Ferritin: another pregnancy-specific protein in human seminal plasma and amniotic fluid, as estimated by six methods

Performance and comparability of laboratory methods for measuring ferritin concentrations in human serum or plasma: A systematic review and meta-analysis

BACKGROUND

Different laboratory methods are used to quantify ferritin concentrations as a marker of iron status. A systematic review was undertaken to assess the accuracy and comparability of the most used methods for ferritin detection.

METHODS AND FINDINGS

National and regional databases were searched for prospective, retrospective, sectional, longitudinal and case-control studies containing the characteristics and performance of at least one method for serum/plasma ferritin determinations in humans published to date. The analysis included the comparison between at least 2 methods detailing: sensitivity, precision, accuracy, predictive values, inter-methods adjustment, and use of international reference materials. Pooled method performance was analyzed for each method and across methods.

OUTCOMES

Search strategy identified 11893 records. After de-duplication and screening 252 studies were assessed, including 187 studies in the qualitative analysis and 148 in the meta-analysis. The most used methods included radiometric, nonradiometric and agglutination assays. The overall within-run imprecision for the most reported ferritin methods was 6.2±3.4% (CI 5.69-6.70%; n = 171), between-run imprecision 8.9±8.7% (CI 7.44-10.35%; n = 136), and recovery rate 95.6% (CI 91.5-99.7%; n = 94). The pooled regression coefficient was 0.985 among all methods analyzed, and 0.984 when comparing nonradiometric and radiometric methods, without statistical differences in ferritin concentration ranging from 2.3 to 1454 μμg/L.

CONCLUSION

The laboratory methods most used to determine ferritin concentrations have comparable accuracy and performance. Registered in PROSPERO CRD42016036222.

Effect of systemic inflammation on level of ferritin seminal in chronic renal male patient undergoing hemodialysis

Background

Most hemodialysis patients present with chronic systemic inflammation characterized by the elevation of serum C-reactive protein (CRP) levels and/or the production of proinflammatory interleukins by the immune system in response to the hemodialysis process. Plasma ferritin(PF) is one of the parameters used to correct anemia. An PF level of >500 ng/mL is not recommended for correction of anemia because of the uncertainty of whether these levels are elevated because of anemia or a mere reaction to inflammation. we aimed to study the effects of inflammation on seminal ferritin (SF) levels and hypothesized that SF is not affected because of the testicular immune privilege.

Methods

A prospective prevalence study was conducted at the Department of Hemodialysis of the University Hospital of Brasília (HuB) between June 2010 and July 2011. The sample included 60 chronic renal patients undergoing hemodialysis and 20 control subjects from the health promotion general outpatient clinic. All participants were males aged 18–60 years. Inflammation was assessed through serum CRP levels, and the testicular condition was determined by measuring sex hormone levels. In the patient group, inflammation was considered to be present when CRP was >5 mg/L (n = 27) and absent when CRP was ≤5 mg/L (n = 33). Control group (n = 20) CRP was ≤1 mg/L. Blood and semen were collected via arm venoclysis and after voluntary masturbation, respectively. CRP was measured by turbidimetry; PF, SF, and sex hormone levels by immunochemoluminescence. Statistical significance was set at p < 0.05.

Results

There was no significant difference in mean SF levels among patients with inflammation (295.34 ± 145.39 ng/mL), those without inflammation (324.42 ± 145.51 mg/mL), and controls (335.70 ± 075.90 ng/mL; p = 0.49). There was no correlation between mean SF and PF levels in the patients with and without inflammation). All participants were eugonadal with mean serum FSH, LH, and testosterone levels of 3.76 ± 2.17 mUI/mL, 7.00 ± 3.53 mUI/mL, and 454.18 ± 173.08 ng/dL, respectively.

Conclusion

Systemic inflammation did not significantly alter SF levels in eugonadal hemodialysis patients.

Enzymatic properties of adult human Sertoli cells in vitro

The adult human Sertoli cells produced lactate, estradiol-17beta, transferrin and inhibin; germ cells modulate synthesis of these compounds. In order to study the functional features of human Sertoli cells in vitro, the aim of this study was to measure the lactic dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and creatine kinase activities (CK) in primary cultures of Sertoli cells prepared from young men (mean age: 29 years, n = 11). Five LDH isozymes have been found in Sertoli cells, the main fractions being the LDH3 and LDH4; each of them represented 30% of the total LDH activity. Furthermore, CK and ALP activities were measured in Sertoli cells. It is of note that the Sertoli cell ALP activity was 50% lower than that of germ cells. Whatever the Sertoli cell parameter measured herein, there is a great variability between patients and FSH (dbc AMP, as well as retinol, insulin, testosterone) is poorly effective in improving these enzymatic activities in vitro. We have confirmed that GGT was exclusively present in Sertoli cells and thus may be considered as a specific marker. LDH is involved in Sertoli cell glucose transformation and thus provided energetic substrates for germ cells. In contrast, the roles of CK and ALP remains to be clarified. In conclusion, we have demonstrated the existence of several enzymes namely LDH, GGT, ALP and CK in Sertoli cells prepared from adult human testis.

Ferritin in cultured human cytotrophoblasts: synthesis and subunit distribution

The present study aims at the role of ferritin in the regulation of syncytiotrophoblast free iron levels. The differentiated cytotrophoblast cell in culture is used as a model for this maternal-fetal interface. Cytotrophoblast cells isolated from term placentae are cultured in iron-poor (Medium 199), iron-depleted [desferrioxamine(DFO)] and iron-supplemented [diferric transferrin (hTF-2Fe), ferric ammonium citrate (FAC)] medium. Distribution and de novo synthesis of isoferritins is studied, together with the cellular iron concentration and the ferritin iron saturation. Compared to ferritin isolated from total placenta, ferritin obtained from villous tissue is enriched with acidic isoforms. This observation is in agreement with measured light (L) to heavy (H) subunit ratios < 1 of de novo synthesized ferritin in cultured cytotrophoblast cells. Neither iron-poor culture medium, nor hTf-2Fe supplemented medium affects the cellular iron or ferritin concentration. FAC increased the cellular ferritin iron saturation and (by synthesis) the acidic isoferritin concentrations. The results strongly suggest, that the term syncytiotrophoblast is able to balance transferrin-mediated iron uptake and iron release. In case of FAC supplementation, the syncytiotrophoblast is unable to keep intracellular iron low, and ferritin synthesis is stimulated. The predominance of acidic ferritins and the preferential synthesis of H subunits can be functionally explained by the established fact that iron incorporation in acidic ferritins is faster due to the presence of ferroxidase centres. Damage by free iron catalysed hydroxyl radical formation is therefore minimized.