Application of urinary N-acetyl-β-D-glucosaminidase combined with serum retinol-binding protein in early detection of diabetic nephropathy

BACKGROUND Diabetic nephropathy(DN)is a microangiopathy of type 2 diabetes mellitus(T2DM),which can damage the kidney through various ways and mechanisms due to the nature of the disease,involving the renal interstitium and glomeruli.However,in the early stage of the disease,patients only showed kidney volume increase and glomerular hyperthyroidism,and typical symptoms that are difficult to arouse individual attention were noticed.AIM To observe the expression of serum retinol-binding protein(RBP)and urinary Nacetyl-β-D-glucosaminidase(NAG)in patients with DN,and to analyze their value in disease prediction,so as to provide new targets for early diagnosis and treatment of DN.METHODS The baseline data of 50 T2DM patients treated in our hospital between January 2021 and December 2022 were retrospectively reviewed and included in group A.The baseline data of 50 patients with type 2 DN admitted to our hospital during the same period were collected and included in group B.The baseline data and serum RBP and urine NAG expression were compared between the two groups to analyze their value in the early prediction of DN.RESULTS There was no significant difference in age,gender,duration of diabetes,combined hyperlipidemia and combined hypertension between the two groups(P>0.05);the expression of urinary NAG and serum RBP in group B was higher than that in group A,and the difference was statistically significant(P<0.05);a multiple logistic regression model was established,and the results showed that urinary NAG and serum RBP were related to the presence or absence of injury in diabetic patients,and overexpression of urinary NAG and serum RBP may be risk factors for renal injury in T2DM patients(OR>1,P<0.05);receiver operating curve curve was plotted,and the results showed that the area under the curve of urinary NAG and serum RBP expression alone and in combination for predicting DN was>0.80,and the predictive value was satisfactory;bivariate Spearman linear correlation analysis showed that there was a positive correlation between urinary NAG and serum RBP expression in patients with DN(r=0.566,P=0.000).CONCLUSION The increased expression of urinary NAG and serum RBP may be the risk factors leading to the progression of T2DM to DN.The possibility of DN can be considered in patients with urinary NAG and serum RBP overexpression by examining the expression of urinary NAG and serum RBP in patients with T2DM in clinical practice.

Denaturation Kinetics of N-Acetyl-β-D-glucosaminidase from Scylla serrata in Urea Solution

N-Acetyl-β-D-glucosaminidase（NAGase, EC 3.2.1.52）, which catalyzes the cleavage of N-acetylgluco- samine polymers, plays important roles in the molting, digestion of chitinous foods in green crab. In the study, the efforts of urea on the activity of NAGase purified from the viscera of green crab（Scylla serrata） have been studied. The results show that appropriate concentrations of urea can lead to reversible inactivation of the enzyme, and the value of the inhibitor concentration leading to 50% of enzyme activity lost（IC50） is estimated to be 0.63 mol/L. The inactivation kinetics has been studied via the kinetic method of the substrate reaction. The rate constants of inactivation have been determined. The value of k＋0 is larger than that of k′＋0, indicating the free enzyme molecule is more fragile than the enzyme-substrate complex in urea solution. It is suggested that the presence of the substrate offers the marked protection of this enzyme against inactivation by urea.

Historical tillage promotes grass-legume mixtures establishment and accelerates soil microbial activity and organic carbon decomposition

Perennial grass-legume mixtures have been extensively used to restore degraded grasslands,increasing grassland productivity and forage quality.Tillage is crucial for seedbed preparation and sustainable weed management for the establishment of grass-legume mixtures.However,a common concern is that intensive tillage may alter soil characteristics,leading to losses in soil organic carbon(SOC).We investigated the plant community composition,SOC,soil microbial biomass carbon(MBC),soil enzyme activities,and soil properties in long-term perennial grass-legume mixtures under two different tillage intensities(once and twice)as well as in a fenced grassland(FG).The establishment of grass-legume mixtures increased plant species diversity and plant community coverage,compared with FG.Compared with once tilled grassland(OTG),twice tilled grassland(TTG)enhanced the coverage of high-quality leguminous forage species by 380.3%.Grass-legume mixtures with historical tillage decreased SOC and dissolved organic carbon(DOC)concentrations,whereas soil MBC concentrations in OTG and TTG increased by 16.0%and 16.4%,respectively,compared with FG.TTG significantly decreased the activity of N-acetyl-β-D-glucosaminidase(NAG)by 72.3%,whereas soil enzymeβ-glucosidase(βG)in OTG and TTG increased by 55.9%and 27.3%,respectively,compared with FG.Correlation analysis indicated a close association of the increase in MBC andβG activities with the rapid decline in SOC.This result suggested that MBC was a key driving factor in soil carbon storage dynamics,potentially accelerating soil carbon cycling and facilitating biogeochemical cycling.The establishment of grass-legume mixtures effectively improves forage quality and boosts plant diversity,thereby facilitating the restoration of degraded grasslands.Although tillage assists in establishing legume-grass mixtures by controlling weeds,it accelerates microbial activity and organic carbon decomposition.Our findings provide a foundation for understanding the process and effectiveness of restoration management in degraded grasslands.

Research progress on markers of urine tubular damage in idiopathic membranous nephropathy

Idiopathic membranous nephropathy is a common primary glomerular disease.Recently,it has been found that the progression and prognosis of glomerular diseases are not only related to the glomeruli itself,but also to the severity of renal tubular injury.Although blood creatinine and urinary protein are recognized biomarkers,they appear late,are insensitive,lack specificity,and are difficult to respond to IMN conditions in a timely and accurate manner.Markers such as N-acetyl-β-D-glucosaminidase,kidney injury molecule 1,neutrophil gelatinase-associated lipoprotein in urine can dynamically reflect the progress of kidney injury in the early stage,and are detected as noninvasive,so It has been applied in IMN,but such research is lacking,and the scope needs to be further expanded and discussed in depth.