Improvement of mnemonic discrimination with acute light exercise is mediated by pupil-linked arousal in healthy older adults.

Physical exercise has positive impacts on hippocampal memory decline with aging. One of the postulated neurobiological mechanisms of the decline is reduced catecholaminergic projections from the locus coeruleus to the hippocampus. Recent human studies revealed that very light exercise rapidly enhances memory and pupil diameter, which suggests that light exercise may improve memory via neural circuits involved in the ascending arousal system, including the locus coeruleus, even in older adults. Thus, we aimed to clarify the effects of a single bout of light-intensity exercise (60% ventilatory threshold) on mnemonic discrimination performance, an index of hippocampal memory function, in healthy older adults using a randomized crossover design. Pupil diameter was measured during exercise as a physiological marker of the ascending arousal system. Discrimination of highly similar stimuli to the targets improved after exercise when compared to the resting control performance. Importantly, causal mediation analysis showed that pupil dilation during exercise mediated the memory improvement. These results suggest that brief light exercise rapidly enhances memory, possibly by upregulating the ascending arousal system.

Sugar-Rich Food Intake Is Negatively Associated with Plasma Pentraxin 3 Levels.

Background: Levels of pentraxin 3 (PTX3), an anti-inflammatory cardioprotective protein, increase after weight loss in obese men and aerobic exercise in non-obese adults. However, the effect of nutritional characteristics on PTX3 levels remains unclear. This population-based, cross-sectional study investigated the association between circulating PTX3 levels and food intake in Japanese adults. Methods: We hypothesized that the consumption of high amounts of high-sugar foods would lead to low plasma PTX3 levels, resulting in obesity. This study included 327 participants categorized depending on the consumption of the recommended amount of confectionary and sugar-sweetened beverages (CSSB) into high and low groups. Results: PTX3 levels were significantly lower in the high CSSB group than in the low CSSB group. Biological sex was the strongest effector of PTX3 levels. Moreover, the intake of Tsukudani and CSSB, as well as some metabolic syndrome factors, also affect PTX3 levels. In the groups categorized by sex and age, the determinants of PTX3 levels differed. Body mass index, waist circumference (WC), and high-density lipoprotein cholesterol (HDL-C) were significantly associated with PTX3 levels in women. Tsukudani, HDL-C, heart rate, saturated fatty acids, systolic blood pressure, and CSSB were associated with PTX3 levels in individuals aged >65 years. Conclusion: Our results show that circulating PTX3 levels are affected by sex, sugar-rich foods, and metabolic syndrome characteristics (WC, HDL-C).

Acute increase in arterial stiffness after swimming in cooler water.

Cold stimuli increase arterial stiffness, but it has not been explored whether arterial stiffness increases after swimming in cooler water. To investigate the effects of water temperature on changes in arterial stiffness after swimming, 13 men participated in three trials of 20-min swimming in 25 and 30°C water (S25 and S30, respectively) and sitting at poolside (CON) in random order. There were no significant differences between the S25 and S30 trials in mean swimming distance (719 vs. 722 m) and heart rate reserve during swimming (63% vs. 63%). Sublingual temperature was lower after swimming in 25°C water versus before swimming. Aortic pulse wave velocity (aortic PWV, an index of central arterial stiffness based on applanation tonometry) and brachial-ankle pulse wave velocity (baPWV, an index of systemic arterial stiffness based on air plethysmography) were higher 30 min after versus before swimming in 25°C water. Aortic PWV recovered to pre-swimming levels by 60 min after swimming in 25°C water, but baPWV was higher even at 60 min after swimming. PWVs did not change in the CON and S30 trials. Systemic vascular resistance based on Doppler ultrasonography did not change, but forearm vascular resistance based on strain-gauge plethysmography was higher 30 and 60 min after swimming in 25°C water. Heart rate was higher, but stroke volume was lower 30 min after swimming in 25°C water, resulting in no detectable change in cardiac output. In conclusion, arterial stiffness increases acutely after moderate-intensity swimming in cooler water.

Combined aerobic and low-intensity resistance exercise training increases basal nitric oxide production and decreases arterial stiffness in healthy older adults.

Meta-analyses have concluded that combined aerobic and high-intensity or moderate-intensity resistance exercise training has no effects on arterial stiffness. However, a recent study demonstrated that combined aerobic training and resistance training using rubber bands increases basal nitric oxide (NO) production and decreases arterial stiffness with marked reduction of body weight in obese adolescent girls. To investigate whether combined aerobic and low-intensity resistance training increases basal NO production and decreases arterial stiffness without body weight reduction in older adults, 27 healthy older individuals participated in a 6-week program as a part of the training group (mean body mass index, 21 kg/m2; walking and resistance training using one's body weight) or the control group (22 kg/m2, asked not to modify their lifestyle). The exercise intervention increased aerobic capacity, muscle strength, and plasma concentrations of nitrite/nitrate (end products of NO) and decreased pulse wave velocity (an index of arterial stiffness) without changes in body weight. In the control group, there were no differences in these measures before and after the study period. These results suggest that combined aerobic and low-intensity resistance exercise training increases basal NO production and decreases arterial stiffness in healthy older adults.

Nitric Oxide and Decreases in Resistance Exercise Blood Pressure With Aerobic Exercise Training in Older Individuals.

An exaggerated blood pressure response to resistance exercise is a marker of masked hypertension and a risk factor for future essential hypertension. Habitual aerobic exercise decreases systolic blood pressure (SBP) during resistance exercise in older individuals, but the underlying mechanisms have not been explored. This study tested the hypothesis that nitric oxide (NO) mediates a reduction of resistance exercise SBP with aerobic training in older individuals. Normotensive older adults participated in a 6-week program as a part of the aerobic training group (n = 23, exercised for an average of 4.4 d/wk and 59 min/d) or the control group (n = 26, asked not to modify their lifestyle during the experimental period). The aerobic exercise intervention increased plasma concentrations of nitrite/nitrate (NOx, end products of NO) and decreased SBP during a one-hand arm curl exercise at 20% and 40% of one-repetition maximum and brachial-ankle pulse wave velocity (an index of arterial stiffness). In the control group, there were no differences in these measures before and after the experimental period. Changes in plasma NOx concentrations during the study period were correlated with changes in resistance exercise SBP. Stepwise regression revealed that changes in plasma NOx concentrations during the experimental period are a significant factor of changes in resistance exercise SBP, independent of age, sex, and changes in serum lipid profile, maximal oxygen uptake, resting SBP, and other variables. These results suggest that NO is associated with decreases in resistance exercise SBP with aerobic training in older individuals and help us better understand why habitual aerobic exercise prevents cardiovascular disease.

Mild Hypobaric Hypoxia Enhances Post-exercise Vascular Responses in Young Male Runners.

It has been reported that sustained post-exercise vasodilation may be linked to exercise-induced angiogenesis. The present study aimed to evaluate whether mild hypobaric hypoxia enhances the post-exercise reduction in systemic vascular resistance in young male runners. Seven male intercollegiate runners (aged 19-21 years) performed maximal incremental treadmill running under conditions of hypobaric hypoxia (corresponding to 2,200 m above sea level, hereinafter referred to as HH) and normobaric normoxia (corresponding to sea level, hereinafter referred to as NN). A third exercise test was performed under NN conditions, consisting of submaximal exercise with the same absolute exercise volume as was achieved during HH (submaximal exercise under NN conditions, hereinafter referred to as NNsubmax). Blood pressure and cardiac output (CO) were measured before and at 15, 30, and 60 (p60) minutes after exercise. Compared with NN, exercise time was shorter in HH and NNsubmax conditions (p < 0.05). Systolic blood pressure and mean blood pressure (MBP) were lower after exercise in HH conditions (p < 0.05). No condition-related differences were found in CO. Total peripheral resistance (TPR, defined as the ratio of MBP to CO) was significantly lower after exercise compared to baseline for all conditions (p < 0.05). However, the decrease in TPR was maintained longer after exercise in HH compared with NN and NNsubmax conditions (p < 0.05). At p60, TPR was lower than baseline for HH conditions (p < 0.05), whereas after exercise in NN, and NNsubmax conditions, TPR recovered to baseline by p60. Decreases in systemic vascular resistance after exercise were maintained longer under mild HH conditions compared with NN despite the lower exercise volume of the former.

Pentraxin 3 increases in adult overweight and obese men after weight loss by dietary modification with exercise training.

The circulatory level of pentraxin 3 (PTX3), an anti-inflammatory cardioprotective protein, has been shown to be lower in obese individuals than in those with normal weight. However, reports on the effects of different weight-loss methods on PTX3 are limited. The present study aimed to investigate the effect of weight loss on circulating PTX3 levels in overweight and obese men and to examine the combined effect of dietary modification and exercise training on PTX3 levels. Forty-eight overweight and obese men were assigned to 2 groups: dietary modification (group D) or exercise training and dietary modification (group DE). Groups D and DE were composed of 27 and 21 participants, respectively. We observed a significant independent relationship between changes in PTX3 and body mass index (BMI) in all participants (ß = -0.617, p < 0.01). Subsequently, we compared the effects of the 2 weight-loss methods on plasma PTX3 in groups D and DE. The magnitude of the increase in plasma PTX3 levels was similar in the 2 groups. Interestingly, we observed that PTX3 levels in group DE increased significantly more than those in group D in subjects who achieved normal weight, based on BMI, after interventions. Our study suggested that weight reduction after lifestyle modification significantly increased PTX3 levels in overweight and obese men, and the addition of habitual exercise to dietary modification enhanced the magnitude of the increase in PTX3 levels in obese individuals achieving normal weight after weight loss.

Older Community Residents Who Participate in Group Activities Have Higher Daily Physical Activity Levels and Lower Medical Costs.

Participation in a group activity improves levels of activities of daily living and self-rated health in community-dwelling older adults. However, whether the group activity is associated with daily physical activity (PA) levels and medical costs has not yet been explored. The author administered a questionnaire to participants of group activities for community-dwelling older adults. Levels of daily PA were greater in those who participated once a month (n = 1147), twice a month (n = 1432), and 4 times a month (n = 635) compared with nonparticipating counterparts (n = 570). In the stepwise regression, group activity participation rate was identified as an independent predictor of daily PA levels. Before group activities began, there were no differences in medical costs between participants (n = 721) and nonparticipants (n = 1124). However, after group activities were established, medical costs were lower in participants than in nonparticipants. These results suggest that older community residents who participate in group activities have higher daily PA levels and lower medical costs.

Effect of Chlorella-derived multicomponent supplementation on maximal oxygen uptake and serum vitamin B2 concentration in young men.

Chlorella is a unicellular green alga that contains high levels of proteins, vitamins and minerals. The present study investigated the effects of a 4-week Chlorella-derived multicomponent supplementation on maximal oxygen uptake and circulating vitamin B2 levels in healthy men. Thirty-four participants were randomly divided into two groups: placebo or Chlorella. Prior to the intervention, we observed that the intake of several minerals and soluble vitamins did not satisfy the nutrient requirements of either group by assessing the frequency of daily food intake. There was a significant negative relationship between the pre-intervention maximal oxygen uptake and serum vitamin B2 concentrations in all subjects (r = -0.372). Maximal oxygen uptake significantly increased after Chlorella supplementation (before vs after, 42.1 ± 1.5 vs 44.9 ± 1.6 ml/kg/min), while serum vitamin B2 concentrations did not (14.6 ± 0.9 vs 14.0 ± 0.9 µg/L). In conclusion, Chlorella-derived multicomponent supplementation increases maximal oxygen uptake in individuals with an insufficient micronutrient status, although there was no association between the increase in aerobic capacity and serum levels of vitamin B2.

Association between blood pressure changes during self-paced outdoor walking and air temperature.

Exaggerated elevation of systolic blood pressure (SBP) during exercise is a risk factor for future cardiovascular disease. Although there are differences between the outdoor exercise and exercise tests in the laboratory setting, there is little information regarding SBP changes during practical outdoor exercise. We investigated SBP changes during self-paced outdoor walking and the relationship to air temperature. Subjects (n = 109, 47-83 years) walked outdoors at their own pace wearing a blood pressure monitor on their wrist. SBP increased during walking compared to rest, but was higher at the 1 km mark than both the 2 and 3 km marks (rest, 124 ± 14 mmHg; 1 km, 140 ± 16 mmHg; 2 km, 136 ± 18 mmHg; 3 km, 135 ± 18 mmHg). SBP at rest, air temperature, body mass index (BMI) and walking intensity during the first 1 km were identified as predictors of SBP at the 1 km mark in the stepwise regression analysis, independent of other confounders (R2  = 0·606). SBP at the 1 km mark was higher in the lower temperature group (11·6-14·3°C, 145 ± 14 mmHg) than in the intermediate (15·1-16·7°C, 140 ± 18 mmHg) and higher (17·0-19·6°C, 136 ± 16 mmHg) temperature groups, independent of SBP at rest, BMI and walking intensity. These results suggest that increases in SBP are higher on lower temperature days and are greater at 1 km than at 2 and 3 km. It is therefore recommended that measures are taken against the cold on lower temperature days to attenuate the SBP response during onset of walking.

Changes in salivary flow rate following Chlorella-derived multicomponent supplementation.

Decreases in saliva secretion compromise food mastication and swallowing, reduce mucosal immune function, and increase the risk for oral diseases like dental caries. Chlorella is a green alga that contains a variety of nutrients including amino acids, vitamins, and minerals. In our previous study, Chlorella-derived multicomponent supplementation did not affect salivary flow rates in healthy young individuals, but Chlorella-derived supplementation attenuated a decrease in saliva secretion that was observed during a kendo training camp. Hence, we hypothesized that Chlorella-derived supplementation increases saliva secretion in individuals with lower rates of saliva flow. Sixty-four subjects took Chlorella-derived tablets for four weeks. Before and after supplementation, saliva samples were collected by chewing cotton. In the complete study group, there was no difference in saliva production before and after supplementation (1.91 ± 0.11 ml/min before vs 2.01 ± 0.12 ml/min after). Analysis of subgroups based on saliva production before supplementation found an increase in saliva secretion in the lower saliva flow group (1.18 ± 0.06 vs 1.38 ± 0.08 ml/min), but no change in the higher saliva flow group (2.63 ± 0.11 vs 2.64 ± 0.15 ml/min). These results suggest that Chlorella-derived multicomponent supplementation increases saliva production in individuals with lower levels of saliva secretion.

Habitual exercise decreases systolic blood pressure during low-intensity resistance exercise in healthy middle-aged and older individuals.

Since aerobic exercise (e.g., walking) and resistance exercise (e.g., lifting objects and mopping) are both parts of the activities of daily living, an exaggerated elevation in systolic blood pressure (SBP) during aerobic and resistance exercise is an early marker of cardiovascular disease. This study investigated the effects of habitual exercise on SBP during low-intensity resistance exercise using both cross-sectional and interventional approaches. First, in 57 normotensive women (61.9 ± 1.0 yr of age), daily physical activity level, as assessed by triaxial accelerometry, was correlated with SBP during resistance exercise at 20 and 40% of the 1 repetition maximum (r = -0.408 and r = -0.348, respectively). Maximal oxygen uptake was correlated with SBP during exercise at 20% (r = -0.385) and 40% (r = -0.457). Physical activity level or maximal oxygen uptake was identified as a predictor of SBP during the exercise in stepwise regression analysis, independent of SBP at rest and other factors (R2 = 0.729-0.781). Second, 66 men and women (64.6 ± 0.9 yr of age) participated in a 6-wk intervention as a part of the training (walking, 4.3 ± 0.3 days/wk, 55.6 ± 4.1 min/day, 70.7 ± 1.2% of maximal heart rate) or control group. SBP during resistance exercise in the training group decreased after the intervention (before vs. after: 20%, 143 ± 4 vs. 128 ± 4 mmHg; and 40%, 148 ± 5 vs. 134 ± 4 mmHg). In the control group, there were no significant differences in SBP before and after the intervention. SBP during resistance exercise after the intervention was lower in the training group relative to the control group. These results suggest that habitual exercise decreases SBP during low-intensity resistance exercise.

Changes in arterial stiffness and nitric oxide production with Chlorella-derived multicomponent supplementation in middle-aged and older individuals.

Chlorella is a unicellular green alga, which contains a variety of nutrients including amino acids, dietary fibers, n-3 unsaturated fatty acid, vitamins, and minerals. We previously demonstrated that Chlorella-derived multicomponent supplementation decreases arterial stiffness in young men. However, mechanisms underlying the reduction in arterial stiffness by Chlorella-derived supplementation and the effect in middle-aged and older individuals have remained unexplored. This study tested our hypothesis that Chlorella-derived supplementation improves arterial stiffness via an increase in nitric oxide (NO, a endothelium-derived relaxing factor) production in middle-aged and older individuals. Thirty-two subjects between 45 and 75 years of age assigned to placebo and Chlorella groups in a double-blinded manner and took respective tablets for 4 weeks. Before and after the supplementations, brachial-ankle pulse wave velocity (baPWV, an index of arterial stiffness) and plasma nitrite/nitrate (NOx, end product of NO) concentration were measured. There was no difference in baPWV between before and after the placebo intake, but baPWV decreased after the Chlorella supplementation. Changes in baPWV with the Chlorella supplementation were correlated with those in plasma NOx concentration. We concluded that Chlorella-derived multicomponent supplementation decreases arterial stiffness in middle-aged and older individuals. It may be associated with increase in NO production by vascular endothelium.

Association between plasma sLOX-1 concentration and arterial stiffness in middle-aged and older individuals.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is implicated in vascular endothelial function. Vascular endothelial function is a potent regulator of arterial stiffness, an independent risk factor for cardiovascular disease. However, it is unknown whether LOX-1 is associated with arterial stiffness. Plasma concentrations of soluble LOX-1 (sLOX-1) and brachial-ankle pulse wave velocity (baPWV, an index of arterial stiffness) were measured in 143 individuals between 51 and 83 years of age. Plasma sLOX-1 concentration was correlated with baPWV (r = 0.288, p = 0.0005). In stepwise regression analysis, plasma sLOX-1 concentration was associated with baPWV, after adjusting for age; body mass index; blood pressure; heart rate; blood levels of cholesterol, triglycerides, glucose, hemoglobin A1c, and insulin; sex; and use of antihypertensives, lipid-lowering agents, and other medications (R (2) = 0.575, p<0.0001). Multiple logistic regression demonstrated that plasma sLOX-1 concentration was independently associated with elevated baPWV (≥14.0 m/s; odds ratio, 1.01; 95% confidence interval, 1.00-1.03; p = 0.03). These results suggest that LOX-1 is associated with arterial stiffness.

A common genetic variant of the chromogranin A-derived peptide catestatin is associated with atherogenesis and hypertension in a Japanese population.

Chromogranin A (CHGA) is a major protein in the secretory granules of chromaffin cells. CHGA also gives rise to cardiovascular/metabolism regulatory peptides, such as catestatin (CST) and pancreastatin (PST). While CST is a potent inhibitor of catecholamine secretion, PST is a potent physiological inhibitor of glucose-induced insulin secretion. Recently, several SNPs were identified in the CST and PST domains of CHGA locus in different populations. Among the discovered SNPs, CST variant allele Ser-364 was associated with blood pressure alteration and PST variant allele Ser-297 was associated with significantly higher plasma glucose level. In this study, we examined whether these CST and PST variant alleles exist and influence cardiovascular and metabolic phenotypes in Japanese population. Our study comprised of 343 Japanese subjects aged 45-85 years (143 men and 200 women, mean age 66 ± 8 years). We determined the genotypes of CST and PST by PCR-direct sequencing method and carried out genotype-phenotype association analysis. In 343 participants, the minor allele frequency of CST variant Ser-364 was 6.10%. On the other hand, we did not detect the PST variant Ser-297 in this entire study population. The presence of Ser-364 allele was associated with increased in baPWV (an index of systemic arterial stiffness) that suggests an initiation and/or progression atherogenesis and hypertension. The Ser-364 allele was also associated with elevated systolic blood pressure and pulse pressure, consistent with increased baPWV. In conclusion, the CST Ser-364 allele may increase the risk for cardiovascular diseases in Japanese population.

Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in young individuals.

Chlorella, a unicellular green alga, contains a variety of nutrients including amino acids, carbohydrates, vitamins, and minerals. A previous animal study found that maximal swimming time in mice increased after 14 days on a diet including Chlorella powder compared to no change in swimming performance on a normal diet. However, it is currently unknown whether Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in humans. We investigated the effects of Chlorella-derived supplementation on peak oxygen uptake during incremental maximal cycling in young individuals using a double-blinded, placebo-controlled, crossover study design. Seven men and three women (mean age, 21.3 year) were allocated to placebo or Chlorella tablets (15 tablets × twice per day) for 4 weeks, with at least a 6-week washout period between trials, in a randomized order. Peak oxygen uptake significantly increased after Chlorella supplementation (before vs after, 37.9 ± 1.9 vs 41.4 ± 1.9 ml/kg/min, p = 0.003), but not with placebo (39.4 ± 2.2 vs 40.1 ± 2.1 ml/kg/min, p = 0.38). The change in peak oxygen uptake over the 4-week trial was significantly greater in the Chlorella trial than in the placebo trial (3.5 ± 0.9 vs 0.7 ± 0.8 ml/kg/min, p = 0.03). These results suggest that Chlorella-derived multicomponent supplementation increases aerobic endurance capacity in young individuals.

Multicomponent supplement containing Chlorella decreases arterial stiffness in healthy young men.

Chlorella, a unicellular green alga, contains various antioxidants and other nutrients such as amino acids and fiber. Previous studies have reported that supplementation with multiple antioxidants reduces arterial stiffness, a well-established cardiovascular risk factor. We investigated the effects of Chlorella intake on arterial stiffness using a single-blinded, placebo-controlled crossover study design. Fourteen young men took placebo or Chlorella tablets for four weeks, with a 12-week washout period between trials, in a randomized order. Before and after each trial, blood pressure, heart rate, and brachial-ankle pulse wave velocity, an index of arterial stiffness, were measured. Treatment compliance was comparable between the two groups. There were no differences in blood pressure and heart rate before and after supplementation in both the placebo and Chlorella groups. Brachial-ankle pulse wave velocity decreased after Chlorella intake (before vs after intake; 11.6 ± 0.2 vs 11.1 ± 0.1 m/s, p = 0.01), but not after placebo intake (11.4 ± 0.2 vs 11.4 ± 0.2 m/s, p = 0.98). Multicomponent analysis of the Chlorella-containing tablet detected nutrients that can reduce arterial stiffness, such as antioxidant vitamins, arginine, potassium, calcium, and n-3 unsaturated fatty acids. These results suggest that intake of a Chlorella-containing multicomponent supplement can decrease arterial stiffness.

Chlorella intake attenuates reduced salivary SIgA secretion in kendo training camp participants.

BACKGROUND: The green alga Chlorella contains high levels of proteins, vitamins, and minerals. We previously reported that a chlorella-derived multicomponent supplement increased the secretion rate of salivary secretory immunoglobulin A (SIgA) in humans. Here, we investigated whether intake of this chlorella-derived supplement attenuated the reduced salivary SIgA secretion rate during a kendo training camp. METHODS: Ten female kendo athletes participated in inter-university 6-day spring and 4-day summer camps. They were randomized into two groups; one took placebo tablets during the spring camp and chlorella tablets during the summer camp, while the other took chlorella tablets during the spring camp and placebo tablets during the summer camp. Subjects took these tablets starting 4 weeks before the camp until post-camp saliva sampling. Salivary SIgA concentrations were measured by ELISA. RESULTS: All subjects participated in nearly all training programs, and body-mass changes and subjective physical well-being scores during the camps were comparable between the groups. However, salivary SIgA secretion rate changes were different between these groups. Salivary SIgA secretion rates decreased during the camp in the placebo group (before vs. second, middle, and final day of camp, and after the camp: 146 ± 89 vs. 87 ± 56, 70 ± 45, 94 ± 58, and 116 ± 71 µg/min), whereas no such decreases were observed in the chlorella group (121 ± 53 vs. 113 ± 68, 98 ± 69,115 ± 80, and 128 ± 59 µg/min). CONCLUSION: Our results suggest that a use of a chlorella-derived dietary supplement attenuates reduced salivary SIgA secretion during a training camp for a competitive sport.

Salivary secretory immunoglobulin A secretion increases after 4-weeks ingestion of chlorella-derived multicomponent supplement in humans: a randomized cross over study.

BACKGROUND: Chlorella, a unicellular green alga that grows in fresh water, contains high levels of proteins, vitamins, minerals, and dietary fibers. Some studies have reported favorable immune function-related effects on biological secretions such as blood and breast milk in humans who have ingested a chlorella-derived multicomponent supplement. However, the effects of chlorella-derived supplement on mucosal immune functions remain unclear. The purpose of this study was to investigate whether chlorella ingestion increases the salivary secretory immunoglobulin A (SIgA) secretion in humans using a blind, randomized, crossover study design. METHODS: Fifteen men took 30 placebo and 30 chlorella tablets per day for 4 weeks separated by a 12-week washout period. Before and after each trial, saliva samples were collected from a sterile cotton ball that was chewed after overnight fasting. Salivary SIgA concentrations were measured using ELISA. RESULTS: Compliance rates for placebo and chlorella ingestions were 97.0 ± 1.0% and 95.3 ± 1.6%, respectively. No difference was observed in salivary SIgA concentrations before and after placebo ingestion (P = 0.38). However, salivary SIgA concentrations were significantly elevated after chlorella ingestion compared to baseline (P < 0.01). No trial × period interaction was identified for the saliva flow rates. Although the SIgA secretion rate was not affected by placebo ingestion (P = 0.36), it significantly increased after 4-week chlorella ingestion than before intake (P < 0.01). CONCLUSIONS: These results suggest 4-week ingestion of a chlorella-derived multicomponent supplement increases salivary SIgA secretion and possibly improves mucosal immune function in humans.

Plasma pentraxin 3 concentration increases in endurance-trained men.

INTRODUCTION: Pentraxin 3 (PTX3), which is mainly produced by endothelial cells, macrophages, and smooth muscle cells in the atherosclerotic region, has a cardioprotective effect. Endurance exercise training has also been known to offer cardioprotection. However, the effect of regular endurance exercise on PTX3 is unknown. This study aimed to investigate whether plasma PTX3 concentrations increase in endurance-trained men. Ten young endurance-trained men and 12 age- and gender-matched sedentary controls participated in this study. METHODS: We measured plasma PTX3 concentrations of the participants in each group. We also determined systemic arterial compliance (SAC) by using simultaneous M-mode ultrasound and arterial applanation tonometry of the common carotid artery and used HDL cholesterol (HDLC) as an index of cardioprotective effect. RESULTS: Maximal oxygen uptake was significantly higher in the endurance-trained men than that in the sedentary controls. SAC and HDLC were significantly higher in the endurance-trained men than that in the sedentary controls (SAC = 1.74 ± 0.11 vs 1.41 ± 0.09 mL·mm Hg(-1), P < 0.05; HDLC = 70 ± 5 vs 57 ± 4 mg·dL(-1), P < 0.05). Plasma PTX3 concentrations were markedly higher in the endurance-trained men than that in the sedentary controls (0.93 ± 0.11 vs 0.68 ± 0.06 ng·mL(-1), P < 0.05). Relationships between plasma PTX3 concentrations and SAC and HDLC were linear. CONCLUSIONS: This is the first study revealing that endurance-trained individuals had higher levels of circulating PTX3 than sedentary controls. PTX3 may play a partial role in endurance exercise training-induced cardioprotection.