Regional estimates of hair cells and supporting cells in the human crista ampullaris

Regional estimates of type I and type II vestibular hair cells (HC) and supporting cell (SC) numbers were obtained from the horizontal crista ampullaris by using design-based stereology in human. Cristae were microdissected from temporal bones obtained post-mortem (N = 16, age range 26-98 years). Three groups were made according to age: group 1, n = 5, ages between 26 and 67 years, average age 51 years; group 2, n = 4, average age 84 years; and group 3, n = 7, average age 94 years. For group 1, the average total HC number was 8,005 +/- 214, corresponding to 4,119 +/- 107 type I HC, 3,886 +/- 117 type II HC, and 10,274 +/- 224 SC. The type I:type II HC ratio was 1.06 +/- 0.01, and HC density was 0.80 cells/100 mu m(2). For group 2, the average total HC number was 7,074 +/- 489, corresponding to 3,733 +/- 212 type I HC, 3,341 +/- 314 type II HC, and 9,321 +/- 858 SC. The type I:II HC ratio was 1.12 +/- 0.06, and HC density was 0.75 cells/100 mu m(2). For group 3, the average HC number was 6,009 +/- 327, corresponding to 3,380 +/- 223 type I HC, 2,628 +/- 235 type II HC, and 10,185 +/- 182 SC. The type I:II HC ratio was 1.34 +/- 0.10, and HC density was 0.63 cells/100 mu m(2). A significant decline in type I, type II, and total HC number and density was found in groups 2 and 3, with individuals exceeding the average human life span. (c) 2005 Wiley-Liss, Inc.