IRON: Bacterial, Fungal, Viral, Protozoan Infections and infectious Processes
As on other Science Library pages, we do not present a lengthy narrative on each body system affected by infection, but rather will briefly summarize or quote the most relevant take-home points and/or research conclusions from each study. Article titles are linked to abstracts archived at the U.S. National Library of Science. Many articles also have Full free text PDF links. Our Iron Science Library pages include:
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Iron availability and infection (1)
In this 2009 review of the literature the author notes that, "
To successfully sustain an infection, nearly all bacteria, fungi and protozoa require a continuous supply of host iron." "Mechanisms of microbial iron acquisition are determinants for the kinds of cells, tissues and hosts in which pathogens can flourish." And with respect to human and other "hosts," "
As a corollary, hosts possess an array of iron withholding devices whereby they can suppress or abort microbial invasions." "
Awareness of environmental and behavioral methods that can prevent iron loading plus development of pharmaceutical agents that can block microbial access to iron may help to reduce our dependence on antibiotics."
Iron loading and disease surveillance (2) Free full paper
This 1999 review and the accompanying full paper describe, "Iron is an oxidant as well as a nutrient for invading microbial and neoplastic cells.
Excessive iron in specific tissues and cells (iron loading) promotes development of infection, neoplasia, cardiomyopathy, arthropathy, and various endocrine and possibly neurodegenerative disorders. To contain and detoxify the metal, hosts have evolved an iron withholding defense system, but the system can be compromised by numerous factors. An array of behavioral, medical, and immunologic methods are in place or in development to strengthen iron withholding. Routine screening for iron loading could provide valuable information in epidemiologic, diagnostic, prophylactic, and therapeutic studies of emerging infectious diseases." [Health-e-Iron note: Tables 1 and 2 from this paper appear below]
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Iron availability increases the pathogenic potential of Salmonella typhimurium and other enteric pathogens at the intestinal epithelial interface (5) Free full text
Reported in 2012, this research team noted, "Recent trials have questioned the safety of untargeted oral iron supplementation in developing regions. Excess of luminal iron could select for enteric pathogens at the expense of beneficial commensals in the human gut microflora, thereby increasing the incidence of infectious diseases." The researchers observed in this laboratory study that, "
Growth of Salmonella typhimurium and other enteric pathogens was increased in response to iron." The researchers concluded, "our data fit with the consensus that oral iron supplementation is not without risk as iron could, in addition to inducing pathogenic overgrowth, also increase the virulence of prevalent enteric pathogens."
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Hepatic iron overload is common in chronic hepatitis B and is more severe in patients coinfected with hepatitis D virus (7)
In this 2012 study from Italy the researchers noted, "Hepatic iron overload has been described in chronic hepatitis C as a cofactor affecting fibrosis progression. Data in patients with chronic hepatitis B infection are scarce. We investigated hepatic iron deposits and serum iron indices in 205 consecutive patients with hepatitis B and compensated liver disease. Mean age of the patients was 42.4 ± 12.4 years and 72.5% were males." "Hepatic iron deposits were detected in 35.1% of patients, most of them being minimal (grade I) (59.7%) or mild (grade II) (27.8%). Variables significantly associated with hepatic iron deposits were male gender (P = 0.001), serum ferritin (P = 0.008), GGT (P = 0.05) and alkaline phosphatase (P = 0.05) levels." "A significant correlation between coinfection with HDV and hepatic iron deposits was also found (OR 4.23, 95% CI 1.52-11.82, P = 0.003). When compared to monoinfected cases, HDV positive patients had more elevated GGT (P = 0.03), more advanced fibrosis and more severe iron deposits (P < 0.0001)." "In conclusion, in well-compensated chronic hepatitis B infection,
hepatic iron deposits and elevation of serum iron indices are common, especially in male gender and in patients coinfected with HDV.
As HBV/HDV liver disease is generally more rapidly progressive than that caused by HBV monoinfection, we speculate that iron overload may be one of the factors contributing to the severity of liver disease."
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Enhanced iron availability by protein glycation may explain higher infection rates in diabetics (12)
This 2012 laboratory study done in California reported, "
The results, in addition to data in the literature, support the hypothesis that glycation of serum proteins may effectively increase the available free iron pool for bacteria in blood serum and weaken our innate immunity. This phenomenon may be partially responsible for higher infection rates in some diabetics, especially those with poor glycemic control."
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