Putative Risk Markers Research Articles

Use of Nonhuman Sera as a Highly Cost-Effective Internal Standard for Quantitation of Multiple Human Proteins Using Species-Specific Tryptic Peptides: Applicability in Clinical LC-MS Analyses.

Quantitation of proteins using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is complex, with a multiplicity of options ranging from label-free techniques to chemically and metabolically labeling proteins. Increasingly, for clinically relevant analyses, stable isotope-labeled (SIL) internal standards (ISs) represent the "gold standard" for quantitation due to their similar physiochemical properties to the analyte, wide availability, and ability to multiplex to several peptides. However, the purchase of SIL-ISs is a resource-intensive step in terms of cost and time, particularly for screening putative biomarker panels of hundreds of proteins. We demonstrate an alternative strategy utilizing nonhuman sera as the IS for quantitation of multiple human proteins. We demonstrate the effectiveness of this strategy using two high abundance clinically relevant analytes, vitamin D binding protein [Gc globulin] (DBP) and albumin (ALB). We extend this to three putative risk markers for cardiovascular disease: plasma protease C1 inhibitor (SERPING1), annexin A1 (ANXA1), and protein kinase, DNA-activated catalytic subunit (PRKDC). The results show highly specific, reproducible, and linear measurement of the proteins of interest with comparable precision and accuracy to the gold standard SIL-IS technique. This approach may not be applicable to every protein, but for many proteins it can offer a cost-effective solution to LC-MS/MS protein quantitation.

P410. Discounting Rates and Reward in the ABCD Cohort: Relationship to Social, Familial and Clinical Factors

Adolescence is a period of development marked by the emergence of substance use and increased risk for other psychiatric disorders. Identifying at-risk individuals before the onset of psychopathology would provide opportunities for early clinical interventions that may reduce future severity. Delay discounting has been proposed as a putative risk marker for early substance-use initiation and other forms of psychopathology. However, the extent to which other key factors (e.g., socioeconomic status, cognitive ability, brain areas subserving reward) relate to discounting behavior in adolescents is not well established.

Hyperbolic discounting rates and risk for problematic alcohol use in youth enrolled in the Adolescent Brain and Cognitive Development study.

Adolescence is the peak period for the emergence of substance use, which can lead to long-term psychosocial, occupational and interpersonal complications. Ongoing large-scale, longitudinal, consortium initiatives, such as the Adolescent Brain and Cognitive Development (ABCD) study, offer unprecedented opportunities to elucidate key risk factors for problematic substance use in a well-powered sample and to examine how changes in risk factors relate to symptoms across time. Delay discounting has been proposed as a putative risk marker for early substance-use initiation and other forms of psychopathology. However, the extent to which other factors (e.g., socio-economic status and cognitive ability) influence discounting behaviour in young adolescents is not well established. The present study leverages data from the ABCD study (n = 11 045) to assess associations between core demographic and familial variables and delay discounting in youth-operationalized using hyperbolic discounting rates (k)-before the onset of significant psychopathology. Model estimates revealed significant effects of individual difference factors (e.g., sex and socio-economic status) and alcohol risk status (based on family history) on delay discounting. No significant differences were observed in the primary sample when comparing the presence of parent drug problems or prenatal drug exposures. These effects will require replication in later waves of ABCD. Nonetheless, these results provide support for delay discounting as a potential risk marker for problematic alcohol use and demonstrate a relationship between key demographic variables and adolescent discounting behaviour. Further, these results provide an empirical baseline from which developmental trajectories of delay discounting and substance use may be tracked throughout future waves of ABCD.

The relationship between alpha asymmetry and ADHD depends on negative affect level and parenting practices

Atypical frontal alpha asymmetry is associated with the approach/withdrawal and affective processes implicated in many psychiatric disorders. Rightward alpha asymmetry, associated with high approach, is a putative endophenotype for attention deficit/hyperactivity disorder (ADHD). However, findings are inconsistent, likely because of a failure to consider emotional heterogeneity within the ADHD population. In addition, how this putative risk marker interacts with environmental factors known to increase symptom severity, such as parenting practices, has not been examined. The current study examined patterns of alpha asymmetry in a large sample of adolescents with and without ADHD, including the moderating role of negative affect and inconsistent discipline. Resting-state EEG was recorded from 169 well-characterized adolescents (nADHD = 79). Semi-structured clinical interviews and well-validated rating scales were used to create composites for negative affect and inconsistent discipline. The relationship between alpha asymmetry and ADHD diagnosis was moderated by negative affect. Right asymmetry was present only for those with ADHD and low levels of negative affect. In addition, greater right alpha asymmetry predicted severity of ADHD symptoms for those with the disorder, but only in the context of inconsistent parenting practices. Results confirm right alpha asymmetry is a possible endophenotype in ADHD but highlight the need to consider emotional heterogeneity and how biological risk interacts with child environment in order to fully characterize its relationship to disorder liability and severity.

The association of dietary animal and plant protein with putative risk markers of colorectal cancer in overweight pre-diabetic individuals during a weight-reducing programme: a PREVIEW sub-study.

Diets with increased protein content are popular strategies for body weight regulation, but the effect of such diets for the colonic luminal environment is unclear. We aimed to investigate the associations between putative colorectal cancer-related markers and total protein intake, plant and animal proteins, and protein from red and processed meat in pre-diabetic adults (> 25years). Analyses were based on clinical and dietary assessments at baseline and after 1year of intervention. Protein intake was assessed from 4-day dietary records. Putative colorectal cancer-related markers identified from 24-h faecal samples collected over three consecutive days were: concentration of short-chain fatty acids, phenols, ammonia, and pH. In total, 79 participants were included in the analyses. We found a positive association between change in total protein intake (slope: 74.72 ± 28.84µmol per g faeces/E%, p = 0.01), including animal protein intake (slope: 87.63 ± 32.04µmol per g faeces/E%, p = 0.009), and change in faecal ammonia concentration. For change in ammonia, there was a dose-response trend from the most negative (lowest tertile) to the most positive (highest tertile) association (p = 0.01): in the high tertile, a change in intake of red meat was positively associated with an increase in ammonia excretion (slope: 2.0 ± 0.5µmol per g faeces/g/day, p < 0.001), whereas no such association was found in the low and medium tertile groups. Increases in total and animal protein intakes were associated with higher excretion of ammonia in faeces after 1year in overweight pre-diabetic adults undertaking a weight-loss intervention. An increase in total or relative protein intake, or in the ratio of animal to plant protein, was not associated with an increase in faeces of any of the other putative colorectal cancer risk markers. ClinicalTrials.gov Identifier: NCT01777893.

A Cautionary Perspective on the Utility of the RoPE Score and Reported High Risk Echocardiographic Features in Managing Cryptogenic Stroke Patients with a Patent Foramen Ovale

Background: The management of cryptogenic stroke (CS) patients with a patent foramen ovale (PFO) is topical following the release of ten-year data supporting PFO closure. The Risk of Paradoxical Embolism (RoPE) score is a 1 to 10 scale derived from patient age and vascular risk factors in which younger patients without risk factors will score higher. Echographic features such as the degree of interatrial septum mobility (IASM), PFO size and the presence of a right-to-left shunt are proposed markers of risk. However, the accuracy and reliability of these tools remain unclear in guiding the selection of CS patients for PFO closure. Method: We reviewed consecutive CS patients who presented for transthoracic echocardiographic (TTE) bubble study between January 2014 and November 2016. The RoPE score was calculated and TTE images were assessed for the aforementioned features of risk. Results: 126 patients aged 26 to 69 years were included. Fifty-six had a confirmed PFO on TTE. Assuming a PFO prevalence of 25% in the general population, the PFO-attributable fraction for RoPE score ≤6 was 67% compared to 70% for RoPE of ≥7 (p = 0.76). A low RoPE score thus did not exclude a PFO-attributable stroke. In outcomes analysis for TTE imaging, the degree of IASM demonstrated a trend towards clinical significance in influencing the PFO closure decision (p = 0.05). Conclusion: There is often uncertainty in attributing stroke to a PFO. Our data shows that great care should be taken when using risk scores and putative echocardiographic risk markers in isolation for clinical decision making on PFO closure.

CD109, a negative regulator of TGF-β signaling, is a putative risk marker in diffuse large B-cell lymphoma.

CD109 is a glycosylphosphatidylinositol-anchored glycoprotein that negatively regulates TGF-β signaling. CD109 was originally identified in hematopoietic tumors; however, the significance of CD109 in hematopoietic malignancies remains unclear. Here, we study the association of CD109 with diffuse large B-cell lymphoma (DLBCL) prognosis. Eighty-four DLBCL specimens were immunohistochemically analyzed for CD109 expression, and 31 and 53 cases were classified into low- and high-CD109 expression groups, respectively. CD109 expression was not associated with overall survival using the Kaplan-Meier analysis and log-rank tests (P=0.17); however, a significant association was observed between high-CD109 expression and low-1-year survival (P=0.01). Moreover, in combination with the revised International Prognostic Index (R-IPI), R-IPI-poor/CD109-high was associated with poorer prognosis compared with R-IPI-poor alone. We assessed TGF-β signaling in CD109-depleted Nalm6 cells (a human B-lymphoblastic leukemia/lymphoma cell line), and found prolonged Smad2 phosphorylation compared with control cells after TGF-β1 stimulation, suggesting that CD109 attenuates TGF-β1 signaling in human B-cell tumors. These results suggest that CD109 is a putative biomarker for identifying a high-risk group among DLBCL patients.

Prevalence and putative risk markers of challenging behavior in students with intellectual disabilities

Numerous studies have reported a high prevalence of challenging behavior among students with intellectual disabilities (ID). They discuss different putative risk markers as well as their influence on the occurrence of challenging behavior. The study investigates the prevalence of challenging behavior and evaluates in terms of a replication study well-known putative risk markers among a representative sample of students with ID (N=1629) in Bavaria, one of the largest regions in Germany. The research is based on a modified version of the Developmental Behavior Checklist (DBC). Findings indicate a prevalence rate of 52% for challenging behavior. The following putative risk markers are associated with challenging behavior: intense need for care, male gender, lack of communication skills, and residential setting. These risk markers explain 8.4% of the variance concerning challenging behavior. These results reveal that challenging behavior either is to a large extent determined by situations and interactions between individuals and environment and cannot be explained by the measured individual and social risk markers alone, or it is determined by further risk markers that were not measured.

Associations of hippocampal metabolism and regional brain grey matter in neuroleptic-naïve ultra-high-risk subjects and first-episode schizophrenia

Hippocampal pathology has been shown to be central to the pathophysiology of schizophrenia and a putative risk marker for developing psychosis. We applied both 1H MRS (proton magnetic resonance spectroscopy) at 3Tesla and voxel-based morphometry (VBM) of high-resolution brain structural images in order to study the association of the metabolites glutamate (Glu) and N-acetyl-aspartate (NAA) in the hippocampus with whole-brain morphometry in 31 persons at ultra-high-risk for psychosis (UHR), 18 first-episode schizophrenia patients (Sz), and 42 healthy controls (all subjects being neuroleptic-naïve). Significantly diverging associations emerged for UHR subjects hippocampal glutamate showed positive correlation with the left superior frontal cortex, not seen in Sz or controls, while in first-episode schizophrenia patients a negative correlation was significant between glutamate and a left prefrontal area. For NAA, we observed different associations for left prefrontal and caudate clusters bilaterally for both high-risk and first-episode schizophrenia subjects, diverging from the pattern seen in healthy subjects. Our results suggest that associations of hippocampal metabolites in key areas of schizophrenia might vary due to liability to or onset of the disorder.

Viral over-expression of D1 dopamine receptors in the prefrontal cortex increase high-risk behaviors in adults: Comparison with adolescents

Adolescents are often described as "lacking brakes" resulting in an increase in several behaviors associated with risk for addiction. Prefrontal cortex dopamine and cortico-limbic interaction play an important role in addiction, and we have previously shown that the dopamine D1 receptor is elevated on prelimbic prefrontal output neurons in adolescent rats. We hypothesized that a constellation of risk-related behaviors is mediated by prefrontal output neuron expression of D1. We aimed to determine the role of the dopamine D1 receptor in behavioral and neural correlates of risk for addiction that are often observed in adolescents. Therefore, high-risk behaviors as well as subcortical D2 receptor expression were investigated in adult animals with experimentally elevated D1 on prefrontal glutamatergic neurons. A lentiviral vector that selectively expressed the D1 receptor within glutamate neurons was injected in the prelimbic prefrontal cortex of adult male rats. Place conditioning to cocaine, alcohol, and nicotine, as well as delay discounting, novelty preferences, anxiety, cocaine self-administration, and sucrose preferences were assessed. Virally mediated D1 over-expression in adults leads to stronger drug-cue associations and greater consumption of sweet solutions, elevates bias towards immediate satisfaction rather than delaying gratification, decreases anxiety, and causes rats to work harder for and take more cocaine. Furthermore, elevated cortical D1 reduces D2 receptors in the accumbens (a putative risk marker). Together, these data suggest a common mechanism for increased motivational drive to seek and consume substances with hedonic value, consistent with adolescent addictive processes.

Molecular Subtypes in Head and Neck Cancer Exhibit Distinct Patterns of Chromosomal Gain and Loss of Canonical Cancer Genes

Head and neck squamous cell carcinoma (HNSCC) is a frequently fatal heterogeneous disease. Beyond the role of human papilloma virus (HPV), no validated molecular characterization of the disease has been established. Using an integrated genomic analysis and validation methodology we confirm four molecular classes of HNSCC (basal, mesenchymal, atypical, and classical) consistent with signatures established for squamous carcinoma of the lung, including deregulation of the KEAP1/NFE2L2 oxidative stress pathway, differential utilization of the lineage markers SOX2 and TP63, and preference for the oncogenes PIK3CA and EGFR. For potential clinical use the signatures are complimentary to classification by HPV infection status as well as the putative high risk marker CCND1 copy number gain. A molecular etiology for the subtypes is suggested by statistically significant chromosomal gains and losses and differential cell of origin expression patterns. Model systems representative of each of the four subtypes are also presented.

The Relationship of Preparation for Future Care to Depression and Anxiety in Older Primary Care Patients at 2-Year Follow-up

: Preparation for future care needs has been hypothesized to help older adults adjust to inevitable life and health transitions and thereby decrease the likelihood of developing depression or anxiety. : A total of 190 primary care patients aged 65 years or more completed semistructured research interviews and mail-back surveys at study intake and 2 years later. Interviews included the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, the Hamilton Depression Rating Scale, Clinical Anxiety Scale and a measure of preparation for future care. Multiple regression analyses were used to determine the independent association of preparation for future care at intake with depression and anxiety severity at 2-year follow-up. : Patients who had made more concrete plans at intake were less likely to meet criteria for depression diagnosis at follow-up. They also had lower anxiety severity scores. Patients who had avoided thinking about future care needs had greater depression symptom severity at follow-up. Findings were independent of potential confounds, including illness burden. : Failure to prepare for future care is a novel putative risk marker for depression and anxiety in older adulthood. Clinicians should be aware that the lack of care planning and frank avoidance may pose a risk for depression and anxiety older their patients. Future research should explore the mechanisms of care planning's effects on subsequent mood.

High urinary excretion of lipid peroxidation-derived DNA damage in patients with cancer-prone liver diseases

Chronic inflammatory processes induce oxidative and nitrative stress that trigger lipid peroxidation (LPO), whereby DNA-reactive aldehydes such as trans-4-hydroxy-2-nonenal (HNE) are generated. Miscoding etheno-modified DNA adducts including 1, N 6-etheno-2′-deoxyadenosine (ɛdA) are formed by reaction of HNE with DNA-bases which are excreted in urine, following elimination from tissue DNA. An ultrasensitive and specific immunoprecipitation/HPLC-fluorescence detection method was developed for quantifying ɛdA excreted in urine. Levels in urine of Thai and European liver disease-free subjects were in the range of 3–6 fmol ɛdA/μmol creatinine. Subjects with inflammatory cancer-prone liver diseases caused by viral infection or alcohol abuse excreted massively increased and highly variable ɛdA-levels. Groups of Thai subjects ( N = 21) with chronic hepatitis, liver cirrhosis, or hepatocellular carcinoma (HCC) due to HBV infection had 20, 73 and 39 times higher urinary ɛdA levels, respectively when compared to asymptomatic HBsAg carriers. In over two thirds of European patients ( N = 38) with HBV-, HCV- and alcohol-related liver disease, urinary ɛdA levels were increased 7–10-fold compared to healthy controls. Based on this pilot study we conclude: (i) high urinary ɛdA-levels, reflecting massive LPO-derived DNA damage in vivo may contribute to the development of HCC; (ii) ɛdA-measurements in urine and target tissues should thus be further explored as a putative risk marker to follow malignant progression of inflammatory liver diseases in affected patients; (iii) etheno adducts may serve as biomarkers to assess the efficacy of (chemo-)preventive and therapeutic interventions.

Increased urinary 1, N6-ethenodeoxyadenosine and 3, N4-ethenodeoxycytidine excretion in thalassemia patients: Markers for lipid peroxidation-induced DNA damage

Thalassemic diseases including homozygous β-thalassemia and β-thalassemia/Hb E (β-Thal/Hb E) are prevalent in Southeast Asia. Iron overload is a common complication in β-thalassemia patients which induces intracellular oxidative stress and lipid peroxidation (LPO). LPO end products generate miscoding etheno adducts in DNA which after their repair are excreted in urine. We investigated whether urinary levels of 1, N 6 -ethenodeoxyadenosine (εdA) and 3, N 4 -ethenodeoxycytidine (εdC) can serve as putative cancer risk markers in β-Thal/Hb E patients. εdA and εdC levels were assayed in collected urine samples by immunoprecipitation-HPLC-fluorescence and 32P-postlabeling TLC, respectively. Mean εdA (fmol/µmol creatinine) levels in urine of β-Thal/Hb E patients ranged from 4.8 to 120.4 (33.8 ± 3.9; n = 37) and were 8.7 times higher compared to asymptomatic controls (1.4–13.8; 3.9 ± 0.8; n = 20). The respective εdC levels ranged from 0.15 to 32.5 (5.2 ± 1.3; n = 37) and were increased some 13 times over controls (0.04–1.2; 0.4 ± 0.7; n = 20). εdC levels were correlated positively with NTBI ( r = 0.517; P = 0.002), whereas εdA showed only a trend ( r = 0.257; P = 0.124). We conclude that the strongly increased urinary excretion of etheno adducts indicates elevated LPO-induced DNA damage in internal organs such as the liver. These highly promutagenic lesions may contribute to the increased risk of thalassemia patients to develop hepatocellular carcinoma.

Genetics of Late-Onset Alzheimer’s Disease: Progress and Prospect

Genetic susceptibility factors for late-onset Alzheimer's disease remain largely elusive, with the exception of apolipoprotein E4 (APOE e4) as the only confirmed genetic risk factor. Numerous other putative risk markers have been proposed, although all suffer inconsistent replication. These results suggest that modest effect sizes are likely to be the norm for non-APOE-related factors. This unsettling situation has been similar to other complex diseases such as diabetes and cardiovascular diseases until very recently, when a spate of new, although weak, genetic markers has been convincingly linked to these conditions. If we assume that multiple weak factors, together with APOE e4, account for the genetic contribution to late-onset Alzheimer's disease risk, it will require the concerted efforts of the greater Alzheimer's genetics community to pool existing genetic resources and/or data to identify novel genetic risk factors that are genuine. Increased confidence in the disease-associated factors will provide the foundation to develop better diagnostic and prognostic tests, select new drug targets and, perhaps, elucidate pharmacogenetic markers that assist in making the best treatment decisions.

High molecular weight adiponectin dominates in cord blood of newborns but is unaffected by pre‐eclamptic pregnancies

This study is the first to report high molecular weight (HMW) adiponectin in newborns from normal and pre-eclamptic pregnancies (PE). Adiponectin is adversely related to Metabolic Syndrome-linked diseases such as obesity, dyslipidaemia, insulin resistance and hypertension. It is abundant in human plasma where it circulates as several characteristic multimeric forms of which the HMW form is the most active. As children from PE-pregnancies have a greater susceptibility to hypertensive disorders later in life, we hypothesized that adiponectin measured in cord blood could be a putative risk marker. Cross-sectional, hospital-based study of newborns from mothers with pre-eclampsia (30 cases and 62 controls). Venous cord blood samples were collected immediately after birth and were analysed for total adiponectin and HMW adiponectin. Total adiponectin and HMW adiponectin were measured by commercially available enzyme-linked immunosorbent assay (ELISA) kits. The PE newborns showed a significantly lower gestational age (GA), total adiponectin and HMW adiponectin levels than the controls. No differences in adiponectin levels were found between case and control groups when correcting for GA. In combined groups, log (total adipo) = 0.40 + 0.027*GA; r = 0.43, P < 0.001. Furthermore, the HMW form is the dominant form of adiponectin: HMW adipo = -5.06 + 0.81*total adipo; r = 0.90, P < 0.001. Adiponectin in cord blood from PE pregnancies may not be a tentative risk marker for Metabolic Syndrome-linked diseases. HMW adiponectin is the dominant form of adiponectin in cord blood. Its role during pregnancy and postnatal life should be further explored.

Progression of microalbuminuria in type 1 diabetes: Ten-year prospective observational study

In patients with diabetes, the presence of persistent microalbuminuria is an established predictor of development of overt diabetic nephropathy, progressive renal insufficiency and increased risk of cardiovascular disease, in both type 1 and 2 diabetes [1‐4]. Approximately 30% of type 1 diabetic patients may develop diabetic nephropathy within 25 years of diabetes, although recent data suggest a declining incidence [5, 6]. In the original studies demonstrating the predictive value of microalbuminuria, up to 80% of patients with microalbuminuria progressed to overt diabetic nephropathy. Recently, it has been suggested that microalbuminuria may not be as sensitive and specific as predictor of diabetic nephropathy as originally suggested [7]. Observational studies have found regression from microalbuminuria to normoalbuminuria in a substantial fraction of patients with type 1 diabetes and microalbuminuria [8]. Furthermore, it has been suggested from uncontrolled studies of patients with long duration of diabetes that microalbuminuria is not a good predictor of progression to overt nephropathy in longstanding type 1 diabetic patients [9]. We conducted a 10-year observational follow-up study of a large cohort of type 1 diabetic patients to elucidate putative risk markers for the progression from microalbuminuria to overt diabetic nephropathy. We have previously demonstrated the presence of poor glycemic control, retinopathy, smoking, and elevated urinary albumin excretion within normal range to be predictors of development of microalbuminuria [10]. In the present study, the factors involved in progression from microalbuminuria to overt nephropathy are evaluated, as well as the predictive value of microalbuminuria in longstanding type 1 diabetes for the development of overt diabetic nephropathy. In addition, we wanted to determine the annual rate of progression in urinary albumin excretion rate in microalbuminuric patients.

Inhibitory effects of laminaran and low molecular alginate against the putrefactive compounds produced by intestinal microflora in vitro and in rats

The inhibitory effects of laminaran and low molecular weight sodium alginate (MW = 49,000) against formation of ammonia, indole compounds and phenol compounds, putrefactive and harmful compounds, induced by human fecal microflora, were examined in vitro. Laminaran was fermented to acetate, propionate, n-butyrate and lactate. The alginate was fermented to acetate and propionate. Both of these polysaccharides inhibited formation of the putrefactive compounds. In the case of rats fed diet containing 2% (w/w) laminaran or low molecular alginate, the fermentation pattern agreed with that of the in vitro experiment. Laminaran suppressed indole, p-cresole and sulfide, significantly. These putrefactive compounds, in rats fed low molecular alginate, also tended to be lower. These results suggest that the fermentation of laminaran by intestinal bacteria suppresses the putative risk markers for colon cancer.

Leptin, but not adiponectin, predicts stroke in males.

To test whether leptin and adiponectin are risk markers for a first-ever stroke. RESEARCH DESIGN, METHODS AND SUBJECTS: A nested case-referent study identified 276 cases with first-ever stroke (234 cases with ischaemic and 42 with haemorrhagic stroke). Prior to the stroke, they had participated in population-based health surveys in northern Sweden (median time between survey and stroke was 4.9 years). Referents were matched for sex, age, date and type of health survey, and geographical region. Putative risk markers for first-ever stroke, including blood pressure (BP), diabetes, smoking, body mass index (BMI), cholesterol, leptin, and adiponectin, were analysed by conditional logistic regression analysis. Increased BMI, high cholesterol and fasting glucose levels, diabetes mellitus and hypertension were found in future stroke patients. Whereas leptin levels were higher in male subjects (P = 0.004), adiponectin did not differ between groups. A high leptin level independently predicted stroke in men (OR = 2.46; 95% CI 1.08-5.62) but not in women. Adiponectin levels did not predict stroke. Males with high leptin levels developed stroke faster than males with low leptin levels (P = 0.0009), independently of traditional risk factors. Leptin may be an important link to the development of cerebrovascular disease in men, whereas adiponectin does not associate with future stroke.

Effect of transgalactooligosaccharides on the composition of the human intestinal microflora and on putative risk markers for colon cancer

Nondigestible oligosaccharides have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and by decreasing the toxicity of the colon contents. We compared the effect of 2 doses of transgalactooligosaccharides and a placebo on the composition and activity of the intestinal microflora in 18 women and 22 men. Strictly controlled experimental diets were supplied to 3 intervention groups in a parallel design. The study was divided into 2 consecutive 3-wk periods during which each participant consumed a run-in diet followed by an intervention diet that differed only in the amount of transgalactooligosaccharides: 0 (placebo), 7.5, and 15 g/d. Breath samples and fecal samples were collected at the end of both the run-in and intervention periods. Apparent fermentability of transgalactooligosaccharides was 100%. The highest dose of transgalactooligosaccharides significantly increased the concentration of breath hydrogen by 130% (P < 0.01) and the nitrogen density of the feces by 8.5% (P < 0.05). The number of bifidobacteria increased after both placebo and transgalactooligosaccharides ingestion, but the differences between these increases were not significantly different. Transgalactooligosaccharides did not significantly affect bowel habits; stool composition; the concentration of short-chain fatty acids or bile acids in fecal water; the concentration of ammonia, indoles, or skatoles in feces; fecal pH; or the composition of the intestinal microflora. We conclude that transgalactooligosaccharides are completely fermented in the human colon, but do not beneficially change the composition of the intestinal microflora, the amount of protein fermentation products in feces, or the profile of bile acids in fecal water.