Fast Moving Fronts Comments by Seiji Fukumoto

ESI Special Topics, January 2008
Citing URL: http://www.esi-topics.com/fmf/2008/january08-SeijiFukumoto.html

From •>>JANUARY 2008

Seiji Fukumoto answers a few questions about this January's fast moving front in the field of Biology & Biochemistry. The author has also sent along images of their work.

Field: Biology & Biochemistry
Article: Increased circulatory level of biologically active full-length FGF-23 in patients with hypophosphatemic rickets/osteomalacia
Authors: Yamazaki, Y;Okazaki, R;Shibata, M;Hasegawa, Y;Satoh, K;Tajima, T;Takeuchi, Y;Fujita, T;Nakahara, K;Yamashita, T;Fukumoto, S
Journal: J CLIN ENDOCRINOL METAB, 87 (11): 4957-4960 NOV 2002
Addresses:
Tokyo Univ Hosp, Dept Lab Med, Tokyo 113, Japan.
Tokyo Univ Hosp, Dept Lab Med, Tokyo 113, Japan.
Kirin Brewery Co Ltd, Pharmaceut Res Labs, Gunma, Japan.
Teikyo Univ, Sch Med, Dept Med 3, Tokyo, Japan.
Tokyo Metropolitan Kiyose Childrens Hosp, Endocrinol Metab & Genet Unit, Tokyo, Japan.
Hokkaido Univ, Sch Med, Dept Pediat, Sapporo, Hokkaido 060, Japan.
Univ Tokyo, Sch Med, Dept Med, Tokyo 113, Japan.

   Why do you think your paper is highly cited? Does it describe a new discovery, methodology, or synthesis of knowledge?

“...although FGF23 measurement is not routinely used in clinical practice at the moment, it is useful for the diagnosis of several diseases caused by deranged actions of FGF23.”

Our article described the first enzyme-linked immunosorbent assay for fibroblast growth factor 23 (FGF23). FGF23 was identified almost simultaneously by several groups, including us. FGF23 had been shown to have an activity which reduces serum phosphate levels. In this article, we have shown for the first time that FGF23 is elevated in several hypophosphatemic patients indicating that FGF23 is involved in the development of hypophosphatemic diseases.

In addition, this assay method can measure FGF23 in rodents as well. Because of this utility, this article has been cited in papers in both clinical and experimental studies. Subsequent investigations indicated that excess and impaired actions of FGF23 cause both hypophosphatemic and hyperphosphatemic diseases, respectively, and FGF23 works as a physiological hormone regulating serum phosphate level.

   Would you summarize the significance of your paper in layman’s terms?

The level of phosphate in blood is regulated within a narrow range. Actually, high and low phosphate levels cause several diseases. FGF23 is a hormone which has a central role in the regulation of phosphate levels. We have developed an assay method for FGF23 and showed for the first time that high FGF23 in blood is the cause of several diseases characterized by low phosphate levels.

   How did you become involved in this research and were there any particular problems encountered along the way?

I am an endocrinologist and took care of an inpatient with severe muscle weakness about 10 years ago. He was suffering from a hypophosphatemic disease called tumor-induced osteomalacia. This disease had been considered to be caused by overproduction of an unidentified hypophosphatemic humoral factor from mainly benign tumors.

We had found the responsible tumor of this patient and identified FGF23 from this tumor as the causative factor for tumor-induced osteomalacia. After this encounter, we wanted to develop an assay method for FGF23.

   Where do you see your research leading in the future?

FGF23 is involved in the development of several diseases. Therefore, the discovery of measures which can modify FGF23 actions or expressions may become new therapeutic means for modifying the effects of these diseases. In addition, although FGF23 measurement is not routinely used in clinical practice at the moment, it is useful for the diagnosis of several diseases caused by the deranged actions of FGF23.

Seiji Fukumoto, M.D., Ph.D.
Lecturer
Division of Nephrology & Endocrinology
Department of Medicine
University of Tokyo Hospital
Tokyo, Japan

A Closer Look...

Below is an image sent in by Seiji Fukumoto which corresponds with the featured paper, or current research.

Figure 1:

Figure 1: FGF23 levels in patients with tumor-induced osteomalacia measured by our assay. In some patients FGF23 levels both before and after the removal of responsible tumors are shown.



Return to Fast Moving Fronts | Return to Special Topics main menu

ESI Special Topics, January 2008
Citing URL: http://www.esi-topics.com/fmf/2008/january08-SeijiFukumoto.html