This is the first clinical study using Japanese cedar pollen under well-controlled conditions in the OHIO chamber in which the induction of allergic symptoms was observed. The OHIO chamber will be useful for studying allergic rhinitis in Japan.

Background: An artificial exposure chamber (OHIO Chamber), which allows dispersal of a fixed concentration of Japanese cedar (JC) pollen under stable conditions, was constructed. This study was conducted to identify the exposure conditions assuring validity of the clinical tests conducted using this chamber. Methods: Twenty-four adult patients with JC pollinosis were exposed to different concentrations of JC pollen: 0 (only during the summer period), 4,000, 8,000 and 12,000 grains/m³, and the nasal and ocular symptoms were self-assessed during a 4-hour period of exposure. The amount of nasal discharge was measured and the sneezing frequency was recorded. This study was conducted twice during the summer and winter periods, i.e. non-pollen seasons. The reproducibility of the symptoms between the two seasons was assessed. Results: None of the subjects developed any symptom at the pollen concentration of 0 grains/m³. No significant differences in the time to the onset of symptoms were found between the summer and winter study, regardless of the pollen concentration. There were no significant differences between the summer and winter study in the total symptom score and total nasal symptom score at any pollen concentration, suggesting the very favorable reproducibility of symptoms. Conclusions: Efficient and reproducible results are obtained in patients exposed to JC pollen in the OHIO Chamber. The results suggest the conditions of JC pollen exposure have scientific validity and the OHIO Chamber has the potential to contribute significantly to basic and clinical studies of JC pollinosis.

Safflower seed extract (SSE) contains characteristic polyphenols and serotonin derivatives (N-( p-coumaroyl) serotonin and N-feruloylserotonin), which are reported to inhibit oxidation of low-density lipoprotein (LDL), formation of atherosclerotic plaques, and improve arterial stiffness as assessed by pulse wave analysis in animal models. The effects of long-term supplementation with SSE on arterial stiffness in human subjects were evaluated. This doubleblind, placebo-controlled study was conducted in 77 males (35–65 years) and 15 postmenopausal females (55–65 years) with high-normal blood pressure or mild hypertension who were not undergoing treatment. Subjects received SSE (70 mg/day as serotonin derivatives) or placebo for 12 weeks, and pulse wave measurements, ie, second derivative of photoplethysmogram (SDPTG), augmentation index, and brachial-ankle pulse wave velocity (baPWV) were conducted at baseline, and at weeks 4, 8, and 12. Vascular age estimated by SDPTG aging index improved in the SSE-supplemented group when compared with the placebo group at four (P = 0.0368) and 12 weeks (P = 0.0927). The trend of augmentation index reduction (P = 0.072 versus baseline) was observed in the SSE-supplemented group, but reduction of baPWV by SSE supplementation was not observed. The SSE-supplemented group also showed a trend towards a lower malondialdehyde-modified-LDL autoantibody titer at 12 weeks from baseline. These results suggest long-term ingestion of SSE in humans could help to improve arterial stiffness.

Summary For basic and clinical studies of Japanese cedar (JC) pollinosis and its treatment, experimental facilities for exposure to pollen under stable environmental conditions are becoming increasingly desirable. We developed an artificial exposure chamber (OHIO Chamber) that allows the dispersal of fixed concentrations of JC pollen in stable environments with a unique pollen supply system, air flow system for fixing the concentration of JC pollen, system for monitoring the number of pollen grains, and automated pure water washing and drying system. In the chamber, temperature and relative humidity (RH) could be successfully maintained at 22±1.1 °C and 45±5%, respectively. The spatial distribution of pollen concentrations in the chamber was within 10% of target, including when subjects were present. Only a few or no pollen grains were detected in the chamber after automatic washing and drying. We conducted a pilot tolerability and safety study in 15 JC pollinosis patients who were exposed to 15 000 pollen grains/m3 for 2 h. Symptoms manifested on average 33 min after start of exposure. The subjects experienced no serious side‐effects, and pollen exposure at 15 000 grains/m3 was confirmed safe. After exposure, the number of intranasal and intraocular pollen grains was 469 and 602, respectively. The lower number of pollen grains in the nose than in the eyes was considered due to sneezing and nasal discharge. Further studies are needed to clarify the number of pollen grains required for the occurrence of symptoms in the OHIO Chamber.

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