title: Feasibility of photodynamic therapy for secondary hyperparathyroidism in chronic renal failure rats.
abstract: BACKGROUND
  Feasibility of photodynamic therapy (PDT) for secondary hyperparathyroidism (SHPT) was examined in a rat model of SHPT.
  
  
  METHODS
  A photosensitizer, 5-aminolevulinic acid (5-ALA), was injected intraperitoneally, and the parathyroid glands were irradiated either after surgical exposure with 385-nm light or transdermally with 630-nm light from a light-emitting diode (LED) lamp.
  
  
  RESULTS
  PDT with high 5-ALA and irradiation doses caused severe hypoparathyroidism in SHPT rats within two days. Low-dose invasive PDT reduced intact parathyroid hormone (iPTH) levels in all rats from 748.9 ± 462.6 pg/mL at baseline to 138.7 ± 117.5 pg/mL at week 6, followed by a further decrease to 80.5 ± 54.0 pg/mL at week 9 in 60 % of rats or an increase to 970.0 ± 215.6 pg/mL at week 9 in 40 % of rats. Low-dose noninvasive PDT reduced iPTH levels from 1612.5 ± 607.8 pg/mL at baseline to 591.9 ± 480.1 pg/mL at week 4 in all rats. Thereafter, iPTH levels remained low in 43 % of rats and were 233.7 ± 51.6 pg/mL at week 9, whereas 57 % showed an increase, reaching 3305.9 ± 107.3 pg/mL at week 9. Control SHPT rats had iPTH levels of 2487.8 ± 350.9 and 2974.6 ± 372.1 pg/mL at week 4 and 9, respectively. The parathyroid glands of the rats with low iPTH levels were atrophied and had few parathyroid cells surrounded by fibrotic materials and no recognizable blood vessels. Those of the rats with high iPTH levels showed well-preserved gland structure, clusters of parathyroid cells, and blood vessels.
  
  
  CONCLUSIONS
  These results demonstrate that 5-ALA-mediated PDT for SHPT is feasible.
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Takayo
authors.initials: T
authors.lastname: Miyakogawa
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Genta
authors.initials: G
authors.lastname: Kanai
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Tatsumi
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Hiroo
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Kaichiro
authors.initials: K
authors.lastname: Sawada
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan. kakuta@is.icc.u-tokai.ac.jp.|Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University Hachioji Hospital, 1838 Ishikawa-cho, Hachioji, Tokyo, 192-0032, Japan. kakuta@is.icc.u-tokai.ac.jp.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kakuta
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukagawa
mesh_terms: D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005240:Feasibility Studies; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D007274:Injections, Intraperitoneal; D007676:Kidney Failure, Chronic / Q000150:complications*; D008297:Male; D010280:Parathyroid Glands / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010281:Parathyroid Hormone / Q000097:blood; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid
keywords: 5-Aminolevulinic acid; Hyperparathyroidism; Parathyroid gland; Parathyroid hormone; Photodynamic therapy