Abstract
After erythropoietin (rHuEPO) therapy, patients with chronic renal failure (CRF) do not improve peak O2 uptake (VO2 peak) as much as expected from the rise in hemoglobin concentration ([Hb]). In a companion study, we explain this phenomenon by the concurrent effects of fall in muscle blood flow after rHuEPO and abnormal capillary O2 conductance observed in CRF patients. The latter is likely associated with a poor muscle microcirculatory network and capillary-myofiber dissociation due to uremic myopathy. Herein, cellular bioenergetics and its relationships with muscle O2 transport, before and after rHuEPO therapy, were examined in eight CRF patients (27 +/- 7.3 [SD] yr) studied pre- and post-rHuEPO ([Hb] = 7.8 +/- 0.7 vs. 11.7 +/- 0.7 g x dl-1) during an incremental cycling exercise protocol. Eight healthy sedentary subjects (26 +/- 3.1 yr) served as controls. We hypothesize that uremic myopathy provokes a cytosolic dysfunction but mitochondrial oxidative capacity is not abnormal. 31P-nuclear magnetic resonance spectra (31P-MRS) from the vastus medialis were obtained throughout the exercise protocol consisting of periods of 2 min exercise (at 1.67 Hz) at increasing work-loads interspersed by resting periods of 2.5 min. On a different day, after an identical exercise protocol, arterial and femoral venous blood gas data were obtained together with simultaneous measurements of femoral venous blood flow (Qleg) to calculate O2 delivery (QO2leg) and O2 uptake (VO2leg). Baseline resting [phosphocreatine] to [inorganic phosphate] ratio ([PCr]/[Pi]) did not change after rHuEPO (8.9 +/- 1.2 vs. 8.8 +/- 1.2, respectively), but it was significantly lower than in controls (10.9 +/- 1.5) (P = 0.01 each). At a given submaximal or peak VO2leg, no effects of rHuEPO were seen on cellular bioenergetics ([PCr]/[Pi] ratio, %[PCr] consumption halftime of [PCr] recovery after exercise), nor in intracellular pH (pHi). The post-rHuEPO bioenergetic status and pHi, at a given VO2leg, were below those observed in the control group. However, at a given pHi, no differences in 31P-MRS data were detected between post-rHuEPO and controls. After rHuEPO, at peak VO2, Qleg fell 20% (P < 0.04), limiting the change in QO2leg to 17%, a value that did not reach statistical significance. The corresponding O2 extraction ratio decreased from 73 +/- 4% to 68 +/- 8.2% (P < 0.03). These changes indicate that maximal O2 flow from microcirculation to mitochondria did not increase despite the 50% increase in [Hb] and explain how peak VO2leg and cellular bioenergetics (31P-MRS) did not change after rHuEPO. Differences in pHi, possibly due to lactate differences, between post-rHeEPO and controls appear to be a key factor in the abnormal muscle cell bioenergetics during exercise observed in CRF patients.
Full Text
The Full Text of this article is available as a PDF (191.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Agustí A. G., Roca J., Barberá J. A., Casademont J., Rodriguez-Roisin R., Wagner P. D. Effect of sampling site on femoral venous blood gas values. J Appl Physiol (1985) 1994 Oct;77(4):2018–2022. doi: 10.1152/jappl.1994.77.4.2018. [DOI] [PubMed] [Google Scholar]
- Bernús G., González de Suso J. M., Alonso J., Martin P. A., Prat J. A., Arús C. 31P-MRS of quadriceps reveals quantitative differences between sprinters and long-distance runners. Med Sci Sports Exerc. 1993 Apr;25(4):479–484. [PubMed] [Google Scholar]
- Bradley J. R., Anderson J. R., Evans D. B., Cowley A. J. Impaired nutritive skeletal muscle blood flow in patients with chronic renal failure. Clin Sci (Lond) 1990 Sep;79(3):239–245. doi: 10.1042/cs0790239. [DOI] [PubMed] [Google Scholar]
- Davenport A. The effect of treatment with recombinant human erythropoietin on skeletal muscle function in patients with end-stage renal failure treated with regular hospital hemodialysis. Am J Kidney Dis. 1993 Nov;22(5):685–690. doi: 10.1016/s0272-6386(12)80431-8. [DOI] [PubMed] [Google Scholar]
- Diesel W., Emms M., Knight B. K., Noakes T. D., Swanepoel C. R., van Zyl Smit R., Kaschula R. O., Sinclair-Smith C. C. Morphologic features of the myopathy associated with chronic renal failure. Am J Kidney Dis. 1993 Nov;22(5):677–684. doi: 10.1016/s0272-6386(12)80430-6. [DOI] [PubMed] [Google Scholar]
- Durozard D., Pimmel P., Baretto S., Caillette A., Labeeuw M., Baverel G., Zech P. 31P NMR spectroscopy investigation of muscle metabolism in hemodialysis patients. Kidney Int. 1993 Apr;43(4):885–892. doi: 10.1038/ki.1993.124. [DOI] [PubMed] [Google Scholar]
- Eschbach J. W., Adamson J. W. Recombinant human erythropoietin: implications for nephrology. Am J Kidney Dis. 1988 Mar;11(3):203–209. doi: 10.1016/s0272-6386(88)80150-1. [DOI] [PubMed] [Google Scholar]
- Eschbach J. W., Egrie J. C., Downing M. R., Browne J. K., Adamson J. W. Correction of the anemia of end-stage renal disease with recombinant human erythropoietin. Results of a combined phase I and II clinical trial. N Engl J Med. 1987 Jan 8;316(2):73–78. doi: 10.1056/NEJM198701083160203. [DOI] [PubMed] [Google Scholar]
- Eschbach J. W., Mladenovic J., Garcia J. F., Wahl P. W., Adamson J. W. The anemia of chronic renal failure in sheep. Response to erythropoietin-rich plasma in vivo. J Clin Invest. 1984 Aug;74(2):434–441. doi: 10.1172/JCI111439. [DOI] [PMC free article] [PubMed] [Google Scholar]
- González de Suso J. M., Bernús G., Alonso J., Alay A., Capdevila A., Gili J., Prat J. A., Arús C. Development and characterization of an ergometer to study the bioenergetics of the human quadriceps muscle by 31P NMR spectroscopy inside a standard MR scanner. Magn Reson Med. 1993 Apr;29(4):575–581. doi: 10.1002/mrm.1910290425. [DOI] [PubMed] [Google Scholar]
- Iotti S., Lodi R., Frassineti C., Zaniol P., Barbiroli B. In vivo assessment of mitochondrial functionality in human gastrocnemius muscle by 31P MRS. The role of pH in the evaluation of phosphocreatine and inorganic phosphate recoveries from exercise. NMR Biomed. 1993 Jul-Aug;6(4):248–253. doi: 10.1002/nbm.1940060404. [DOI] [PubMed] [Google Scholar]
- Kemp G. J., Radda G. K. Quantitative interpretation of bioenergetic data from 31P and 1H magnetic resonance spectroscopic studies of skeletal muscle: an analytical review. Magn Reson Q. 1994 Mar;10(1):43–63. [PubMed] [Google Scholar]
- Kemp G. J., Taylor D. J., Radda G. K. Control of phosphocreatine resynthesis during recovery from exercise in human skeletal muscle. NMR Biomed. 1993 Jan-Feb;6(1):66–72. doi: 10.1002/nbm.1940060111. [DOI] [PubMed] [Google Scholar]
- Macdougall I. C., Lewis N. P., Saunders M. J., Cochlin D. L., Davies M. E., Hutton R. D., Fox K. A., Coles G. A., Williams J. D. Long-term cardiorespiratory effects of amelioration of renal anaemia by erythropoietin. Lancet. 1990 Mar 3;335(8688):489–493. doi: 10.1016/0140-6736(90)90733-l. [DOI] [PubMed] [Google Scholar]
- Marrades R. M., Roca J., Campistol J. M., Diaz O., Barberá J. A., Torregrosa J. V., Masclans J. R., Cobos A., Rodríguez-Roisin R., Wagner P. D. Effects of erythropoietin on muscle O2 transport during exercise in patients with chronic renal failure. J Clin Invest. 1996 May 1;97(9):2092–2100. doi: 10.1172/JCI118646. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCully K. K., Iotti S., Kendrick K., Wang Z., Posner J. D., Leigh J., Jr, Chance B. Simultaneous in vivo measurements of HbO2 saturation and PCr kinetics after exercise in normal humans. J Appl Physiol (1985) 1994 Jul;77(1):5–10. doi: 10.1152/jappl.1994.77.1.5. [DOI] [PubMed] [Google Scholar]
- Metra M., Cannella G., La Canna G., Guaini T., Sandrini M., Gaggiotti M., Movilli E., Dei Cas L. Improvement in exercise capacity after correction of anemia in patients with end-stage renal failure. Am J Cardiol. 1991 Oct 15;68(10):1060–1066. doi: 10.1016/0002-9149(91)90496-8. [DOI] [PubMed] [Google Scholar]
- Moore G. E., Bertocci L. A., Painter P. L. 31P-magnetic resonance spectroscopy assessment of subnormal oxidative metabolism in skeletal muscle of renal failure patients. J Clin Invest. 1993 Feb;91(2):420–424. doi: 10.1172/JCI116217. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore G. E., Parsons D. B., Stray-Gundersen J., Painter P. L., Brinker K. R., Mitchell J. H. Uremic myopathy limits aerobic capacity in hemodialysis patients. Am J Kidney Dis. 1993 Aug;22(2):277–287. doi: 10.1016/s0272-6386(12)70319-0. [DOI] [PubMed] [Google Scholar]
- Painter P., Moore G. E. The impact of recombinant human erythropoietin on exercise capacity in hemodialysis patients. Adv Ren Replace Ther. 1994 Apr;1(1):55–65. doi: 10.1016/s1073-4449(12)80022-7. [DOI] [PubMed] [Google Scholar]
- Park J. S., Kim S. B., Park S. K., Lim T. H., Lee D. K., Hong C. D. Effect of recombinant human erythropoietin on muscle energy metabolism in patients with end-stage renal disease: a 31P-nuclear magnetic resonance spectroscopic study. Am J Kidney Dis. 1993 Jun;21(6):612–618. doi: 10.1016/s0272-6386(12)80033-3. [DOI] [PubMed] [Google Scholar]
- Piiper J., Scheid P. Model for capillary-alveolar equilibration with special reference to O2 uptake in hypoxia. Respir Physiol. 1981 Dec;46(3):193–208. doi: 10.1016/0034-5687(81)90121-3. [DOI] [PubMed] [Google Scholar]
- Robertson H. T., Haley N. R., Guthrie M., Cardenas D., Eschbach J. W., Adamson J. W. Recombinant erythropoietin improves exercise capacity in anemic hemodialysis patients. Am J Kidney Dis. 1990 Apr;15(4):325–332. doi: 10.1016/s0272-6386(12)80079-5. [DOI] [PubMed] [Google Scholar]
- Roca J., Agusti A. G., Alonso A., Poole D. C., Viegas C., Barbera J. A., Rodriguez-Roisin R., Ferrer A., Wagner P. D. Effects of training on muscle O2 transport at VO2max. J Appl Physiol (1985) 1992 Sep;73(3):1067–1076. doi: 10.1152/jappl.1992.73.3.1067. [DOI] [PubMed] [Google Scholar]
- Roca J., Hogan M. C., Story D., Bebout D. E., Haab P., Gonzalez R., Ueno O., Wagner P. D. Evidence for tissue diffusion limitation of VO2max in normal humans. J Appl Physiol (1985) 1989 Jul;67(1):291–299. doi: 10.1152/jappl.1989.67.1.291. [DOI] [PubMed] [Google Scholar]
- Roca J., Sanchis J., Agusti-Vidal A., Segarra F., Navajas D., Rodriguez-Roisin R., Casan P., Sans S. Spirometric reference values from a Mediterranean population. Bull Eur Physiopathol Respir. 1986 May-Jun;22(3):217–224. [PubMed] [Google Scholar]
- Satoh K., Masuda T., Ikeda Y., Kurokawa S., Kamata K., Kikawada R., Takamoto T., Marumo F. Hemodynamic changes by recombinant erythropoietin therapy in hemodialyzed patients. Hypertension. 1990 Mar;15(3):262–266. doi: 10.1161/01.hyp.15.3.262. [DOI] [PubMed] [Google Scholar]
- Taylor D. J., Bore P. J., Styles P., Gadian D. G., Radda G. K. Bioenergetics of intact human muscle. A 31P nuclear magnetic resonance study. Mol Biol Med. 1983 Jul;1(1):77–94. [PubMed] [Google Scholar]
- Taylor D. J., Rajagopalan B., Radda G. K. Cellular energetics in hypothyroid muscle. Eur J Clin Invest. 1992 May;22(5):358–365. doi: 10.1111/j.1365-2362.1992.tb01474.x. [DOI] [PubMed] [Google Scholar]
- Thompson C. H., Kemp G. J., Taylor D. J., Ledingham J. G., Radda G. K., Rajagopalan B. Effect of chronic uraemia on skeletal muscle metabolism in man. Nephrol Dial Transplant. 1993;8(3):218–222. [PubMed] [Google Scholar]
- Táborský P., Sotorník I., Kaslíková J., Schück O., Hájek M., Horská A. 31P magnetic resonance spectroscopy investigation of skeletal muscle metabolism in uraemic patients. Nephron. 1993;65(2):222–226. doi: 10.1159/000187478. [DOI] [PubMed] [Google Scholar]
- Wagner P. D. Algebraic analysis of the determinants of VO2,max. Respir Physiol. 1993 Aug;93(2):221–237. doi: 10.1016/0034-5687(93)90007-w. [DOI] [PubMed] [Google Scholar]
- Wagner P. D. Diffusion and chemical reaction in pulmonary gas exchange. Physiol Rev. 1977 Apr;57(2):257–312. doi: 10.1152/physrev.1977.57.2.257. [DOI] [PubMed] [Google Scholar]
- Wagner P. D., Roca J., Hogan M. C., Poole D. C., Bebout D. C., Haab P. Experimental support for the theory of diffusion limitation of maximum oxygen uptake. Adv Exp Med Biol. 1990;277:825–833. doi: 10.1007/978-1-4684-8181-5_94. [DOI] [PubMed] [Google Scholar]