7.4 +/- 2.1; control, 9.1 +/- 2.6, P = 0.063; APD-PAPS, 11.6 +/- 2.3; control, 14.4 +/- 3.8, P = 0.015; ED-PAPS, 8.4 +/- 2.0; control, 10.9 +/- 3.2, P = 0.011) in PAPS patients compared with controls. FCD (PAPS, 8.5 +/- 3.2; control, 8.3 +/- 2.9, P +/- 0.862), mean resting CBFV (PAPS, 0.73 +/- 0.31; control, 0.88 +/- 0.41, P = 0.278), mean peak CBFV after occlusion (PAPS, 1.07 +/- 0.52; control, 1.59 +/- 0.91, P = 0.063) and mean time (s) to reach it (PAPS, 5.2 +/- 1.7; control, 4.6 +/- 1.8, P = 0.101) were not statistically different between the two groups. CONCLUSION: Our results suggest that nailfold capillary morphology is altered in patients with PAPS, but these changes could not be correlated to impairment of functional parameters.

Effects of L-NA and sodium nitroprusside on ischemia/reperfusion-induced leukocyte adhesion and macromolecular leakage in hamster cheek pouch venules.

Our objective was to study how the topical application of a nitric oxide synthase inhibitor (l-NA, Nomega-nitro-L-arginine) and a nitric oxide donor, sodium nitroprusside (SNP), could modulate leukocyte adhesion (sticking) and microvascular permeability as altered by ischemia/reperfusion (I/R) and topically applied histamine after I/R. Golden hamsters were prepared for intravital microscopy. Ischemia was induced by an inflatable silicon rubber cuff mounted around the neck of the cheek pouch prepared for intravital microscopy. Saline, L-NA, sodium nitroprusside, and histamine were applied in the superfusion solution. FITC-dextran was injected iv 30 min before initiation of ischemia as a marker of microvascular permeability. L-NA 10(-5) M inhibited both the increase in number of sticking leukocytes and the increase in vascular permeability after I/R compared with the untreated control group of hamsters. SNP neutralized this effect of L-NA on leukocytes and vascular permeability and caused arteriolar dilation at the concentration used, 10(-6) M. Both SNP and L-NA + SNP enhanced the I/R-induced macromolecular leakage. The topical application of SNP and SNP + L-NA did not modify the response to histamine after I/R compared with the untreated control group. In hamsters not subjected to I/R, histamine-induced macromolecular leakage was inhibited by L-NA and L-NA + SNP but was unchanged by SNP. It is concluded that inhibition of nitric oxide formation by L-NA reduced both leukocyte adhesion in postcapillary venules and the increase in macromolecular leakage and that a NO donor such as SNP could enhance the macromolecular leakage response to I/R.

Effects of Ringer-acetate and Ringer-dextran solutions on the microcirculation after LPS challenge: observations in the hamster cheek pouch.

The effects of NaCl 0.9%, Ringer-acetate, and Ringer-dextran given as intravenous infusions in the microcirculatory changes observed in early stages of endotoxemia were investigated in male hamsters treated with Escherichia coli lipopolysaccharide (LPS). The cheek pouch was studied in vivo by means of intravital microscopy. Mean arterial (MAP) and venous pressures (CVP), heart rate, mean arteriolar internal diameter, spontaneous arteriolar vasomotion (AV), red blood cell velocity (RBCV) in these vessels, and long-term effects of LPS were evaluated in animals treated with either LPS alone or the combination of LPS with NaCl 0.9%, Ringer-acetate and Ringer-dextran. The intravenous injection of LPS (0.3 mg/kg) elicited a significant reduction in MAP and CVP, cessation of AV and a decrease in RBCV. In our study, the heart rate and the arteriolar diameter did not change significantly, compared with the control values obtained before the LPS injection. No improvement in the MAP could be detected with infusions of NaCl 0.9% or Ringer-acetate but the infusion of Ringer-dextran increased it significantly. All infusions tested maintained the CVP until the end of the observation period and the Ringer-dextran increased it significantly. The heart rate was maintained around 360 beats/min with a tendency to decrease 70 min after the LPS infusion in all groups studied except the group which received NaCl 0.9% where the heart rate decreased significantly. In all the four groups, the mean arteriolar diameter did not change significantly with time during the observed period. RBCV decrease with the combination LPS + NaCl 0.9% and the infusions of Ringer-acetate and Ringer-dextran maintained it until the end of the observation period. The combination of LPS + NaCl 0.9% maintained the spontaneous arteriolar vasomotion during 50 min after LPS injection and the infusion of Ringer-acetate maintained it for the 3-h observation period. The infusion of Ringer-dextran maintained the amplitude of the spontaneous arteriolar vasomotion and increased its frequency significantly. The long-term effects of LPS showed weight loss and pus on the periorbital area. Our results suggest that the best solution to maintain the microcirculatory parameters during the early stage of endotoxemia after LPS injection was the Ringer-dextran.

Leukocyte adhesion after oxidant challenge in the hamster cheek pouch microcirculation.

Oral administration of S-5682 (Daflon 500 mg, 90% diosmin, 10% hesperidin) inhibits oxidant-induced increase in macromolecular permeability in the postcapillary venules of the hamster cheek pouch microcirculation. In this study, the effect of S-5682 on leukocyte-endothelium interaction was evaluated using the same experimental model. Hamsters kept on a standard diet were divided into 5 groups (n = 6) and treated orally, twice a day, with placebo (10% lactose solution), S-5682, 5, 20 or 80 mg/kg/day (suspended in 10% lactose solution) or alpha-tocopherol, 1 mg/kg/day, for 10 days prior to the oxidant challenge with tert-butylhydroperoxide (TBOOH). Topical application of TBOOH (10(-4) M for 5 min) to hamsters given acridine orange prior to TBOOH resulted in increases in the number of rolling and sticking (no movement for at least 30 s) leukocytes in postcapillary venules. No changes in the number of rolling leukocytes could be observed in the treated groups compared with the placebo group (p > 0.05). On the contrary, leukocyte adhesion was inhibited in groups treated with S-5682 (5, 20 and 80 mg/kg/day) or alpha-tocopherol: placebo 105 +/- 3/6 mm(2) (mean +/- SEM); S-5682, 5 mg/kg/day 68 +/- 3/6 mm(2) (p < 0.01), 20 mg/kg/day 55 +/- 3/6 mm(2) (p < 0.001) and 80 mg/ kg/day 39 +/- 2/6 mm(2) (p < 0.001) and alpha-tocopherol 36 +/- 1/6 mm(2) (p < 0.001). The inhibition of oxidant-induced leukocyte adhesion by S-5682 was similar to that seen for ischemia-reperfusion and the higher dose of S-5682 was as effective as alpha-tocopherol in inhibiting it.

Vascular permeability increase and plasma volume loss induced by endotoxin was attenuated by hypertonic saline with or without dextran.

Endotoxin given intravenously is known to cause plasma leakage and subsequent loss of circulating plasma volume. Hypertonic saline resuscitation has been successfully applied in hemorrhagic and traumatic shock, but its application for the treatment or prevention of septic or endotoxin shock is less well studied. Our aim was to investigate the effects of endotoxin on plasma leakage in hamsters when administered in two different ways: applied locally to the hamster cheek pouch microcirculation or systemically by i.v. injection. The cheek pouch was studied by intravital microscopy using FITC-labeled dextran as a tracer of plasma leakage. Escherichia coli lipopolysaccharide (LPS) was continuously added into the superfusion buffer of the cheek pouch preparation during 120 min in two control groups (each n = 6) and two further groups (each n = 6) treated with either hypertonic saline (HS) or hypertonic saline and dextran (HSD). Treatment was given as an i.v. injection 0.35 mL NaCl 7.5%/100 g b.w. during 4 min starting 15 min prior to the start of endotoxin application. Endotoxin caused a reversible increase in the number of postcapillary venular leaks with a maximal response at 70 min after start of endotoxin application. The maximal responses were reduced to 36% in the HS-treated and to 37% in the HSD-treated group in comparison to what was seen in the control groups. In the second part of the study endotoxin was given i.v. 0.3 mg/kg to anesthetized hamsters (n = 41) and arterial blood samples were collected at 0, 60, 120, and 180 min after endotoxin injection for measurement of hematocrit and plasma FITC-dextran concentration. Hamsters were divided into seven groups: untreated control group (n = 6); HSC control group given only an i.v. injection of hypertonic saline (n = 6); LPS group given endotoxin 0.3 mg/kg during 1 min (n = 9); HSp group given hypertonic saline (NaCl 7.5%) 10 min prior to i.v. endotoxin (n = 6); HSa group given hypertonic saline 10 min after i.v. endotoxin (n = 6); HSD group given hypertonic saline with dextran 40, 10 min prior to i.v. endotoxin (n = 6); HSD control group given only i.v. hypertonic saline + dextran and no endotoxin (n = 2). Injection of endotoxin caused a significant increase in hematocrit, which was counteracted by hypertonic saline treatment, with or without dextran, probably due to reduced extravasation of plasma in postcapillary venules.

Vascular permeability increase as induced by histamine or bradykinin is enhanced by advanced glycation endproducts (AGEs).

Advanced glycation endproducts (AGEs) may enhance vascular permeability in diabetic subjects. To test this hypothesis, AGEs were prepared in the presence of albumin (AGE-Alb). Control albumin (Alb) and AGE-Alb were then labeled with FITC (fluoresceinisothiocyanate) and injected i.v. into anesthetized hamsters at a dose of 7 mg/100 g B.W. Normal hamsters were given FITC-Alb or FITC-AGE-Alb and FITC-dextran. Vascular permeability changes were measured by direct intravital microscopy of the hamster cheek pouch preparations in fluorescent light and recorded as number of sites (=leaks) with extravasation of FITC-labeled albumin in postcapillary venules. No changes were seen during 1 hour after i.v. injection of FITC-Alb or FITC-AGE-Alb. Repeated local application of histamine 5 x 10(6) M or bradykinin 5 x 10(7) M to the cheek pouch for 5 min with 30-min intervals induced reversible increases in vascular permeability in all hamsters. Maximal number of leaks/cm2 before and at 30 and 60 min after FITC-Alb-injection and histamine application was 257 +/- 6 (SEM), 243 +/- 6 and 231 +/- 6 leaks/cm2 in the FITC-Alb-group and 258 + 6 (SEM), 302 +/- 12 and 316 +/- 11 leaks/cm2 in the FITCAGE-Alb-group, respectively, (P < 0.05 at 30 and 60 min). Similar results were seen with bradykinin. Our conclusions showed that i.v.-injected AGEs augmented the histamine- and bradykinin-induced increase in vascular permeability by 34% and 46%.

Nailfold capillaroscopy in hypothyroidism and hyperthyroidism: blood flow velocity during rest and postocclusive reactive hyperemia.

Direct intravital microscopic examinations of nailfold capillaries were made in three groups of subjects: 15 healthy volunteers (C) and 11 patients, six with hypothyroidism (h) and five with hyperthyroidism (H). The groups h and H were examined twice, before the onset of treatment and when they returned to euthyroidism. Capillary blood flow velocity (CBFV) was measured during rest and after release of 60-second arterial occlusion. To assess autoregulatory capacity the authors determined peak CBFV postocclusion and time to reach it in single capillaries. In patients with hypothyroidism, before the onset of the treatment, the mean resting and the mean peak CBFV were significantly lower (resting CBFV-group C: 0.93+/-0.11 mm/s (mean+/-SE); group h: 0.33+/-0.09 mm/s; and mean peak CBFV-group C: 1.49+/-0.14 mm/s; group h: 0.79+/-0.19 mm/s). The time to reach mean peak CBFV postocclusion was significantly prolonged (group C: 8.9+/-0.65 s and group h: 19.2+/-2.0 s) compared with the group of healthy volunteers. When these patients achieved euthyroidism, all the studied parameters returned to control levels. In patients with hyperthyroidism only minor changes in CBFV could be detected. In patients with hypothyroidism, the skin microvascular autoregulatory mechanisms are disturbed. The impairments of the reactive hyperemia response could be correlated with the control of the disease (thyroid state).