Schistosomiasis mansoni: ultrasound-evaluated hepatic fibrosis and serum concentrations of hyaluronic acid

Abstract

Schistosomiasis mansoni is a fibrogenic liver disease that constitutes a major health problem in north-eastern Brazil. Although one common manifestation of the disease, periportal fibrosis (PPF), can be assessed by ultrasonography by well-trained physicians, the necessary equipment and personnel are not always readily available. Serum markers, including hyaluronic acid (HA), have been used as alternative means of measuring fibrosis. Recently serum concentrations of HA have been evaluated in 77 Brazilians (61 cases of schistosomiasis mansoni and 16 healthy controls) and compared against the ultrasound-evaluated PPF in the same subjects. The HA was measured using a non-competitive fluorescence-based assay, while the PPF was explored using a portable ultrasound scanner (SSD-500; Aloka, Tokyo) and graded, as patterns A-F, according to the World Health Organization's 'Niamey protocol'. In general, the serum concentrations of HA were found to be positively correlated with the severity of the PPF. The mean concentration of HA in the sera of the 16 controls was significantly lower than that recorded in the schistosomiasis cases who showed PPF of patterns D or E (P,0.001 for each). The cases who showed pattern-C PPF also had significantly less HA in their sera than the cases with PPF of patterns D or E (P,0.001 for each), and the cases with pattern-D fibrosis had significantly lower HA concentrations in their sera than the cases with PPF of pattern E (P,0.001).In an analysis based on a receiver-operating-characteristic (ROC) curve, an HA concentration of 20.2 mg/litre of serum was identified as a threshold that could be used to distinguish moderate cases of PPF (i.e. patterns C or D) from the more advanced cases (i.e. patterns E or F), with a sensitivity of 60% and specificity of 65%.In conclusion, it appears that serum concentrations of hyaluronic acid could be used as markers for periportal fibrosis in patients with schistosomiasis mansoni.Although the human morbidity and mortality caused by schistosomiasis mansoni have been reduced over the last 25 years by chemotherapy, the disease still represents a significant health hazard, particularly in north-eastern Brazil (Katz and Peixoto, 2000;Araú jo et al., 2007).It is believed that between 2% and 7% of humans infected with Schistosoma mansoni go on to develop hepato-splenic disease, which is associated with portal hypertension and digestive bleeding brought on by the rupture of oesophageal varices or hypertensive

New index for the diagnosis of liver fibrosis in Schistosomiasis mansoni

“…Despite the widespread use of US for diagnosing and monitoring changes caused by fibrosis, its use has some limitations, such as its low sensitivity in the initial forms of the disease; the need for a trained examiner, and the fact that it is not available at all centers, especially not those located in rural areas (17) . As a result of these US limitations, studies are emerging in an attempt to develop non-invasive methods that are capable of identifying and evaluating PPF via serum markers (6,9,16,21,25,28,30) . In Brazil, it is estimated that the Schistosomiasis mansoni affects about 2.5 to 6 million individuals, residing mainly in the Northeastern region, and approximately 5% to 10% of whom will develop the severe form of the disease (hepatosplenic) (5) .…”

Schistosoma mansoni Morbidity among School-Aged Children: A SCORE Project in Kenya

“…Liver texture patterns, PBT, and PVD do not fit our criteria as good indicators of morbidity in children because they were not associated with schistosomiasis in this age group. This does not appear to be a flaw in the tool (ultrasound examination), but rather reflects the point that these morbidity indicators are typically associated with S. mansoni infection in adults who have more chronic infections 47,48 and are rare in school-aged children. 18,45,49 This suggests that the Niamey protocol, which was designed for assessing morbidity in adult populations, is not adequate for assessing morbidity in children and that development of more age-appropriate tools should be considered.…”

Correlation Between Platelet Count and Both Liver Fibrosis and Spleen Diameter in Patients With Schistosomiasis Mansoni

“…Due to the drawbacks of liver biopsies and the large-scale use of ultrasound, substances involved in the production or degradation of collagen have recently been investigated for the determination of fibrosis in liver disease (10,12,19,22,27) . Stellate liver cells (Kupffer cells), which are mediators of liver fibrosis, are activated by tumor necrosis factor-alpha (TNF-α), platelet-derived growth factor (PDGF) and fibrogenic cytokines, such as TGF-β, IL-13, angiotensin II and (2,14,15) .…”

“…Indeed, a correlation has been described between the intensity of periportal fibrosis and pressure levels in the portal vein, which can lead to bleeding through esophageal varices; moreover, an association has been described between the presence of esophageal varices and spleen diameter (1,21) . Liver biopsy (7) , an ultrasound examination of the abdomen (3,8) , serum markers (5,10,16,22) , platelet count (4,12) and, more recently, liver stiffness (elastography) measurement (9) have been used to assess the fibrosis that develops in chronic liver disease. With SM, the liver-wedge biopsy is the most accurate method for measuring periportal fibrosis, but implies the use of laparotomy.…”