ABSTRACT
Hyaluronic acid (HA), which is a highly versatile glycosaminoglycan, is widely applied across the fields of food, cosmetics, and pharmaceuticals. It is primary produced through Streptococcus fermentation, but the product presents inherent challenges concerning consistency and potential pathogenicity. However, recent strides in molecular biology have paved the way for genetic engineering, which facilitates the creation of high-yield, nonpathogenic strains adept at synthesizing HA with specific molecular weights. This comprehensive review extensively explores the molecular biology underpinning pivotal HA synthase genes, which elucidates the intricate mechanisms governing HA synthesis. Moreover, it delineates various strategies employed in engineering HA-producing strains.
Subject(s)
Genetic Engineering , Hyaluronic Acid , Streptococcus , Hyaluronic Acid/biosynthesis , Streptococcus/genetics , Streptococcus/metabolism , Genetic Engineering/methods , Fermentation , Hyaluronan Synthases/genetics , Hyaluronan Synthases/metabolism , Biosynthetic Pathways/geneticsABSTRACT
BACKGROUND AND AIM: Preventing rebleeding is crucial, but the best prevention technique for patients with cirrhosis and portal vein thrombosis (PVT) remains debatable. Therefore, this systematic review and meta-analysis compared a transjugular intrahepatic portosystemic shunt (TIPS) with endoscopic therapy (ET) plus nonselective beta-blockers (NSBBs) for preventing variceal rebleeding in this patient population. METHODS: The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from their inception until May 18, 2023. The studies were screened using predetermined criteria, relevant data were extracted, and pooled analyses were performed using the Reviewer Manager 5.4.1 software. RESULTS: We retrieved 1032 studies, of which 5 studies comprising a total of 272 patients were included. The postoperative variceal rebleeding rate was significantly lower in the TIPS group than in the ET + NSBBs group (odds ratio [OR] = 0.19, 95% confidence interval [CI] = 0.11-0.35, P < 0.05, I2 = 0%), but the portal vein recanalization rate was higher (OR = 7.92, 95% CI = 3.04-20.67, P < 0.05, I2 = 0%). The rates of hepatic encephalopathy (HE) and mortality did not differ between the groups. CONCLUSIONS: Our results suggest that TIPS prevents variceal rebleeding without increasing the hepatic encephalopathy risk more effectively than ET plus NSBBs, but this benefit did not translate into improved survival. Thus, it may be preferable to ET plus NSBBs for preventing variceal rebleeding in patients with cirrhosis and PVT. However, more large-scale and multicenter randomized controlled trials involving other patient populations are required to verify the clinical efficacy of both these treatments and ensure generalizability.
