The full content of Annals is available to subscribers

Subscribe/Learn More  >
Brief Communications |

Neocytolysis on Descent from Altitude: A Newly Recognized Mechanism for the Control of Red Cell Mass

Lawrence Rice, MD; Wilson Ruiz, MD; Theda Driscoll, CNT; Carl E. Whitley, MT; Rosario Tapia, BS; David L. Hachey, PhD; Gustavo F. Gonzales, MD; and Clarence P. Alfrey, MD
[+] Article, Author, and Disclosure Information

From Baylor College of Medicine, Houston, Texas, and Universidad Peruana Cayetano Heredia, Lima, Peru.

Acknowledgments: The authors thank the following persons for essential technical and logistic support: Bertha Mendoza, Ruben Morcial Albiyor, Hortencia Carmelo, Mary Moir, Robert Talamini, Dr. Henry van Dyk, Dr. Holly van Dyk, and John Moulds. They also thank the volunteer participants for their cooperation.

Grant Support: By National Aeronautics and Space Administration grants NAGW 4993 and NASA/NSBRI NCC9-58.

Requests for Single Reprints: Lawrence Rice, MD, 6565 Fannin, MS 902-Main, Houston, TX 77030; e-mail, lrice@bcm.tmc.edu.

Current Author Addresses: Drs. Rice and Alfrey, Ms. Driscoll, and Mr. Whitley: Section of Hematology, Department of Medicine, Baylor College of Medicine, 6565 Fannin, MS 902-Main, Houston, TX 77030.

Drs. Ruiz and Gonzales and Ms. Tapia: Instituto de Investigaciones de la Altura, and Department of Physiological Sciences, Universidad Peruana Cayetano Heredia, Lima 1843, Peru.

Dr. Hachey: Department of Pharmacology, Vanderbilt University, 2201 West End Avenue, Nashville, TN 37232-6400.

Author Contributions: Conception and design: L. Rice, W. Ruiz, T. Driscoll, G.F. Gonzalez, C.P. Alfrey.

Analysis and interpretation of the data: L. Rice, T. Driscoll, C.E. Whitley, C.P. Alfrey.

Drafting of the article: L. Rice.

Critical revision of the article for important intellectual content: L. Rice, W. Ruiz, D.L. Hachey, G.F. Gonzalez, C.P. Alfrey.

Final approval of the article: L. Rice, W. Ruiz, T. Driscoll, C.E. Whitley, R. Tapia, D.L. Hachey, G.F. Gonzalez, C.P. Alfrey.

Provision of study materials or patients: W. Ruiz, R. Tapia, G.F. Gonzalez.

Statistical expertise: T. Driscoll.

Obtaining of funding: L. Rice, C.P. Alfrey.

Administrative, technical, or logistic support: W. Ruiz, T. Driscoll, C.E. Whitley, R. Tapia, D.L. Hachey, G.F. Gonzalez.

Collection and assembly of data: L. Rice, W. Ruiz, T. Driscoll, C.E. Whitley, R. Tapia, D.L. Hachey, C.P. Alfrey.

Ann Intern Med. 2001;134(8):652-656. doi:10.7326/0003-4819-134-8-200104170-00010
Text Size: A A A

Background: Studies of space-flight anemia have uncovered a physiologic process, neocytolysis, by which young red blood cells are selectively hemolyzed, allowing rapid adaptation when red cell mass is excessive for a new environment.

Objectives: 1] To confirm that neocytolysis occurs in another situation of acute plethora—when high-altitude dwellers with polycythemia descend to sea level; and 2) to clarify the role of erythropoietin suppression.

Design: Prospective observational and interventional study.

Setting: Cerro de Pasco (4380 m) and Lima (sea level), Peru.

Participants: Nine volunteers with polycythemia.

Interventions: Volunteers were transported to sea level; three received low-dose erythropoietin.

Measurements: Changes in red cell mass, hematocrit, hemoglobin concentration, reticulocyte count, ferritin level, serum erythropoietin, and enrichment of administered 13C in heme.

Results: In six participants, red cell mass decreased by 7% to 10% within a few days of descent; this decrease was mirrored by a rapid increase in serum ferritin level. Reticulocyte production did not decrease, a finding that establishes a hemolytic mechanism. 13C changes in circulating heme were consistent with hemolysis of young cells. Erythropoietin was suppressed, and administration of exogenous erythropoietin prevented the changes in red cell mass, serum ferritin level, and 13C-heme.

Conclusions: Neocytolysis and the role of erythropoietin are confirmed in persons with polycythemia who descend from high altitude. This may have implications that extend beyond space and altitude medicine to renal disease and other situations of erythropoietin suppression, hemolysis, and polycythemia.


Grahic Jump Location
Figure 2.
Changes in serum ferritin values.rP

Serum ferritin values are plotted before and after descent from high altitude to sea level on day 11. The three white symbols represent different participants who received low-dose erythropoietin on descent; the other six symbols represent the participants who did not. The dotted line connects the mean values for the participants receiving erythropoietin, and the solid line connects the mean values for those who did not. Serum ferritin levels closely correlated with changes seen in red cell mass (Spearman coefficient, = 0.96;  < 0.01).

Grahic Jump Location
Grahic Jump Location
Figure 1.
Change in red blood cell mass after descent from high altitude.51

Cr red cell mass at baseline and changes after 10 days at sea level are presented. White bars indicate participants who did not receive low-dose erythropoietin after descent; gray bars represent the volunteers who did receive low-dose erythropoietin. (Values for red cell mass determined by carbon monoxide rebreathing were almost identical.).

Grahic Jump Location




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Submit a Comment/Letter
Submit a Comment/Letter

Summary for Patients

A New Mechanism for Controlling the Number of Red Cells in the Blood

The summary below is from the full report titled “Neocytolysis on Descent from Altitude: A Newly Recognized Mechanism for the Control of Red Cell Mass.” It is in the 17 April 2001 issue of Annals of Internal Medicine (volume 134, pages 652-656). The authors are L Rice, W Ruiz, T Driscoll, CE Whitley, R Tapia, DL Hachey, GF Gonzales, and CP Alfrey.


Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.


Buy Now for $32.00

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Related Articles
Journal Club
Topic Collections
PubMed Articles
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.