Environmental health and clinicians: time to promote more action

Climate change and ambient air pollution are threats to human health, with dramatic short- and long-term effects on mortality and morbidity. Pollution generates fears among citizens who rarely receive adequate information for risk mitigation. A large burden of evidence is describing since decades the health effects of pollution, linking environmental exposure to pathophysiological mechanisms (mainly, low-grade chronic inflammation) that lead to an array of chronic non-communicable diseases. Epidemiologists are deeply involved to depict environment-related diseases, identify risk factors as well as to offer suggestions for prevention policies. However, their warnings are frequently disregarded by clinicians and policymakers. In clinical practice, diagnostic evidence is the basis for therapeutic interventions. Conversely, epidemiological evidence in the field of environmental health rarely generates appropriate preventive and clinical actions. Despite the great interest and concerns of citizens and epidemiologists, the perception of pollution as a major hazard to health is often scarce among clinicians, as witnessed by the poor presence of environmental health in the majority of clinical guidelines, meetings of scientific societies, and medical curricula. As a consequence, inaction is not uncommon among clinicians, who often fail to routinely engage in counseling their patients on how to reduce their health risks from living in an unsafe environment nor to act as advocates in order to enact changes in the community. This gap should be urgently bridged by creating opportunities for health professionals to be adequately informed and trained to play an active role in tackling environmental risks.

Effects of MBOAT7 polymorphism and steatosis on liver function assessed by methacetin breath test

BACKGROUND

MBOAT7 rs641738 variant is a risk factor for nonalcoholic fatty liver disease (NAFLD) and liver fibrosis, but the relationship between this polymorphism and early liver dysfunction remains uncertain.

METHODS

Eighty outpatients underwent blood analyses, liver imaging by ultrasound and acoustic radiation force impulse shear wave elastography and were genotyped for MBOAT7 (wild-type [WT], rs641738 heterozygous or homozygous) polymorphism using TaqMan assays.

RESULTS

NAFLD was confirmed in 53 patients. Portal uptake and hepatocyte microsomal metabolization of (13 C)-methacetin were explored by measuring 13 CO2 appearance in exhaled air. The distribution of the MBOAT7 genotypes was comparable in subjects with or without NAFLD. The majority of subjects with or without NAFLD had fibrosis ≤ F1 but decreased portal extraction of (13 C)-methacetin, i.e. 78.6% in homozygous, 45.0% in heterozygous and 46.2% in WT for the MBOAT7 variant. Both substrate extraction and microsomal metabolization were mostly defective in the homozygous carriers. The extraction efficiency from portal blood flow was minimal in subjects with both homozygous rs641738 polymorphism and NAFLD, as compared to those with WT/heterozygous polymorphism, with or without NAFLD.

CONCLUSIONS

The homozygous MBOAT7 rs641738 polymorphism per se is associated with a reduced extraction efficiency of (13 C)-methacetin from the portal flow pointing to subclinical liver dysfunction independently from liver fibrosis. Liver steatosis worsens (13 C)-methacetin extraction efficiency. We urge to better explore the mechanisms of interaction between external factors and multiple gene polymorphisms (including MBOAT7), paving the road to primary prevention and novel therapeutic strategies.

Adipocyte-hepatocyte crosstalk in cellular models of obesity: Role of soluble factors

Hepatic steatosis is often a consequence of obesity. Adipose tissue is an important endocrine regulator of metabolic homeostasis in the body. In obesity, adipocytes become hypertrophic and develop an inflammatory phenotype, altering the panel of secreted adipokines. Moreover, excess fatty acids are, in part, released by adipocytes and delivered to the liver. These multiple pathways of adipose-liver crosstalk contribute to the development and progression of liver disease: TNFα induces hepatocyte dysfunction, excess of circulating fatty acids promotes hepatic steatosis and inflammation, whilst adipokines mediate and exacerbate liver injury. In this study, we investigated in vitro the effects and mechanisms of the crosstalk between adipocytes and hepatocytes, as a function of the different adipocyte status (mature vs hypertrophic) being mediated by soluble factors. We employed the conditioned medium method to test how mature and hypertrophic adipocytes distinctively affect the liver, leading to metabolic dysfunction. The media collected from adipocytes were characterized by high triglyceride content and led to lipid accumulation and fat-dependent dysfunction in hepatocytes. The present findings seem to suggest that, in addition to triglycerides, other soluble mediators, cytokines, are released by mature and hypertrophic adipocytes and influence the metabolic status of liver cells. Understanding the precise factors involved in the pathogenesis and pathophysiology of NAFLD in obesity will provide important insights into the mechanisms responsible for the metabolic complications of obesity, paving the way for new possible approaches.

MicroRNA in colorectal cancer: new perspectives for diagnosis, prognosis and treatment

Colorectal cancer (CRC) is a common condition and represents a lethal disease, following a sequential progression from adenoma to carcinoma. Interfering with such natural history of CRC offers clues to prevention and cure, but current screening methods for CRC are still limited by unsatisfactory sensitivity and specificity. Novel diagnostic, prognostic tools are therefore being actively investigated for CRC. The discovery of microRNAs (miRNAs) has led to active research focusing on their role in cancer and several crucial pathways involving angiogenesis, cancer-stem-cell biology, epithelial-mesenchymal transition, formation of metastasis, and drug resistance. MiRNAs might soon represent novel prognostic and diagnostic tools in patients at high risk of CRC or being diagnosed with CRC. MiRNA might prove useful also as therapeutic tools, since dysregulation of miRNAs in cancer cells results in higher levels of messenger RNA (mRNA) specific to tumor promoter genes or tumor suppressor genes. Thus, novel anticancer therapies might originate from manipulation of oncogenic or tumor suppressor miRNAs in CRC. In this review, the innovative aspects of miRNA are discussed, with respect to biogenesis, their role in CRC, and their potential use as biomarkers. Before miRNAs can become available in the clinical setting, however, a number of large prospective studies are still required.

Improving Diagnosis and Management of Opioid-Induced Constipation (OIC) in Clinical Practice: An Italian Expert Opinion

Opioid-induced constipation (OIC) is a very common and troublesome gastrointestinal side effect following the use of opioids. Despite existing international guidelines, OIC is largely underdiagnosed and undertreated. ECHO OIC is a European project designed to improve the diagnosis and management of OIC at the primary care level. The next phase of the ECHO OIC project is to review and adapt the proposed European pathway at national level, considering the local patient journey and clinical practice. A multidisciplinary group of 12 Italian experts reviewed and discussed the European path and formulated a seven-step guide for the practical management of OIC that is also easily applicable in primary care: 1. When prescribing long-term opioids, the physician should inform the patient of the possibility of the onset of OIC; 2. At opioid prescription, doctors should also prescribe a treatment for constipation, preferably macrogol or stimulant laxatives; 3. The patient should be evaluated for OIC within the second week of initiating opioid treatment, by clinical history and Rome IV criteria; 4. In the presence of constipation despite laxatives, prescription of a PAMORA (Peripherally Acting Mu Opioid Receptor Antagonist) should be considered; 5. When prescribing a PAMORA, prescribing information should be carefully reviewed, and patients should be accurately instructed for appropriate use; 6. Efficacy and tolerability of the PAMORA should be monitored regularly by Bowel Function Index, considering a cut-off of 30 for the possible step-up of OIC treatment; 7. After 4 weeks of treatment, if the efficacy of PAMORA is deemed inadequate, discontinuation of the PAMORA, addition of an anti-constipation drugs, change of opioid type, or referral to a specialist should be considered. Spreading knowledge about the OIC problem as much as possible to the health community is crucial to obtain not only an early treatment of the condition but also to promote its prevention.

Gallstone prevalence and gallbladder volume in children and adolescents: an epidemiological ultrasonographic survey and relationship to body mass index

To assess the prevalence of gallstone disease and the behavior of gallbladder (GB) volume in childhood and adolescence, an ultrasonographic survey was carried out on 1570 subjects (age range 6-19 yr). Entered in the study were 750 males and 752 females (attendance rate, 95.7%). Gallstones were detected in two females aged 13 and 18 yr, respectively. None of the subjects in the study population had undergone cholecystectomy. The overall prevalence of gallstone disease was equal to 0.13% (0.27% in the female sex). A positive family history for biliary calculous disease was present in one of the two lithiasic girls. A progressive increase of GB volume with age was observed in both sexes, and figures were greater in males, than in age-matched females. A positive and statistically significant relationship was found between GB volume and body mass index (BMI) in both sexes. Obesity was recognized in 188 males (25.3%) and 167 females (25.0%). Obese subjects exhibited larger GB volumes than the nonobese age- and sex-matched controls. The study supports the view of a very low prevalence of gallstone disease in people younger than 20. It also provides information on GB size in relation to age, sex, and BMI.

Nutritional and Physiological Properties of Thymbra spicata: In Vitro Study Using Fecal Fermentation and Intestinal Integrity Models

(Poly)phenolic-rich Mediterranean plants such as Thymbra spicata have been associated with several health-promoting effects. The nutritional value, as well as physiological interaction of T. spicata with the gastrointestinal tract, has not been investigated before. The nutritional composition of T. spicata leaves was here characterized by standard analytical methods. T. spicata leaves were subjected to ethanolic extraction, simulated gastrointestinal digestion, and anaerobic microbial gut fermentation. Phenols/flavonoid contents and radical scavenging activity were assessed by colorimetric methods. The volatile organic compounds (VOCs) were detected by gas chromatography coupled with mass spectrometry. The effect on intestinal integrity was evaluated using a Caco-2 monolayers mounted in a Ussing chamber. T. spicata contains a high amount of fiber (12.3%) and unsaturated fatty acids (76% of total fat). A positive change in VOCs including short-chain fatty acids was observed without significant change in viable microbe. T. spicata and carvacrol (main phenolic compound) enhanced ionic currents in a concentration-dependent manner without compromising the Caco-2 monolayer's integrity. These effects were partially lost upon simulated digestion and completely abolished after colonic fermentation in line with polyphenols and carvacrol content. Conclusion: T. spicata represents a promising nutrient for the modulation of gut microbiota and the gut barrier. Further studies must better define its mechanisms of action.

Portal Hypertension in Nonalcoholic Fatty Liver Disease: Challenges and Paradigms

Portal hypertension in cirrhosis is defined as an increase in the portal pressure gradient (PPG) between the portal and hepatic veins and is traditionally estimated by the hepatic venous pressure gradient (HVPG), which is the difference in pressure between the free-floating and wedged positions of a balloon catheter in the hepatic vein. By convention, HVPG≥10 mmHg indicates clinically significant portal hypertension, which is associated with adverse clinical outcomes. Nonalcoholic fatty liver disease (NAFLD) is a common disorder with a heterogeneous clinical course, which includes the development of portal hypertension. There is increasing evidence that portal hypertension in NAFLD deserves special considerations. First, elevated PPG often precedes fibrosis in NAFLD, suggesting a bidirectional relationship between these pathological processes. Second, HVPG underestimates PPG in NAFLD, suggesting that portal hypertension is more prevalent in this condition than currently believed. Third, cellular mechanoresponses generated early in the pathogenesis of NAFLD provide a mechanistic explanation for the pressure-fibrosis paradigm. Finally, a better understanding of liver mechanobiology in NAFLD may aid in the development of novel pharmaceutical targets for prevention and management of this disease.

Ultrasonographic assessment of gastric and gallbladder dynamics in human health and disease

The diagnosis of functional disorders of the upper gastrointestinal tract relies on clinical evaluation after exclusion of most frequent organic diseases. Diagnostic techniques contribute to better characterization of disease, choice of specific therapy, and follow-up. Functional ultrasonography was introduced in the early '80 s for the non-invasive study of gastric and gallbladder emptying without ionizing radiation, during fasting and postprandially. This technique detects dysfunctional motility in several gastrointestinal and systemic conditions, and can be used along with the assessment of real-time satiety and gastrointestinal symptoms after food ingestion, and dosing of hormones involved in the modulation of gastrointestinal and metabolic homeostasis. Functional ultrasonography has been increasingly used to explore the gastrointestinal pathophysiology, the gut-brain interaction, the effects of drugs (such as antidiabetics), the response to specific dietary and feeding patterns, and to support the development of nutraceuticals. In this evolving scenario, ultrasonography stands as a widely available, highly sustainable, non-invasive, repeatable, safe and low-cost tool, as compared with more expensive, less sustainable or still scarcely standardized procedures to study gastric and gallbladder motility as scintigraphy, wireless motility capsule tests, 13C breath tests, or magnetic resonance imaging. Functional ultrasonography not only provides reliable data in experimental protocols, but also in the assessment of clinical conditions as dyspeptic symptoms, diabetes, gastroenteric and neurological diseases, critical illness, and as a benchmark to evaluate the gastrointestinal effects of innovative drugs.

Surgically-induced bile duct injury is followed by early hepatic oxidative stress. A preliminary experimental study in rats

BACKGROUND/AIMS

To study in the rat whether oxidative stress appears early in a model of short-term cholestasis induced by bile duct ligation.

METHODOLOGY

Adult male rats underwent proximal bile duct ligation; controls underwent a sham operation. Animals were sacrificed at days 0, 1, 3, 7 and 10. Livers were removed for histological studies and biochemical analysis.

RESULTS

GSH and PSH levels declined earlier in mitochondria than cytosol. Data were analyzed for statistical significance by ANOVA analysis.

CONCLUSIONS

This study represents an experimental model which helps in the interpretation of the damage induced by bile duct injury in humans emphasizing an early detection of bile duct injury after surgery to ensure appropriate treatment and optimal patient outcome.

The emerging problem of nonalcoholic steatohepatitis (NASH)

Nonalcoholic steatohepatitis (NASH) is an increasing recognized form of chronic liver condition affecting both children and adults within the wide spectrum of fatty liver diseases. Recently NASH has been often associated with insulin resistance and has shown potential harmful evolution towards end-stage liver disease. Its incidence and prevalence is increasing, paralleling the rise in obesity and diabetes mellitus in Western Countries. Once all the other causes of persistent elevation of serum transaminase levels are excluded, the diagnosis of NASH can be only confirmed by liver histology. Non-invasive diagnostic tools, however, are awaited to allow the follow-up of patients at higher risk for major liver dysfunction. This article focus on current thoughts on the natural history and clinical presentation of NASH and describes current trends in the diagnosis and treatment of this emerging condition.

Tauroursodeoxycholic acid, ursodeoxycholic acid and gallbladder motility in gallstone patients and healthy subjects

Fasting and postprandial gallbladder volumes have been measured by sonography both in healthy subjects and gallstone patients ingesting: (a) tauroursodeoxycholic acid; (b) ursodeoxycholic acid; (c) placebo. Each bile salt was given at a dose of 10 mg kg-1. Sonography was repeated in gallstone patients fed tauroursodeoxycholic acid or ursodeoxycholic acid (10 mg kg-1 day-1) for 1 month. Gallstone patients had gallbladder stasis (increase in fasting and residual volumes) and decreased postprandial emptying. Acute ingestion of tauroursodeoxycholic acid or ursodeoxycholic acid did not modify postprandial gallbladder emptying in both groups of subjects. After one month's therapy with tauroursodeoxycholic acid or ursodeoxycholic acid, fasting gallbladder volume further increased in gallstone patients, although gallbladder emptying remained unchanged. Thus, therapeutic doses of tauroursodeoxycholic acid or ursodeoxycholic acid do not acutely modify postprandial gallbladder emptying in either healthy subjects or gallstone patients. Chronic treatment with either bile salts results in an increase in fasting gallbladder volume without interfering with the extent of postprandial gallbladder emptying.

Sonographic evaluation of gallstone burden in humans

A prospective blind study was performed to compare sonographic with postoperative findings of gallstone burden in 34 patients (10 males, 24 females; mean age 52 years). Gallstone size was assessed in single calculi (n = 15) by measuring the largest diameter by ultrasonography (US). The ellipsoid algorithm was used to estimate US volume for both single and multiple gallstones. After cholecystectomy, diameters were measured in single stones; stone volume was assessed by the ellipsoid formula (single stones) and fluid displacement (single and multiple stones). Stone volumes assessed by the ellipsoid formula and fluid displacement correlated closely (r = 0.98; p < 0.0001, n = 15). In the case of single gallstones, the mean length assessed by US was 25.3 +/- 3.2 mm and compared well with the value measured "in vitro" (24.8 +/- 3.1 mm). A highly significant and positive relationship existed between the sonographic size and the true stone size (r = 0.93; p < 0.0001, n = 15). Stone volumes assessed "in vivo" and by fluid displacement were comparable and correlated for both single (US: 6.6 +/- 1.3 vs fluid displacement: 5.8 +/- 1.4 ml; r = 0.79; p < 0.0005, n = 15) and multiple stones (US: 3.8 +/- 0.8 vs fluid displacement: 3.7 +/- 0.8 ml; r = 0.85; p < 0.0001, n = 19).(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental observations and clinical implications of fasting and diet supplementation in fatty livers

Fatty accumulation per se does not appear to affect liver function; however, interest has recently renewed to fatty liver because of the clinical relevance of non alcoholic steato-hepatitis (NASH) and for the increased risk of post-transplant failure in grafted livers with steatosis. Clinical and experimental studies have doubtless demonstrated that oxidative stress ensues in steatotic livers. Mitochondria represent the preferential target of the oxidative injury associated to fatty degeneration and show reduced content of glutathione, higher levels of oxidative products and damages to enzymes involved in the process of ATP synthesis, which become more evident under stressing conditions. Although obese patients with fatty liver are advantaged by weight loss, clinical and experimental observations suggest that fatty livers poorly tolerate excessive food deprivation. These observations represent the rationale for treatment strategies based on the supplementation of antioxidants and energetic substrates rather than solely a diet restriction. This review focuses on data emerging from a series of investigations performed in rats with fatty livers induced by a choline-deficient diet, which resembles human steatosis due to an excessive intake of carbohydrates, and aims to give the cue for the development of therapeutic options able to preserve hepatic function after transplantation of steatotic organs.