Effect of 5-year continuous positive airway pressure treatment on MMPs and TIMPs: implications for OSA comorbidities

Association of matrix metalloproteinase‐9 and nitric oxide with hypertension in obstructive sleep apnea

Background

Patients with obstructive sleep apnea (OSA) are more likely to suffer from hypertension. At the same time, the serum levels of matrix metalloproteinase‐9 (MMP‐9) and nitric oxide (NO) in patients with OSA are also changed in OSA patients. We investigated the correlation between serum levels of MMP‐9, NO in patients with OSA and their association with hypertension in those patients, and the effects of continuous positive airway pressure therapy (CPAP) on these serum biomarkers and blood pressure.

Methods

Serum MMP‐9 and NO levels and blood pressure of 57 patients with newly diagnosed OSA and 30 controls were measured; among them, 30 patients with moderate to severe OSA underwent 3‐month CPAP treatment.

Results

In comparison to the control group, the MMP‐9 serum levels were higher (232.8 ± 103.2 ng/ml versus 161.6 ± 56.5 ng/ml, p < .001*), there was no statistical significance difference among serum NO (26.7 ± 9.1 IU/ml versus 31.0 ± 11.7 IU/ml, p = .06), and MMP‐9 was negatively correlated to NO, especially in patients with hypertension (r = −.644, p = .02*). MMP‐9, NO, and blood pressure were significantly recovered in the patients with OSA after CPAP treatment for 3 months (p < .05*).

Conclusion

The MMP‐9 level and the NO level were altered in OSA patients. The relationship between the two especially in patients with hypertension suggests the potential mechanism of OSA‐induced hypertension.

The function of matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor (TIMP-1) in several clinical conditions: Results and analysis of our survey

The goal of this research was to evaluate the plasma concentration of MMP-9 and its tissue inhibitor (TIMP-1) in different clinical conditions. It included several groups of subjects: 31 overweight subjects; 91 obese adults divided into two subgroups according to the BMI value (BMI 30-35 Kg/m2 and BMI >  35 Kg/m2); 90 subjects with metabolic syndrome (MS) divided into two subgroups (with and without diabetes mellitus); 100 subjects with preclinical carotid atherosclerosis (PCA) divided according to the number of cardiovascular risk factors and to the insulin resistance degree; 48 subjects with obstructive sleep apnoea syndrome (OSAS) divided according to the apnoea/hypopnea index (AHI); 27 subjects with chronic kidney disease (CKD) on conservative management; 31 subjects with CKD on regular haemodialysis treatment. We have found a significant increase of MMP-9 and TIMP-1 in overweight subjects, in obese adult and in MS subjects. In obese adults, the behaviour of these two parameters was not influenced by the degree of obesity, while in the group of MS subjects both these parameters were clearly influenced by the presence of diabetes mellitus. In subjects with PCA, we observed an increase of MMP-9 associated with a significant decrease of TIMP-1; the same trend was found by subdividing the entire group in accordance with the number of cardiovascular risk factors and with the insulin resistance degree. In subjects with OSAS, we noted an increase in MMP-9 and TIMP-1; this increase was more evident in subjects with OSAS having AHI >  30. In individuals with CKD on conservative and haemodialysis treatment we have found, at baseline, a marked increase in MMP-9 and a significant decrease of TIMP-1. In dialyzed subjects, after a standard dialysis session was noted, a significant increase in MMP-9 was associated with a further decrease in TIMP-1.