Different contribution of sympathetic nerve activity to arterial velocity pulse index in hypertensive patients with and without diastolic dysfunction

Introduction

Left ventricular diastolic dysfunction (LVDD) is the main cause of heart failure with preserved ejection fraction (HFpEF). LVDD is related not only to arterial stiffness but also sympathetic nerve activity (SNA). Recent study demonstrated that increased muscle sympathetic nerve activity (MSNA) may be one of contributing factor for arterial stiffness. In clinical practice, Cardio-ankle vascular index (CAVI) provides a reproducible index of arterial stiffness, independent of blood pressure (BP). Recently, Arterial Velocity pulse Index (AVI), which is an index of arterial reflected waves, have been proposed as new index of arterial stiffness. We reported that AVI was associated with MSNA in hypertensive (HT) patients. However, it is still uncertain the effect of LVDD on the association between AVI and SNA in HT patients. Thus, we tested the hypothesis that AVI would be increased and related to MSNA in HT patients with LVDD.

Methods

Patients with essential HT subjects were included in this study. HT was diagnosed as systolic blood pressure (SBP) ≥140mmHg or diastolic blood pressure (DBP) ≥90mmHg. Patients with secondary HT was excluded. AVI was measured from left upper arm by NAS-1000 (Nihon Koden, Japan). CAVI was measured by VaSera VS-1500A (Fukuda Denshi, Japan). Transthoracic echocardiography was performed by trained sonographers. SNA was evaluated by direct recording of MSNA from peroneal nerves.

Results

25 HT patients were included (age 63±14 years, Male/Female 9/16). They were divided into two groups according to E/e' (no LVDD group, E/e' ≤9, N=12; LVDD group, E/e' >9, N=13). There were no significant differences between no LVDD and LVDD groups in age (63±9 vs 69±9 years p=0.205), body mass index (23±3 vs 24±4 p=0.355), BP (SBP 139±16 vs 144±20mmHg p=0.524, DBP 87±15 vs 78±14mmHg p=0.167). LV Ejection Fraction (EF) and Stroke Volume (SV) did not differ between two groups (EF 66±7 vs 69±6% p=0.471, SV 58±7 vs 62±14ml p=0.599). MSNA had tendency to increase in LVDD group compared to no LVDD group (MSNA 53±10 vs 44±12 bursts/100 heartbeats, p=0.052). Contrary to our hypothesis, AVI and CAVI did not differ between two groups (AVI 27±7 vs 29±7 p=0.398, CAVI 8.7±1.4 vs 8.6±1.4 p=0.894). However, a significant correlation was seen between AVI and MSNA in no LVDD group (r=0.57, p<0.05), but no correlation in LVDD group. There is no correlation between CAVI and MSNA in no LVDD and LVDD group. Significant relationship was observed between AVI and CAVI in LVDD group (r=0.61, p<0.05), but no relationship in no LVDD group.

Conclusion

AVI was significantly associated with MSNA in HT patients without LVDD, but not with LVDD. CAVI was related to AVI in HT patients with LVDD, but not without LVDD. MSNA was slightly increased in HT patients with LVDD compared to without LVDD. These results indicate that augmented SNA could contribute to the increase in arterial stiffness in HT patients without LVDD, however, this contribution might be attenuated in HT patients with LVDD.

Funding Acknowledgement

Type of funding sources: None.

Higher ratio of plasma nitric oxide to asymmetric dimethylarginine levels affects aerobic exercise training-induced reduction of arterial stiffness in middle-aged and older adults

Introduction

Regular aerobic exercise reverses aging-induced deterioration of arterial stiffness via an increased arterial nitric oxide (NO) production. Concurrently, asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, was decreased by aerobic exercise training. A recent study showed that the NOx/ADMA ratio reflects endothelial function and may be an index of the states of cardiovascular disease. However, whether changes in the NOx/ADMA ratio by aerobic exercise training are associated with a decrease in arterial stiffness in healthy middle-aged and older male and female adults remains unclear.

Purpose

This study aimed to clarify whether the relationship between plasma ADMA and NOx levels affected aerobic exercise training-induced reduction of arterial stiffness in middle-aged and older adults. Additionally, we examined whether the effect of AT on circulating ADMA levels differed according to sex.

Methods

Thirty-one healthy middle-aged and older male and female subjects (male = 13, female = 18, 66.4±1.3 years) participated in the study. The subjects were randomly divided into 2 groups: a training group (n=16 [male = 6 / female = 10], 64.8±2.0 years) and a control group (n=15 [male = 7 / female = 8], 68.1±1.6 years). Subjects in the training group performed the AT program, which consisted of cycling on a leg ergometer at 60–70% of peak oxygen uptake (V(·)O2peak)for 45 min/day, 3 days/week for 8 weeks. Before and after the 8-week aerobic exercise training intervention, V(·)O2peak, plasma ADMA levels and plasma NOx levels were measured in all subjects. Also, carotid β-stiffness as an index of arterial stiffness was determined with ultrasonography.

Results

Aerobic exercise training significantly increased V(·)O2peak (P<0.05) and decreased carotid b-stiffness (P<0.01). Moreover, plasma ADMA levels were significantly decreased, and plasma NOx levels and NOx/ADMA ratio were significantly increased by aerobic exercise training (P<0.01). Additionally, no sex differences in aerobic exercise training-induced changes in circulating ADMA and NOx levels, NOx/ADMA ratio, and carotid β-stiffness were observed. Furthermore, the aerobic exercise training-induced increase in circulating ADMA levels was negatively correlated with the increase in circulating NOx levels (r=−0.414, P<0.05), and aerobic exercise training induced increase in NOx/ADMA ratio was negatively correlated with the decrease in carotid β-stiffness (r=−0.514, P<0.01).

Conclusion

These results suggest that higher NOx/ADMA ratio affects aerobic exercise training-induced reduction of arterial stiffness, regardless of sex in middle-aged and older adults.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This work was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan

Effect of pulmonary vein isolation on left atrial remodeling and muscle sympathetic nerve activity in patients with atrial fibrillation

Background

Catheter ablation (CA) for atrial fibrillation (AF) improves left ventricular function and induces left atrium reverse remodeling (LARR). CA is also associated with the modulation of ganglionated plexi in the left atrium (LA), including stretch-sensitive sympathetic and parasympathetic nerve mechanoreceptors. Increased filling pressure and enlargement of LA stimulate stretch-sensitive sympathetic nerve mechanoreceptors in heart failure, which contribute augmented sympathetic nerve activity. However, little is known about an effect of CA on the interaction between the changes of LARR and sympathetic nerve activity.

Purpose

To test the hypothesis that CA induce the reduction in sympathetic nerve activity in accordance with LARR in patients with atrial fibrillation.

Methods

This study was conducted as a retrospective, observational study. Twenty-eight AF patients (65.4±12.1 years old) were included in this study. We measured mean blood pressure (BP), heart rate (HR), brain natriuretic peptide (BNP), and direct recording of muscle sympathetic nerve activity (MSNA) using microneurography technique before and 12 weeks after CA. Echocardiogram was also performed to assess LARR and left ventricular function. To evaluate the interaction between LARR and MSNA, AF patients were divided into two groups by presence (LARR group; n=18) and absence (no LARR group; n=10) of LARR according to left atrium volume index (LAVi) following CA.

Results

No significant differences were observed at baseline in BP, MSNA and LAVi between two groups. BP did not change significantly after CA in both groups. HR significantly increased in the LARR group (63.1±5.7 vs 69.9±7.8, p<0.01) compared to no LARR group. CA significantly reduced MSNA in the LARR group (37.8±10.1 vs 24.9±8.8 bursts/min, p<0.01), but there was no significant change in the no LARR group. The septal E/e' ratio (11.3±3.8 vs 9.8±2.9, p<0.05), left ventricular end-systolic volume index (LVESVi) (24.4±11.9 vs 19.6±7.8 ml/m2, p<0.05) and Ln BNP (4.0±1.2 vs 3.3±1.0 log/pg/ml, p<0.05) were also significantly improved in the LARR group. On the other hand, in the no LARR group, there were no significancy in the changes of the septal E/e' ratio, LVESVi and Ln BNP. LVEF was not significantly changed in both two groups.

Conclusion

Our study shows CA reduced MSNA accompanied by LARR in AF patients. The reduction in MSNA, septal E/e' ratio, LVESVi and Ln BNP were all more pronounced in the LARR group compared to the no LARR group. These findings suggest that LARR is associated with the reduction in MSNA in AF patients, which was attributed to CA-induced modulation of stretch-sensitive sympathetic nerve mechanoreceptors.

Funding Acknowledgement

Type of funding sources: None.

Age differences in the association between arterial velocity pulse index and muscle sympathetic nerve activity in hypertensive patients

Background

Increased arterial stiffness characterize by aging. It is reported that age-related increases in muscle sympathetic nerve activity (MSNA) may be one of contributing factor for arterial stiffness. Arterial reflected wave was composed of SNA and aging. Increased arterial reflected wave partly plays an important role in blood pressure. Recently, we reported that arterial velocity pulse index (AVI), a novel index of arterial reflected waves, was associated with MSNA in hypertensive patients. It is still uncertain the effect of age on the association between AVI and SNA in hypertensive patients.

Method

Patients with essential HT and matched non-hypertensive control subjects were included in this study. HT was diagnosed as systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥90 mmHg. AVI was measured from left upper arm by NAS-1000. SNA was evaluated by direct recording of muscle sympathetic nerve activity (MSNA) from peroneal nerves.

Results

45 HT patients and 46 control subjects were included. Age, SBP and DBP were significantly increased in HT group compared to control (Age 63±14 vs 42±16 years, p<0.001; SBP 144±16 vs 115±9 mmHg, p<0.001; DBP 80±14 vs 67±9 mmHg, p<0.001). MSNA and AVI were significantly increased in HT group compared to control (MSNA 34±10 vs 25±8 bursts/min, p<0.05; AVI 28±9 vs 17±5, p<0.05). AVI was significantly correlated with MSNA, age, and SBP in HT group. HT group was divided into two groups according to their age (group 1, age ≤63 N=21, group 2, age ≥64 N=26). AVI in group 1 showed correlation with MSNA (r=0.59, p<0.05), but no correlation was seen in group 2. However excluded SBP>160 mmHg subjects in group 2, significant correlation was clarified between AVI and MSNA (r=0.62, p<0.05).

Conclusion

The relationship between AVI and MSNA in HT patients is preserved regardless of aging, however, high blood pressure over 160mmHg might obscure its correlation. These results indicate that AVI is useful to estimate sympathetic nerve activity in high aging HT patient treated <160 blood pressure.

Funding Acknowledgement

Type of funding sources: None.

Novel index of arterial reflected waves, Arterial Velocity pulse Index, relates to muscle sympathetic nerve activity independent of Arterial Pressure volume Index in patients with hypertension

Background

Arterial reflected wave is determined by not only atherosclerosis but also sympathetic nerve activity. Recently, Arterial Velocity pulse Index (AVI), which is an index of arterial reflected waves, and Arterial Pressure volume Index (API), which is an index of volume of a conductive blood vessel, have been proposed as new index of arterial stiffness. However, it is unclear whether API and AVI would be associated with muscle sympathetic nerve activity (MSNA) in hypertensive subjects.

Purpose

The purpose of this study was to evaluate the correlation between AVI, API and MSNA in hypertensive subjects.

Method

41 hypertensive patients and 40 non-hypertensive subjects were included in this study. We performed a cross-sectional, observational study. Hypertension (HT) was defined as systolic blood pressure (SBP) ≥140 mmHg, diastolic blood pressure (DBP) ≥90 mmHg or medical treatment for HT. AVI and API was measured by NAS-1000 (Nihon Koden, Japan). MSNA, central sympathetic outflow to peripheral muscle, was recorded directly from peroneal nerve. MSNA was expressed by burst frequency (bursts/minute) and burst incidence (bursts/100heartbeats). Blood pressure, heart rate and MSNA were recorded simultaneously.

Results

Age, systolic and diastolic pressure were significantly higher in hypertensive patients compared to control (40±15 vs 61±13 years, p<0.001; 142±16 vs 113±9 mmHg, p<0.001; 81±14 vs 67±9 mmHg, p<0.001). MSNA and AVI were significantly augmented in hypertensive patients compared to control (34±11 vs. 23±6 bursts/min, p<0.05; 26±7 vs. 16±4, p<0.05). AVI was correlated with MSNA in each group (hypertension: r=0.59, P<0.001, non-hypertension: r=0.51, p<0.001). However, no correlation was shown between API and MSNA in each group (hypertension: r=0.22, p=0.15, non-hypertension: r=0.07, p=0.63). Multiple regression analysis also showed MSNA was significantly related with AVI but was not with API.

Conclusion

Our finding showed that AVI relates to MSNA independent of API in patients with hypertension. It suggested that Novel index of arterial reflected waves, AVI, is helpful to estimate augmented SNA in hypertensive subjects regardless of volume of a conductive blood vessel.

Funding Acknowledgement

Type of funding source: None

Time course of improvement in novel nitric oxide-regulated hormones in response to exercise training in middle-aged and older adults

Introduction

Cardiovascular disease risk augments with advance of age. The mechanism of the increased cardiovascular disease risk by aging is related to attenuation of arterial function via endothelium-derived relaxing factor, such as nitric oxide (NO). Recently, apelin and adropin have identified as NO-upregulated hormones, whereas augmented secretion of asymmetric dimethylarginine (ADMA) have identified as NO-downregulated hormones. However, the effects of exercise training-induced changes in NO-regulated hormones on the reduction of arterial stiffness via NO productions remain unclear.

Purpose

This study aimed to determine the time-dependent changes in NO-regulated hormones related to exercise-training effects of arterial stiffness via NO productions in healthy middle-aged and older adults.

Methods

Thirty-two Japanese healthy middle-aged and older subjects (67±1 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed 8-week of aerobic exercise training (60–70% peak oxygen uptake [VO2peak] for 45 min, 3 days/week). We evaluated plasma nitrite/nitrate (NOx), apelin, and ADMA levels, serum apelin level and carotid-femoral pulse wave velocity (cfPWV) as an index of arterial stiffness, measured every 2 weeks for 8-week in the training group.

Results

cfPWV was gradually declined from baseline to 8-week and significantly decreased from baseline at weeks 6 (P<0.05) and 8 (P<0.01). Plasma NOx level was gradually elevated during exercise intervention and significantly increased from baseline at weeks 6 (P<0.05) and 8 (P<0.01). Interestingly, plasma apelin and serum adropin levels were gradually elevated during exercise intervention and significantly increased from baseline at weeks 4, 6 and 8 (each P<0.01). Additionally, plasma ADMA level was significantly decreased at 8-week intervention (P<0.01). Furthermore, the exercise training-induced increase in plasma NOx level was significantly correlated with the changes in circulating apelin (r=0.505, P<0.05), adropin (r=0.662, P<0.01), or ADMA (r=−0.483, P<0.05) levels before and after the 8-week. The exercise training-induced increase in plasma NOx level was significantly correlated with training-induced changes in circulating apelin (r=0.483, P<0.05) or adropin (r=0.556, P<0.05) before and after the 6-week.

Conclusions

These results suggest that the NO-upregulated hormones (apelin and adropin) were increased at the early stage of exercise training intervention and NO-downregulated hormone (ADMA) was decreased at the late stage of exercise training intervention, and these changes in NO-regulated hormones may be contributed to the reduction of arterial stiffness in the middle-aged and older adults.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

Novel method for endovascular fenestration using radiofrequency transseptal needle for aortic dissection with malperfusion syndrome

Malperfusion syndrome is considered one of the most significant adverse events in aortic dissection disease and often requires invasive strategies to improve ischemia. We report the case of a patient who was presented with worsening claudication and leg rest pain due to malperfusion syndrome of type B aortic dissection. We successfully performed endovascular fenestration therapy to relieve the symptom by using a NRG radiofrequency transseptal needle (Baylis Medical, Montreal, Canada). We suggest that this novel method would be available for the patients with malperfusion syndrome of aortic dissection

62 Time course of improvement in secretory unbalance of asymmetric dimethylarginine and nitric oxide productions in response to exercise training in middle-aged and older adults

Funding Acknowledgements

Supported by Grants-in-Aid for Scientific Research (#17H02182, #16K13059, M. Iemitsu; #18J01024, S. Fujie)

Introduction

Aging is well known to elevate risks of cardiovascular diseases. As a mechanism of these increased risks with aging, a reduction of nitric oxide (NO) production via augmented secretion of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis is related. Habitual aerobic exercise has shown to improve secretory unbalance of endothelium-derived regulating factors with aging, such as increase in NO and decrease in ADMA, resulting in the reduction of arterial stiffness. However, the time course of improvement in secretory unbalance of NO and ADMA productions in response to exercise training in middle-aged and older adults remains unclear.

Purpose

This study aimed to determine the time course of changes in plasma nitrite/nitrate (NOx) and ADMA levels related to exercise-training effects of arterial stiffness in healthy middle-aged and older adults.

Methods

Thirty-two Japanese healthy middle-aged and older subjects (67 ± 1 years) were randomly divided into two groups: exercise intervention and sedentary controls. Subjects in the training group completed 8-week of aerobic exercise training (60-70% peak oxygen uptake [VO2peak] for 45 min, 3 days/week). We evaluated plasma NOx and ADMA concentrations and carotid-femoral pulse wave velocity (cfPWV) as an index of arterial stiffness, measured every 2 weeks for 8-week in the training group.

Results

cfPWV was gradually declined from baseline to 8-week and significantly decreased from baseline at weeks 6 (P < 0.05) and 8 (P < 0.01). Plasma NOx level was gradually elevated during exercise intervention and significantly increased from baseline at weeks 6 (P < 0.05) and 8 (P < 0.01). Interestingly, plasma ADMA level was significantly decreased at 8-week intervention (P < 0.05). Furthermore, the exercise training-induced reduction in plasma ADMA level was negatively correlated with the change in plasma NOx level before and after the 8-week (r = -0.483, P < 0.05). The exercise training-induced change in plasma ADMA concentration was positively correlated with training-induced change in cfPWV before and after the 8-week (r = 0.633, P < 0.01). Additionally, there was a negative correlation between the changes in plasma NOx level and cfPWV before and after the 8-week (r = -0.642, P < 0.05).

Conclusions

These results suggest that habitual aerobic exercise can normalize the secretory unbalance of NO and ADMA productions in 6 to 8 weeks, and these balance normalizations may be contributed to the reduction of arterial stiffness in the middle-aged and older adults.

1417Effect of sodium glucose cotransporter 2 inhibitor on sympathetic nerve activity in type 2 diabetes mellitus patients

Background

Diabetes mellitus (DM) is a well-known risk factor for cardiovascular diseases. Augmented sympathetic nerve activity plays an important role in the progressive worsening disease severity. Most of anti-diabetic drugs were demonstrated to not only decrease blood glucose, but also increase sympathetic nerve activity. Recently, it has been reported that sodium glucose cotransporter 2 (SGLT2) inhibitor has beneficial effects on cardiovascular events in spite of the decrease in blood glucose in type 2 DM patients. The underlying mechanisms remain speculative; however, it is assumed that SGLT2 inhibitor would improve sympathetic nerve activity in type 2 DM patients.

Purpose

The purpose of this study was to evaluate the effect of SGLT2 inhibitor on sympathetic nerve activity in type 2 DM patients.

Methods

This study was designed as the prospective single-arm study. Type2 DM patients whose HbA1c >7.0% with at least one atherosclerotic risk factors (Hypertension, obesity, smoking history, aging ...) were included. Patients who had renal failure (eGFR<45ml/min/1.73m2) or high age patients (>80 years old) were excluded. We measured blood glucose, HbA1c and blood insulin concentration at baseline and 12 weeks after treatment of dapagliflozin (5mg/day). Muscle sympathetic nerve activity (MSNA) was applied to scrutinize accurate sympathetic nerve activity in type 2 DM patients. Also, baroreflex sensitivity was calculated by examining the relationship between MSNA and beat to beat diastolic blood pressure.

Results

Eleven type2 DM patients were included in this study. Body mass index, blood pressure, HbA1c and blood insulin concentration tended to decrease at 12weeks after dapagliflozin (body mass index: 27.2±6.3 vs. 24.9±3.2 kg/m2. systolic blood pressure: 121±12.3 vs. 118±13.6 mmHg. diastolic blood pressure: 74.3±6.3 vs. 72.5±7.6 mmHg. HbA1c: 7.6±0.3 vs. 7.2±0.7%. insulin: 9.7±7.2 vs. 8.8±5.1 μU/ml). Dapagliflozin significantly decrease MSNA and heart rate compared to baseline (46.7±7.5 vs. 38.6±6.9 bursts/minute, P<0.05. Heart rate: 80.6±8.5 vs. 72.8±7.4 beats per minute, P<0.05). However, there is no interaction between the reduction in MSNA and baroreflex sensitivity or insulin resistance.

12 weeks administration decreased MSNA

Conclusion

Our data demonstrated that dapagliflozin significantly decreased MSNA and HR beyond the lowering effect of blood glucose in type2 DM patients. These results indicate the favorable effect of SGLT2 inhibitor might be, in part, attributed to the improvement in sympathetic nerve activity.

P3495Long-term engraftment of human CD271-positive adipose-derived stem cells with pericytic and less-aged gene profile in a mouse model of hindlimb ischemia

Background

Therapeutic angiogenesis using adipose-derived stem cells (ADSCs) is an attractive strategy for ischemic cardiovascular diseases. We previously reported that human CD271+ population of adipose-derived stem cells (ADSCs) promoted neovascularization with enhanced engraftment in a mouse model of hindlimb ischemia. However, whether and how CD271+ ADSCs promote the long-term engraftment is still uncertain.

Purpose

We aimed to examine whether the angiogenic effect and cell engraftment capacity of CD271+ ADSCs would be sustained in long-term period. Then, comparative gene profiling between CD271+ and CD271- ADSCs were analyzed. Finally, cell proliferation and endothelial differentiation assays were conducted.

Methods

ADSCs were isolated from subcutaneous adipose tissue of 5 patients received cardiovascular surgery. CD271+ and CD271- ADSCs were sorted from CD45-CD31-CD34+ ADSCs fraction by FACS sorting (Fig. A). Cultured CD271+ and CD271- ADSCs at passage 6 were labeled by PKH26 cell linker dye and used for xenograft experiments. Briefly, athymic nude mice were subjected to hindlimb ischemia and one million of human ADSCs were injected into the ischemic muscles. In control group, PBS was solely injected. At 2 and 5 weeks, neovascularization was evaluated by immunohistochemistry (capillary density using lectin perfusion). Cell engraftment was assessed by counting PKH26-positive cells. Furthermore, we compared gene profiling between CD271+ and CD271- ADSCs by microarray. Proliferative capacity was evaluated by colony-forming unit (CFU) assay with Giemsa staining. In endothelial differentiation assay, CD271+ and CD271- ADSCs were cultured in differentiation induction medium containing vascular endothelial growth factor for 2 weeks and stained with anti-human CD31 antibody.

Results

Cell therapy using CD271+ ADSCs demonstrated approximately 3-fold more enhanced neovascularization than those using CD271- ADSCs or PBS in histological analysis of capillary density at 2 weeks from cell therapy (Fig. B and C). At 5 weeks, mice treated with CD271+ ADSCs were significantly rescued from limb ischemia and this was accompanied by sustained engraftment of ADSCs (Fig. D). In microarray analysis, the differentially expressed 2167 genes were extracted to classify CD271+ and CD271- ADSCs. Pathway analysis demonstrated CD271 expression on ADSCs was associated with the pathways related to stemness and cell differentiation. Indeed, we found that genes related to cell proliferation (PI3K, Cyclin D, and Cyclin D2) were up-regulated in CD271+ ADSCs. Additionally, we found the pericytic marker nestin which was significantly up-regulated in CD271+ ADSCs. Consistent with these findings, CD271+ ADSCs were more proliferative and capable for endothelial differentiation while CD271- ADSCs were not.

FACS and cell therapy experiments

Conclusion

These results suggest that CD271+ ADSCs possess long-term engraftment and angiogenic capacity due to their less-aged and more pericytic gene profile.

Acknowledgement/Funding

Japan Society for the Promotion of Science (JSPS) KAKENHI (Tokyo, Japan) Grant Number JP16H06828

Ischemic Preconditioning Enhances Muscle Endurance during Sustained Isometric Exercise

Ischemic preconditioning (IPC) enhances whole-body exercise endurance. However, it is poorly understood whether the beneficial effects originate from systemic (e. g., cardiovascular system) or peripheral (e. g., skeletal muscle) adaptations. The present study examined the effects of IPC on local muscle endurance during fatiguing isometric exercise. 12 male subjects performed sustained isometric unilateral knee-extension exercise at 20% of maximal voluntary contraction until failure. Prior to the exercise, subjects completed IPC or control (CON) treatments. During exercise trial, electromyography activity and near-infrared spectroscopy-derived deoxygenation in skeletal muscle were continuously recorded. Endurance time to task failure was significantly longer in IPC than in CON (mean±SE; 233±9 vs. 198±9 s, P<0.001). Quadriceps electromyography activity was not significantly different between IPC and CON. In contrast, deoxygenation dynamics in the quadriceps vastus lateralis muscle was significantly faster in IPC than in CON (27.1±3.4 vs. 35.0±3.6 s, P<0.01). The present study found that IPC can enhance muscular endurance during fatiguing isometric exercise. Moreover, IPC accelerated muscle deoxygenation dynamics during the exercise. Therefore, we suggest that the origin of beneficial effects of IPC on exercise performance may be the enhanced mitochondrial metabolism in skeletal muscle.

Effects of habitual aerobic exercise on the relationship between intramyocellular or extramyocellular lipid content and arterial stiffness

The accumulation of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) is associated with arterial stiffness in middle-aged and older adults. Habitual aerobic exercise induces the improvement of arterial stiffness with reduction in fat accumulation. However, the relationship between aerobic exercise-induced changes in muscular lipids and arterial stiffness remains unclear. The purpose of this study was to investigate whether habitual aerobic exercise-induced changes in IMCL and EMCL content would lead to an improvement of arterial stiffness. First, in a cross-sectional study, we investigated whether cardiorespiratory fitness level affects the association between IMCL or EMCL content and arterial stiffness in 60 middle-aged and older subjects (61.0±1.3 years). Second, in an intervention study, we examined whether aerobic exercise training-induced changes in IMCL and EMCL content are associated with a reduction in arterial stiffness in 18 middle-aged and older subjects (67.0±1.7 years). In the cross-sectional study, IMCL content was negatively correlated with brachial-ankle pulse wave velocity (baPWV) (r=-0.47, P<0.05), whereas EMCL content was positively correlated with baPWV (r=0.48, P<0.05) in the low-fitness group, but was not correlated in the high-fitness group. Furthermore, 8-week aerobic exercise training in older adults increased IMCL content and reduced EMCL content. The training-induced change in baPWV was negatively correlated with training-induced changes in IMCL but was positively correlated with training-induced changes in EMCL. These findings suggest that aerobic exercise training-induced changes in IMCL and EMCL content may be related to a reduction in arterial stiffness in middle-aged and older adults.

Elevated pentraxin 3 level at the early stage of exercise training is associated with reduction of arterial stiffness in middle-aged and older adults

Regular exercise improves aging-induced deterioration of arterial stiffness, and is associated with elevated production of pentraxin 3 (PTX3) and anti-inflammatory as well as anti-atherosclerotic effects. However, the time-dependent effect of exercise training on arterial stiffness and PTX3 production remains unclear. The purpose of this study was to investigate the time course of the association between the effects of training on the circulating PTX3 level and arterial stiffness in middle-aged and older adults. Thirty-two healthy Japanese subjects (66.2±1.3 year) were randomly divided into two groups: training (exercise intervention) and sedentary controls. Subjects in the training group completed 8 weeks of aerobic exercise training (60-70% peak oxygen uptake (VO2peak) for 45 min, 3 days per week); during the training period, we evaluated plasma PTX3 concentration and carotid-femoral pulse wave velocity (cfPWV) every 2 wk. cfPWV gradually declined over the 8-week training period, and was significantly reduced after 6 and 8 week of exercise intervention (P<0.05). Plasma PTX3 level was significantly increased after 4 weeks of the intervention (P<0.05). In addition, the exercise training-induced reduction in cfPWV was negatively correlated with the percent change in plasma PTX3 level after 6 week (r=-0.54, P<0.05) and 8 weeks (r=-0.51, P<0.05) of the intervention, but not correlated at 4 weeks. Plasma PTX3 level was elevated at the early stage of the exercise training intervention, and was subsequently associated with training-induced alteration of arterial stiffness in middle-aged and older adults.

Planned Overreaching and Subsequent Short-term Detraining Enhance Cycle Sprint Performance

We investigated the effect of a training program consisting of planned overreaching and subsequent short-term detraining on sprint performance. 24 physically active men participated in an 18-day sprint-training program. They were divided into 2 groups: the overreaching-detraining (OR-DT) and the control (CON) groups. Subjects in the OR-DT group performed 12 consecutive days of maximal cycle sprint training followed by 6 days of detraining, whereas a rest day was provided after every 2 successive training days for the CON group. Peak power output during maximal pedaling increased significantly after 6 days of detraining in the OR-DT group compared with the baseline (P<0.05), whereas no change was observed in CON group. Intramuscular phosphocreatine concentration increased significantly after 12 days of daily training in the OR-DT group (69.3±45.8% increase vs. baseline, P<0.05), and it was maintained after the detraining period (46.6±33.6% increase vs. baseline, P<0.05). However, no change was observed in CON group. No significant changes in blood variables were observed after the training period except significant reduction of serum cortisol in the CON group. Daily sprint training and subsequent short-term detraining enhanced peak power output after the detraining period.

Relationship between reduced lower abdominal blood flows and heart rate in recovery following cycling exercise

AIM

To examine the blood flow (BF) response in the lower abdomen (LAB) in recovery following upright cycling exercise at three levels of relative maximum pulmonary oxygen consumption (VO(2max)) and the relationship of BF(LAB) to heart rate (HR) and target intensity.

METHODS

For 11 healthy subjects, BF (Doppler ultrasound) in the upper abdominal aorta (Ao) above the coeliac trunk and in the right femoral artery (RFA) was measured repeatedly for 720 s after the end of cycling exercises at target intensities of 30%, 50% and 85% VO(2max), respectively. Blood flow in the lower abdomen (BF(LAB)) can be measured by subtracting bilateral BF(FAs) (≈twofolds of BF(RFA)) from BF(Ao). Change in BF(LAB) (or BF(LAB) volume) at any point was evaluated by difference between change in BF(Ao) and in BF(FAs). Heart rate and blood pressure were also measured.

RESULTS

At 85% VO(2max), significant reduction in BF(LAB) by approx. 89% was shown at 90 s and remained until 360 s. At 50% VO(2max), reduction in BF(LAB) by approx. 33% was found at 90 s although it returned to pre-exercise value at 120 s. On the contrary at 30% VO(2max), BF(LAB) showed a light increase (<20%) below 70 bpm of HR. There was a close negative relationship (P < 0.05) between change in BF(LAB) and recovery HR, as well as between change in BF(LAB) volume and both recovery HR and % VO(2max).

CONCLUSION

This study suggests that the lower abdominal BF in recovery may be influenced by sympathetic-vagus control, and dynamics of BF(LAB) may be closely related to the level of relative exercise intensities.

Low-volume muscle endurance training prevents decrease in muscle oxidative and endurance function during 21-day forearm immobilization

AIM

To examine the effects of low-volume muscle endurance training on muscle oxidative capacity, endurance and strength of the forearm muscle during 21-day forearm immobilization (IMM-21d).

METHODS

The non-dominant arm (n = 15) was immobilized for 21 days with a cast and assigned to an immobilization-only group (Imm-group; n = 7) or an immobilization with training group (Imm+Tr-group; n = 8). Training comprised dynamic handgrip exercise at 30% of pre-intervention maximal voluntary contraction (MVC) at 1 Hz until exhaustion, twice a week during the immobilization period. The duration of each exercise session was 51.7 +/- 3.4 s (mean +/- SE). Muscle oxidative capacity was evaluated by the time constant for phosphocreatine recovery (tau(off)PCr) after a submaximal handgrip exercise using (31)phosphorus-magnetic resonance spectroscopy. An endurance test was performed at 30% of pre-intervention MVC, at 1 Hz, until exhaustion.

RESULTS

tau(off)PCr was significantly prolonged in the Imm-group after 21 days (42.0 +/- 2.8 and 64.2 +/- 5.1 s, pre- and post-intervention respectively; P < 0.01) but did not change for the Imm+Tr-group (50.3 +/- 3.0 and 48.8 +/- 5.0 s, ns). Endurance decreased significantly for the Imm-group (55.1 +/- 5.1 and 44.7 +/- 4.6 s, P < 0.05) but did not change for the Imm+Tr-group (47.9 +/- 3.0 and 51.7 +/- 4.0 s, ns). MVC decreased similarly in both groups (P < 0.01).

CONCLUSIONS

Twice-weekly muscle endurance training sessions, each lasting approx. 50 s, effectively prevented a decrease in muscle oxidative capacity and endurance; however, there was no effect on MVC decline with IMM-21d.

HER-2 expression on circulating tumor cells in metastatic breast cancer

Abstract #5020

Background: HER-2 Overexpression in breast cancer is associated with poor prognosis. The circulating tumor cells (CTCs) in peripheral blood can be identified in patients with breast cancer. They are recognized as a predictor of the effect of systemic therapy, and also as a prognostic marker recently. Cristofanilli et al reported that progression-free Survival (PFS) and overall survival(OS) in metastatic breast cancer patients with &lt;5CTCs per7.5ml are significantly better than those with &gt;5CTCs before initiation of a new line of therapy and at the 1st follow-up visit. However, the detection rate and value of HER-2 Overexpression on CTCs has been not determined well.Materials and Methods:CTCs were obtained prospectively for 22 patients with metastatic breast cancer to start a new line of treatment at single institution. Blood specimens were collected at monthly intervals for a period of up to 12 weeks. CT scans were also performed before start of the treatment and 12 weeks after. HER-2 expression on primary lesions and CTCs were determined by both immunohistochemical methods and fluorescence in situ hybridization (FISH) analysis. Mean age was 54.4 years (range, 32-75 years). 8 patients received first line therapy, one patient received second line therapy, and 13 patients received over third line therapy. Of the 22 primary cancer, 7(31.8%) were HER-2 positive(score,+3 or +2/FISH positive) and 15 (68.2%) were HER-2 negative. CTCs were determined using Cell Search™ System.Results:14(63.6%) patients had clinical benefit (partial response and stable disease) during the course. CTCs were detected in 16 patients (72.7%). OS for patients with &lt;5CTCs were significantly longer than those with 5&lt; at any period. In 15 patients with HER-2 negative primary cancer, 5 patients (33.3%) were with HER-2 positive CTCs. However, in 7 patients with HER-2 positive primary cancer, 6 patients (85.7%) who had been treated with trastuzumab was with HER-2 negative CTCs. But only one patient (14.3%) treated without trastuzumab was with HER-2 positive CTCs. The patient had been treated with trastuzumab and failed in past. And the median OS time for those patients with HER2 Positive CTCs were significantly shorter (130.5 days) than for those patients with HER2 negative CTCs (283.3 days). Surprisingly, 5 (83.3%) of 6 patients with HER-2 positive CTCs were dead within 7 months.Conclusion:The number of CTCs is a prognostic marker for the patients with metastatic breast cancer. Furthermore, HER-2 positive CTCs is much related to poor prognosis. And these results indicated that the possibility of negative conversion of HER2 expression on CTCs for patients with HER-2 positive primary cancer due to trastuzumab. Trastuzumab may be effective for the patients with HER2 negative primary cancer and HER-2 positive CTCs.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5020.

Response to neoadjuvant chemotherapy in patients with triple negative breast cancer

Abstract #6069

Background:&#x2028; Triple negative breast cancer (TNBC) is defined by the lack of estrogen receptor(ER), progesterone receptor (PR), and human epidermal growth factor receptor2 (HER-2) expression. TNBC has poor outcome due to no specific therapeutic agents. But TNBC includes two major phenotypes, basal-like and non basal-like phenotypes. Basal-like phenotype has poor prognosis and is associated with positive expression of basal markers. We compared response to neoadjuvant chemotherapy between patients with TNBC and non-TNBC, in addition, basal-like and non basal-like phenotype.&#x2028; Material and Methods:&#x2028; We retrospectively reviewed a total of 1948 operated patients with a diagnosis of primary breast cancer from November 2002 to December 2006 at St. Luke's International Hospital. 369 (18.9%) patients received neoadjuvant chemotherapy. Clinical and pathological response rates, survival measurements and relapse rates were compared between patients with TNBC and non-TNBC. Clinical response was determined by MRI or CT which was performed before and after neoadjuvant chemotherapy. Histopathological parameter(ER, PGR, HER-2, nuclear grade, mitosis) were confirmed from the specimens of needle biopsy performed before treatment. The specimens were also stained with basal markers (cytokeratin 5/6 and EGFR) to identify basal-like phenotype in TNBC. Basal-like phenotype was defined by the expression of CK5/6 and/or EGFR in &gt;10% of tumor cells.&#x2028; Results:&#x2028; Fifty-four of 369 patients (14.6%) had TNBC. Progressive disease (PD) rate was significantly higher in patients with TNBC than those patients with non-TNBC (20.7% v 2.3%).And pathologic complete response rate (pCR) was also higher in patients with TNBC than those patients with non-TNBC (17% v 9.6%).14of 48 patients (29.1%) was diagnosed as Basal-like phenotype in TNBC. Clinical response rate for basal-like phenotype was worse than non basal-like phenotype (42.9% v 67.6%). Furthermore, both disease free survival and overall survival for basal-like subtype were significantly worse than non basal-like phenotype (p&lt;0.05).Other parameters including age, histological grade, and tumor size were not significant for response to neoadjuvant chemotherapy.&#x2028; Conclusions:&#x2028; Patients with TNBC have higher PD rate but also pCR rate to treatment compared with non TNBC. Furthermore, basal-like phenotype could predict poor prognosis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6069.

Th1-biased humoral immune responses against Wilms tumor gene WT1 product in the patients with hematopoietic malignancies

The Wilms' tumor gene WT1 is highly expressed in leukemias and myelodysplastic syndrome (MDS), and WT1 expression levels increase along with the disease progression in chronic myeloid leukemia and MDS. We previously reported that IgM and IgG WT1 antibodies were detected with significantly higher detection rate and antibody titers in leukemias and MDS compared to those in healthy volunteers. In this study, whether IgG humoral immune responses against WT1 protein were Th1- or Th2-type were determined by measurement of four subclasses of IgG WT1 antibody, IgG1, IgG2, IgG3, and IgG4. In leukemias and MDS, Th1-type WT1 antibodies such as IgG1, IgG2, and IgG3 were significantly increased in both detection rate and antibody titers compared to those in healthy volunteers, whereas Th2-type WT1 antibody such as IgG4 did not increase. These results showed that Th1-biased humoral immune responses against WT1 protein were generated in leukemias and MDS. These results should allow us to consider that Th1-biased cellular immune responses against WT1 protein, which was essentially needed for cancer immunotherapy targeting WT1, should be elicited in patients with hematopoietic malignancies.

A stochastic-modeling evaluation of the foot-and-mouth-disease survey conducted after the outbreak in Miyazaki, Japan in 2000

When foot-and-mouth-disease (FMD) was identified in Miyazaki prefecture in March 2000, Japan conducted an intensive serological and clinical survey in the areas surrounding the index herd. As a result of the survey during the 21 days of the movement-restriction period, two infected herds were detected and destroyed; there were no other cases in the months that followed. To evaluate the survey used for screening the disease-control area and surveillance area, we estimated the herd-level sensitivity of the survey (HSe) through a spreadsheet model using Monte-Carlo methods. The Reed-Frost model was incorporated to simulate the spread of FMD within an infected herd. In the simulations, 4, 8 and 12 effective-contact scenarios during the 5-day period were examined. The estimated HSes of serological tests (HSeE) were 71.0, 75.3 and 76.3% under the 4, 8 and 12 contact scenarios, respectively. The sensitivity analysis showed that increasing the number of contacts beyond 12 did not improve HSeE, but increasing the number of sampled animals and delaying the dates of sampling did raise HSeEs. Small herd size in the outbreak area (>80% of herds have <20 animals) seems to have helped in maintaining HSeE relatively high, although the serological inspection was carried out before sero-positive animals had a chance to increase in infected herds. The estimated herd-level specificity of serological tests (HSpE) was 98.6%. This HSpE predicted 224 false-positive herds (5th percentile estimate was 200 and 95th percentile was 249), which proved close to the 232 false-positive herds actually observed. The combined-test herd-level sensitivity (serological and clinical inspections combined; CTHSe), averaged 85.5, 87.6 and 88.1% for the 4, 8 and 12 contact scenarios, respectively. Using these CTHSes, the calculated probability that no infected herd was overlooked by the survey was > or =62.5% under the most-conservative, four-contact scenario. The probability that no more than one infected herd was overlooked was > or =89.7%.

Quantitative effects of respiration on venous return during single knee extension-flexion

Respiration and the muscle pump play major roles in increasing venous return. However, the relative contribution of each of these factors remains unclear. The present study investigates the quantitative effects of interaction between respiration and the muscle pump on femoral venous blood flow (FVBF) during a single voluntary knee extension-flexion (KEF) using duplex-Doppler ultrasound. During various respiration modes, which consisted of arrested respiration, normal respiration and deep respiration (inspiration or expiration), eight subjects performed a supine one-legged voluntary KEF. FVBF was measured during respiration only (Protocol A) and during KEF synchronized with respiration (Protocol B). The difference between FVBF values obtained in Protocol B and Protocol A was defined as DeltaFVBF. When KEF was synchronized with normal or deep respiration, FVBF with inspiration was significantly lower than that with expiration. However, DeltaFVBF was significantly higher with inspiration than with expiration during deep respiration but was not significant during normal respiration. Furthermore, DeltaFVBF was significantly higher at both normal and deep respiration than at arrested respiration. The effects upon the venous return during KEF differed between inspiration and expiration. The present findings indicate that during a single supine KEF, respiration might promote venous return to a range of 1.5- to 2.3-fold DeltaFVBF during arrested respiration.

A mandatory role for STAT4 in IL-12 induction of mouse T cell CCR5

IL-12 was recently shown to induce CCR5 on TCR-triggered mouse T cells. Considering that STAT4 is the most critical of IL-12 signaling molecules, this study investigated the role for STAT4 in the induction of CCR5 expression. IL-12R was induced by stimulation with anti-CD3 plus anti-CD28 mAb similarly on T cells from wild-type (WT) and STAT4-deficient (STAT4(-/-)) mice, but the levels of IL-12R induced on IFN-gamma-deficient (IFN-gamma(-/-)) T cells were lower compared with WT T cells. Exposure of TCR-triggered WT T cells to IL-12 induced CCR5 expression. In contrast, TCR-triggered STAT4(-/-) T cells failed to express CCR5 in response to IL-12. IL-12 stimulation induced detectable albeit reduced levels of CCR5 expression on IFN-gamma(-/-) T cells. Addition of rIFN-gamma to cultures of IFN-gamma(-/-) T cells, particularly to cultures during TCR triggering resulted in restoration of CCR5 expression. However, CCR5 expression was not induced in STAT4(-/-) T cells by supplementation of rIFN-gamma. These results indicate that for the induction of CCR5 on T cells, 1) STAT4 plays an indispensable role; 2) such a role is not substituted by simply supplementing rIFN-gamma; and 3) IFN-gamma amplifies CCR5 induction depending on the presence of STAT4.

[Clinical analysis of multidrug-resistant tuberculosis]

Forty-three patients with multidrug-resistant tuberculosis at National Chiba-Higashi Hospital were studied retrospectively. TB cases excreting tubercle bacilli which are resistant to both 0.1 microgram/ml of isoniazid and 50 micrograms/ml of rifampicin were defined as multidrug-resistant cases. From 1993 to 1997, we experienced 1627 patients with pulmonary tuberculosis, and among them 43 patients (23-79 years old, 35 males and 8 females) were proved to be multidrug-resistant. Six cases were initially treated cases and other 37 cases had been treated previously. On admission, 40 out of 43 cases (93.0%) were smear positive by sputum examination of mycobacteria and 38 out of 43 cases (88.4%) had cavitary lesions on chest X-ray. Six patients were complicated with diabetes mellitus, two with cancer, one with alcohol dependence, one with chronic hepatitis, and others did not have prominent complications. Three operated patients were cured, the fact shows that the surgical treatment is still a useful measure for cases with the indication. Sixteen patients were cured, eight were still under treatment, and thirteen were died of tuberculosis. One of reasons of poor prognosis of multidrug-resistant tuberculosis is that multidrug-resistant tubercle bacilli are usually resistant to other drugs, too. In case of multidrug-resistant tuberculosis, patients were obliged to be treated in a hospital long-term to prevent the spread of tubercle bacilli. Therefore, it is very important to find out new tuberculosis cases as an early as possible, treat them with proper regimen and prevent dropout by directly observed therapy, thus preventing the emergence of multidrug-resistant tuberculosis. Development of new antituberculous agents is strongly expected.

IFN-alpha acts on T-cell receptor-triggered human peripheral leukocytes to up-regulate CCR5 expression on CD4+ and CD8+ T cells

Interleukin-12 (IL-12) as well as IL-2 was recently shown to up-regulate CCR5 expression on T-cell receptor (TCR)-triggered human T cells. Because of the functional similarity between interferon-alpha (IFN-alpha) and IL-12, the present study investigated whether IFN-alpha also up-regulates T cell CCR5 expression. CCR5 was marginally detected on T cells from unstimulated human peripheral blood leukocytes (PBLs) and only slightly induced on PBL T cells following stimulation with anti-CD3 plus anti-CD28 monoclonal antibodies (mAbs). When anti-CD3/anti-CD28-triggered PBLs were exposed to IFN-alpha, T cells expressed high levels of CCR5. The levels of CCR5 expression were comparable to those induced by IL-12. However, when purified T cells instead of unfractionated PBL were stimulated with anti-CD3/CD28 and then exposed to IL-12 or IFN-alpha, CCR5 expression was induced by IL-12 but not by IFN-alpha. IFN-alpha was found to act on anti-CD3/anti-CD28-stimulated PBL to promote their IL-12 production. Moreover, addition of anti-IL-12 mAb to IFN-alpha-stimulated cultures of anti-CD3/CD28-pretreated PBL resulted in considerable inhibition of CCR5 expression. Together, these results indicate that IFN-alpha as well as IL-12 up-regulates CCR5 expression on TCR-triggered T cells and that IFN-alpha functions not by acting directly on T cells but via enhancing IL-12 production by PBL.

Stable pulmonary capillary haemangiomatosis without symptomatic pulmonary hypertension

Pulmonary capillary haemangiomatosis is a rare disorder characterised by multiple angiomatous lesions composed of proliferating capillary vessels in the lung parenchyma that usually progress rapidly to establish fatal pulmonary hypertension. The 29 year old man presented here, however, has been stable for 3.5 years since the diagnosis without symptoms of pulmonary hypertension. High resolution computed tomographic findings of the pulmonary lesions seemed specific to the disease.

IL-12 plays a pivotal role in LFA-1-mediated T cell adhesiveness by up-regulation of CCR5 expression

The chemokine receptor CCR5 has been implicated in the recruitment of T cells to inflammatory sites. However, the regulation of CCR5 induction on T cells and its contribution to T cell adhesiveness are poorly understood. Using a Th1 clone, 2D6, that can be maintained with interleukin (IL)-12 or IL-2 alone (designated 2D6(IL-12) or 2D6(IL-2), respectively), we investigated how CCR5 is induced on T cells and whether CCR5 is responsible for up-regulating the function of adhesion molecules. 2D6(IL-12) grew, forming cell aggregates, in culture containing IL-12. This was due to lymphocyte function-associated antigen (LFA)-1-intercellular adhesion molecule (ICAM)-1 interaction, because 2D6(IL-12) expressed both LFA-1 and ICAM-1 and cell aggregation was inhibited by anti-ICAM-1 monoclonal antibody. Despite comparable levels of LFA-1 and ICAM-1 expression, 2D6(IL-2) cells did not aggregate in culture with IL-2. It is important that there was a critical difference in CCR5 expression between 2D6(IL-12) and 2D6(IL-2); the former expressed high levels of CCR5, and the latter expressed only marginal levels. Both types of cells expressed detectable albeit low levels of RANTES (regulated on activation, normal T expressed and secreted) mRNA. Unlike IL-12 or IL-2, IL-18 induced high levels of RANTES mRNA expression without modulating CCR5 expression. Therefore, combined stimulation with IL-12 and IL-18 strikingly up-regulated 2D6 cell aggregation. Notably, LFA-1-mediated aggregation of 2D6(IL-12) cells was suppressed by anti-CCR5 antibody. These results indicate that IL-12 plays a critical role in CCR5 expression on Th1 cells and consequently contributes to CCR5-mediated activation of LFA-1 molecules.

A survey of Theileria sergenti infection, daily weight gain and conception proportions in 85 herds of grazing heifers in Japan

A survey of Theileria sergenti infections, daily weight gain and conception proportion was conducted in 85 herds of grazing heifers in Japan. Basic information and epidemiological data from participating herds were obtained by mailed questionnaires, which were completed by field veterinarians. The average cumulative incidence and proportion of treated animals in the participating herds were 25.7 and 21.1%, respectively. The average daily weight gain and conception proportion were 0.51 kg per day and 56.9%, respectively. The basic information and epidemiological data had a large range and standard deviation, which reflect the wide diversity of the grazing herds in Japan. Herds with heavy tick infestation had significantly higher cumulative incidence and proportion of treated animals, therefore, this factor can be a good estimator to predict the occurrence and loss by theileriosis of the herds. The present questionnaire survey was useful for obtaining information about herds in different regions, and this survey method can be applied to the research of other animal diseases in Japan.

CD28 costimulation is required not only to induce IL-12 receptor but also to render janus kinases/STAT4 responsive to IL-12 stimulation in TCR-triggered T cells

The activation of resting T cells for the acquisition of various functions depends on whether CD28 costimulatory signals are provided upon T cell receptor stimulation. Here, we investigated how CD28 costimulation functions to allow TCR-triggered resting T cells to acquire IL-12 responsiveness. When T cells are stimulated with low doses of anti-CD3 mAb, CD28 costimulation was required for the optimal levels of IL-12 receptor (IL-12R) expression. However, stimulation of T cells with high doses of anti-CD3 alone induced comparable levels of IL-12R expression to those induced upon CD28 costimulation. Nevertheless, there was a substantial difference in IL-12 responsiveness between these two groups of T cells: compared to anti-CD28-costimulated T cells, T cells that were not costimulated with anti-CD28 exhibited decreased levels of Janus kinases (JAK) JAK2/TYK2 and STAT4 phosphorylation and IFN-y production following IL-12 stimulation. Importantly, STAT6 phosphorylation following IL-4 stimulation was not decreased in anti-CD28-uncostimulated T cells. These resutls indicate that CD28 costimulation not only contributes to up-regulating IL-12R expression but is also required to render JAKs/STAT4 responsive to IL-12 stimulation.

An absolute requirement for STAT4 and a role for IFN-gamma as an amplifying factor in IL-12 induction of the functional IL-18 receptor complex

IL-12 and IL-18 are both proinflammatory cytokines that contribute to promoting Th1 development and IFN-gamma expression. However, neither IL-12R nor IL-18R is expressed as a functional complex on most resting T cells. This study investigated the molecular mechanisms underlying the induction of an IL-18R complex in T cells. Resting T cells expressed IL-18Ralpha chains but did not exhibit IL-18 binding sites as detected by incubation with rIL-18 followed by anti-IL-18 Ab, suggesting a lack of IL-18Rbeta expression in resting T cells. Although they also failed to express IL-12R, stimulation with anti-CD3 plus anti-CD28 generated IL-12R. Exposure of these cells to IL-12 led not only to up-regulation of IL-18Ralpha expression but also to induction of IL-18R binding sites on both CD4(+) and CD8(+) T cells concomitant with IL-18Rbeta mRNA expression. The IL-18 binding site represented a functional IL-18R complex capable of exhibiting IL-18 responsiveness. IL-12 induction of an IL-18R complex and IL-18Rbeta mRNA expression was not observed in STAT4-deficient (STAT4(-/-)) T cells and was substantially decreased in IFN-gamma(-/-) T cells. However, the failure of STAT4(-/-) T cells to induce an IL-18R complex was not corrected by IFN-gamma. These results indicate that STAT4 and IFN-gamma play an indispensable role and a role as an amplifying factor, respectively, in IL-12 induction of the functional IL-18R complex.

A critical role for IL-12 in CCR5 induction on T cell receptor-triggered mouse CD4(+) and CD8(+) T cells

Despite increasing evidence for the role of the chemokine system in leukocyte trafficking, the mechanism underlying the induction of chemokine receptors is poorly understood. Here, we investigated how CCR5, a chemokine receptor implicated in T cell migration to inflammatory sites, is induced in the T cell. CCR5 mRNA was hardly detected in resting T cells and marginally induced following T cell receptor (TCR) stimulation. However, TCR-triggered T cells expressed IL-12 receptor, and stimulation with recombinant IL-12 resulted in high levels of CCR5 expression on both CD4(+) and CD8(+) T cells. In contrast, IL-2 failed to up-regulate CCR5 expression. The effect of IL-12 was selective to CCR5 because IL-12 did not up-regulate CXCR3 expression. Surface expression of CCR5 was shown by staining with anti-CCR5 monoclonal antibody. Stimulation of these CCR5-positive T cells with the relevant chemokine MIP-1 alpha elicited Ca(2+) influx, showing that IL-12-induced CCR5 is functional. These results indicate a critical role for IL-12 in the induction of CCR5 on TCR-triggered T cells.

Involvement of SHP-1 tyrosine phosphatase in TCR-mediated signaling pathways in lipid rafts

To elucidate the process of TCR-mediated signaling pathways in lipid rafts, we constructed a chimeric molecule that localizes activated SHP-1 to rafts. Raft targeting of activated SHP-1 in Jurkat-derived transfectants completely inhibited the expression of CD69 and transcriptional factors after TCR cross-linking. Whereas the inducible tyrosine phosphorylation of TCR zeta and ZAP-70 and the kinase activity of Lck were intact, phosphorylated LAT was rapidly dephosphorylated by raft targeting of activated SHP-1, leading to defects in LAT activation and subsequent downstream signaling events. Intriguingly, recruitment of endogenous SHP-1 to rafts and its association with LAT were dramatically increased after TCR engagement, suggesting that SHP-1 is involved in raft-mediated T cell activation.

CD28 costimulation is required not only to induce IL-12 receptor but also to render janus kinases/STAT4 responsive to IL-12 stimulation in TCR-triggered T cells

The activation of resting T cells for the acquisition of various functions depends on whether CD28 costimulatory signals are provided upon T cell receptor stimulation. Here, we investigated how CD28 costimulation functions to allow TCR-triggered resting T cells to acquire IL-12 responsiveness. When T cells are stimulated with low doses of anti-CD3 mAb, CD28 costimulation was required for the optimal levels of IL-12 receptor (IL-12R) expression. However, stimulation of T cells with high doses of anti-CD3 alone induced comparable levels of IL-12R expression to those induced upon CD28 costimulation. Nevertheless, there was a substantial difference in IL-12 responsiveness between these two groups of T cells: compared to anti-CD28-costimulated T cells, T cells that were not costimulated with anti-CD28 exhibited decreased levels of Janus kinases (JAK) JAK2/TYK2 and STAT4 phosphorylation and IFN-y production following IL-12 stimulation. Importantly, STAT6 phosphorylation following IL-4 stimulation was not decreased in anti-CD28-uncostimulated T cells. These resutls indicate that CD28 costimulation not only contributes to up-regulating IL-12R expression but is also required to render JAKs/STAT4 responsive to IL-12 stimulation.

A role of interferon-gamma (IFN-gamma) in tumor immunity: T cells with the capacity to reject tumor cells are generated but fail to migrate to tumor sites in IFN-gamma-deficient mice

IFN-gamma-deficient (IFN-gamma-/-) mice induce potent in vitro immune responses such as anti-allo mixed lymphocyte reaction and CTL responses, whereas they often fail to exhibit in vivo immunity. Here, we investigated whether there exists a defect in tumor rejection responses and if so, which process of responses is impaired. IFN-gamma-/- and wild-type (WT) BALB/c mice were immunized with attenuated syngeneic CSA1M tumor cells. The capacity of T cells to mediate tumor protection was examined in Winn assays to assess the growth of tumor cells admixed with tumor-sensitized T cells. Splenic T cells from both groups of mice exhibited comparable levels of tumor-neutralizing activity. When portions of immunized mice were directly challenged with viable tumor cells, tumor rejection was induced only in WT mice. CD4(+) and CD8(+) T-cell infiltration were observed at the site of tumor challenge in WT mice, whereas such a T-cell infiltration did not occur in IFN-gamma-/- mice. Similarly, splenic T cells from interleukin 12-treated CSA1M-bearing IFN-gamma-/- and WT mice neutralized tumor cells at comparable efficacies in Winn assays. However, the migration of these T cells to tumor masses and the resultant interleukin 12-induced tumor regression took place in WT mice, but neither intratumoral T-cell infiltration nor tumor regression occurred in IFN-gamma-/- mice. These results indicate a critical requirement for IFN-gamma in the process of inducing T-cell migration to tumor sites rather than of generating antitumor protective T cells.

Coordination of chemokine and adhesion systems in intratumoral T cell migration responsible for the induction of tumor regression

T cell migration into tumor masses is critical to the process of immunologically induced tumor regression. Like other lymphoid populations, T cells are recruited to inflammatory sites depending on the interaction of T cell integrin receptors with their ligands expressed on vasculature. It is increasingly becoming evident that the adhesive capacity of integrins is upregulated by signals from chemokine receptors. A model of intratumoral T cell migration has been established using IL-12 to induce tumor regression. Focusing on this particular model, we review how IL-12 works to upregulate the expression and/or function of chemokines/chemokine receptors as well as adhesion molecules and to induce collaboration between chemokine and adhesion systems. This article will also describe why such an IL-12-induced activation of chemokine and adhesion systems leads to T cell-mediated tumor regression in some tumor models, but not in others.

IL-12 as well as IL-2 upregulates CCR5 expression on T cell receptor-triggered human CD4+ and CD8+ T cells

The expression of chemokine receptors on leukocytes is related to their activation state. However, the exact mechanism underlying the induction of each chemokine receptor is poorly understood. Here, we investigated how CCR5, a chemokine receptor implicated in T cell trafficking and HIV infection, is induced in human T cells. CCR5 was marginally detected on a freshly prepared human peripheral blood mononuclear cell (PBMC) population. Long-term (8-day) stimulation of PBMC with IL-2 resulted in high levels of CCR5 expression on T cells. IL-12 failed to induce CCR5 on T cells in such a directly stimulated PBMC population. Stimulation of PBMC T cells with anti-CD3 plus anti-CD28 induced detectable albeit very low levels of CCR5 along with the induction of IL-12 receptor. However, these TCR-triggered T cells expressed much higher levels of CCR5 when stimulated with IL-12. Although IL-2 also induced CCR5 expression, CCR5 expression was more potent in IL-12 than IL-2 stimulation. These results indicate that, in addition to IL-2, IL-12 plays an important role in the induction of CCR5 expression on T cells, particularly TCR-triggered T cells.

A pivotal role of cysteine 3 of Lck tyrosine kinase for localization to glycolipid-enriched microdomains and T cell activation

Lck, a Src family protein tyrosine kinase (PTKs), is post-translationally modified by palmitoylation, a process thought to regulate the biological function, membrane affinity and glycolipid-enriched microdomain (GEM) localization of this molecule. To examine the importance of palmitoylation sites Cys3 and Cys5 in Lck, one or both of these residues was mutated to serine to create mutants S3, S5, and S3,5, respectively. Immunofluorescence and confocal microscopy of COS-7 cells transfected with these constructs showed that while S5 and S3 localized to the plasma membrane, S3,5 was localized to the cytoplasm, suggesting that palmitoylation at at least one site is essential for membrane localization. Sucrose gradient based fractionation of these mutants expressed in COS-7 cells showed that while S5 localized to GEMs in similar fashion to the wild type, GEM localization of S3 was severely inhibited. Expression of these mutants in Lck-negative JCaM1 cells showed that although S5 reconstituted activation of nuclear factor NFAT as per the wild type, S3 expression failed to do so. These results suggest that Cys3 of Lck plays a more important role than Cys5 in GEM localization and T cell activation. Additionally, it was found that the degree of T cell function recovery is positively correlated with the degree of Lck expression in GEMs.

Validity of NIR spectroscopy for quantitatively measuring muscle oxidative metabolic rate in exercise

The purpose of this study was to examine the validity of the quantitative measurement of muscle oxidative metabolism in exercise by near-infrared continuous-wave spectroscopy (NIRcws). Twelve male subjects performed two bouts of dynamic handgrip exercise, once for the NIRcws measurement and once for the (31)P-magnetic resonance spectroscopy (MRS) measurement as a standard measure. The resting muscle metabolic rate (RMRmus) was independently measured by (31)P-MRS during 15 min of arterial occlusion at rest. During the first exercise bout, the quantitative value of muscle oxidative metabolic rate at 30 s postexercise was evaluated from the ratio of the rate of oxyhemoglobin/myoglobin decline measured by NIRcws during arterial occlusion 30 s after exercise and the rate at rest. Therefore, the absolute values of muscle oxidative metabolic rate at 30 s after exercise [VO(2NIR(30))] was calculated from this ratio multiplied by RMRmus. During the second exercise bout, creatine phosphate (PCr) resynthesis rate was measured by (31)P-MRS at 30 s postexercise [Q((30))] under the same conditions but without arterial occlusion postexercise. To determine the validity of NIRcws, VO(2NIR(30)) was compared with Q((30)). There was a significant correlation between VO(2NIR(30)), which ranged between 0.018 and 0. 187 mM ATP/s, and Q((30)), which ranged between 0.041 and 0.209 mM ATP/s (r = 0.965, P < 0.001). This result supports the application of NIRcws to quantitatively evaluate muscle oxidative metabolic rate in exercise.