Gut microbiota exerts a significant role in the pathogenesis of the metabolic syndrome, as confirmed by studies conducted both on humans and animal models. Gut microbial composition and functions are strongly influenced by diet. This complex intestinal "superorganism" seems to affect host metabolic balance modulating energy absorption, gut motility, appetite, glucose and lipid metabolism, as well as hepatic fatty storage. An impairment of the fine balance between gut microbes and host's immune system could culminate in the intestinal translocation of bacterial fragments and the development of "metabolic endotoxemia", leading to systemic inflammation and insulin resistance. Diet induced weight-loss and bariatric surgery promote significant changes of gut microbial composition, that seem to affect the success, or the inefficacy, of treatment strategies. Manipulation of gut microbiota through the administration of prebiotics or probiotics could reduce intestinal low grade inflammation and improve gut barrier integrity, thus, ameliorating metabolic balance and promoting weight loss. However, further evidence is needed to better understand their clinical impact and therapeutic use.
Summary
Background
Non‐alcoholic fatty liver disease (NAFLD) encompasses a wide spectrum of clinical conditions, actually representing an emerging disease of great clinical interest. Currently, its diagnosis requires liver biopsy, an invasive procedure not free from potential complications. However, several non‐invasive diagnostic strategies have been proposed as potential diagnostic alternatives, each with different sensitivities and accuracies.
Aim
To review non‐invasive diagnostic parameters and tools for NAFLD diagnosis and to formulate a diagnostic and prognostic algorithm for a better classification of patients.
Methods
A literature search was carried out on MEDLINE, EMBASE, Web of Science and Scopus for articles and abstracts in English. The search terms used included ‘NAFLD’, ‘non invasive method and NAFLD’, ‘transient elastography’ and ‘liver fibrosis’. The articles cited were selected based on their relevancy to the objective of the review.
Results
Ultrasonography still represents the first‐line diagnostic tool for simple liver steatosis; its sensitivity could be enhanced by the complex biochemical score SteatoTest. Serum cytokeratin‐18 is a promising and accurate non‐invasive parameter (AUROCs: 0.83; 0.91) for the diagnosis of non‐alcoholic steatohepatitis (NASH). The staging of liver fibrosis still represents the most important prognostic problem: the most accurate estimating methods are FibroMeter, FIB‐4, NAFLD fibrosis score (AUROCs: 0.94; 0.86; 0.82) and transient elastography (AUROC: 0.84–1.00).
Conclusions
Different non‐invasive parameters are available for the accurate diagnosis and prognostic stratification of non‐alcoholic fatty liver disease which, if employed in a sequential algorithm, may lead to a reduced use of invasive methods, i.e. liver biopsy.
The recurrence of hepatocellular carcinoma, the sixth most common neoplasm and the third leading cause of cancer-related mortality worldwide, represents an important clinical problem, since it may occur after both surgical and medical treatment. The recurrence rate involves 2 phases: an early phase and a late phase. The early phase usually occurs within 2 years after resection; it is mainly related to local invasion and intrahepatic metastases and, therefore, to the intrinsic biology of the tumor. On the other hand, the late phase occurs more than 2 years after surgery and is mainly related to de novo tumor formation as a consequence of the carcinogenic cirrhotic environment. Since recent studies have reported that early and late recurrences may have different risk factors, it is clinically important to recognize these factors in the individual patient as soon as possible. The aim of this review was, therefore, to identify predicting factors for the recurrence of hepatocellular carcinoma, by means of invasive and non-invasive methods, according to the different therapeutic strategies available. In particular the role of emerging techniques (e.g., transient elastography) and biological features of hepatocellular carcinoma in predicting recurrence have been discussed. In particular, invasive methods were differentiated from non-invasive ones for research purposes, taking into consideration the emerging role of the genetic signature of hepatocellular carcinoma in order to better allocate treatment strategies and surveillance follow-up in patients with this type of tumor.
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