| Objective:Parkinson's disease(PD)is the second most common neurodegenerative disease.Its clinical manifestations primarily include progressive bradykinesia,tremor,rigidity,postural instability and gait abnormality.There are also some non-motor symptoms such as rapid eye movement sleep behavior disorder,olfactory impairment,autonomic dysfunction,cognitive impairment,depression.In addition,motor fluctuation,dyskinesia compromise the motor complications.Furthermore,biochemical changes are also associated with PD.Recent studies have investigated the alterations in hemoglobin level of PD patients before disease onset and the incidence of PD in anemic people.A retrospective study found that patients with PD had a higher proportion of anemia than the control group before disease onset.Some prospective studies have also found that patients with lower hemoglobin levels have a higher risk of PD.These studies suggest that anemia may be a risk factor for Parkinson's disease.Parkinson's disease is a slowly progressive disease that the pathological damage have been existed for many years before clinical symptoms developed.Thus,even though changes in hemoglobin levels appear preceding disease onset(before motor symptoms developed),these may still be a very early pathologic manifestation of PD.Therefore,in order to explore the relationship between the alterations of hemoglobin levels and Parkinson's disease,it is also needed to study hemoglobin levels after disease onset and to trace its dynamic changes.However,there is a lack of systematic study on hemoglobin levels after the onset of Parkinson's disease.To date,only a small sample-size study explored such issue and showed that there was no significant difference in erythrocyte counts and hemoglobin levels between the PD patients and the control group.Iron is an important component of hemoglobin and a variety of metabolic enzymes.A large number of pathological studies confirmed that PD patients have abnormal iron metabolism and iron deposition in the brain.The serum iron metabolism in Parkinson's patients has also received much attention.Some studies suggest that PD patients may also undergo alterations in systemic iron metabolism,but these results remain controversial.Is there any association between the changes of hemoglobin levels and iron metabolism in patients with Parkinson's disease?Current studies just found that hemoglobin levels and iron metabolism have changed in PD patients,but did not discuss the relationship between them,or investigate the relationship between hemoglobin or iron metabolism changes and disease severity or disease duration.Considering that iron metabolism is closely related to hemoglobin,we suspect that abnormal iron metabolism may affect hemoglobin levels in Parkinson's patients.Tracking the dynamic changes of iron metabolism and hemoglobin levels throughout the course of Parkinson's disease will help us to better understand the role of iron metabolism and hemoglobin changes in the pathogenesis of Parkinson's disease,thus to find new biomarker and to develop new ways of intervention.Therefore,the aim of present study is to elucidate the changes in hemoglobin level and iron metabolism after onset of Parkinson's disease,and explore the relationship between these changes.Methods:We enrolled a total of 213 patients(114 male and 99 female)who were diagnosed with PD and admitted to the Third Affiliated Hospital of Sun Yat-sen University and Nanfang Hospital of Southern Medical University from June 2013 to December 2014.The patients were diagnosed according to the United Kingdom IPD Society Brain Bank(UK-PDSBB)criteria.The exclusion criteria included secondary parkinsonism,atypical parkinsonism,hereditary cases,and PD patients who have received surgical treatment.Those who suffered from diseases that would influence the blood test or iron metabolism were also ruled out.In addition,219 controls(119 male and 100 female),who had no diseases that would influence the blood test or iron metabolism and were matched for age and gender with patients group,were recruited from the outpatient population.The general information of two groups such as age,sex and ethnicity were collected.Blood samples were collected after 8 h of fasting for routine blood tests and analysis of parameters of serum iron metabolism.The patients were evaluated by neurologists who were familiar with Parkinson's disease,and clinical data such as the age of onset,disease duration,medical history,family history and risk factors were collected.Revised Hoehn&Yahr staging scale score were also taken at on time for assessment of disease severity.SPSS 13.0 software was used for statistical analysis.Results:Hemoglobin levels decreased with age in both groups,and were significantly lower in PD patients(125.1 ± 15.68g/L)than those in control group(139.9 ±11.83g/L)(p<0.001).The red blood cell count(RBC)and hematocrit(HCT)were also significantly declined in PD group.Such difference still existed when subgroup analysis based on gender or disease severity were carried out.The serum iron were 14.92 ± 4.88p?mol/L in PD group and 15.73 ± 4.40?mol/L in control group,and there was no significant difference between the two groups(p =0.35).The serum total iron binding capacity(TIBC)were 48.29 ± 9.13(P<0.05)in PD group and 49.74 ± 8.35?mol/L in control group.There was also no significant difference between the two groups(p = 0.43).However,the serum ferritin in PD group(174.07 ± 74.04 ng/mL)was significantly lower than that in control group(191.82 ± 91.49 ng/mL)(p = 0.04).After separating the data by gender,we found no significant differences in ferritin,serum iron,or TIBC between PD patients and controls,either for women or men.Subgroup analysis based on disease severity revealed that significant difference in serum iron,serum ferritin and serum total iron binding(TIBC)were only found between late-stage PD patients(H&Y score = 3?5)and late controls.To identify the underlying causes of the changes in blood parameters that we observed(especially HGB),we conducted a correlation test and linear regression.This revealed a statistically significant,inverse correlation between RBC,serum iron,ferritin,TIBC and disease severity or disease duration.We found relatively few correlations between parameters of routine blood test and iron metabolism.Only ferritin was significantly correlated with HGB levels and HCT levels.Additionally,serum iron levels were correlated with RBC and MCV after age-adjustment.Conclusion:Hemoglobin levels in PD patients would decline after disease onset and decrease with disease duration and severity.Serum iron metabolism in patients with Parkinson's disease also changed with disease duration and severity.In early stage,such changes were not significant.But the serum iron,serum ferritin and total iron binding would decrease evidently in advanced stage.Changes in hemoglobin levels in PD patients have some relationship with alterations in serum iron metabolism.There was a positive correlation between serum hemoglobin and serum ferritin. |
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