San Diego, CA May 16, 2008 -- Histogen Inc., a regenerative medicine company developing solutions based on the products of newborn fibroblasts, today presented findings from preliminary evaluations of the Company's HGEN-001 formulation, during International Investigative Dermatology 2008, taking place May 14-17, 2008 in Kyoto, Japan.

Histogen's HGEN-001 liquid formulation is produced through a proprietary bioreactor system which simulates the embryonic environment, including hypoxic conditions of 3-5% oxygen. Under these conditions, a number of growth factors key to tissue development and regeneration are significantly elevated, specifically WNT proteins 5A, 6, 7A, 10A and 11. HGEN-001 is the first evidence of naturally-secreted, native human WNT proteins in a commercially scalable growth system.

The HGEN-001 formula was evaluated as a post-laser resurfacing treatment in 49 patients, with 26 receiving a placebo gel and 23 receiving a gel with HGEN-001. The products were applied several times per day for 8 days, after a micro-fractional ablative and non-ablative laser treatment to the face.
Patients were monitored for 14 days with mexameter readings, survey data, as well as independent clinical assessment of re-epithelialization,

The preliminary results indicate that patients receiving the active HGEN-001 product experienced less dramatic post-laser symptoms, such as erythema, edema, and flaking, with a more rapid recovery when compared to the placebo group. The data suggests that topical application of a skin gel supplemented with HGEN-001 can provide overall improved visible re-epithelialization of post ablative laser facial skin, and thereby accelerate patient recovery, while keeping superficial cutaneous side effects to a minimum.

"The ability to provide a treatment that results in better patient comfort and overall healing outcomes is key to many plastic surgery treatments," said Dr. Mark Hubka, Histogen's Director of Clinical Affairs. "Histogen is dedicated to developing a product pipeline to provide multiple patient benefits post dermatological and plastic surgery procedures."

Because of the native soluble WNT proteins and growth factors contained in the formula, HGEN-001 was also evaluated as a stimulus for new hair follicle creation. In the C57 Bl mouse model, an animal model widely used for hair growth, HGEN-001 was shown to significantly increase hair growth and new follicle formation.

"HGEN-001 induced a significant increase in hair follicle growth, as compared to the control, in our preclinical model," Said Frank Zeigler, General Manager of In Vitro Products for Histogen. "Researchers have reported the importance of wnt proteins and wound healing growth factors in the induction of new hair follicles for over a decade. Our research helps to substantiate the importance of these active agents in follicular neogenesis, all of which are components in HGEN-001."

Clinical trials for HGEN-001 as an application for hair growth are planned for late 2008.

About Histogen
Histogen, launched in 2007, seeks to redefine regenerative medicine by developing a series of high value products without the use of embryonic stem cells or animal products. Through Histogen's proprietary bioreactors that mimic the embryonic environment, newborn fibroblasts are encouraged to naturally produce the vital proteins and growth factors from which the company has developed its rich product portfolio. Histogen has two product families - ExceltrixTM, Histogen's human Extracellular Matrix (ECM) and HGEN-001, Histogen's proprietary liquid formula. For more information, please visit http://www.histogeninc.com.