Erythropoietin and glucose homeostasis in women at varying degrees of future diabetic risk

Non-hematopoietic effects of endogenous erythropoietin on lean mass and body weight regulation

OBJECTIVE

To investigate the concurrent relationships between human plasma erythropoietin concentrations and energy expenditure (EE), body composition, plasma leptin concentrations, and associations with weight change.

METHODS

Plasma to measure erythropoietin and leptin; data for body composition; 24-h EE measured in a whole-room calorimeter; and 75 g oral glucose tolerance testing were available from 109 full-heritage Pima Indians (55% male) from a larger study designed to understand the causes of obesity. Seventy-nine subjects had data for weight at a later visit (mean follow-up = 4.3 ± 1.9 years) to calculate percent weight change per year.

RESULTS

Erythropoietin, adjusted for covariates, correlated with 24-h EE (r = 0.26, P = 0.007), sleeping EE (r = 0.29, P = 0.003), fat-free mass (r = 0.19, P = 0.05), and fat mass (r = 0.27, P = 0.005), but not insulin or glucose measures. The association of erythropoietin with 24-h EE was fully mediated by fat-free mass. Erythropoietin associated with leptin in women (ρ = 0.36, P = 0.01), but not in men (P = 0.9), independently from fat mass. The association of erythropoietin with percent weight change per year was in opposing directions (interaction: P = 0.002) in males (r = -0.35, P = 0.02) versus females (r = 0.37, P = 0.02).

CONCLUSIONS

Non-hematopoietic endogenous erythropoietin action may be involved in body weight regulation in opposing directions in men and women, i.e., weight loss in men and weight gain in women.

Reduction in new-onset diabetes mellitus after renal transplant with erythropoietin-stimulating agents: a retrospective cohort study

BACKGROUND

Studies have shown that erythropoietin-stimulating agents (ESAs) protect mice against the development of diabetes through direct effects on pancreatic ß cells. However, the effect of ESAs on the incidence of diabetes in humans has not been well studied. It is unknown whether exposure to ESAs is associated with a reduced incidence of new-onset diabetes after transplant (NODAT).

OBJECTIVE

The objective of this study is to examine the relationship between ESA exposure post-renal transplant and the development of NODAT.

DESIGN

We performed a single center, retrospective cohort analysis.

PATIENTS

We compared patients who received a first live or deceased donor renal allograft, with any exposure to an ESA vs. those without such exposure and who developed NODAT and who did not. Patients with a prior history of diabetes mellitus or multi-organ transplant, including a second renal transplant were excluded.

MEASUREMENTS AND METHODS

NODAT was defined based on the 2008 Canadian Diabetes Association criteria. Multivariate logistic regression analysis was performed to determine factors independently associated with NODAT.

RESULTS

One hundred thirty-two (29 %) patients were exposed to an ESA, four of which developed NODAT compared to 128 who did not develop NODAT (p < 0.0001). Of those not exposed to an ESA, 15 % (48/319) developed NODAT. By Fisher's exact test, exposure to an ESA at any time post-transplant reduced the risk of developing NODAT; odds ratio (OR) = 0.08, 95 % confidence interval (CI) (0.018-0.352), p = 0.0008. Older age; OR = 1.41, 95 % CI (1.036-1.933), p < 0.02, higher random blood sugar at discharge; OR = 1.30, 95 % CI (1.077-1.57), p < 0.006 and deceased donor; OR 2.18 CI (1.009-4.729), p = 0.04 were associated with an increased risk of NODAT.

LIMITATIONS

The limitations of this study include its retrospective nature, single center, and homogenous population; thus, generalizability of the results must be approached with caution.

CONCLUSION

ESA exposure may be associated with a reduced incidence of NODAT in the post-renal transplant population. The role of ESA in preventing NODAT requires further investigation.