**4. Discussion**

Brain has low storing capacity of oxygen though it is a demanding consumer: brain uses about 20 % of oxygen total supply. In degenerative diseases like Alzheimer's, Parkinson's disease the etiology often are not fully known. In Alzheimer's disease pathophysiological theories have been proposed e.g. heat shock protein interactions [4], Tau-protein abnormality [5] neuroin‐ flamation and neuronal loss [6, 7], β-amyloid interactions [8], mitochondrial misfunction [9]. An overlooked possibility may be using ICP-MS for analysis of elemental profiles of erythro‐ cytes as biomarker for Alzheimer 's disease. Small changes in metabolism of oxygen dependent cells may give symptoms difficult to identify due to lack of suitable biomarkers [10, 11, 12. 13, 14]. Erythrocytes carrying excess lead, cadmium, silver and uranium ions may induce damages in cells including brain cells. Accumulation of elements in the human erythrocytes are a result of low exposure and not of a sudden insult which calls for sensitive biomarkers.

#### **4.1. Effects of accumulated lead, cadmium, silver and uranium in the erythrocytes**

**Figure 3.** Distribution of silver in erythrocytes of 13 patients with Alzheimer's disease. Patient 1-9 men, 10-13 women. Error bar 10%. The mean value of Ag in Alzheimer's patients was 7.4 μg/kg, standard error 1.5 μg/kg, mean of con‐ trols 1.3 μg/kg, The concentration of silver in the erythrocytes of patients was significant higher (Wilcoxon, p< 0.005)

**Figure 4.** Concentration of uranium in erythrocytes of 13 patients with Alzheimers disease. Patient 1-9 men, 10-13 women. Error bar 10 %. The mean value of U in Alzheimer's patients was 0.55 μg/kg, standard error 0.16 μg/kg, mean of controls 0.11 μg/kg, The concentration of uranium in the erythrocytes of patients with Alzheimer's disease was sig‐

Brain has low storing capacity of oxygen though it is a demanding consumer: brain uses about 20 % of oxygen total supply. In degenerative diseases like Alzheimer's, Parkinson's disease the etiology often are not fully known. In Alzheimer's disease pathophysiological theories have been proposed e.g. heat shock protein interactions [4], Tau-protein abnormality [5] neuroin‐ flamation and neuronal loss [6, 7], β-amyloid interactions [8], mitochondrial misfunction [9]. An overlooked possibility may be using ICP-MS for analysis of elemental profiles of erythro‐ cytes as biomarker for Alzheimer 's disease. Small changes in metabolism of oxygen dependent cells may give symptoms difficult to identify due to lack of suitable biomarkers [10, 11, 12. 13, 14]. Erythrocytes carrying excess lead, cadmium, silver and uranium ions may induce damages

than that of controls.

**4. Discussion**

nificant higher (Wilcoxon, p<0.01) than that of controls

408 Pharmacology and Nutritional Intervention in the Treatment of Disease

At present there is lack of methods to describe the accumulated effects of metal ions in erythrocytes in terms of stability constants or conditional constants. There is lacking informa‐ tion of e.g. solvent properties, pH, temperature, redox properties, lack of knowledge of interacting compounds. Elemental profiles of erythrocytes may be an alternative to estimate changes of trace elements and metal ions at the cellular level. The discussion below will be focused on some effects on membrane integrity by lead, cadmium, silver and uranium because it is not fully known how these ions are associated to other compounds.

#### **4.2. Initiation of eryptosis by accumulated lead, cadmium silver and uranium in erythrocytes**

It has been suggested that mature erythrocytes may enter programmed death without the aid of caspase systems [15,16]. Heavy metal ions and organic compounds may be involved in early senescence [17, 18, 19]. When erythrocytes are growing old they will change gradually, fragments will be cleaned up [20, 21], mainly in spleen, liver, bone marrow by the macro‐ phages. Most material of captured senescent erythrocytes e.g. iron and metabolized organic material will be reused [22, 23].

Silver, cadmium ions induce suicidal erythrocyte death [24, 25] and it is likely that erythro‐ cytes and cells dependent on erythrocytes of patients with Alzheimer's disease with accumulated silver and also lead, cadmium and uranium may show early eryptosis. Eryptosis may also be initiated via formation of phosphatidylserine by lead, cadmium, hemin as stimulator [26, 27, 28].

#### **4.3. Erythrocyte channels exposed to accumulated ions of lead, cadmium, silver and uranium**

The accumulated lead, cadmium, silver and uranium may interfere the activity in the eryth‐ rocyte channels for cations, anions and water. Cadmium, lead, silver may interfere with potassium, calcium [29, 30] and other ions in erythrocyte membranes [31, 32]. Binding in vitro of cadmium to β-amyloid channels was reported by [33]. Exposure to accumulated lead, cadmium, silver, uranium ions to β-amyloid or other compounds is likely to support the pathophysiological process by association to available binding sites.

Anions e.g. chlorides, carbonates ions are transported in anion channels [34, 35, 36] may react with silver, lead, cadmium and uranium disturbing channel transport and oxygen handling.

Aquaporin channels in the erythrocyte membrane are important for flow of water and shape [37, 38, 39]. Accumulated cadmium, lead, silver, uranium ions associated to erythrocyte aquaporin channels may decrease the capacity to shrink and expand. Water exchange may also be important for osmotic regulation when the erythrocytes enter capillaries. It cannot be excluded that lead, cadmium, silver, uranium may release important elements. e.g. calcium from their association sites. Released calcium may form non-selective channels in membranes [40].

#### **4.4. Accumulated cadmium, lead, silver and uranium ions may compete with essential elements in carrier systems**

secondary messengers. More research is needed to interpret early symptoms of Alzheimer

Metabolism Changes as Indicated by the Erythrocytes of Patients with Alzheimer's Disease

http://dx.doi.org/10.5772/57511

411

Monitoring changes of elements in the erythrocytes by ICP-MS may be used as an early biomarker of Alzheimer's disease and may support the pharmaceutical treatment. The accumulated lead, cadmium, silver and uranium may interfere with channel activities, have effects on apoptosis, react with secondary messenger and support pathophysiological

We thank Crafoord foundation for economic support and Åbo Academy for putting instru‐ mental facilities to our disposal. We also thank dr Sture Brishammar, Evert Karlsson for

, Paul Ek3

[1] Johansson E, Westermarck T, Hasan MY, Nilsson B et.al. Alterations in nickel and cadmium concentrations in erythrocytes and plasma of patients with Parkinson's dis‐

[2] Johansson E and Liljefors T. Heavy elements in root tips from teeth with amalgam

\*Address all correspondence to: erland.johansson@uppsala.mail.telia.com

4 Department of Pharmacology and Toxicology, University of Helsinki, Finland

ease. Trends in Biomedicine in Finland 2007; XXI 2(4),17-32.

fillings: in TEMA 7 (ed. Momcilovic B), pp 11-18-11-20. Zagreb 1991.

and Faik Atroshi4

disease and pathophysiological processes.

**5. Conclusions**

**Acknowledgements**

processes.

discussions.

**Author details**

**References**

Erland Johansson1\*, Tuomas Westermarck2

1 EJSelenium Consultant Ltd, Uppsala, Sweden

2 Rinnekoti Research Center, Helsinki, Finland

3 Laboratory of Analytical Chemistry, Åbo Academy, Finland

Cadmium is known to compete with zinc in e.g. metallothionein (MT), carrier of zinc. Metal ions having higher affinity than zinc may interact with the binding sites in MT or other carrier. Lead and uranium ions is known to compete with calcium metabolism. Magnesium and calcium ions in calmodulin (calcium carrier) may be displaced by accumulated lead, cadmium, silver, uranium ions and release essential elements e.g. Mg, Ca, Zn. Release of secondary messenger e.g. Mg may disturb ATP metabolism, Ca may activate translocases flippases, floppases, scramblases and start apoptosis signals. Ca may also activate platelets and make them sticky, ready for clot. Sticky platelets may associate to proteins and form placks.

#### **4.5. Sources of cadmium, lead, silver and uranium — Food and implants**

The food intake is not known for individual patients. In Finland cadmium uptake from food is about 5-10 µg/day, lead 20-66 µg /day, uranium and, silver was not mentioned [41]. In Sweden is reported cadmium uptake from wheat, rice, potatoes, root-crops 10-20 µg /day, lead 15-30 µg /day, uranium 1-4 µg /day, silver not indicated [42]. Cd uptake from nutrition may disturb the heme synthesis. Cadmium rich diet in Nigeria decreased Hb and erythrocyte counts in mice [43]. It cannot be excluded that cadmium, lead, silver, uranium contaminated food may accumulate in human erythrocytes and in similar manner decrease erythrocyte counts and hemoglobin synthesis. Smoker may have higher cadmium values in blood but there was no information about smoking habits. Elevated uranium in drinking water may damage the kidneys and increase protein loss in urine [44, 45].

In Finland some districts have drinking water with high uranium concentrations (> 100 µg/L) which together with cadmium, lead and silver may increase kidney damage and disturb erythrocyte metabolism. Uranium in the drinking water may explain the significant elevated uranium concentrations of erythrocytes of Alzheimer patients.

Implants may be a source of metal ion supply. Amalgam is an alloy which is not stable [2, 3, 46, 47, 48] (release mercury, silver). Guttapercha may sometime contain cadmium [2] but the released amount is not known for the examined patients. Mercury was not analyzed as mercury will associate strong to liver, kidney also to pituary, low mercury will be found in blood. Mercury has also capacity to displace secondary messenger e.g. Mg, Ca, Zn, Fe when not properly associated.

#### **4.6. Elemental profiles of erythrocytes as biomarkers of Alzheimer's disease by ICP-MS**

The early diagnosis of a neurological disease like Alzheimer's and Parkinson's disease is difficult. In Parkinson's disease about 25 % of the patients may get wrong diagnosis [49]. The present study indicate that the elemental profile of erythrocytes may be used as a support in the diagnosis and pathophysiology of Alzheimer's disease. Changes in the elemental profile should be possible to identify earlier due to high sensitivity of ICP-MS. Monitoring elements in the erythrocytes may also be used to observe effects of applied pharmacy and effects on secondary messengers. More research is needed to interpret early symptoms of Alzheimer disease and pathophysiological processes.
