The measurement and importance of red cell survival

Franco, Robert S.

doi:10.1002/ajh.21298

Cited by 127 publications

(140 citation statements)

References 78 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…This is possibly related to red cell survival (;115-125 days [16,17]) and the analytical challenges facing detection of a biologically significant change in HbA 1c at intervals of less than 2 months. It is, however, complicated by the finding that erythrocyte survival is itself highly variable between individuals and by suggestions that it is reduced in patients with poor glycemic control (estimated at a reduction in survival of ;7 days per 1% [11 mmol/mol] rise in HbA 1c in one study [16]), though data on this link between survival and glycemic control are inconsistent (17,18).…”

Section: Discussionmentioning

confidence: 99%

Reduced Testing Frequency for Glycated Hemoglobin, HbA1c, Is Associated With Deteriorating Diabetes Control

et al. 2014

View full text Add to dashboard Cite

OBJECTIVE We previously showed that in patients with diabetes mellitus, glycated hemoglobin (HbA1c) monitoring outside international guidance on testing frequency is widespread. Here we examined the relationship between testing frequency and diabetes control to test the hypothesis that retest interval is linked to change in HbA1c level. RESEARCH DESIGN AND METHODS We examined repeat HbA1c tests (400,497 tests in 79,409 patients, 2008–2011) processed by three U.K. clinical laboratories. We examined the relationship between retest interval and 1) percentage change in HbA1c and 2) proportion of cases showing a significant HbA1c rise. The effect of demographics factors on these findings was also explored. RESULTS Our data showed that the optimal testing frequency required to maximize the downward trajectory in HbA1c was four times per year, particularly in those with an initial HbA1c of ≥7% (≥53 mmol/mol), supporting international guidance. Testing 3-monthly was associated with a 3.8% reduction in HbA1c compared with a 1.5% increase observed with annual testing; testing more frequently provided no additional benefit. Compared with annual monitoring, 3-monthly testing was associated with a halving of the proportion showing a significant rise in HbA1c (7–10 vs. 15–20%). CONCLUSIONS These findings provide, in a large, multicenter data set, objective evidence that testing outside guidance on HbA1c monitoring frequency is associated with a significant detrimental effect on diabetes control. To achieve the optimum downward trajectory in HbA1c, monitoring frequency should be quarterly, particularly in cases with suboptimal HbA1c. While this impact appears small, optimizing monitoring frequency across the diabetes population may have major implications for diabetes control and comorbidity risk.

show abstract

Section: Discussionmentioning

confidence: 99%

Reduced Testing Frequency for Glycated Hemoglobin, HbA1c, Is Associated With Deteriorating Diabetes Control

et al. 2014

View full text Add to dashboard Cite

show abstract

“…35,36 In addition, elevated EPC may affect macrophage functions such as cytokine secretion or their efficiency in removing pathogens and apoptotic cells. Transfusion of RBC that had been stored from a long time led to elevated EPC and an inflammatory cytokine response that was mediated by macrophages and iron overload.…”

Section: © F E R R a T A S T O R T I F O U N D A T I O Nmentioning

confidence: 99%

“…13,28,[35][36][37] RBC from subjects with such diseases have been used for EPC studies. 28 Although the results using damaged RBC provided some insight into the process of EPC in vitro, the use of physiologically aged RBC to elucidate the normal mechanism of EPC is a prerequisite to understand phagocytosis of sRBC and the role of this process in pathology.…”

Section: Introductionmentioning

confidence: 99%

Physiologically aged red blood cells undergo erythrophagocytosis in vivo but not in vitro

Gottlieb¹,

Topaz²,

Cohen³

et al. 2012

Haematologica

View full text Add to dashboard Cite

The online version of this article has a Supplementary Appendix. BackgroundThe lifespan of red blood cells is terminated when macrophages remove senescent red blood cells by erythrophagocytosis. This puts macrophages at the center of systemic iron recycling in addition to their functions in tissue remodeling and innate immunity. Thus far, erythrophagocytosis has been studied by evaluating phagocytosis of erythrocytes that were damaged to mimic senescence. These studies have demonstrated that acquisition of some specific individual senescence markers can trigger erythrophagocytosis by macrophages, but we hypothesized that the mechanism of erythrophagocytosis of such damaged erythrocytes might differ from erythrophagocytosis of physiologically aged erythrocytes. Design and MethodsTo test this hypothesis we generated an erythrocyte population highly enriched in senescent erythrocytes by a hypertransfusion procedure in mice. Various erythrocyte-aging signals were analyzed and erythrophagocytosis was evaluated in vivo and in vitro. ResultsThe large cohort of senescent erythrocytes from hypertransfused mice carried numerous aging signals identical to those of senescent erythrocytes from control mice. Phagocytosis of fluorescently-labeled erythrocytes from hypertransfused mice injected into untreated mice was much higher than phagocytosis of labeled erythrocytes from control mice. However, neither erythrocytes from hypertransfused mice, nor those from control mice were phagocytosed in vitro by primary macrophage cultures, even though these cultures were able to phagocytose oxidatively damaged erythrocytes. ConclusionsThe large senescent erythrocyte population found in hypertransfused mice mimics physiologically aged erythrocytes. For effective erythrophagocytosis of these senescent erythrocytes, macrophages depend on some features of the intact phagocytosing tissue for support. ABSTRACT© F e r r a t a S t o r t i F o u n d a t i o n

show abstract

“…[15][16][17] Importantly, there was no change in the vitamin E content of RCM, which integrates vitamin E exposure and is more representative of tissue vitamin E levels. 18,19 The average erythrocyte lifespan is around 115 days, 20 and thus, in case of a clinically relevant reduction in the availability of vitamin E, the vitamin E content of RCM would be reduced at week 52. These observations are supported by the fact that patients with biallelic PCSK9 loss-of-function mutations have very low LDL-C but no clinical evidence of vitamin E deficiency.…”

Section: Discussionmentioning

confidence: 99%

Effects of Evolocumab on Vitamin E and Steroid Hormone Levels

Blom

Djedjos

Monsalvo

et al. 2015

Circulation Research

View full text Add to dashboard Cite

Rationale : Vitamin E transport and steroidogenesis are closely associated with low-density lipoproteins (LDLs) metabolism, and evolocumab can lower LDL cholesterol (LDL-C) to low levels. Objective: To determine the effects of evolocumab on vitamin E and steroid hormone levels. Methods and Results: After titration of background lipid-lowering therapy per cardiovascular risk, 901 patients with an LDL-C ≥2.0 mmol/L were randomized to 52 weeks of monthly, subcutaneous evolocumab, or placebo. Vitamin E, cortisol, adrenocorticotropic hormone, and gonadal hormones were analyzed at baseline and week 52. In a substudy (n=100), vitamin E levels were also measured in serum, LDL, high-density lipoprotein, and red blood cell membranes at baseline and week 52. Absolute vitamin E decreased in evolocumab-treated patients from baseline to week 52 by 16% but increased by 19% when normalized for cholesterol. In the substudy, vitamin E level changes from baseline to week 52 mirrored the changes in the lipid fraction, and red blood cell membrane vitamin E levels did not change. Cortisol in evolocumab-treated patients increased slightly from baseline to week 52, but adrenocorticotropic hormone and the cortisol:adrenocorticotropic hormone ratio did not change. No patient had a cortisol:adrenocorticotropic hormone ratio <3.0 (nmol/pmol). Among evolocumab-treated patients, gonadal hormones did not change from baseline to week 52. Vitamin E and steroid changes were consistent across subgroups by minimum postbaseline LDL-C <0.4 and <0.6 mmol/L. Conclusions: As expected, vitamin E levels changed similarly to lipids among patients treated for 52 weeks with evolocumab. No adverse effects were observed in steroid or gonadal hormones, even at very low LDL-C levels. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01516879.

show abstract

The measurement and importance of red cell survival

Cited by 127 publications

References 78 publications

Reduced Testing Frequency for Glycated Hemoglobin, HbA1c, Is Associated With Deteriorating Diabetes Control

Reduced Testing Frequency for Glycated Hemoglobin, HbA1c, Is Associated With Deteriorating Diabetes Control

Physiologically aged red blood cells undergo erythrophagocytosis in vivo but not in vitro

Effects of Evolocumab on Vitamin E and Steroid Hormone Levels

Contact Info

Product

Resources

About