416 JOURNAL OF COSMETIC SCIENCE ENHANCING EPIDERMAL NEURONAL METABOLISM Objective James V. Gruber1, Ph.D. and Robert Holtz2 1 Arch Personal Care, 70 Tyler Place, South Plainfield, NJ 07080 2 Bioinnovation Laboratories, 321 N. Central Expressway, McKinney, TX 75070 An in vitro cell culture study was developed to screen a series of bioactive test materials applied to dorsal root ganglia cells to determine whether any of the bioactive materials could enhance neuronal cellular metabolism as detennined by increased nerve ce11 oxygen consumption. Methods Dorsal root ganglia cells (Cambrex) were grown in vitro under conditions that maintained a normal pseudounipolar morphology (i.e., two axons emanating from the cell body) but that allowed the cells to fonn a neurite network, Figure 1. Figure 1. In Vitro Dorsal Root Ganglion A soluble fluorescent dye, A65N-l (Alexis Biochemicals) which is known to be fluorescently quenched in the presence of oxygen, was added to the growing cells. Test materials were then applied to the cells and the cultures were covered by mineral oil to minimize further contact with external oxygen. As the growing cells consumed oxygen, the level of fluorescence in the cell cultures increased. Changes in nerve cell oxygen consumption were determined by calculating the rate of fluorescence increase over time. Test materials were compared against phosphate buffer solution (PBS) as a negative control and against isoproterenol (CAS# 7683-59-2), a catecholamine derivative that has been shown previously to increase oxygen consumption in nerve cells and creatine (CAS# 57-00-1), a well known nutritional supplement that has been shown to enhance neural oxygen consumption [ 1,2].

2006 ANNUAL SCIENTIFIC SEMINAR 417 Results and Discussion- The role of the epidermal neural network in maintaining the general health and well being of the skin is becoming more widely appreciated [3,4]. Recent investigations have shown that as a person ages, the density and function of epidermal innervations decreases resulting in changes in the skin's ability to handle general daily stresses such as thermoregulation, sensory perception, and inflammation and immune response [3,5]. These changes are also dependent on a variety of extrinsic factors such as solar exposure, environmental pollution and temperature among others. While increasing the number of epidermal nerve branches might be one potential way to improve the skin's nerve cell functions, another way would be to improve the ability of the existing nerves to work better. Dorsal root ganglia were treated with various test products to see if cellular metabolism could be enhanced. Using the above described testing protocol, two test products, I% of an aqueous extract of Rhodia/a rosea (active content, 0.0 I%), previously shown to enhance oxygen respiration in human white adipocytes and a I% aqueous extract of lysed Sacchaormyces cerevesiae (active content 0.25%) were shown to increase nerve cell oxygen consumption compared to PBS and I% creatine and statistically comparable to IO micromoles of isoproterenol [6]. References 1. Huang CC et al., Selective enhancement of P-type calcium currents by isoproterenol in the rat amygdale. J Neurosci 1998 18: 2276-2282. 2. Low PA et al., The effect of age on energy metabolism and resistance to ischaemic conduction failure in rat peripheral nerve. J Physiol 1986 374: 263-271. 3. Besne I et al., Effect of age and anatomical site on density of sensory innervation in human epidermis. Arch Dermatol 2002 138: 1445-1450. 4. Peter E. Nerves in the skin: from anatomy to function. Eur Soc Dermatol Res 2005 125(S): A88. 5. Lauria Get al., Epidermal innervation changes with aging, topographic location and in sensory neuropathy. J Neuro Sci 1999 164: 172-178. 6. Gruber JV et al., Rhodia/a rosea: the influence of an adaptogen on cutaneous cellular metabolisms. Cosmet Sci Tech 2006, In Press.