Impairment of cytochrome P-450-dependent liver activity in cirrhotic patients with Helicobacter pylori infection

Infection by CagA-Positive Helicobacter pylori Strains and Bone Fragility: A Prospective Cohort Study

Helicobacter pylori (HP) infection is a common and persistent disorder acting as a major cofactor for the development of upper gastrointestinal diseases and several extraintestinal disorders including osteoporosis. However, no prospective study assessed the effects of HP on bone health and fracture risk. We performed a HP screening in a population-based cohort of 1149 adults followed prospectively for up to 11 years. The presence of HP infection was assessed by serologic testing for serum antibodies to HP and the cytotoxin associated gene-A (CagA). The prevalence of HP infection did not differ among individuals with normal bone mineral density (BMD), osteoporosis, and osteopenia. However, HP infection by CagA-positive strains was significantly increased in osteoporotic (30%) and osteopenic (26%) patients respect to subjects with normal BMD (21%). Moreover, anti-CagA antibody levels were significantly and negatively associated with lumbar and femoral BMD. Consistent with these associations, patients affected by CagA-positive strains had a more than fivefold increased risk to sustain a clinical vertebral fracture (HR 5.27; 95% CI, 2.23-12.63; p < .0001) and a double risk to sustain a nonvertebral incident fracture (HR 2.09; 95% CI, 1.27-2.46; p < .005). Reduced estrogen and ghrelin levels, together with an impaired bone turnover balance after the meal were also observed in carriers of CagA-positive HP infection. HP infection by strains expressing CagA may be considered a risk factor for osteoporosis and fractures. Further studies are required to clarify in more detail the underlying pathogenetic mechanisms of this association. © 2020 American Society for Bone and Mineral Research (ASBMR).

Helicobacter pylori infection in hepatic encephalopathy: Relationship to plasma endotoxins and blood ammonia

BACKGROUND/AIM

Hepatic encephalopathy (HE) is frequently observed in patients with advanced liver disease and manifests a wide variety of neuropsychiatric signs and symptoms. Ammonia toxicity and bacterial endotoxins have been suggested as key determinants of HE onset whereas a role for Helicobacter pylori infection has not been established. We investigated the correlation between H. pylori infection and HE severity (evaluated through functional tests) in 60 outpatients with established liver cirrhosis and 20 non-cirrhotic controls.

METHODS

Fasting arterial blood ammonia, plasma endotoxins, and H. pylori infection status were investigated in all subjects.

RESULTS

H. pylori infection was documented in 35/60 (58%) patients and in 6/20 (30%) controls (P = 0.039). Significant differences were observed between patients with and withoutHE for age, presence of ascites, fasting arterial blood ammonia, plasma endotoxin, and H. pylori infection. Further, a significant increase in fasting arterial blood ammonia and plasma endotoxin was associated with H. pylori infection in cirrhotic patients. Last, medical treatment of H. pylori infection led to a significant decrease in HE severity and fasting arterial blood ammonia levels.

CONCLUSION

In conclusion, we submit that H. pylori infection might, in fact, play a role in increasing the circulating levels of ammonia and endotoxins in cirrhotic patients, thus facilitating the onset of HE.

Regulation of drug metabolism and disposition during inflammation and infection

The expression and activity of cytochrome P450 (CYP) is altered during periods of infectious disease or when an inflammatory response is activated. Most of the major forms of CYP are affected in this manner and this leads to a decrease in the capacity of the liver and other organs to handle drugs, chemicals and some endogenous compounds. The loss in drug metabolism is predominantly an effect resulting from the production of cytokines and the modulation of the transcription factors that control the expression of specific CYP forms. In clinical medicine numerous examples have been reported indicating the occurrence of compromised drug clearance and changes to pharmacokinetics during disease states with an inflammatory component or during infections. For any drug that is metabolised by CYP and has a narrow therapeutic index, there is a significant risk in placing patients in a position where an infection or inflammatory response might lead to aberrant drug handling and an adverse drug response.

Influence of 1-week Helicobacter pylori eradication therapy with rabeprazole, clarithromycin, and metronidazole on 13C-aminopyrine breath test

Helicobacter pylori eradication therapy is commonly prescribed in the general population. Treatment consists of drugs that are mainly metabolized by the liver cytochrome P-450 (CYP) enzymatic pool. Most H. pylori-infected patients often take drugs for comorbid illnesses, therefore increasing the potential for drug-drug interactions. We aimed to evaluate the interactions of rabeprazole, clarithromycin, and metronidazole 1-week H. pylori eradication therapy with CYP-dependent liver metabolic function in clinical practice. Ten patients referred to our unit for H. pylori infection underwent 1-week eradication therapy with rabeprazole (20 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and metronidazole (500 mg, b.i.d.). We chose the 13C-aminopyrine breath test (13C-ABT) to evaluate CYP-dependent liver function since it is noninvasive and nonharmful. All patients underwent 13C-ABT at three time points: before therapy (to), at the end of therapy (t8), and after 1 month of follow-up (t38). Mean 13C-ABT dose/hr (t0 = 14.0 +/- 5.4, t8 = 13.5 +/- 4.0, t38 = 16.1 +/- 5.6) as well as 13C-ABT cumulative dose (t0 = 2.4 +/- 1.1, t8 = 2.4 +/- 0.8, t38 = 2.6 +/- 1.0) were not statistically different at the three time points of the study. These results did not seem to be influenced by drugs being administered concomitantly. In everyday clinical practice rabeprazole-based H. pylori eradication therapy does not seem to display any significant interactions with CYP-dependent liver function, even in patients on multiple drugs.

Prevalence of Helicobacter pylori infection in male patients with osteoporosis and controls

Cytokines that regulate bone turnover (tumor necrosis factor-alpha, interleukin-6, etc.) may influence the pathogenesis of skeleton disorders, such as osteoporosis. Since Helicobacter pylori infection increases the systemic levels of inflammatory cytokines, we investigated the possibility that this infection increases the risk of developing osteoporosis and affects the bone metabolism in a group of male patients with osteoporosis. We examined 80 osteoporotic male patients and 160 controls for serum antibodies to H. pylori and the CagA protein and determined, in patients alone, the most important biochemical and instrumental parameters of the disease. Fifty-one patients (63.7%) and 107 controls (66.8%) were seropositive for H. pylori infection (nonsignificant); 30 infected patients (58.8%) and 43 infected controls (40.1%) were positive for anti-CagA antibodies (P = 0.028; OR = 2.13). Levels of estradiol in infected CagA-positive patients were significantly lower than in infected CagA-negative patients (28.5 [SD = 10.18] vs. 39.5 [SD = 14.50] pg/ml; P = 0.002) and uninfected patients (35.2 [SD = 12.7] pg/ml; P = 0.028). Levels of urinary cross-laps(a marker of bone resorption) were increased in patients infected by CagA-positive strains compared to patients infected by CagA-negative strains (282.9 [SD = 103.8] vs. 210.5 [SD = 150.1]microg/mmol; P = 0.048) and uninfected patients (204.3 [SD = 130.1] microg/mmol; P = 0.016). Differences among uninfected and infected patients, independent of CagA status, were observed for other markers of bone turnover, but they did not reach statistical significance. Infection by CagA-positive H. pylori strains is more prevalent in men with osteoporosis, who show reduced systemic levels of estrogens and increased bone turnover. H. pylori infection by strains expressing CagA may therefore be considered a risk factor for osteoporisis in men.

Relationship between thrombopoietin serum levels and liver function in patients with chronic liver disease related to hepatitis C virus infection

OBJECTIVES

Thrombopoietin (Tpo) is an important regulator of megakaryocyte maturation and platelet production, and is mainly produced by the liver. A decrease in Tpo production is partly responsible for the thrombocytopenia observed in patients with chronic liver disease (CLD). The aim of this study was to evaluate the relationship between Tpo serum levels and liver function in patients with CLD related to hepatitis C virus (HCV) infection.

METHODS

We studied 37 patients with various degrees of HCV-related CLD. Of the patients, 17 had chronic hepatitis and 20 liver cirrhosis. Liver function was evaluated in all patients by the following hepatic blood flow dependent and independent tests that explore various hepatic metabolic functions: carbon-13 (13C)-aminopyrine breath test (13C-ABT), 13C-galactose breath test (13C-GBT), and monoethylglycinexylidide (MEGX) test. Liver function tests results were correlated with Tpo serum levels.

RESULTS

Tpo serum levels were significantly lower in patients with liver cirrhosis (88 +/- 23 pg/ml) as compared to those in patients with chronic hepatitis (128 +/- 55 pg/ml, p=0.0031). However, they did not correlate with serum albumin, bilirubin, or prothrombin activity. Tpo serum levels showed a significant positive correlation with 13C-ABT results (hourly dose at 30 min, rs=0.489, p=0.002; cumulative dose at 120 min, rs=0.425, p=0.008). Moreover, they showed a fair, positive correlation with 13C-GBT hourly dose at 30 min (rs=0.366, p=0.028), and a trend toward a positive correlation with the various MEGX test sampling times (MEGX15, rs=0.314, p=0.059; MEGX30, rs=0.284, p=0.088; and MEGX60, rs=0.320, p=0.059).

CONCLUSIONS

In this study we have shown that a progressive decline in liver function in patients with HCV-related CLD is paralleled by a decrease in Tpo production. The different correlations observed between Tpo and the various liver function tests suggests that this finding is mainly the result of a decrease in hepatic functional mass rather than dependent on alteration in splanchnic hemodynamic.

Helicobacter pylori infection in patients with liver cirrhosis: facts and fictions

Helicobacter pylori infection could play a role in different clinical alterations observed in cirrhosis, from gastroduodenal lesions to hepatic encephalopathy. Although its prevalence in cirrhotics is similar to that in controls, H. pylori infection is responsible for the increased prevalence of peptic ulcer observed in these patients. The ammonia production by H. pylori urease does not seem to increase blood ammonia levels during cirrhosis, indicating that its role in hepatic encephalopathy could be marginalized in clinical practice. Dual and triple therapies have been shown to be equally effective for H. pylori eradication in these patients.