New Insights into Red Blood Cell Microcytosis upon mTOR Inhibitor Administration

Microplastics exposure altered hematological and lipid profiles as well as liver and kidney function parameters in albino rats (Rattus norvegicus)

The global occurrence of microplastics and their poorly understood health implications underscore the need for scientific investigation. This study aimed to assess the effects of microplastics exposure. Twenty-five (25) albino rats (Rattus norvegicus) were divided into five (5) groups, each consisting of five rats. Group 1 (the negative control) received normal feed; group 2 (the positive control) was administered a 10 % lead acetate solution; and groups 3, 4, and 5 were administered 1 %, 5 %, and 10 % microplastic solutions, respectively. The rats were monitored for 28 days, after which blood samples were taken for hematological and lipid profiles as well as liver and kidney function parameters. The results revealed dose-dependent significant (p < 0.05) alterations in the health indices of the treated rats and the positive control compared with the negative control. Specifically, the hematological parameters, including the white blood cells (WBC) and its subtypes, were reduced, indicating immunosuppressive effects, and the red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), platelets, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were reduced, indicating anemia. The 1 % and 5 % microplastic solutions raised the lipid profiles of the treated rats, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL), while the 10 % concentration decreased them, causing hyperlipidemia and hypolipidemia, respectively. The liver function parameters, including total protein (TP), albumin (ALB), aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), were elevated, indicating liver damage. Elevation of kidney function parameters, including sodium ion (Na+), potassium ion (K+), chloride ion (Cl-), urea, and creatinine (CRT), were noticed, suggesting kidney injuries. It can be inferred from these results that microplastics are toxic. Hence, human exposure to microplastics should be reduced to a minimum.

mTOR Inhibitors Induce Erythropoietin Resistance in Renal Transplant Recipients

Aim

To elucidate the role of mTOR inhibitors on iron, hepcidin and erythropoietin-mediated regulation of hemopoiesis in stable renal transplant recipients (RTR).

Background

Impaired hemopoiesis is common following renal transplantation managed using mTOR inhibitors. The mechanisms responsible are uncertain but include direct effects on iron, hepcidin or erythropoietin-mediated hemopoiesis.

Methods

We conducted a single center prospective case-control study of 26 adult RTR with stable allograft function. RTR received stable mTOR dosing (cases, 11/26 [42%]) or stable tacrolimus dosing (controls, 15/26 [58%]). Baseline demographics, full blood count, renal function, iron studies, hepcidin-25, Interleukin-6 (IL-6) and erythropoietin (EPO) levels were determined.

Results

There were no differences in age, gender or allograft function. Mean daily sirolimus dose for cases was 1.72 mg, with mean trough level of 8.46 ng/mL. Mean daily tacrolimus dose for controls was 4.3 mg, with mean trough level of 5.8 ng/mL. There were no differences in mean hemoglobin (143 vs. 147 g/L; p = 0.59), MCV (88 vs. 90 fL; p = 0.35), serum ferritin (150 vs. 85.7 μg/L; p = 0.06), transferrin saturation (26 vs. 23.3%; p = 0.46), IL-6 (11 vs. 7.02 pg/ml; p = 0.14) or hepcidin-25 (3.62 vs. 3.26 nM; p = 0.76) between the groups. EPO levels were significantly higher in the group receiving mTOR therapy (16.8 vs. 8.49 IU/L; p = 0.028). On logistic regression analysis EPO level was the only variable that had a significant impact providing an odds ratio of 0.84 (95%CI 0.66–0.98). The area under the receiver operator characteristic curve (ROC) for the analysis was 0.77 (95%CI 0.54–0.94) with p = 0.04.

Conclusion: Higher levels of EPO in the absence of deranged iron biochemistry or hepcidin-25 levels suggest that EPO resistance rather than impaired iron metabolism may contribute to the impaired hemopoiesis previously demonstrated in RTR on mTOR therapy.