Objective: To explore the expression levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) protein and the change of MMP-9/TIMP-1 ratio in wound exudates of patients with stages Ⅲ and Ⅳ pressure ulcers during wound healing. Methods: From July 2017 to July 2018, 30 patients with stage Ⅲ pressure ulcers [30 wounds, 16 males and 14 females, aged (65±10) years] and 34 patients with stage Ⅳ pressure ulcers [50 wounds, 17 males and 17 females, aged (65±9) years] admitted to Hebei General Hospital who met the inclusion criteria were enrolled in this prospective cohort study. According to the principle of wound treatment and the characteristics and needs of wound in different periods, individualized intervention measures were formulated for patients and appropriate dressings were selected. At the time of admission and on 7, 14, 21, 28 days of treatment, the healing of pressure ulcer wounds was evaluated by Pressure Ulcer Healing Scale. Afterwards, the wound exudate was collected at each time point to detect the expression levels of MMP-9 and TIMP-1 protein by enzyme-linked immunosorbent assay, and the MMP-9/TIMP-1 ratio was calculated. Data were processed with analysis of variance for repeated measurements of single group and linear trend test. Results: (1) There were significantly statistical differences in wound healing scores of patients with stages Ⅲ and Ⅳ pressure ulcers among the time of admission and on 7, 14, 21, 28 days of treatment within each stage (F=145.382, 153.234, P<0.01), and they all showed a gradually decreasing trend (F=170.466, 284.585, P<0.01). (2) At the time of admission and on 7, 14, 21, 28 days of treatment, the expression levels of MMP-9 protein in wound exudates of patients with stages Ⅲ and Ⅳ pressure ulcers were (171±104), (138±88), (110±70), (85±55), (62±41) ng/L and (193±107), (173±104), (139±83), (114±70), (89±56) ng/L, respectively. There were significantly statistical differences within each stage (F=58.007, 111.680, P<0.01), and they all showed a gradually decreasing trend (F=62.901, 134.628, P<0.01). At the time of admission and on 7, 14, 21, 28 days of treatment, the expression levels of TIMP-1 protein in wound exudates of patients with stages Ⅲ and Ⅳ pressure ulcers were (6.2±3.9), (5.6±3.4), (5.1±3.1), (4.4±2.5), (3.8±2.3) ng/L and (4.8±2.5), (4.7±2.6), (4.4±2.6), (4.6±2.7), (4.1±2.4) ng/L, respectively. There were significantly statistical differences within each stage (F=25.479, 7.778, P<0.01), and there was a gradually decreasing trend in stage Ⅲ (F=62.901, P<0.01) and a decreasing trend in stage Ⅳ (F=134.628, P<0.01). At the time of admission, the expression levels of MMP-9 and TIMP-1 in wound exudates of patients with stage Ⅲ pressure ulcers were similar to those of patients with stage Ⅳ pressure ulcers (t=-1.03, 1.47, P>0.05). (3) At the time of admission and on 7, 14, 21, 28 days of treatment, the MMP-9/TIMP-1 ratios in the wound exudates of patients with pressure ulcers of stages Ⅲ and Ⅳ were 30±13, 25±9, 22±9, 20±8, 17±6 and 43±19, 37±13, 32±10, 26±9, 22±9, respectively. There were significantly statistical differences within each stage (F=37.173, 97.191, P<0.01), and they all showed a gradually decreasing trend (F=54.183, 130.088, P<0.01). At the time of admission, the MMP-9/TIMP-1 ratio in wound exudates of patients with stage Ⅳ pressure ulcers was significantly higher than that of patients with stage Ⅲ pressure ulcers (t=-3.42, P<0.01). Conclusions During the wound healing process of patients with stages Ⅲ and Ⅳ pressure ulcers, the expression levels of MMP-9 and TIMP-1 protein and the MMP-9/TIMP-1 ratio in wound exudates show a decreasing trend. The stage of wound healing can be predicted according to the expression level of MMP-9 protein and the MMP-9/TIMP-1 ratio.

Chronic wounds are with characteristics of long last time and cannot heal in time, which is a problem in clinic. Wound pH value plays an important role in the process of healing of chronic wounds. In this paper, we review the relative researches on wound pH value and wound microenvironment, summarize the potential relationship between wound pH value and healing of chronic wounds, as well as the method to change pH value of chronic wounds, thereby to provide theoretical basis for the treatment of chronic wounds in clinic.

Objectives To assess the plasma levels of acyl ghrelin (AG) and dys-acyl ghrelin (DG) in chronic kidney disease (CKD) and hemodialysis (HD) patients and analyze their relationships with different stages of CKD and hemodialysis. Methods Forty-six CKD stage 1-5 patients and 15 hemodialysis patients were enrolled into the study. Body weight, height, hemoglobin, biochemical parameters, inflammatory parameters, preprandial, postprandial and 3 hours after hemodialysis plasma AG and DG levels were measured. Appetite and food intake were assessed. Body mass index (BMI), and estimated glomerular filtration rate (eGFR) were calculated. Results There were no significant differences in BMI, SGA, appetite, food intake and malnutrition among CKD patients of different stages. eGFR was declining with the progression of CKD stages and patients received a three-week hemodi-alysis. Compared with that in CKD stage 1-2 patients, the level of preprandial and postprandial DG was remarkably increased in stage 3-5 patients (P<0.01). The level of DG was significantly decreased after a standard breakfast in CKD patients (P<0.01). CKD stage was positively correlated with preprandial (r=0.31, P<0.05)a nd postprandi-al DG (r=0.34, P < 0.05), TNF-α (r=0.33, P < 0.05), IL-6 (r=0.40, P < 0.05), leptin (r=0.34, P < 0.05), and age (r=0.41, P<0.05). CKD stage was also highly and positively correlated with the proportion of preprandial and postprandial DG (r=0.61, P<0.01;r=0.55, P<0.01). Multivariate partial-correlation analysis showed that CKD was independently associated with the proportion of preprandial and postprandial DG (r=0.55, P < 0.01; r=0.43, P < 0.01).There was no decrease in AG postprandially, nor any changes in AG resultant from dialysis (P > 0.05);levels of DG decreased slightly postprandially and were markedly decreased by hemodialysis (P<0.01), even lower than those seen postprandially in CKD stage 1-2;Both preprandial and postprandial DG were negatively correlated with serum albumin levels (r=-0.64, P < 0.05; r=-0.59, P < 0.05), while there was no correlation between AG and serum albumin levels. Conclusions There is a strong and independent correlation of DG with CKD stage. Postprandial suppression of ghrelin is impaired with reduced renal function. Hemodialysis removes DG but not AG.