Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients.

For the first time, a paper-based analytical device (PAD) was developed for the assessment of transferrin saturation (TSAT), which is defined as the ratio between iron bound to transferrin (Tf) and the total iron-binding capacity (TIBC) of Tf. Both parameters were simultaneously measured on the same PAD using ferrozine as a chromophore and a smartphone as the color reader. To this end, Tf was first isolated from serum using anti-Tf immunomagnetic beads to ensure that only the Tf-bound iron was measured, improving the selectivity and accuracy of TSAT assessment. To demonstrate the practical utility of the device, it was validated by analyzing a certified reference material, showing excellent accuracy (Er < 4%) and good precision (RSD ≤ 6%). Finally, 18 diagnosed serum samples from ischemic stroke patients were analyzed by this approach, and the results were compared with those obtained by urea-PAGE, showing not only an excellent correlation (r = 0.93, p < 0.05) but that the PAD approach has become statistically identical to the free-interference urea-PAGE. In comparison with the slow, tedious, and non-miniaturized-PAGE, this PAD approach exhibited attractive characteristics such as low cost, disposability, and connectivity, showing great potential for future point-of-care testing, especially in developing countries and/or remote areas, where access to medical or clinical facilities is limited.

Tocilizumab Treatment Effect on Iron Homeostasis in Severe COVID-19 Patients.

BACKGROUND: Tocilizumab has been proposed as an effective treatment for severe COVID-19. We aimed to investigate whether tocilizumab administration is associated with increased availability of serum iron which may possibly be associated with adverse effects on clinical outcomes. METHODS: We performed an observational, retrospective cohort study. We included adults, who were hospitalized in ICU with the diagnosis of severe COVID-19 infection eligible for tocilizumab treatment. Laboratory data including serum iron, ferritin, transferrin saturation, hemoglobin, and C-reactive protein levels of all patients were collected shortly before and 24 h, 48 h, and 72 h after tocilizumab administration. RESULTS: During the study period, 15 patients fulfilled the inclusion criteria and were eligible to receive tocilizumab treatment. Tocilizumab therapy was associated with a prominent increase in serum iron and transferrin saturation levels (26 ± 13 µg/dL and 15 ± 8% before treatment and 79 ± 32 µg/dL and 41 ± 15% 72 h after treatment, respectively, p < 0.001) and decrease in serum ferritin levels (1,921 ± 2,071 ng/mL before and 1,258 ± 1,140 ng/mL 72 h after treatment, p = 0.027). CONCLUSION: Treatment of severe COVID-19 patients with tocilizumab is associated with a profound increase in serum iron and ferritin saturation levels along with a decrease in ferritin levels. This may represent an undesirable side effect that may potentiate viral replication.

Possible Association of Energy Availability with Transferrin Saturation and Serum Iron during Summer Camp in Male Collegiate Rugby Players.

Low energy availability (LEA) may persist in rugby players. However, timely assessment of energy balance is important but is difficult. Therefore, a practical index that reflects energy availability (EA) is essential. A total of 19 male college rugby players participated in a 2-week pre-season summer camp. Their blood sample was collected after overnight fast prior to (Pre), in the middle (Middle), and after (Post) the camp. Their physical activity in the first half of the camp was calculated using the additive factor method in the forwards (FW; numbers 1-8) and backs (BK; numbers 9-15). The participants were categorized as tight five (T5; numbers 1-5), back row (BR; numbers 6-8), and BK for analysis. All the participants lost weight during the camp (range: from -5.9% to -0.1%). Energy balance in the first half of the camp was negative. Transferrin saturation (TSAT) and serum iron levels significantly decreased to half, or even less, compared with the Pre levels at week 1 and remained low. The changes in TSAT and serum iron levels exhibited a significant positive correlation with the changes in body weight (R = 0.720; R = 0.627) and with energy intake (R = 0.410; R = 461) in T5. LEA occurs in rugby summer camp but is difficult to assess using weight change. Alternately, TSAT and serum iron levels after overnight fast may be better predictors of LEA.

Iron deficiency and short-term adverse events in patients with decompensated heart failure.

BACKGROUND: For patients with heart failure (HF), iron deficiency (ID) is a common therapeutic target. However, little is known about the utility of transferrin saturation (TSAT) or serum ferritin for risk stratification in decompensated HF (DHF) or the European Society of Cardiology's (ESC) current definition of ID (ferritin < 100 µg/L or TSAT < 20% if ferritin is 100-299 µg/L). We evaluated the association between these potential markers of ID and the risk of 30-day readmission for HF or death in patients with DHF. METHODS: We retrospectively included 1701 patients from a multicenter registry of DHF. Serum ferritin and TSAT were evaluated 24-72 h after hospital admission, and multivariable Cox regression was used to assess their association with the composite endpoint. RESULTS: Participants' median (quartiles) age was 76 (68-82) years, 43.8% were women, and 51.7% had a left ventricular ejection fraction > 50%. Medians for NT-proBNP, TSAT, and ferritin were 4067 pg/mL (1900-8764), 14.1% (9.0-20.3), and 103 ug/L (54-202), respectively. According to the current ESC definition, 1,246 (73.3%) patients had ID. By day 30, there were 177 (10.4%) events (95 deaths and 85 HF readmission). After multivariable adjustment, lower TSAT was associated with outcome (p = 0.009) but serum ferritin was not (HR 1.00; 95% confidence interval 0.99-1.00, p = 0.347). CONCLUSIONS: Lower TSAT, but not ferritin, was associated with a higher risk of short-term events in patients with DHF. Further research is needed to confirm these findings and the utility of serum ferritin as a marker of ID in DHF.

Influence of Pretransplant Factors on Posttransplant Anemia Recovery Rate in Primary Deceased Donor Kidney Transplant Recipients.

OBJECTIVES: Our objective was to evaluate the influence of pretransplant risk factors on posttransplant anemia recovery. MATERIALS AND METHODS: This single-center observational retrospective study included 80 deceased donor kidney transplant recipients who had been followed up to 16 months after kidney transplant. Time point of posttransplant anemia recovery was considered the time when hemoglobin of 11.0 g/dL was achieved and maintained for 3 consecutive monthly visits. We collected donor/transplant characteristics (age, sex, hypertension history, cause of death, donor kidney function, expanded criteria donor status, deceased donor score, HLA mismatch, and cold ischemia time) and recipient data (pretransplant hemoglobin, parathyroid hormone, kidney graft function, delayed graft function, acute rejection, infections, surgical bleeding, posttransplant parathyroid hormone, iron stores, and C-reactive protein and tacrolimus levels). We used univariate and multivariate Cox proportional hazards analyses and Kaplan-Meier plots to determine associations between variables and posttransplant anemia recovery rate. P < .05 was considered significant. RESULTS: We identified 62 deceased donors (33 male; mean age 50 ± 15.1 years) and 80 kidney transplant recipients (52 male; mean age 47.0 ± 10.6 years). Mean pretransplant hemoglobin was 11.4 ± 1.5 g/dL. Donor age, deceased donor score, pretransplant parathyroid hormone, posttransplant transferrin saturation (all P < .05), and tacrolimus level (P < .01) were significantly related to posttransplant anemia recovery. Kaplan-Meier curve identified that recipients of deceased donors below 60 years old achieved hemoglobin of 11.0 g/dL more frequently and earlier than recipients of deceased donors above 60 years old (P < .05). CONCLUSIONS: Deceased donor age, deceased donor score, pretransplant serum parathyroid hormone, posttransplant transferrin saturation, and tacrolimus level were significantly associated with posttransplant anemia recovery rate in deceased donor kidney transplant recipients. Anemia recovery was more frequent and earlier in recipients of deceased donors below 60 years than in recipients of donors 60 years old and above.

Transferrin saturation is independently associated with the severity of obstructive sleep apnea syndrome and hypoxia among obese subjects.

INTRODUCTION & AIMS: Obstructive sleep apnea syndrome (OSAS) is a frequent complication of obesity. Intermittent chronic hypoxia which frequently results from OSAS could modulate the systemic control of iron metabolism and alter serum iron parameters, especially among obese patients. AIMS: to evaluate whether serum parameters of iron bioavailability and storage (primary), as well as age, waist circumference, arterial hypertension and tobacco use (secondary) are associated with OSAS severity and/or hypoxia. METHODS: design: a single-center retrospective study with prospective data collection; inclusion criteria: consecutive patients referred for initial assessment for obesity underwent nocturnal respiratory polygraphy and iron status serum assessment within a 3-month period. The adjusted analyzes were performed using ANOVA and reported as adjusted means and 95% confidence interval (95% CI). RESULTS: 13 men and 56 women were included. OSAS prevalence: 72% (n = 50). Ferritin (mean ± SD, 260 ± 276 vs. 111 ± 89 µg/l, p = 0.01) and transferrin saturation (31 ± 10 vs. 24 ± 9%, p = 0.002) were significantly higher in case of moderate/severe OSAS than in absent/mild OSAS, independently from gender and tobacco use. Serum iron (19.4 µg/l [CI95%, 16.5-22.3] vs. 16.2 µg/l ([14.1-18.2], p = 0.056) and transferrin saturation (31.5% [26.3-36.7]) vs. 25.3% [21.6-29.1], p = 0.043) were higher when time under oxygen saturation <90% was >15%. Age (mean ± SD, 51 ± 11 vs. 41 ± 12 yr, p = 0.001), waist circumference (136 ± 18 vs. 123 ± 12 cm, p = 0.003), arterial hypertension (59% (n = 13/22) vs. 23% (n = 11/47), p = 0.004) and tobacco use (64% (n = 14/22) vs. 32% (n = 15/47), p = 0.01) were significantly greater in moderate/severe OSAS than in absent/mild OSAS. CONCLUSIONS: Transferrin saturation was associated with OSAS severity and time under hypoxia. This suggests a relationship between OSAS-induced hypoxia and iron metabolism among obese patients.

Serum transferrin predicts end-stage Renal Disease in Type 2 Diabetes Mellitus patients.

Background: To investigate the relationship between serum iron status and renal outcome in patients with type 2 diabetes mellitus (T2DM). Methods: Chinese patients (n=111) with T2DM and biopsy-proven diabetic nephropathy (DN) were surveyed in a longitudinal, retrospective study. Serum iron, total iron-binding capacity, ferritin, and transferrin were measured at the time of renal biopsy. Iron deposition and transferrin staining were performed with renal biopsy specimens of DN patients and potential kidney donors. End-stage renal disease (ESRD) was the end-point. ESRD was defined as an estimated glomerular filtration rate <15 mL/min/1.73 m2 or the need for chronic renal replacement therapy. Cox proportional hazard models were used to estimate the hazard ratios (HRs) for the influence of serum iron metabolism on ESRD. Results: During a median follow up of 30.9 months, 66 (59.5%) patients progressed to ESRD. After adjusting for age, sex, baseline systolic blood pressure, renal functions, hemoglobin, HbA1c, and pathological findings, lower serum transferrin concentrations were significantly associated with higher ESRD in multivariate models. Compared with patients in the highest transferrin quartile (≥1.65 g/L), patients in the lowest quartile (≤1.15 g/L) had multivariable-adjusted HR (95% confidence interval) of 7.36 (1.40-38.65) for ESRD. Moreover, tubular epithelial cells in DN exhibited a higher deposition of iron and transferrin expression compared with healthy controls. Conclusions: Low serum transferrin concentration was associated with diabetic ESRD in patients with T2DM. Free iron nephrotoxicity and poor nutritional status with accumulated iron or transferrin deposition might contribute to ESRD.

Comparative accuracy of ferritin, transferrin saturation and soluble transferrin receptor for the diagnosis of iron deficiency in inflammatory bowel disease.

BACKGROUND: The diagnosis of iron deficiency is based on ferritin and transferrin saturation (TfS) in inflammatory bowel disease (IBD) patients, yet guideline thresholds are not evidence-based. Soluble transferrin receptor (sTfR) is one of the best noninvasive tests in patients with inflammation. AIMS: To evaluate the accuracy of ferritin and/or TfS for diagnosing iron deficiency in IBD and identify the optimal thresholds of these parameters using sTfR as reference. METHODS: Two hundred and two patients (2072 samples) receiving at least one infusion of biologic (vedolizumab or infliximab) were included. RESULTS: In ulcerative colitis patients with C-reactive protein (CRP) <10 mg/L, optimal iron deficiency diagnostic performances were observed with ferritin and TfS thresholds of 65 µg/L (sensitivity of 0.78 and specificity of 0.76) and 16% (sensitivity of 0.79 and specificity of 0.90), respectively. For ulcerative colitis patients with CRP > 10 mg/L, the thresholds with the best diagnostic performance were 80 µg/L (sensitivity of 0.75 and a specificity of 0.82) for ferritin and 11% for TfS (sensitivity of 0.75 and a specificity of 0.82). There was no added value for combined ferritin and TfS. No ferritin or TfS threshold had good diagnostic performance in Crohn's disease patients (AUC for ferritin was 0.65 (95% CI 0.55-0.75) and the AUC for TfS was 0.70 (95% CI 0.61-0.78). CONCLUSION: Ferritin and TfS are reliable parameters for iron deficiency diagnosis only in ulcerative colitis patients, at thresholds different from current guidelines. In Crohn's disease patients, sTfR should be used given the poor diagnostic performance of ferritin and TfS.

The target hemoglobin content values of reticulocytes for efficient anemia improvement are achieved by low ferritin levels and moderate transferrin saturation: a retrospective observational study.

Objectives: The optimal iron level in hemodialysis (HD) patients remains unclear. The hemoglobin content of reticulocytes (CHr) is a sensitive indicator of iron used for hematopoiesis. To identify the optimal iron content for HD patients, we investigated the relation between CHr levels and iron status, as well as the levels of hepcidin, a main regulator of iron metabolism.Methods: This study enrolled 181 HD outpatients treated with recombinant human erythropoietin (rHuEPO). A sensitivity analysis, using a generalized linear regression model that included the interaction term, was applied to determine the correlations between levels of CHr and those of serum ferritin (s-ft), transferrin saturation (TSAT), and hepcidin.Results: The greatest changes in correlation coefficients for levels of s-ft and TSAT with CHr levels indicated optimal cut-off points of 50 ng/mL (≤50 ng/mL, r = 0.47 vs >50 ng/mL, r = 0.22) and 24% (≤24%, r = 0.58 vs >24%, r = 0.08), respectively. The correlation coefficient for levels of CHr and hepcidin showed that the optimal lower and upper cut-off points were 20 ng/mL (≤20 ng/mL, r = 0.52 vs >20 ng/mL, r = -0.01) and 70 ng/mL (≤70 ng/mL, r = 0.36 vs >70 ng/mL, r = -0.45), respectively.Discussion: This study indicates that the amount of iron in HD patients is sufficient for hematopoiesis under conditions of low s-ft and moderate TSAT levels. High levels of hepcidin could induce negative iron metabolism in hematopoiesis.Conclusion: Therefore, controlling hepcidin levels to within approximately 20-70 ng/mL may prevent iron deficiency and reduced Hb synthesis, and may thus facilitate effective iron utilization in hematopoiesis.

Unsuccessful intravenous D-mannose treatment in PMM2-CDG.

BACKGROUND: PMM2-CDG (Phosphomannomutase 2 - Congenital disorder of glycosylation-Ia; CDG-Ia) is the most common glycosylation defect, often presenting as a severe multisystem disorder that can be fatal within the first years of life. While mannose treatment has been shown to correct glycosylation in vitro and in vivo in mice, no convincing effects have been observed in short-term treatment trials in single patients so far. RESULTS: We report on a boy with a severe PMM2-CDG who received a continuous intravenous mannose infusion over a period of 5 months during the first year of life in a dose of 0.8 g/kg/day. N-glycosylation of serum glycoproteins and mannose concentrations in serum were studied regularly. Unfortunately, no biochemical or clinical improvement was observed, and the therapy was terminated at age 9 months. CONCLUSION: Postnatal intravenous D-mannose treatment seems to be ineffective in PMM2-CDG.