A Smartphone Application Using Artificial Intelligence Is Superior To Subject Self-Reporting When Assessing Stool Form.

INTRODUCTION: Stool form assessment relies on subjective patient reports using the Bristol Stool Scale (BSS). In a novel smartphone application (app), trained artificial intelligence (AI) characterizes digital images of users' stool. In this study, we evaluate this AI for accuracy in assessing stool characteristics. METHODS: Subjects with diarrhea-predominant irritable bowel syndrome image-captured every stool for 2 weeks using the app, which assessed images for 5 visual characteristics (BSS, consistency, fragmentation, edge fuzziness, and volume). In the validation phase, using 2 expert gastroenterologists as a gold standard, sensitivity, specificity, accuracy, and diagnostic odds ratios of subject-reported vs AI-graded BSS scores were compared. In the implementation phase, agreements between AI-graded and subject-reported daily average BSS scores were determined, and subject BSS and AI stool characteristics scores were correlated with diarrhea-predominant irritable bowel syndrome symptom severity scores. RESULTS: In the validation phase (n = 14), there was good agreement between the 2 experts and AI characterizations for BSS (intraclass correlation coefficients [ICC] = 0.782-0.852), stool consistency (ICC = 0.873-0.890), edge fuzziness (ICC = 0.836-0.839), fragmentation (ICC = 0.837-0.863), and volume (ICC = 0.725-0.851). AI outperformed subjects' self-reports in categorizing daily average BSS scores as constipation, normal, or diarrhea. In the implementation phase (n = 25), the agreement between AI and self-reported BSS scores was moderate (ICC = 0.61). AI stool characterization also correlated better than subject reports with diarrhea severity scores. DISCUSSION: A novel smartphone application can determine BSS and other visual stool characteristics with high accuracy compared with the 2 expert gastroenterologists. Moreover, trained AI was superior to subject self-reporting of BSS. AI assessments could provide more objective outcome measures for stool characterization in gastroenterology.

Gastroesophageal reflux reported on esophagram does not correlate with pH monitoring and high-resolution esophageal manometry.

Gastroesophageal reflux disease (GERD) is commonly reported on esophagram (UGI) studies. The correlation of findings suggestive of GERD on UGI with pH monitoring and high-resolution esophageal manometry (HRM) studies is unclear. We investigate the correlation between reflux on UGI with the findings on pH studies and HRM. Subjects completed a symptom questionnaire before their scheduled study. Data from pH and HRM studies were compared with findings of the UGI. Sixty-five patients were evaluated. Reflux was reported on UGI in 19 of 65 (29.2%). Thirty-six patients had both UGI and pH studies; 22 of 36 (61.1%) had reflux on pH studies. UGI had a false-negative finding in 11 of 20 (55%) with no radiographic evidence of reflux. There was a false-positive finding in five of 16 (31.2%) patients on UGI. There was concordance in 11 of 36 (30.5%). Sixty-three patients had both UGI and HRM; there was positive concordance in eight of 63 (12.7%). Using pH monitoring as the gold standard for GERD, sensitivity was 0.50, specificity 0.64, positive predictive value 0.68, and negative predictive value 0.45 for reflux on UGI. The correlation between reflux reported on UGI and 24-hour pH monitoring is poor. Esophagram (UGI) should be reserved for defining structural defects in the esophagus and not reflux.

Recorded lower esophageal pressures as a function of electronic sleeve placement and location of gastric pressure measurement in patients with hiatal hernia.

BACKGROUND/AIMS: In high-resolution manometry lower esophageal sphincter pressure (LESP) is measured relative to intragastric pressure, however Gastric Marker™ (GM) location used to determine resting LESP is not well established with hiatal hernia (HH). We test the hypothesis that measured resting LESP varies with HH based on GM location. METHODS: Subjects with HH ≥ 2 cm were included. The eSleeve™ was adjusted to span only the LES, excluding the crural diaphragm (CD). Resting LESP was determined by placing the GM below and above the CD (in the position yielding the highest resting LESP). Resting pressure across the lower esophageal sphincter (LES) to CD and pressure in the HH relative to subdiaphragmatic intragastric pressure were also measured. RESULTS: HH ≥ 2 cm was present in 98 patients (mean length 2.7 cm). LESP decreased when GM was moved from below the CD into the HH: respiratory minimum LESP 7.5 ± 1.1 to 3.6 ± 0.9 mmHg; P < 0.001, mean LESP 17.7 ± 1.3 to 13.7 ± 1.1 mmHg; P < 0.001. When the eSleeve encompassed the LES and CD, the respiratory minimum pressure was 12.2 ± 0.9 mmHg and mean pressure was 23.9 ± 1.0 mmHg pressure (P < 0.001 for both). Pressure in the hernia pouch was greater than intragastric pressure: respiratory minimum 3.0 ± 0.7 mmHg and mean 9.0 ± 0.8 mmHg (P < 0.001 for both). pH studies showed a trend toward an association between abnormal distal esophagus acid exposure and lower resting LESP. CONCLUSIONS: GM placement in the HH produces lower resting LESPs. This may provide a more physiologic representation of LESP in HH.

Hepcidin is a key mediator of anemia of inflammation in Crohn's disease.

UNLABELLED: Anemia often complicates the course of Inflammatory Bowel Disease (IBD). Hepcidin, a liver-produced peptide hormone, is a key mediator of anemia of chronic disease (ACD). We hypothesized that hepcidin is significantly elevated in anemic CD patients and that hepcidin may cause iron restriction and, therefore, mediate ACD. METHODS: We enrolled 17 patients with CD and ACD recruited from the Cedars-Sinai IBD Center. Routine blood tests included hemoglobin (Hgb), hematocrit, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Anemia was defined as hemoglobin <12g/dL and <13.5g/dL, in men and women, respectively. ACD was diagnosed on the basis of a combination of the following: a) normal or elevated ferritin b) lowered serum iron and total iron binding capacity and c) normal percent iron saturation. Serum and urine hepcidin, as well as IL-6 levels were also measured. Patients with documented iron-deficiency anemia were excluded. RESULTS: There was an excellent correlation between urine (expressed as ng/mg of creatinine) and serum hepcidin levels expressed as ng/ml (r=0.853, p<0.001). We also found a strong positive correlation between serum hepcidin and ferritin levels (r=0.723, p=0.0015). There was a positive correlation between serum hepcidin and IL-6 levels (r=0.546, p=0.023). We found a strong negative correlation between serum hepcidin concentrations and Hgb levels (r=0.528, p=0.029). CONCLUSION: We demonstrate that ACD in CD is characterized by high serum IL-6 and hepcidin levels, which negatively correlate with Hgb levels. Our data support the hypothesis that IL-6-driven hepcidin production mediates ACD in patients with CD.

Evaluation of peripapillary lymphocytosis and lymphocytic esophagitis in adult inflammatory bowel disease.

Lymphocytic esophagitis (LE) is a newly described entity characterized histopathologically by peripapillary lymphocytosis (PL) without significant granulocytes (neutrophils and eosinophils). In an initial study, a significant portion of patients with LE had Crohn's disease (CD). A subsequent study revealed LE in one quarter of children with CD. The aim of this study was to test the hypothesis that LE is associated with adult inflammatory bowel disease (IBD) and assess the disease variables that link LE and IBD. Random esophageal biopsies from consecutive adults with CD, ulcerative colitis (UC), or indeterminate colitis (IC) were evaluated. The numbers of lymphocytes, eosinophils, and neutrophils were counted from 3 high-power fields (HPF) in each specimen. Four of 47 patients (8.5%; 3/30 CD, 1/15 UC, and 0/2 IC) had PL (esophageal biopsies with ≥50 lymphocytes/HPF; mean, 100.5±31.1/HPF). A significant number of granulocytes were seen in biopsies from 3 of the 4 patients with PL, leaving 1 who met criteria for LE (PL without significant granulocytes). PL was associated with a higher erythrocyte sedimentation rate (90.3±17.6 mm/hr vs 24.5±3.6 mm/hr; P<.001) and C-reactive protein level (5.5±2.2 mg/dL vs 1.0±0.2 mg/dL; P<.001), with risk ratios of 2.06 (95% confidence interval [CI], 1.45-2.93; P=.031) and 3.56 (95% CI, 2.04-6.19; P=.033), respectively, for elevated values. All patients with PL had a relapsing CD course. The mean Harvey-Bradshaw index (HBI) was higher in these patients (8.5±0.6 vs 4.3±0.7; P=.026), with a risk ratio of 4.78 for moderate-to-severe disease (95% CI, 2.67-8.54; P=.004). We found a less frequent association between IBD and LE than was previously reported. This may be due to differences between pediatric and adult IBD. Alternatively, it may be methodologic because, unlike in previous reports, we evaluated consecutive patients with IBD. PL was associated with elevated inflammatory markers and HBI. These observations suggest that PL may be a marker of disease activity in IBD.

Colorectal cancer screening and surveillance in Crohn's colitis.

AIMS: To assess colonoscopic screening and surveillance for detecting neoplasia in patients with long-standing colonic Crohn's disease (CD). PATIENTS AND METHODS: Colonoscopy and biopsy records from patients with colonic CD were evaluated at the Cedars-Sinai Inflammatory Bowel Disease Center during a 17-year period (1992-2009). RESULTS: Overall, 904 screening and surveillance examinations were performed on 411 patients with Crohn's colitis (mean 2.2 examinations per patient). The screening and surveillance examinations detected neoplasia in 5.6% of the patient population; 2.7% had low-grade dysplasia (LGD) (n=11), 0.7% had high-grade dysplasia (HGD) (n=3), and 2.2% had carcinoma (anal carcinoma n=3; rectal carcinoma n=6). Mean age of CD diagnosis was 25.6±0.8 years in those with normal examinations, compared to 17.7±2.7 years (p<0.001) in those with HGD, 36.85±1.43 in those with LGD (p=0.021) and 28.32±3.24 years in those with any dysplasia/cancer (p=0.034). Disease duration in patients with normal examinations was 19.1±0.5 years, compared to 36.8±4.4 years (p<0.001) in HGD, 16.88±2.59 in those with LGD (p=0.253) and 30.68±4.03 years in those with any dysplasia/cancer (p=0.152). The mean interval between examinations was higher in HGD (31.5±9.4 months) compared to those with normal colonoscopies (12.92±1.250 months; p=0.002). CONCLUSIONS: We detected cancer or dysplasia in 5.6% of patients with long-standing Crohn's colitis enrolled in a screening and surveillance program. Younger age at diagnosis of CD, longer disease course, and greater interval between exams were risk factors for the development of dysplasia.

Intestinal methane production in obese individuals is associated with a higher body mass index.

BACKGROUND: Obesity is an epidemic that affects 1 in 3 individuals in the United States, and recent evidence suggests that enteric microbiota may play a significant role in the development of obesity. This study evaluated the association between methanogenic archaea and obesity in human subjects. METHODS: Subjects with a body mass index (BMI) of 30 kg/m² or higher were prospectively recruited from the weight loss program of a tertiary care medical center. Subjects who met the study's inclusion criteria were asked to complete a questionnaire that included a series of visual analogue scores for bowel symptom severities. Subjects then provided a single end-expiratory breath sample to quantitate methane levels. Bivariate and multivariate analyses were used to determine associations with BMI. RESULTS: A total of 58 patients qualified for enrollment. Twenty percent of patients (n = 12) had breath test results that were positive for methane (>3 parts per million [ppm]), with a mean breath methane concentration of 12.2±3.1 ppm. BMI was significantly higher in methane-positive subjects (45.2±2.3 kg/m²) than in methane-negative subjects (38.5±0.8 kg/m²; P=.001). Methane-positive subjects also had a greater severity of constipation than methane-negative subjects (21.3±6.4 vs 9.5±2.4; P=.043). Multiple regression analysis illustrated a significant association between BMI and methane, constipation, and antidepressant use. However, methane remained an independent predictor of elevated BMI when controlling for antidepressant use (P<.001) and when controlling for both constipation and antidepressant use (6.55 kg/m² greater BMI; P=.003). CONCLUSION: This is the first human study to demonstrate that a higher concentration of methane detected by breath testing is a predictor of significantly greater obesity in overweight subjects.

Current national incidence, trends, and health care resource utilization of cleft lip-cleft palate.

BACKGROUND: Available reports on the epidemiology of cleft lip, cleft palate, and cleft lip-cleft palate have been numerous yet inconsistent, and have originated only from institutional or regional studies. The need for current national data and the recognition of recent trends exists. METHODS: The authors examined the Kids' Inpatient Database to obtain national information on pediatric orofacial cleft discharges from 1997 to 2007. The authors examined patient and hospital characteristics to discern differences in use of care, hospital charges, type of hospital, untoward events, and other variables among various groups. A detailed investigation searching for significant trends during the 6-year study period was also conducted. RESULTS: Trends appreciated from 1997 to 2007 included (1) an increase in cleft operations performed at teaching hospitals compared with nonteaching hospitals (teaching increased 13.4 percent and nonteaching decreased 15.8 percent); (2) an increase in the mean overall charges (74.5 percent increase; p < 0.001) and a rate of rise higher than that of aggregate charges (60 percent; p < 0.001); and (3) a lower rate of perioperative complications in teaching hospitals from 2000 to 2007, ranging from 14 to 27 percent less than in nonteaching hospitals. CONCLUSIONS: The authors' data show that there is a current trend of cleft patients receiving treatment at teaching hospitals, with higher costs and decreasing complications. An understanding of such trends and disparities in resource use among various patient, hospital, and geographic settings is important for physicians and policy makers.

Acute and chronic histological changes of the small bowel secondary to C. jejuni infection in a rat model for post-infectious IBS.

BACKGROUND: Campylobacter jejuni has been implicated in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS) in humans, effects which may be because of cytolethal distending toxin (CDT). In this study, we characterized both acute and chronic-phase histological changes of the small bowel in rats exposed to wild-type C. jejuni 81-176, or a strain that does not produce CDT, by using a validated rat model of PI-IBS. METHODS: Sprague-Dawley rats were given 1.0 × 10(8) CFU of either wild-type C. jejuni 81-176 (C+, PI/C+) or the CDT-negative strain (CDT-), or vehicle alone (Control). Acute-phase rats (C+, CDT-) were euthanized on days 2, 4, 8, 16, and 32. Chronic-phase rats (PI/C+, Control) were euthanized 3 months after clearing the initial infection. Segments of duodenum, jejunum, and ileum were resected and the contents plated for C. jejuni culture, and tissue sections were stained for histology. RESULTS: We observed preferential infection of the ileum and jejunum by Campylobacter jejuni. Compared with controls, epithelial cell basal membrane ballooning, villous tip disruption, and reduced villous-to-crypt ratios were observed for both C+ and CDT- rats. Villous widening, the only result significantly different in C+ vs. CDT- rats, was greatest at day 4 (134.1 ± 21.12 µm vs. 109.9 ± 10.6 µm for CDT-, P < 0.01). Little or no cellular inflammatory changes were seen during acute C. jejuni infection. Three months after clearing the initial infection, no histological changes remained. CONCLUSION: Significant histological changes, with the absence of inflammatory cells, are seen in the duodenum, jejunum, and ileum of rats during acute infection with C. jejuni. These changes occurred irrespective of the presence or absence of the CDT toxin.

Dysplasia and cancer in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease associated with an increased risk of colorectal cancer (CRC). Although CRC occurs in a minority of IBD patients (1%), it carries a high mortality and accounts for 20% of IBD-related mortality. Established risk factors for the development of CRC in IBD include disease duration of 8 years or more, family history of CRC, extensive colitis and primary sclerosing cholangitis. Meticulous colonoscopy and anti-inflammatory medications can reduce the risk of developing CRC. The future of IBD surveillance involves the use of novel endoscopic techniques (chromoendoscopy, narrow-band imaging, confocal laser endomicroscopy and autofluorescence) to enhance colonoscopic accuracy, in concert with chemopreventative medications to help reduce the risk of CRC in IBD.

Apple sauce improves detection of esophageal motor dysfunction during high-resolution manometry evaluation of dysphagia.

BACKGROUND: Esophageal manometry utilizes water swallows to evaluate esophageal motor abnormalities in patients with dysphagia, chest pain, or reflux symptoms. Although manometry is the gold standard for evaluation of these symptoms, patients with dysphagia often have normal results in manometry studies. AIM: The objective of this work was to test the hypothesis that challenging the esophagus with viscous apple sauce boluses uncovers motor abnormalities in patients with dysphagia not seen when using water swallows. METHODS: High-resolution esophageal manometry was performed using ten water swallows followed by ten apple sauce swallows in consecutive subjects presenting with dysphagia. Subjects with grossly abnormal water swallow evaluations were excluded. Each swallow was categorized as normal, hypotensive (distal isobaric contour plots of < 30 mmHg over >5 cm), or simultaneous (distal esophageal velocity ≥ 8.0 cm/s). Ineffective esophageal motility (IEM) was defined as ≥ 30% hypotensive swallows, and pressurization was defined as ≥ 20% simultaneous pressure waves. RESULTS: Data from 41 subjects was evaluated. Overall, 96.3% of water swallows were normal, 2.9% hypotensive, and 0.7% simultaneous. Only 70.3% of viscous swallows were normal; 16.7% were hypotensive and 13.0% were simultaneous (P < 0.001 all groups). Seven (17.1%) met criteria for IEM, and pressurization with viscous swallows was observed for nine (22.0%). Fourteen subjects (34.1%) had abnormal results from viscous studies. The presence of any abnormal water swallows was predictive of abnormal viscous swallows (OR = 9.00, CI = 2.15-80.0), although the presence of hypotensive or simultaneous water swallows was not associated with IEM (OR = 0.63, CI = 0.16-2.17) or pressurization (OR = 7.00, CI = 0.90-315.4) with viscous apple sauce. CONCLUSIONS: Apple sauce challenge increased identification of classifiable motor disorders in patients with dysphagia and may be preferred to alternative bolus materials.

Pulmonary manifestations of inflammatory bowel disease: case presentations and review.

Inflammatory bowel disease (IBD) is associated with a number of extraintestinal manifestations that may involve most organ systems. Extraintestinal manifestations are more common in Crohn disease (CD) and may include rheumatologic, ocular, dermatologic, biliary and pulmonary manifestations. The most common pulmonary manifestations of IBD are drug-induced lung disease. Other manifestations include parenchymal disease, pleuritis and overlap syndromes. We present a case series of 7 patients with non-infectious pulmonary manifestations of IBD, which included cryptogenic organizing pneumonia, usual interstitial pneumonitis (UIP), Langerhan's granulomatosis, and eosinophilic pneumonia. Concurrent extraintestinal manifestations present in these patients included arthralgia, iritis, and pyoderma gangrenosum. In most patients the development of pulmonary disease parallels that of the intestinal disease activity, extraintestinal manifestations and concurrent use of 5-ASA medications.

Esophageal motor dysfunction and gastroesophageal reflux are prevalent in lung transplant candidates.

BACKGROUND: Gastroesophageal reflux and aspiration contribute to the development of bronchiolitis obliterans and accelerate graft deterioration after lung transplantation (LTx). We evaluated LTx candidates for esophageal motor abnormalities and gastroesophageal reflux. METHODS: Consecutive patients evaluated for LTx underwent 24-hour pH monitoring using a dual-channel pH probe and high-resolution esophageal manometry. High-resolution manometry was also performed in healthy control subjects. The prevalence of abnormal acid exposure was noted in the LTx candidates. RESULTS: Thirty LTx candidates and 10 control subjects were evaluated. Lung transplantation candidates had higher residual upper and lower esophageal sphincter pressures. The mean proportion of peristaltic swallows was 21% lower in LTx candidates. Both hypotensive and aperistaltic swallows were sixfold more prevalent in LTx candidates than in control subjects. All control subjects had normal high-resolution manometry whereas 23 LTx candidates (76.7%) had esophageal peristaltic dysfunction. Abnormal acid exposure time was seen in the proximal and distal esophagus in 25% and 36% of LTx candidates, respectively. Lung transplantation candidates with idiopathic pulmonary fibrosis had more aperistaltic contractions, more negative minimum intrathoracic pressure, and a higher frequency of abnormal distal esophagus acid exposure. The majority of patients with complications after LTx demonstrated motor, anatomic, or pH abnormalities. CONCLUSIONS: Disordered esophageal motor function and gastroesophageal reflux are common in LTx candidates. We believe high-resolution esophageal manometry is a valid tool to use and the abnormalities we identified may be representative of this unique patient population. The role of this study in predicting a worse outcome should be further studied in patients after LTx.

Comorbidities associated with the increasing burden of hepatitis C infection.

BACKGROUND: Hepatitis C virus (HCV) infection is implicated in an increasing number of liver transplantations, hospitalizations and healthcare costs. AIMS: We present an updated assessment of comorbidities associated with HCV in comparison to the general US population. METHODS: Cross-sectional retrospective review of data from 800 patients with HCV evaluated between January 1998 and November 2007. Patient data were prospectively collected using a standardized questionnaire completed at the first encounter and was compared with general US epidemiological data. Odds ratios and 95% confidence intervals (CI) are reported. RESULTS: HCV conferred a 44% (CI 1.16-1.78) and 25% (CI 1.01-1.54) increased risk of diabetes (12.5 vs. 7.3-8.4%; P=0.001) and obesity (23.9 vs. 19.8-33.1%; P=0.041), respectively, compared with the US population. Human immunodeficiency virus (HIV) (5.3 vs. 0.3%; P<0.001) and end-stage renal disease (ESRD) (4.5 vs. 0.2%; P<0.001) were 16- and 13-fold more prevalent in HCV. Interestingly, HCV bestowed 90% decreased odds (CI 0.09-0.15) for hyperlipidaemia (12.3 vs. 53.2-56.1%; P<0.001). The HCV population had a higher prevalence of significant alcohol consumption (41.5 vs. 4.7%; P<0.001), current smoking (57.7 vs. 18.8-20.8%; P<0.001), drug use (46.8 vs. 14.6-15.6%; P<0.001), incarceration (6.6 vs. 2.7%; P<0.001) and tattoos (20.3 vs. 14%; P=0.011), as well as chronic fatigue (44.6 vs. 11.3-19%; P<0.001) and depression (29.3 vs. 5.0-10.3%; P<0.001). CONCLUSION: HCV poses an increasing healthcare burden associated with increased prevalence of diabetes, obesity, HIV, ESRD, maladaptive lifestyle habits and poor quality of life. Practitioners should be cognizant of these trends in order to appropriately manage these comorbidities.

Autoimmune hemolytic anemia in treatment-naive chronic hepatitis C infection: a case report and review of literature.

The hepatitis C virus (HCV) is the most common blood-borne pathogen and currently infects over two hundred and fifty million individuals worldwide. Chronic HCV infection may result in cirrhosis, hepatocellular carcinoma, and liver failure. An exceedingly rare extrahepatic manifestation of HCV is autoimmune hemolytic anemia (AIHA). We discuss an interesting case of direct Coombs'-positive AIHA in a treatment-naive 53-year-old male with a past medical history of HCV cirrhosis, genotype 3a, who presented with fatigue, abdominal pain, and jaundice. Complete blood cell count demonstrated anemia, thrombocytopenia, elevated mean corpuscular hemoglobin and corpuscular volume worrisome for hemolytic anemia. Upon further workup, the patient was found to have increased bilirubin, reticulocyte count, and lactate dehydrogenase with concomitant direct Coombs'-positive test, consistent with the diagnosis of AIHA. A comprehensive workup was conducted to elucidate the underlying etiology of the AIHA, including malignancy, systemic lupus erythematosus (SLE), and medication side-effects. Malignancy was ruled out with an imaging and bone marrow biopsy. SLE was subsequently eliminated with a negative anti-nuclear antibody (ANA), and the patient had never received ribavirin, interferon, cephalosporins or other medications associated with drug-induced immune hemolytic anemia (DI-IHA). While the relationship between DI-IHA and HCV is well-described in the literature, primary AIHA in treatment-naive patients is a rare and intriguing extrahepatic manifestation of HCV and only four reports have been described in the literature. Given the prevalence of HCV and this interesting extrahepatic manifestation, HCV testing should be considered in patients presenting with AIHA with an otherwise negative workup and a history of parenteral or lifestyle risk factors.

Oxysterols regulate differentiation of mesenchymal stem cells: pro-bone and anti-fat.

UNLABELLED: Pluripotent mesenchymal stem cells can undergo lineage-specific differentiation in adult organisms. However, understanding of the factors and mechanisms that drive this differentiation is limited. We show the novel ability of specific oxysterols to regulate lineage-specific differentiation of mesenchymal stem cells into osteogenic cells while inhibiting their adipogenic differentiation. Such effects may have important implications for intervention with osteoporosis. INTRODUCTION: Oxysterols are products of cholesterol oxidation and are formed in vivo by a variety of cells including osteoblasts. Novel pro-osteogenic and anti-adipogenic effects of specific oxysterols on pluripotent mesenchymal cells are demonstrated in this report. Aging and osteoporosis are associated with a decrease in the number and activity of osteoblastic cells and a parallel increase in the number of adipocytic cells. MATERIALS AND METHODS: The M2-10B4 pluripotent marrow stromal cell line, as well as several other mesenchymal cell lines and primary marrow stromal cells, was used to assess the effects of oxysterols. All results were analyzed for statistical significance using ANOVA. RESULTS AND CONCLUSION: Pro-osteogenic and anti-adipogenic effects of specific oxysterols were assessed by the increase in early and late markers of osteogenic differentiation, including alkaline phosphatase activity, osteocalcin mRNA expression and mineralization, and the decrease in markers of adipogenic differentiation including lipoprotein lipase and adipocyte P2 mRNA expression and adipocyte formation. Complete osteogenic differentiation of M2 cells into cells expressing early and late markers of differentiation was achieved only when using combinations of specific oxysterols, whereas inhibition of adipogenesis could be achieved with individual oxysterols. Oxysterol effects were in part mediated by extracellular signal-regulated kinase and enzymes in the arachidonic acid metabolic pathway, i.e., cyclo-oxygenase and phospholipase A(2). Furthermore, we show that these specific oxysterols act in synergy with bone morphogenetic protein 2 in inducing osteogenic differentiation. These findings suggest that oxysterols may play an important role in the differentiation of mesenchymal stem cells and may have significant, previously unrecognized, importance in stem cell biology and potential therapeutic interventions.

High-density lipoprotein regulates calcification of vascular cells.

Accumulating evidence has suggested the protective role of HDL in cardiovascular disease processes. Calcification is a common feature of atherosclerotic lesions and contributes to cardiovascular complications due to the loss of aortic resilience and function. Recent studies have suggested that vascular calcification shares several features with skeletal bone formation at the cellular and molecular levels. These include the presence of osteoblast-like calcifying vascular cells in the artery wall that undergo osteoblastic differentiation and calcification in vitro. We hypothesized that HDL may also protect against vascular calcification by regulating the osteogenic activity of these calcifying vascular cells. When treated with HDL, alkaline phosphatase activity, a marker of osteogenic differentiation of osteoblastic cells, was significantly reduced in those cells. Prolonged treatment with HDL also inhibited calcification of these cells, further supporting the antiosteogenic differentiation property of HDL when applied to vascular cells. Furthermore, HDL inhibited the osteogenic activity that was induced by inflammatory cytokines interleukin (IL)-1beta and IL-6 as well as by minimally oxidized LDL. HDL also partially inhibited the IL-6-induced activation of signal transducer and activator of transcription 3 in calcifying vascular cells, suggesting that HDL may inhibit cytokine-induced signal transduction pathways. The inhibitory effects of HDL were mimicked by lipids extracted from HDL but not by HDL-associated apolipoproteins or reconstituted HDL. Furthermore, oxidation of HDL rendered it pro-osteogenic. Taken together, these results suggest that HDL regulates the osteoblastic differentiation and calcification of vascular cells and that vascular calcification may be another target of HDL action in the artery wall.