The theoretical implications and experimental and clinical results of radiolabeled antiferritin

Ferritins: a family of molecules for iron storage, antioxidation and more

Ferritins are characterized by highly conserved three-dimensional structures similar to spherical shells, designed to accommodate large amounts of iron in a safe, soluble and bioavailable form. They can have different architectures with 12 or 24 equivalent or non-equivalent subunits, all surrounding a large cavity. All ferritins readily interact with Fe(II) to induce its oxidation and deposition in the cavity in a mineral form, in a reaction that is catalyzed by a ferroxidase center. This is an anti-oxidant activity that consumes Fe(II) and peroxides, the reagents that produce toxic free radicals in the Fenton reaction. The mechanism of ferritin iron incorporation has been characterized in detail, while that of iron release and recycling has been less thoroughly studied. Generally ferritin expression is regulated by iron and by oxidative damage, and in vertebrates it has a central role in the control of cellular iron homeostasis. Ferritin is mostly cytosolic but is found also in mammalian mitochondria and nuclei, in plant plastids and is secreted in insects. In vertebrates the cytosolic ferritins are composed of H and L subunit types and their assembly in a tissues specific ratio that permits flexibility to adapt to cell needs. The H-ferritin can translocate to the nuclei in some cell types to protect DNA from iron toxicity, or can be actively secreted, accomplishing various functions. The mitochondrial ferritin is found in mammals, it has a restricted tissue distribution and it seems to protect the mitochondria from iron toxicity and oxidative damage. The various functions attributed to the cytosolic, nuclear, secretory and mitochondrial ferritins are discussed.

Undernutrition as a risk factor for cervical intraepithelial neoplasia: a case-control analysis

To evaluate the relationship between cervical intraepithelial neoplasia (CIN) and undernutrition, a pair-matched case-control study was conducted in a low-income urban population. As a broad measure of nutritional status, serum albumin, serum ferritin, hematocrit, percent desirable weight, and percent calories consumed as protein were examined. Cases (n = 102) had biopsy-confirmed CIN I, II, or III, and clinic controls (n = 102), matched on age, race, and clinic, had normal Pap smears. Survey-collected data and frozen serum were utilized to study the hypothesized association. Crude and adjusted odds ratios and 95% confidence intervals were estimated using conditional logistic regressions. Results suggest a protective role for serum ferritin for those in the highest quartile relative to those in the lowest quartile. Controlling for smoking and monthly personal income, an adjusted odds ratio of 0.2 with a corresponding 95% confidence interval of 0.1-0.7 was observed. Similar findings were noted when all other available CIN risk factors were controlled. In addition, a dose gradient was present for dietary iron intake (p = 0.01). No associations were observed between each of the other undernutrition indexes and CIN. Although only high levels of serum ferritin were associated with a protective effect against CIN, when coupled with the results from other studies that suggest carotenoids, folates, and vitamin C to be protective, the overall hypothesis that poor nutriture is associated with CIN remains viable. Lack of an association with the other nutritional indexes may reflect the relatively sufficient nutritional status of low-income individuals residing in the United States, as opposed to the undernourished population of the Third World.