Effects Of Parathyroid Hormone On Renal Anemia In The Patients With Chronic Kindney Disease

Objective:To detect parathyroid hormone(PTH), erythrocytes intracellular calcium ([Ca²⁺]_i) and phosphatidylserine (PS) exposure level in the patients with chronic kidney disease(CKD), thus to find out the mechanism of elevating PTH to erythrocytes phosphatidylserine exposure. The purpose of the study is to provide new basis for the pathogenesis and prevention of renal anemia in the patients with CKD.Methods: The experimental group: From Nov 2009 to May 2010, 75 cases of chronic kidney disease (40 women, 35 men, mean age, 45.5 years, range, 23-68) were recruited. Based on CKD-EPI formula, all patients were divided into 3 group: stage CKD1², stage CKD3⁴ and stage CKD5. The patients in stage CKD1² were 25 cases of mild mesangial proliferative and glomerular minor lesions (12 women, 13 men, mean age, 41.6 years, range, 35-53) diagnosed by renal biopsy. The etiology of patients of stage CKD3⁵ ( 23 women, 37 men, mean age, 43.9 years, range, 23-68 ) was chronic glomerulonephritis ( 41 cases ), hypertensive nephrosclerosis. The control group: The healthy volunteers are demonstrated by physical examination 30 cases (15 women, 15 men ), mean age 40.35 years, ( range 25-61 ). Inclusion criteria: dietary structure stability in 2 months, types and doses of calcium channel antagonists stability, without infection and stress, unused erythropoietin, glucocorticoid, vitamin D and their analogues, intravenous iron supplements and angiotensin converting enzyme inhibitors in 3 months. Without blood transfusion or bleeding in 6 months.Acute kidney injury, primary hyperparathyroidism, hemopathy and other chronic diseases anemia person are excluded. Intact parathyroid hormone (iPTH) was detected by Immunochemiluminometry. The erythrocytes phosphatidylserine (PS) exposure and intracellular calcium concentration ([Ca²⁺]_i) were measured by flow cytometry. The clinical data were collected such as hemoglobin, serum creatinie, serum albumin, blood lipid, serum uric acid. By SPSS13.0 software to process and analysis the data. (x|ˉ±s) means measurement data, according to the normality and the homogeneity of variance choose one-way ANOVA test or nonparametric statistical test,the group differences by SNK test.The correlation of date by person correlation analysis according to the data type. The regression analysis by linear correlation analysis and multiple linear regression analysis . P<0.05 means the difference was statistically significant.Results:1 There was no statistically significant difference between age, gender, body mass index, levels of serum TC and TG in stages 1-5 of CKD and control group(P>0.05). The systolic pressure and diastolic pressure in stages 3-5 of CKD is higher than the stages 1-2 of CKD and control group. The serum Alb in stages 1-5 of CKD is slightly lower than control group, however, the serum UA and 24-hour urinary protein excretion in stages 1-5 of CKD is higher than control group, the difference was statistically significant (P<0.05).2 Levels of serum PTH, [Ca²⁺]_i and erythrocytes PS exposure increased gradually with the decline of renel function in stages 3-5 of CKD, whose differences were significant with CKD 1-2 stages and control group, the difference was statistically significant (P<0.05). The Hb and Hct decrease from 139.85±19.19g/L and 42.83±13.89% in stages of CKD 1-2 to 81.59±18.74g/L and 23.26±5.15% in stage of CKD 5.however, the PTH, erythrocytes intracellular calcium and PS exposure level of CKD 1-2 stages 47.13±13.20 pg/ml,3.34±0.70 and 0.44±0.36% ascend to 411.11±115.00 pg/ml,3.59±0.70 and 1.24±0.29% of CKD 5 stage.3 There was no statistically significant difference on the levels of serum Ca, P and in stages 1-4 of CKD(P>0.05). The level of serum Ca in stage of CKD 5 is significant lower than other groups, meanwhile serum P and Ca×P product in stage of CKD 5 is significant higher than other groups, the difference was statistically significant (P<0.01). The levels of serum Ca decrease from 2.36±0.17 mmol/L in stages of CKD 1-2 to 2.04±0.37 mmol/L in stage of CKD 5. However, the levels of serum P and Ca×P product increase from1.25±0.31 mmol/L and 2.86±0.76 in stages of CKD 1-2 to 2.18±0.53 mmol/L and 4.49±1.16 in stage of CKD 5.4 Pearson correlation analysis revealed, during CKD 3-5 stages, Hb was negatively correlated with PTH and erythrocyte PS exposure respectively(r=-0.830 and -0.791,P both <0.01); PTH was positively correlated with [Ca²⁺]_i and erythrocyte PS exposure(r=0.882 and 0.924,P both <0.01), whereas negatively correlated with Ca respectively(r=-0.544,P<0.01); Erythrocyte PS exposure was positively correlated with [Ca²⁺]_i(r=0.923,P<0.01)and not correlated with Ca(r=-0.138,P=0.365).5 The linear regression equation of[Ca²⁺]_i(Y)for PTH (X) is Y=3.327+ 0.213X(F=21.529,P<0.05);The multiple linear regression equation of erythrocytes PS exposure (Y) for PTH (X₁) and [Ca²⁺]_i (X₂) is Y= -0.303+0.283X₂+0.139X₁(F=6.59,P<0.01).Conclusions: Through adding intracellular calcium, PTH can lead to an increase of the erythrocyte PS exposure, which will cause the occurrence of erythrocytes lives span shortened. As a result, the renal anemia will become more severe.