| Objective: The purpose of this study was not only to investigate the expression level of Kidney Injury Molecule l(KIM-1), Cystatin C(Cys C) and β2-microglobulin(β2-MG) in patients with obstructive sleep apnea and hypopnea syndrome(OSAHS) disease, but also to explore the relationship and to assess the clinical significance among these factors in OSAHS patients with early renal injury.Methods: Total 80 OSAHS patients diagnosed by polysomnogram(PSG) in the sleep disorder lab. of the Second Hospital of Hebei Medical University from 2013/6 to 2014/6 were selected as experimental group and 15 healthy adults who were normal in PSG examinations were selected as control group. Measured the levels of Cys C, β2-MG in fasting venous blood in the morning and detected the level of KIM-1 in midpiece urine after centrifugation by enzyme-linked immunolsorbent assay(ELISA). All data were analyzed and compared by the SPSS13.0 statistical software.Results: 1 The detection results of KIM-1 1.1 According to AHI grouping: The average levels of uric KIM-1(renal damage threshold: 0.059-2.146 ng/ml) in mild, moderate and severe OSAHS patients were separately 2.23±0.71 ng/ml, 3.20±0.49 ng/ml and 4.18±0.62 ng/ml. The average level of uric KIM-1 in healthy control group was 2.24±0.42 ng/ml. The average levels of uric KIM-1 in the moderate and severe patients were higher than healthy control group(P<0.01). The difference between the mild patients and the healthy control group was not statistically significant(P>0.05). Besides, the difference of the average levels of uric KIM-1 among the mild, moderate and severe OSAHS patients was statistically significant(P<0.01). The results indicated that the renal might has injury in mild OSAHS patients. The average level of uric KIM-1 was abnormal in moderate and severe OSAHS patients, and it increased along with the aggravation of the conditions. That means the level of KIM-1 could not only reflect but also assess the outcomes of early renal injury in OSAHS patients of all stages. The level of uric KIM-1 might be a sensitive indicator in OSAHS patients with early renal injury. 1.2 According to LSa O2 grouping: The average levels of uric KIM-1 in mild, moderate and severe groups were separately 2.12±0.50 ng/ml, 2.67±0.58 ng/ml and 3.79±0.69 ng/ml. The average level of uric KIM-1 in normal control group was 2.15±0.47 ng/ml. The average level of uric KIM-1 in the severe group was higher than normal control group(P<0.01). The difference between the mild, moderate groups and the normal control group was not statistically significant(P>0.05). Besides, the average level of uric KIM-1 in severe group was higher than mild and moderate groups(P<0.01). The difference between the mild and moderate groups was not statistically significant(P>0.05). The results indicated that nocturnal hypoxemia could cause renal injury, compared with AHI, LSa O2 contribute less to KIM-1 level change. Grouped by AHI was better than LSa O2 in analyzing their relationships with KIM-1 for early renal injury assessment. It could reflect the development of OSAHS dynamic process grouping by AHI. Oxygen was still an important part in OSAHS disease development because of its important reference value. Due the cases in this study were not big enough, it need further discussion and proof in the future scientific research. 2 The detection results of Cys C 2.1 According to AHI grouping: The serum average levels of Cys C in mild, moderate and severe OSAHS patients were separately 0.88±0.12 mg/ml, 0.93±0.16 mg/ml and 3.21±0.46 mg/ml. The serum average level of Cys C in healthy control group was 0.81±0.11 mg/ml. The serum level of Cys C in severe OSAHS patients was higher than healthy control group(P<0.01). The difference between the mild, moderate patients and the healthy control group were not statistically significant(P>0.05). Besides, the serum level of Cys C in severe OSAHS patients was higher than mild and moderate OSAHS patients(P<0.01). The difference between the mild and moderate OSAHS patients was not statistically significant(P>0.05). The results indicated that although the level of Cys C had a gradual progress in different stages of OSAHS patients, it was significant abnormal when the patients’ conditions were severe. The serum level of Cys C could not reflect the condition of early renal injury in OSAHS patients during all stages. It was more insensitive than KIM-1 in assessing the outcomes of renal injury in OSAHS patients. 2.2 According to LSa O2 grouping: The serum average levels of Cys C in mild, moderate and severe groups were separately 0.83±0.14 mg/ml, 0.86±0.14 mg/ml and 2.19±1.18 mg/ml. The serum average level of Cys C in normal control group was 0.81±0.13 mg/ml. The serum level of Cys C in severe groups was higher than normal control group(P<0.01). The difference between the mild, moderate groups and the normal control group were not statistically significant(P>0.05). Besides, the serum level of Cys C in severe group was higher than mild and moderate groups(P<0.01). The difference between the mild and moderate groups was not statistically significant(P>0.05). The results were same as 2.1. There was no significant difference in analyzing the renal injury in OSAHS patients through the change of Cys C between grouped by LSa O2 and AHI. We couldn’t know that the two groups which has more advantages from the above results at least. 3 The detection results of β2-MG 3.1 According to AHI grouping: The serum average levels of β2-MG in mild, moderate and severe OSAHS patients were separately 1.66±0.45 mg/ml, 1.60±0.43 mg/ml and 3.46±0.43 mg/ml. The serum average level of β2-MG in healthy control group was 1.66±0.57 mg/ml. The serum level of β2-MG in severe OSAHS patients was higher than healthy control group(P<0.01). The difference between the mild, moderate patients and the healthy control group were not statistically significant(P>0.05). Besides, the serum level of β2-MG in severe OSAHS patients was higher than mild and moderate OSAHS patients(P<0.01). The difference between the mild and moderate OSAHS patients was not statistically significant(P>0.05). The results indicated that although the level of β2-MG had a gradual progress in different stages of OSAHS patients, it was significant abnormal when the patients’ conditions were severe. The serum level of β2-MG could not reflect the condition of early renal injury in OSAHS patients during all stages. It was more insensitive than KIM-1 in assessing the outcomes of renal injury in OSAHS patients. 3.2 According to LSa O2 grouping: The serum average levels of β2-MG in mild, moderate and severe groups were separately 1.93±0.42 mg/ml, 1.27±0.26 mg/ml and 2.56±1.10 mg/ml. The serum average level of β2-MG in normal control group was 1.73±0.54 mg/ml. The serum level of β2-MG in severe group was higher than normal control group(P<0.01). The difference between the mild, moderate groups and the normal control group were not statistically significant(P>0.05). Besides, the serum level of β2-MG in severe group was higher than mild and moderate groups(P<0.01). The difference between the mild and moderate groups was not statistically significant(P>0.05). The results were same as 3.1. There was no significant difference in analyzing the renal injury in OSAHS patients through the change of β2-MG between grouped by LSa O2 and AHI. We couldn’t know that the two groups which has more advantages from the above results at least. 4 The correlation among KIM-1, Cys C and β2-MG and their correlations with AHI in OSAHS patients: KIM-1, Cys C and β2-MG were positive correlated with each other(r 0.686, 0.517, 0.847, respectively, P<0.01). KIM-1, Cys C and β2-MG were positive correlated with AHI(r 0.862, 0.780, 0.633, respectively, P<0.01). 5 The correlation among KIM-1, Cys C, β2-MG and LSa O2 in OSAHS patients:KIM-1, Cys C and β2-MG were negative correlated with LSa O2(r-0.899,-0.689 and-0.607, respectively, P<0.01).Conclusions:1 The levels of KIM-1, Cys C and β2-MG in OSAHS patients were higher than the healthy control group respectively, it showed that OSAHS can cause and increase the renal injury.2 The urine average level of KIM-1 could not only reflect but also assess the outcomes of early renal injury in OSAHS patients of all stages. The urine level of KIM-1 might be a sensitive indicator in OSAHS patients with early renal injury. Compared with KIM-1, the serum average levels of Cys C and β2-MG couldn’t reflect the condition of early renal injury in OSAHS patients during all stages.3 KIM-1 had no advantage when grouping by LSa O2. It was better to evaluate renal injury by AHI grouping than LSa O2 in OSAHS patients. 4 KIM-1, Cys C, β2-MG and AHI had positive correlation with each other which indicated that each of these factors changed consistently. The levels of them would rise along with the aggravating the degree of renal injury in OSAHS patients, the more severe the degree of AHI, the more injuries on renal function.5 KIM-1, Cys C and β2-MG had negative correlation with LSa O2, suggesting that OSAHS causes renal injury may be related with nocturnal hypoxemia. The more severe the degree of nocturnal hypoxemia, the more injuries on renal function.6 Hypoxia was an important part in the process of OSAHS development and had important reference value to assess the occurrence of OSAHS development. Due the cases of samples in this study were not big enough, we couldn’t categorically denied the use of hypoxia combined with KIM-1, Cys C and β2-MG in evaluating the renal injury in OSAHS patients. It needs further discussion and proof in the future scientific research. |
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