The morphology and application of stem cells in digestive system surgery.

BACKGROUND: Stem cells constitute a group of cells which possess the ability to self-renew as well as the capacity to differentiate into a vast number of different cells within the human organism. Moreover, stem cells are able to undergo a potentially unlimited number of divisions and this characteristic is clinically essential. Specific fields of its application include treatment of diseases mainly in the field of haematology, orthopaedics, surgery, dentistry, and neurology. MATERIALS AND METHODS: In the following work, the current knowledge concerning mechanisms of stem cell treatment in different parts of the digestive system with its diseases as well as adjacent therapy for surgery has been revised. RESULTS: Stem cells therapy may be used in the treatment of various diseases of different parts of the digestive system. This also applies to the end part of the digestive tract (proctological diseases) because stem cells can be used to treat fistulas. Liposuction allows more recovery of mesenchymal stem cells, compared to previous bone marrow harvesting methods. Despite the application of stem cells in the treatment of different diseases used for many years so far, the therapeutic use for the regeneration of the gastrointestinal tract is still rare and unfamiliar. CONCLUSIONS: Regenerative medicine seems to be a promising tool in medical research, especially when insulated cells and designed biomaterials are taken into consideration. Major points of discussion include types of stem cells, their origin or differentiation for the treatment of many diseases.

Effects of temporary sacral nerve stimulation on gastrointestinal motility and function in patients with chronic refractory slow-transit constipation.

BACKGROUND: The efficacy of sacral nerve stimulation (SNS) on patients with chronic refractory slow-transit constipation is controversial and its mechanism of action on gastrointestinal motility and transit is not fully understood. The aim of this study was to document the effects of temporary SNS on the gastrointestinal and biliary tract motility and on gastrointestinal transit in patients with refractory slow-transit constipation. METHODS: This was a prospective interventional study. Patients with slow-transit chronic constipation, unresponsive to any conservative treatment, were enrolled between January 2013 and December 2018. Patients' quality of life [patient assessment of constipation quality of life (PAC-QOL) questionnaire], constipation scores (Cleveland Clinic Constipation Score) colonic transit time (CTT), orocecal transit time (OCTT), gastric and gallbladder kinetics, together with the assessment of the autonomic nerve function were evaluated before and during temporary SNS. RESULTS: 14 patients (12 females, median age 38 years, range 24-42 years) had temporary SNS. The Cleveland Clinic Constipation Score did not change compared to baseline (23 ± 3 vs 21.4; p = 070). The PAC-QOL did not improve significantly during the stimulation period. Gallbladder/stomach motility (half-emptying time) did not change significantly before and after SNS. OCTT was delayed at baseline, as compared to standard internal normal values, and did not change during SNS. CTT did not improve significantly, although in two patients it decreased substantially from 97 to 53 h, and from 100 to 65 h. CONCLUSIONS: Temporary SNS did not have any effect on upper/lower gastrointestinal motility and transit in patients with severe constipation.

Impact of adipokines and myokines on fat browning.

Since the discovery of leptin in 1994, the adipose tissue (AT) is not just considered a passive fat storage organ but also an extremely active secretory and endocrine organ that secretes a large variety of hormones, called adipokines, involved in energy metabolism. Adipokines may not only contribute to AT dysfunction and obesity, but also in fat browning, a process that induces a phenotypic switch from energy-storing white adipocytes to thermogenic brown fat-like cells. The fat browning process and, consequently, thermogenesis can also be stimulated by physical exercise. Contracting skeletal muscle is a metabolically active tissue that participates in several endocrine functions through the production of bioactive factors, collectively termed myokines, proposed as the mediators of physical activity-induced health benefits. Myokines affect muscle mass, have profound effects on glucose and lipid metabolism, and promote browning and thermogenesis of white AT in an endocrine and/or paracrine manner. The present review focuses on the role of different myokines and adipokines in the regulation of fat browning, as well as in the potential cross-talk between AT and skeletal muscle, in order to control body weight, energy expenditure and thermogenesis.

Reproducibility and validity of the Italian version of the International Physical Activity Questionnaire in obese and diabetic patients.

PURPOSE: Aims of this study were to evaluate the agreement between the short and long versions of the International Physical Activity Questionnaire (IPAQ: Italian versions), their reproducibility (agreement and reliability) and construct validity (relative to pedometry) in a clinical population. METHODS: Ninety patients affected by obesity (N = 39), type 2 diabetes mellitus (N = 26) or both (N = 25) were recruited. They were asked to maintain their usual physical activity habits during two consecutive weeks and to fill the questionnaires twice (at the end of each week). They were also asked to wear a pedometer for 7 consecutive days after the first administration of the questionnaires. RESULTS: We found acceptable agreement between the IPAQ short and long versions (ICC2,1 values were 0.81 and 0.77 for the 1st and 2nd administration), uncertain reproducibility (acceptable reliability but poor agreement) and inadequate validity relative to pedometry (the correlation coefficients between all IPAQ scores and daily steps were <0.50) for both IPAQ short and IPAQ long. CONCLUSIONS: The IPAQ use may be justified in daily clinical practice and in clinical research (e.g., in cross-sectional studies) for a simple and rapid evaluation of the physical activity level for discriminative purposes. However, the use of these questionnaires does not appear suitable for prospective interventional studies in which the level of physical activity of the recruited patients has to be assessed over time.

Colon neoplasia in patients with type 2 diabetes on metformin: A meta-analysis.

BACKGROUND: A growing body of evidence has suggested that metformin potentially reduces the risk of cancer. OBJECTIVE: We performed a meta-analysis of available studies to better define the effect of metformin on colon neoplasia (cancer and polyps) in patients with type 2 diabetes. METHODS: Medical literature searches for human studies were performed through December 2015, using suitable keywords. Pooled estimates were obtained using fixed or random-effects models. Heterogeneity between studies was evaluated with the Cochran Q test whereas the likelihood of publication bias was assessed by constructing funnel plots. Their symmetry was estimated by the Begg and Mazumdar adjusted rank correlation test and by the Egger's regression test. In addition subgroup and sensitivity analyses were performed. RESULTS: A total number of 709,980 patients, with type 2 diabetes, were included in 17 studies eligible for meta-analysis [1 RCT and 16 observational studies (13 cohort and 3 case-controls)]. The risk of colon neoplasia was significantly lower among metformin users than controls (non-metformin users) [pooled RRs (95% CI)=0.75 (0.65-0.87), test for overall effect Z=-3.95, p<0.001]. This observation applied separately for colon cancer [0.79 (0.69-0.91), Z=-3.34, p<0.001] and for colon polyps [0.58 (0.42-0.80), Z=-3.30, p<0.001]. CONCLUSION: This meta-analysis shows that the use of metformin in patients with type 2 diabetes is associated with significantly lower risk of colon neoplasia.

Simvastatin increases AQP2 urinary excretion in hypercholesterolemic patients: A pleiotropic effect of interest for patients with impaired AQP2 trafficking.

We previously reported that statins improve the symptoms of X-linked nephrogenic diabetes insipidus (X-NDI) in animal models. The aim of this study was to verify whether the pleiotropic effect of statins on AQP2 trafficking and kidney-concentrating ability, observed in rodents, was attainable in humans at therapeutic doses. We enrolled 24 naïve hypercholesterolemic patients and measured urine excretion of AQP2 (uAQP2) at baseline and during 12 weeks of treatment with simvastatin 20 mg/day. Simvastatin induced a rapid and significant increase of uAQP2, reduced the 24-hour diuresis, and increased urine osmolality. These effects were also maintained in patients chronically treated with statins for at least 1 year. This study strongly suggests that statins may effectively enhance the efficacy of current pharmacological treatment of patients with urine-concentrating defects caused by defective AQP2 plasma membrane trafficking, like X-NDI.

Colchicine, Biologic Agents and More for the Treatment of Familial Mediterranean Fever. The Old, the New, and the Rare.

Familial Mediterranean Fever (FMF) is a rare autosomal recessive autoinflammatory disorder involving the innate immunity and affecting almost exclusively populations with Mediterranean origin. Clinical features include recurrent episodes of fever, leukocitosis, serositis (peritonitis or pleuritis, arthritis), myalgia or erysipelas-like skin lesions, lasting 12-72 hrs. The MEFV gene mutations on chromosome 16p13.3 encodes the abnormal pyrin (marenostrin), a protein expressed in granulocytes, monocytes, serosal and synovial fibroblasts and involved in the activation of caspase-1 and the processing and release of active pro-inflammatory IL-1ß. Since the first report in 1972, maintenance therapy with colchicine, a tricyclic neutral alkaloid, remains the mainstay of treatment in symptomatic FMF patients since it reduces the disease activity and prevents the development of secondary amyloidosis and renal damage. Adjunctive symptomatic therapy to colchicine includes nonsteroideal antinflammatory drugs and corticosteroids. In a small group of colchicine-intolerant or colchicine-resistant FMF patients, alternative treatments must be considered. Evolving experiences have focussed on the potential effectiveness of biologic agents working as TNF-α inhibitors (etanercept, infliximab), IL-1 trap (Rilonacept), IL-1 inhibitors (Anakinra, Canakinumab) and IL-6 receptor antibody (Tocilizumab). Interferon-α and thalidomide have also been employed in FMF patients. Still, clinical trials are mainly uncontrolled and restricted to few cases, thus requiring definitive conclusions. Old, and new treatments are discussed in the rare FMF disease, with the concept that any ideal treatment has to stand the test of time.

Management of gallstones and its related complications.

The majority of gallstone patients remain asymptomatic; however, interest toward the gallstone disease is continuing because of the high worldwide prevalence and management costs and the development of gallstone symptoms and complications. For cholesterol gallstone disease, moreover, a strong link exists between this disease and highly prevalent metabolic disorders such as obesity, dyslipidemia, type 2 diabetes, hyperinsulinemia, hypertriglyceridemia and the metabolic syndrome. Information on the natural history as well as the diagnostic, surgical (mainly laparoscopic cholecystectomy) and medical tools available to facilitate adequate management of cholelithiasis and its complications are, therefore, crucial to prevent the negative outcomes of gallstone disease. Moreover, some risk factors for gallstone disease are modifiable and some preventive strategies have become necessary to reduce the onset and the severity of complications.

Lack of endogenous cholecystokinin promotes cholelithogenesis in mice.

BACKGROUND: Celiac disease is an autoimmune enteropathy caused by a permanent intolerance to dietary gluten in genetically predisposed individuals. Cholecystokinin (CCK) release from the proximal small intestine and gallbladder emptying in response to a fatty meal are greatly reduced in celiac patients before they start the gluten-free diet, showing a genetic predisposition to gallstones. METHODS: To elucidate the complex pathophysiological mechanisms determining the biliary characteristic of celiac disease, we investigated the effect of the absence of endogenous CCK on cholesterol crystallization and gallstone formation in mice fed a lithogenic diet for 28 days. KEY RESULTS: Fasting gallbladder volumes were increased and the response of gallbladder emptying to the high-fat diet was impaired in CCK knockout (KO) mice compared to wild-type mice. Because of the absence of CCK, small intestinal transit time was prolonged and intestinal cholesterol absorption was increased. During 28 days of feeding, elevated biliary cholesterol concentrations and gallbladder stasis promoted the growth and agglomeration of solid cholesterol crystals into microlithiasis and stones. Thus, cholesterol crystallization and gallstone formation were accelerated in CCK KO mice. In contrast, daily intraperitoneal administration of CCK-8 reduced gallstone formation in CCK KO mice even on the lithogenic diet. CONCLUSIONS & INFERENCES: The lack of endogenous CCK enhances susceptibility to gallstones by impairing gallbladder contractile function and small intestinal motility function. These findings show that celiac disease is an important risk factor for gallstone formation and the gallbladder motility function should be routinely examined by ultrasonography and gallbladder stasis should be prevented in celiac patients.

Fecal microRNA profile in patients with colorectal carcinoma before and after curative surgery.

PURPOSE: The purpose of this study was to explore the potential role of deranged fecal microRNA (miRNA) pattern as a reliable warning signal of colorectal cancer (CRC), a subset of fecal CRC-related miRNAs was evaluated in CRC patients, before and after surgery, and in healthy controls. METHODS: Twenty CRC patients and 20 age/sex-matched healthy volunteers with negative colonoscopy entered the study. Cancer biopsy, colonic mucosa from the resected specimens, and fecal samples from patients and controls were screened for 13 miRNAs involved in CRC onset and progressions by reverse transcription quantitative PCR (RT-qPCR). Postoperative evaluation of fecal miRNAs was carried out after a median follow-up of 18 months (range 12-30). RESULTS: Two out 13 miRNAs (RNU6B, miR-16-3p) were used as internal controls leaving 11 available for analysis. Cancer tissue contained significantly higher expression of all miRNAs, compared to normal mucosa (p < 0.05). Expression of preoperative levels of five fecal miRNAs, (miR-19-b-3p, miR-20a-5p, miR-21-3p, miR92a-3p, miR141) was significantly higher in CRC patients compared to controls and significantly decreased after curative surgery. Three out of these five miRNAs (miR20a-5p, miR21-3p, and miR141) returned to values comparable to normal controls. CONCLUSIONS: A set of three specific fecal miRNAs is overexpressed before surgery, and return within the normal range after cancer removal could be considered as an appealing opportunity for a new reliable tool for CRC secondary prevention. However, their role needs to be explored in large prospective trials and compared with the existing screening tools.

Small intestinal bacterial overgrowth is associated to symptoms in irritable bowel syndrome. Evidence from a multicentre study in Romania.

BACKGROUND AND AIMS: Small intestinal bacterial overgrowth (SIBO) is involved in the pathogenesis of irritable bowel syndrome (IBS). It has been suggested that by treating SIBO in IBS, symptoms may be improved. The aim of this study was to evaluate the prevalence of SIBO in patients with IBS compared with healthy volunteers (HV), to assess the effect of an intestinal antibiotic in eradicating SIBO and on the symptoms, in patients with IBS. METHODS: Design: a cross-sectional multicentre study with cohort comparison performed in 6 medical centers from Romania. 331 consecutive patients diagnosed with IBS according to Rome III criteria and 105 HV were screened for SIBO using glucose hydrogen breath test (GHBT). Positive patients received 7 days therapy with the antibiotic rifaximin 1200 mg/day and were retested 1 week after completing the treatment. The IBS symptoms were assessed before and after treatment. The group was controlled with 20 age and sex matched IBS patients who did not receive any antibiotic therapy for their condition (control patients). RESULTS: SIBO was found in 105 patients with IBS (31.7%) and in 7 HV (6.6%) (OR= 6.5, p < 0.0001). Patients with IBS have been classified according to Rome III criteria into 4 groups: IBS-constipation, IBS-diarrhea, IBS-mixed (alternation of constipation/and diarrhea) and IBS-unclassified. Diarrhea and mixed symptoms were found to be predictive for SIBO (OR= 2.5 for IBS-diarrhea and OR = 2.23 for mixed). Among patients with SIBO, 85.5% were found negative after treatment (p = 0.0026). SIBO patients showed an important relief of their symptoms, with complete improvement in 46.6% and partial in 31.4%. CONCLUSIONS: This study is the first to estimate the prevalence of SIBO in ibs patients from Romania (31.7%). SIBO was present in nearly half of the IBS-D patients (45.7%). Rifaximin is effective in treating SIBO in IBS patients and controlled trials are warranted.

Influence on functional parameters of intestinal tract induced by short-term exposure to fumonisins contaminated corn chyme samples.

The gut is a possible target toward mycotoxin fumonisins (FBs) exposure. The study aims to investigate the effects induced by FBs contaminated-corn chyme samples on functional parameters of human and rat intestine by using Ussing chamber. Fumonisins-contaminated corn and processed corn samples were undergone to in vitro digestion process and then added to luminal side. A reduction (about 90%) of short circuit current (Isc µA/cm(2)) during exposure of human colon tissues to fumonisins-free corn chyme samples was observed, probably related to increased chyme osmolality. This hyperosmotic stress could drain water towards the luminal compartment, modifying Na(+) and Cl(-) transports. The presence of FBs in corn chyme samples, independently to their concentration, did not affect significantly the Isc, probably related to their interference towards epithelial Na(+) transport, as assessed by using a specific inhibitor (Amiloride). The rat colon tract represents a more accessible model to study FBs toxicity showing a similar functional response to human. In the rat small intestine a significant reduction (about 15%) of Isc parameter during exposure to uncontaminated or FBs contaminated corn chyme samples was observed; therefore such model was not suitable to assess the FBs toxicity, probably because the prevalent glucose and amino acids electrogenic absorption overwhelmed the FBs influence on ionic transport.

Novel therapeutics for the treatment of familial Mediterranean fever: from colchicine to biologics.

Familial Mediterranean fever (FMF), an inherited autosomal recessive disorder, is characterized by sporadic, paroxysmal attacks of fever and serosal inflammation, lasting 1-3 days. Patients may develop renal amyloidosis, arthritis, serositis, and skin and oral lesions. Diagnosis is based on clinical features, response to treatment with colchicine, and genetic analysis. Colchicine prevents attacks and renal amyloidosis, in addition to reversing proteinuria. Nonresponders may receive novel therapy, including interleukin (IL)-1 receptor antagonists and IL-1 decoy receptor. Recently, new options have been considered.

Randomised clinical trial: mesalazine and/or probiotics in maintaining remission of symptomatic uncomplicated diverticular disease--a double-blind, randomised, placebo-controlled study.

BACKGROUND: Placebo-controlled studies in maintaining remission of symptomatic uncomplicated diverticular disease (SUDD) of the colon are lacking. AIM: To assess the effectiveness of mesalazine and/or probiotics in maintaining remission in SUDD. METHODS: A multicentre, double-blind, placebo-controlled study was conducted. Two hundred and ten patients were randomly enrolled in a double-blind fashion in four groups: Group M (active mesalazine 1.6 g/day plus Lactobacillus casei subsp. DG placebo), Group L (active Lactobacillus casei subsp. DG 24 billion/day plus mesalazine placebo), Group LM (active Lactobacillus casei subsp. DG 24 billion/day plus active mesalazine), Group P (Lactobacillus casei subsp. DG placebo plus mesalazine placebo). Patients received treatment for 10 days/month for 12 months. Recurrence of SUDD was defined as the reappearance of abdominal pain during follow-up, scored as ≥5 (0: best; 10: worst) for at least 24 consecutive hours. RESULTS: Recurrence of SUDD occurred in no (0%) patient in group LM, in 7 (13.7%) patients in group M, in 8 (14.5%) patients in group L and in 23 (46.0%) patients in group P (LM group vs. M group, P = 0.015; LM group vs. L group, P = 0.011; LM group vs. P group, P = 0.000; M group vs. P group, P = 0.000; L group vs. P group, P = 0.000). Acute diverticulitis occurred in six group P cases and in one group L case (P = 0.003). CONCLUSION: Both cyclic mesalazine and Lactobacillus casei subsp. DG treatments, particularly when given in combination, appear to be better than placebo for maintaining remission of symptomatic uncomplicated diverticular disease. (ClinicalTrials.gov: NCT01534754).

Unexpected discovery of massive liver echinococcosis. A clinical, morphological, and functional diagnosis.

We report a case of symptomatic massive liver echinococcosis due to Echinococcus granulosus, unexpectedly found in a 34 year old woman living in Apulia, Italy. Based on size (max diameter 18 cm), clinical presentation, geographical area, and natural history of echinococcosis, we estimate that the initial infection should have occurred 9-20 yrs before. Presenting symptoms were those of typical mass effect with RUQ pain, pruritus, malaise, and recent weight loss. Abdominal ultrasound diagnosis of probable echinococcal cyst was subsequentely confirmed by positive serology and further detailed by radiological imaging. The cyst was massively occupying subdiaphragmatic liver segments and extending to the omentum and the stomach. The characteristics of the lesion were compatible with the WHO 2003 classification type CE2l, indicating a large active fertile cyst with daughter cysts. The cyst was successfully treated with medical therapy followed by surgery. The prevalence, diagnostic workup, management, and costs of echinococcosis are discussed in this case presentation.

Breath tests with novel 13C-substrates for clinical studies of liver mitochondrial function in health and disease.

Mitochondrial dysfunction determines the onset and progression of chronic deleterious conditions including liver diseases. The in vivo assessment of mitochondrial function, by providing more insight into the pathogenesis of liver diseases, would be a helpful tool to study specific functions and to develop diagnostic, prognostic and therapeutic strategies. The application of breath tests in the clinical setting to evaluate mitochondrial fitness may elegantly and noninvasively overcome the difficulties due to previous complex techniques and may provide clinically relevant information, i.e the effects of drugs presenting mitochondrial liabilities. Substrates meeting this requirement include alpha-ketoisocaproic acid and methionine, both decarboxylated by mitochondria. Long and medium chain fatty acids that are metabolized through the Krebs cycle and benzoic acid, which undergoes glycine conjugation, may also reflect the mitochondrial performance. This review focuses on the utility of breath tests to assess mitochondrial function in humans, thus contributing to unravel potential mechanisms associated with the dysfunction of this organelle network in the pathophysiology of liver diseases.

Small intestinal bacterial overgrowth produces symptoms in irritable bowel syndrome which are improved by rifaximin. A pilot study.

AIM: Searching for the role of small intestinal bacterial overgrowth (SIBO) in the pathogenesis of mechanisms and symptoms in patients with irritable bowel syndrome (IBS). METHOD: 72 patients with IBS according to Rome III criteria were screened for proximal small intestinal bacterial overgrowth by glucose hydrogen breath test (GHBT). Positive patients received a 14 day therapy with the antibiotic rifaximin 1200 mg/day and were retested 1 week after completing the treatment. RESULTS: SIBO was found in 8 patients out of 72 (11.1%) All patients receiving rifaximin according to an open label protocol and retested 1 week after the end of treatment were found negative for SIBO 85.7% . Simultaneously the symptoms of IBS improved, according to the measurement by a Likert scale. Patients with IBS-D had a 5.6 RR of presenting SIBO than non IBS-D. CONCLUSIONS: Rifaximin effectively normalized the GHBT and reduced the IBS symptoms by possibly counteracting the SIBO. Whether such therapeutic approach is ultimately associated with symptom improvement in the long term, however, requires additional studies.

Diagnostic value of calprotectin in irritable bowel syndrome and in inflammatory bowel disease.

The inflammation is an important component of the bowel wall structure. The amount of inflammation is gradually increased from normal state, to functional bowel disorders and to inflammatory bowel disease. Calprotectin is a recently established marker for intestinal inflammation. This paper surveys the present knowledge on fecal calprotectin testing as predictor of intestinal inflammation. We also show on a sample of patients that inflammation as tested with fecal calprotectin test may also be found, in lower degree, in irritable bowel syndrome. In inflammatory bowel disease, the calprotectin fecal test shows higher intensity values.

Re-wiring the circuit: mitochondria as a pharmacological target in liver disease.

Mitochondria play a key role in intracellular energy-generating processes, cell life and death, and are heavily involved in several metabolic pathways by integrating signaling networks; thus, a very large number of conditions are characterized by mitochondrial bioenergetic in humans. Often, mitochondrial changes are directly or indirectly dependent on the activation of intracellular stress cascades or death receptor-mediated pathways. Reactive oxygen species (ROS) formation, glutathione (GSH) depletion, protein alkylation and respiratory complex alterations are major events associated with mitochondrial dysfunction and represent critical initiating events in most forms of chronic liver disease. Through creating an analogy with a disrupted electric circuit gone bad, the present review focuses initially on how hepatic mitochondrial bioenergetics is affected in the context of drug and disease-induced liver failure and how targeting mitochondria with several antioxidant agents can be helpful for preventing the disruption of the mitochondrial electric circuit.

Biliary proteins and their redox status changes in gallstone patients.

BACKGROUND: Proteins might act as pronucleating agents of cholesterol crystallization in bile. However, little is known about the redox status of biliary proteins in humans and their interaction with crystallization of biliary cholesterol. MATERIALS AND METHODS: Gallbladder biles were obtained at cholecystectomy from 86 symptomatic patients with either cholesterol gallstones (32 multiple and 32 solitary stones) or pigment stones (n = 22), and studied for protein redox status [carbonyl and sulfhydryl (PSH) concentrations], total lipid and protein levels and cholesterol saturation index (CSI). First appearance of cholesterol crystals in ultrafiltered bile (crystal observation time, COT) was studied with polarizing light microscopy during 21 days. RESULTS: Patients with cholesterol stones had significantly shorter COT (3 days vs. >21 days, P < 0.05), higher CSI (149 +/- 10% vs. 97 +/- 7%, P < 0.05) and higher total biliary proteins (1.96 +/- 0.1 mg mL(-1) vs. 0.55 +/- 0.1 mg mL(-1), P < 0.05) than patients with pigment stones. Patients with cholesterol stones had significantly lower (P < 0.05) level of protein sulfhydryl concentrations (18 +/- 4 nmol mg(-1) protein vs. 49 +/- 16 nmol mg(-1) protein), while total lipid and carbonyl proteins concentrations were similar between cholesterol and pigment stone patients. Crystallization probability was influenced by the number/type of gallstones (multiple > solitary > pigment stones, P = 0.009) and total protein concentration (high > low levels, P = 0.004). COT was negatively correlated with total protein content (r = -0.45, P = 0.03). CONCLUSIONS: Biles with cholesterol stones show high CSI and total protein concentration, and rapid COT, which is even faster in patients with multiple stones and high protein concentration. Low PSH levels in cholesterol stone patients point to a biochemical shift, potentially able to affect cholesterol crystallization.