Modification of Association of Cystatin C With Kidney and Cardiovascular Outcomes by Obesity

RATIONALE & OBJECTIVE

Cystatin C-based estimated glomerular filtration rate (eGFRcys) has stronger associations with adverse clinical outcomes than creatinine-based eGFR (eGFRcr). Obesity may be associated with higher cystatin C levels, independent of kidney function, but it is unknown whether obesity modifies associations of eGFRcys with kidney and cardiovascular outcomes.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

27,249 US adults in the Reasons for Geographic and Racial Differences in Stroke Study.

PREDICTORS

eGFRcys, eGFRcr, waist circumference, and body mass index (BMI).

OUTCOME

All-cause mortality, kidney failure, incident atherosclerotic cardiovascular disease (ASCVD), and incident heart failure (HF).

ANALYTICAL APPROACH

Multivariable Cox and Fine-Gray models with multiplicative interaction terms were constructed to investigate whether waist circumference quartiles or BMI categories modified associations of eGFRcys with risks of 4 clinical outcomes.

RESULTS

Participants had a mean age of 65 years; 54% were women, 41% were Black, and 21% had an eGFRcys<60mL/min/1.73m2. The baseline prevalence of abdominal obesity (waist circumference≥88cm for women or≥102cm for men) was 48% and obesity was 38%. In multivariable adjusted analyses, each 15mL/min/1.73m2 lower eGFRcys was associated with higher HR and 95% CI of mortality in each waist circumference quartile (first quartile, 1.19 [1.15-1.24]; second quartile, 1.22 [1.18-1.26]; third quartile, 1.20 [1.16-1.24]; fourth quartile, 1.19 [1.15-1.23]) as well as within each BMI category (BMI<24.9: 1.21 [1.17-1.25]; BMI 25.0-29.9: 1.21 [1.18-1.25]; BMI 30.0-34.9: 1.20 [1.16-1.25]; BMI≥35: 1.17, [1.12-1.22]). Neither waist circumference nor BMI modified the association of eGFRcys with mortality, kidney failure, incident ASCVD, or incident HF (all Pinteraction>0.05).

LIMITATIONS

Included only Black and White persons in the United States.

CONCLUSION

Obesity did not modify the association of eGFRcys with all-cause mortality, kidney failure, incident ASCVD, or incident HF. Among individuals with obesity, cystatin C may be used to provide eGFR-based risk prognostication for adverse outcomes.

PLAIN-LANGUAGE SUMMARY

Cystatin C is increasingly used in clinical practice to estimate kidney function, and cystatin C-based eGFR (eGFRcys) may be used to determine risk for adverse clinical outcomes. Adiposity may increase serum levels of cystatin C, independent of kidney function. This cohort study investigated whether associations of eGFRcys with adverse kidney and cardiovascular outcomes are modified by measures of obesity, waist circumference, and body mass index. We found that obesity does not modify associations of eGFRcys with 4 clinical outcomes and conclude that among individuals with obesity, cystatin C may be used to provide eGFR-based risk prognostication for adverse outcomes.

Exploring the health-related decision-making experiences of people with chronic kidney disease and their caregivers: A qualitative study

BACKGROUND

This study aimed to explore the decision-making experience of patients with chronic kidney disease (CKD) and their caregivers.

METHODS

This was a qualitative descriptive study of the decision-making experiences of individuals with stage 3-end-stage CKD and their family caregivers. One-on-one, semistructured interviews were conducted using a guide developed and approved by a community advisory group. Data were analyzed using thematic analysis.

RESULTS

Three themes were identified: (1) decisions triggered by declining health and broad in scope, (2) challenges to decision-making and (3) factors influencing decision-making. Participants' experiences with health-related decision-making demonstrated that decisions were triggered when health declined. Yet, decisions that impact disease progression were being made in stage 3. Decision-making was made difficult due to lack of information, complex co-morbidities, and poor resource utilization. However, the structure and nature of the medical appointment, supportive caregivers, and resources served to remove challenges.

CONCLUSION

Decision-support interventions must train patients and caregivers to be empowered participants in answer-seeking behaviours upstream of advanced illness.

PUBLIC CONTRIBUTIONS

This work was conducted in full collaboration with a community advisory board consisting of patients with CKD, caregivers and clinicians. These members are noted in the acknowledgement section, and those who worked with the team to develop the interview guide, study protocols, and manuscript preparation are included as authors. As part of their role, advisory members met monthly, providing input on recruitment, study progress, inclusion of diverse voices and added relevance to study findings.

Including measures of chronic kidney disease to improve cardiovascular risk prediction by SCORE2 and SCORE2-OP

AIMS

The 2021 European Society of Cardiology (ESC) guideline on cardiovascular disease (CVD) prevention categorizes moderate and severe chronic kidney disease (CKD) as high and very-high CVD risk status regardless of other factors like age and does not include estimated glomerular filtration rate (eGFR) and albuminuria in its algorithms, systemic coronary risk estimation 2 (SCORE2) and systemic coronary risk estimation 2 in older persons (SCORE2-OP), to predict CVD risk. We developed and validated an 'Add-on' to incorporate CKD measures into these algorithms, using a validated approach.

METHODS

In 3,054 840 participants from 34 datasets, we developed three Add-ons [eGFR only, eGFR + urinary albumin-to-creatinine ratio (ACR) (the primary Add-on), and eGFR + dipstick proteinuria] for SCORE2 and SCORE2-OP. We validated C-statistics and net reclassification improvement (NRI), accounting for competing risk of non-CVD death, in 5,997 719 participants from 34 different datasets.

RESULTS

In the target population of SCORE2 and SCORE2-OP without diabetes, the CKD Add-on (eGFR only) and CKD Add-on (eGFR + ACR) improved C-statistic by 0.006 (95%CI 0.004-0.008) and 0.016 (0.010-0.023), respectively, for SCORE2 and 0.012 (0.009-0.015) and 0.024 (0.014-0.035), respectively, for SCORE2-OP. Similar results were seen when we included individuals with diabetes and tested the CKD Add-on (eGFR + dipstick). In 57 485 European participants with CKD, SCORE2 or SCORE2-OP with a CKD Add-on showed a significant NRI [e.g. 0.100 (0.062-0.138) for SCORE2] compared to the qualitative approach in the ESC guideline.

CONCLUSION

Our Add-ons with CKD measures improved CVD risk prediction beyond SCORE2 and SCORE2-OP. This approach will help clinicians and patients with CKD refine risk prediction and further personalize preventive therapies for CVD.

Hyperphosphatemia increases inflammation to exacerbate anemia and skeletal muscle wasting independently of FGF23-FGFR4 signaling

Elevations in plasma phosphate concentrations (hyperphosphatemia) occur in chronic kidney disease (CKD), in certain genetic disorders, and following the intake of a phosphate-rich diet. Whether hyperphosphatemia and/or associated changes in metabolic regulators, including elevations of fibroblast growth factor 23 (FGF23) directly contribute to specific complications of CKD is uncertain. Here, we report that similar to patients with CKD, mice with adenine-induced CKD develop inflammation, anemia, and skeletal muscle wasting. These complications are also observed in mice fed high phosphate diet even without CKD. Ablation of pathologic FGF23-FGFR4 signaling did not protect mice on an increased phosphate diet or mice with adenine-induced CKD from these sequelae. However, low phosphate diet ameliorated anemia and skeletal muscle wasting in a genetic mouse model of CKD. Our mechanistic in vitro studies indicate that phosphate elevations induce inflammatory signaling and increase hepcidin expression in hepatocytes, a potential causative link between hyperphosphatemia, anemia, and skeletal muscle dysfunction. Our study suggests that high phosphate intake, as caused by the consumption of processed food, may have harmful effects irrespective of pre-existing kidney injury, supporting not only the clinical utility of treating hyperphosphatemia in CKD patients but also arguing for limiting phosphate intake in healthy individuals.

Abstract LB083: Characterizing colon and prostate cancers with comorbid chronic kidney disease in NHANES

In the US, the prevalence of chronic kidney disease (CKD) is estimated at 30 million, or approximately 15% of the population. Compared to Caucasians (CA), African Americans (AAs) have a higher prevalence of CKD, and faster decline in kidney function. Relationships between low socio-economic status (SES), area-level social disadvantages, and CKD are well documented. In cancer patients, CKD impedes overall survival, treatment, and surgical outcomes. Given the link between kidney disease preceding cancer, as well as the higher risk of mortality for cancer patients with CKD, the goals of this research were to identify the tumor types most associated with CKD prevalence and to elucidate the modifying effects of age, race, gender, and lifestyle/environmental measures on these relationships. Using the National Health and Nutrition Examination Survey (NHANES), we generated cross-sectional associations between CKD and various cancer types for the years of 2007-2018. After exclusion for age under 18 years, non-AA or non-CA race, or incomplete information for exposure (CKD) or outcome (cancer), a nationally representative, weighted sample of ~25,000 subjects was included in the analysis. CKD was defined as estimated glomerular function (eGFR) &lt;60 ml/min/1.73 m2. Self-reported measures of ever having any type of cancer and type of cancer were used for tumor variables. CKD was present in 15% of all NHANES subjects, and 21% of those with CKD reported having any cancer versus 12% of those without CKD. In a cancer-only analysis, overrepresented tumor types in CKD vs. non-CKD patients were prostate (23% vs. 6%) and colon (7% vs. 4%). Cases of colon cancer were significantly higher for CKD patients of all races, with the largest CKD-related difference for female AAs (28% in CKD vs. 7% in non-CKD). For both races, prostate cancer had higher CKD comorbidity, strongest for male AAs. While eGFR normally decreases with age, AAs had low eGFR in younger cases (50-60years), for both prostate and colon cancers, notably in female AAs with colon cancer. Body mass index (BMI) was higher for those with CKD (29.4) versus non-CKD (28.9). In a gender/race stratified analysis, AA women with colon cancer who were obese (BMI 30+) had 1.66 times the odds of also having CKD relative to all other BMI categories. Men with colon cancer also showed increased odds of CKD in obese versus all other BMI categories (AA 1.98, CA 1.21). There was no effect of BMI on prostate cancer. Overall, CKD is a more frequent in cancer patients than for cancer-free patients even when accounting for age. This relationship is modified by tumor type, race, and gender. Prostate and colon cancers have strong associations with CKD which are independent of age in AAs. Obesity is linked to CKD-comorbid colon cancers for AAs and males. These findings identify high-risk subgroups for colon cancer and suggest dietary/metabolic/environmental etiology and intervention strategies.

Citation Format: Michael Behring, Dawna Nelson, Tina Vazin, Ram Alagan, Seela Aladuwaka, Manoj Mishra, Tariq Shafi, Orlando Gutierrez, Upender Manne. Characterizing colon and prostate cancers with comorbid chronic kidney disease in NHANES [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB083.

Incorporating kidney disease measures into cardiovascular risk prediction: Development and validation in 9 million adults from 72 datasets

BACKGROUND

Chronic kidney disease (CKD) measures (estimated glomerular filtration rate [eGFR] and albuminuria) are frequently assessed in clinical practice and improve the prediction of incident cardiovascular disease (CVD), yet most major clinical guidelines do not have a standardized approach for incorporating these measures into CVD risk prediction. "CKD Patch" is a validated method to calibrate and improve the predicted risk from established equations according to CKD measures.

METHODS

Utilizing data from 4,143,535 adults from 35 datasets, we developed several "CKD Patches" incorporating eGFR and albuminuria, to enhance prediction of risk of atherosclerotic CVD (ASCVD) by the Pooled Cohort Equation (PCE) and CVD mortality by Systematic COronary Risk Evaluation (SCORE). The risk enhancement by CKD Patch was determined by the deviation between individual CKD measures and the values expected from their traditional CVD risk factors and the hazard ratios for eGFR and albuminuria. We then validated this approach among 4,932,824 adults from 37 independent datasets, comparing the original PCE and SCORE equations (recalibrated in each dataset) to those with addition of CKD Patch.

FINDINGS

We confirmed the prediction improvement with the CKD Patch for CVD mortality beyond SCORE and ASCVD beyond PCE in validation datasets (Δc-statistic 0.027 [95% CI 0.018-0.036] and 0.010 [0.007-0.013] and categorical net reclassification improvement 0.080 [0.032-0.127] and 0.056 [0.044-0.067], respectively). The median (IQI) of the ratio of predicted risk for CVD mortality with CKD Patch vs. the original prediction with SCORE was 2.64 (1.89-3.40) in very high-risk CKD (e.g., eGFR 30-44 ml/min/1.73m² with albuminuria ≥30 mg/g), 1.86 (1.48-2.44) in high-risk CKD (e.g., eGFR 45-59 ml/min/1.73m² with albuminuria 30-299 mg/g), and 1.37 (1.14-1.69) in moderate risk CKD (e.g., eGFR 60-89 ml/min/1.73m² with albuminuria 30-299 mg/g), indicating considerable risk underestimation in CKD with SCORE. The corresponding estimates for ASCVD with PCE were 1.55 (1.37-1.81), 1.24 (1.10-1.54), and 1.21 (0.98-1.46).

INTERPRETATION

The "CKD Patch" can be used to quantitatively enhance ASCVD and CVD mortality risk prediction equations recommended in major US and European guidelines according to CKD measures, when available.

FUNDING

US National Kidney Foundation and the NIDDK.

Urinary Markers of Fibrosis and Risk of Cardiovascular Events and Death in Kidney Transplant Recipients: The FAVORIT Trial

Cardiovascular risk remains high in kidney transplant recipients (KTRs) despite improved kidney function after transplant. Urinary markers of kidney fibrosis and injury may help to reveal mechanisms of this risk. In a case-cohort study among stable KTRs who participated in the FAVORIT trial, we measured four urinary proteins known to correlate with kidney tubulointerstitial fibrosis on biopsy (urine alpha 1 microglobulin [α1m], monocyte chemoattractant protein-1 [MCP-1], procollagen type I [PINP] and type III [PIIINP] N-terminal amino peptide) and evaluated associations with cardiovascular disease (CVD) events (n = 300) and death (n = 371). In adjusted models, higher urine α1m (hazard ratio [HR] per doubling of biomarker 1.40 [95% confidence interval [CI] 1.21, 1.62]), MCP-1 (HR 1.18 [1.03, 1.36]), and PINP (HR 1.13 [95% CI 1.03, 1.23]) were associated with CVD events. These three markers were also associated with death (HR per doubling α1m 1.51 [95% CI 1.32, 1.72]; MCP-1 1.31 [95% CI 1.13, 1.51]; PINP 1.11 [95% CI 1.03, 1.20]). Higher concentrations of urine α1m, MCP-1, and PINP may identify KTRs at higher risk for CVD events and death. These markers may identify a systemic process of fibrosis involving both the kidney and cardiovascular system, and give new insights into mechanisms linking the kidney with CVD.

Effects of extremely low frequency electromagnetic fields on in-vitro cellular cultures HeLa and CHO

This paper presents the cellular proliferation effects of the exposure to extremely low frequency electromagnetic fields (ELF-EMF) on in-vitro cellular cultures HeLa and CHO. Through the magnetic stimulation system (MSS) the cells were exposed to magnetic fields with sinusoidal waveform at 50 Hz; initially for 40 minutes at intensities of 0.4 mT, 1.4 mT, 2.13 mT, 2.49 mT and 2.53 mT in parallel and perpendicular directions to the culture plates. Subsequently, the repetitive electromagnetic field (rEMF) was applied to 2.49 mT in parallel direction (for 40 minutes every twelve hours during 4 days) with which the highest cellular proliferation rate was obtained at 66.6 %. The results show a greater effect on proliferation in radiated cell lines, particularly in the application of rEMF a greater effect of ELF-EMF was observed in the proliferation rate of HeLa cells than in CHO cells, in contrast to the respective control cells. These results supported by other studies serve as a reference in the search for alternatives for the treatment of cervical cancer and the maintenance and preservation of cell lines.

[Cilioretinal artery occlusion in hemochromatosis]

CLINICAL CASE

We report a case of a 31 year-old woman with a sudden visual loss due to a cilioretinal artery occlusion. The physical examinination showed hepatomegaly. Serum iron and ferritin and transferrin saturation were unusually high. The doppler scan of carotid arteries showed no relevant signs of atheromatous disease. Dilated cardiomiopaty was revealed in the B-scan with subendocardial calcium deposits. Genetic tests were positive for hemochromatosis.

DISCUSSION

Subendocardial calcification due to hemochromatosis could be the embolic source in our patient. This embolic ocular disease is the first presentation of hemochromatosis in this patient.

Abstract T P134: Fibroblast Growth Factor 23 and Risk of Incident Stroke in the Regards Study

Objective: Fibroblast growth factor 23 (FGF23) is a hormone that regulates phosphorus and vitamin D metabolism. Elevated levels of FGF23 are strongly associated with heart disease and death, particularly in persons with chronic kidney disease (CKD). Whether FGF23 is also associated with stroke risk is unclear.

Methods: Using a case cohort design we examined the association of plasma FGF23 with incident stroke in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a cohort of black and white participants from across the United States. Baseline assessment occurred between 2003 and 2007. All physician-adjudicated stroke cases through July 1, 2011 were included in the analysis. Using stored samples, FGF23 was measured on 610 stroke cases and 939 cohort members, all of whom were stroke-free at baseline. The cohort random sample was selected to ensure approximately equal numbers of black and white participants and an equal distribution across ages. We used Cox proportional hazards models weighted back to the original 30,239 participants sampled by the REGARDS study to account for oversampling of stroke cases.

Results: Participants were followed for a mean of 4.4 years. Higher FGF23 was associated with older age, female sex, lower socioeconomic status, diabetes, and CKD (estimated glomerular filtration rate < 60 ml/min or urinary albumin to creatinine ratio ≥ 30 mg/g). After adjustment for age, race, sex, education, diabetes, hypertension, smoking, atrial fibrillation, heart disease, physical activity, calcium, phosphorus, and serum vitamin D, higher FGF23 levels were associated with greater risk of incident stroke (HR per doubling of FGF23=1.19; 95%CI=1.03, 1.37). After further adjustment for CKD, this association was attenuated and no longer statistically significant (HR per doubling of FGF23=1.06, 95%CI 0.90, 1.25).

Discussion: Higher FGF23 is associated with greater risk of stroke, but this association is largely explained by CKD.

Field validation of a new low-cost method for determining occurrence and duration of combined sewer overflows

Combined sewer overflow (CSO) events produced in combined sewer systems (CSS) during wet weather conditions are a threat for the receiving water bodies. The large number of CSO structures normally present in a CSS makes that the monitoring of the complete CSO network in a simultaneous way would drastically increase the investment costs. In this paper, a new methodology is presented aiming to characterize the occurrence and duration of CSO events by means of low-cost temperature sensors. Hence, a large number of CSO structures can be simultaneously monitored and the system can be characterized as a whole. The method assumes temperature differences between the overflowing mix of wastewater and stormwater and the sewer gas phase, so the temperature shift produced during a rainfall episode is related to a CSO event occurrence. The method has been tested and validated in La Garriga CSS (Spain) where the temperature at 13 CSO weirs was monitored for a period of 1 year (57 rainfall episodes). For the whole set of CSO events, occurrence and duration were successfully determined in 80% of cases. Advantages, limitations and potential applications of the method are discussed at the end of the paper.

Abstract 144: Southern Diet Pattern Increases Risk Of Stroke While Plant-based Pattern Decreases Risk Of Stroke in the REGARDS Study

Background: Diet is one of many potential factors proposed to explain racial and regional differences in stroke. We examined prospectively the association of diet patterns with risk of stroke in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

Methods: Between 2003-2007, REGARDS enrolled black and white Americans aged 45 years or older. A two-stage analytic approach was employed. First, principle components analysis was used to assess underlying diet patterns using 56 food groups for 20,480 participants who completed the Block98 food frequency questionnaire. Second, participant scores (divided into quartiles) on these patterns were then considered as predictors of incident stroke using Cox regression. The factor analysis identified five dietary patterns: “Convenience” (Chinese and Mexican foods, pasta, pizza), “Plant-based” (fruits, vegetables, legumes), and “Southern” (fried foods, organ meats, sweetened beverages), “Sweets/Fats” (desserts, added sugars, sweet snacks) and “Alcohol/Salads” (alcohol, fats, vegetables).

Results: Participants with a higher adherence to the Southern dietary pattern were more likely to reside in the Southeast (comparing Q4 to Q1: 64% vs 48%) and experienced a 41% increased risk of stroke (comparing Q4 to Q1: HR=1.41; 95% CI = 1.07, 1.85). In contrast, higher adherence to the Plant-based pattern was association with a 29% reduction in stroke risk (comparing Q4 to Q1: HR=0.71; 95% CI = 0.55, 0.91). The trend across quartiles was <0.001 indicating a dose response for adherence to each pattern. Adding socio-economic status, smoking, physical activity and total energy (calories) intake to the models attenuated the association but the direction remained the same and persisted in sub-group analysis examining only ischemic strokes. The Convenience, Sweets, and Alcohol patterns were not associated with stroke risk.

Discussion: The present study suggests that foods common to Southern cuisine such as fried foods and sweetened beverages may increase the risk of stroke while diets rich in legumes, fruits, vegetables, and fish may reduce stroke risk. Interventions focusing on increasing plant-based foods and fish while reducing fried foods and sweetened beverages are needed.

Abstract 2212: Vitamin D Intake: A Novel Neuroprotectant?

Introduction Vitamin D is both a nutrient and hormone and has become increasingly studied as it relates to circulatory and neurological functioning. Vitamin D deficiency has been associated with Parkinson's disease, Alzheimer's disease, stroke, and dementia. It has also been related to hypertension and diabetes. We examined the role of vitamin D intake on incident stroke and incident cognitive impairment in a cohort of middle aged and older adults.

Methods The Reasons for Geographic And Racial Differences in Stroke (REGARDS), a cohort of 30,239 participants, was recruited between 2003 and 2007 and is comprised of black and white Americans age 45 and older at baseline. Vitamin D intake was measured by the Block 98 food frequency questionnaire and categorized into tertiles. Participants are surveyed every six months for incident strokes which are adjudicated using medical record review. Cognitive functioning is assessed annually using the Six-item Screener (SIS)(score range 0-6). A score of 4 or below indicates impairment. For the incident stroke analysis, we excluded all people with prior history of stroke, and for the incident cognitive impairment analysis we excluded those with SIS scores<5 at baseline.

Results: 26,039 participants were available for this analysis and were followed over a mean of 5 years. Higher intake of vitamin D was more likely for whites but did not differ by gender or age. Compared to the lowest tertile (range: 0-53.1 IU/day vitamin D), the highest tertile (range: 382-1774 IU/day) of vitamin D intake was associated with a 11% reduction in stroke (HR=0.89; 95% CI =0.79, 1.01) and 24% reduction in cognitive impairment (HR=0.76; 95% CI =0.67,0.86) after adjustment for age, race, income, education, hypertension, diabetes, dyslipidemia, history of heart disease, and BMI. When stratifying by race results were similar for both stroke and cognitive decline. Adding dairy intake to the models slightly attenuated the association but did not meaningfully change the interpretation of the results.

Discussion: Results suggest a potential role of vitamin D in incident stroke and cognitive impairment. Clinical trials could evaluate the potential of Vitamin D as a neuroprotectant.

Prevalence and prognosis of unrecognized myocardial infarctions in chronic kidney disease

BACKGROUND

Unrecognized myocardial infarctions (UMIs) are common in the general population but have not been well studied in patients with chronic kidney disease (CKD). The purpose of this study was to determine the prevalence and prognosis for mortality of UMI among adults with CKD.

METHODS

The current study included 18 864 participants in the population-based REasons for Geographic And Racial Differences in Stroke (REGARDS) study who completed a baseline examination including a 12-lead electrocardiogram (ECG). UMI was defined as the presence of myocardial infarction (MI) by Minnesota ECG classification in the absence of self-reported or recognized MI (RMI). Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation and albuminuria using albumin-to-creatinine ratio from a spot urine sample. All-cause mortality was assessed over a median 4 years of follow-up.

RESULTS

The prevalence of UMI was 4, 6, 6 and 13% among participants with eGFR levels of ≥ 60, 45-59.9, 30-44.9 and <30 mL/min/1.73 m(2), respectively, and 4, 5, 7 and 10% among participants with albuminuria levels of <10, 10-29.9, 30-299.9 and ≥ 300 mg/g, respectively. Compared to those with no MI, the multivariable adjusted hazard ratio for all-cause mortality associated with UMI and RMI was 1.65 [95% confidence interval (CI): 1.09-2.49] and 1.65 (95% CI: 1.20-2.26), respectively, among individuals with an eGFR <60 mL/min/1.73 m(2) and 1.49 (95% CI: 1.03-2.16) and 1.88 (95% CI: 1.40-2.52) among individuals with albuminuria ≥ 30 mg/g. Conclusion UMIs are common among individuals with an eGFR <60 mL/min/1.73 m(2) and albuminuria and associated with an increased mortality risk.

Impact of nitrate addition on biofilm properties and activities in rising main sewers

Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L(-1) for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.

PAR bZIP-bik is a novel transcriptional pathway that mediates oxidative stress-induced apoptosis in fibroblasts

PAR bZIP (cells knockout for PAR bZIP transcription factors) proteins, thyrotroph embryonic factor (TEF), albumin D-site-binding protein (DBP), and hepatic leukemia factor (HLF), are a family of transcription factors that have been shown to contribute to the expression of genes involved in detoxification and drug metabolism. Recently, we showed that PAR bZIP proteins were able to regulate the BH3-only gene bcl-gS in tumor cells. Here, we have extended the role of these transcription factors in the control of apoptosis executors by analyzing the expression of BH3-only genes in PAR bZIP triple knockout mouse fibroblasts. We found that bik was the only BH3-only gene downregulated in knockout cells. Consistently, transfection of TEF or DBP induces the expression of endogenous bik, regardless of the presence of active p53. Moreover, both promoter-reporter and chromatin immunoprecipitation assays indicate that PAR bZIP proteins activate the bik promoter directly. Treatment with different stress stimuli reveals a higher survival of knockout fibroblasts compared with that of wild-type cells, especially after incubation with H(2)O(2), which suggest that PAR bZIP proteins participate in oxidative stress-induced apoptosis. Furthermore, the apoptotic cell death promoted by treatment with H(2)O(2) can be impaired by reducing the expression of Bik in wild-type fibroblasts or enhanced by the overexpression of Bik in knockout cells. These findings reveal a novel transcriptional pathway relevant in transducing the apoptotic response to oxidative stress.

Nitrite effectively inhibits sulfide and methane production in a laboratory scale sewer reactor

The production and emission of hydrogen sulfide and methane by anaerobic microoganisms in sewer systems is a well-documented problem. The effectiveness of nitrite in controlling sulfide and methane production was tested in a laboratory scale sewer reactor. Nitrite was continuously dosed in the reactor for 25 days at concentrations of 20-140mgN/L. No sulfide and methane accumulation was observed in the reactor in the presence of nitrite. A significant reduction was observed in the sulfate reduction and methane production capabilities of the biofilm. Nitrite also stimulated biological sulfide oxidation within the biofilm. The nitrite uptake rate of the reactor increased over the nitrite dosing period and nitrous oxide production was observed within the biofilm. When nitrite addition was stopped, sulfate reduction and methane production gradually resumed, and reached pre-nitrite addition levels after 2.5 months. The slow recovery suggests that nitrite can be applied intermittently for sulfide and methane control, which represents a key advantage over similar chemicals such as nitrate and oxygen. The study demonstrates nitrite addition as a promising and effective strategy for the management of sulfide and methane in sewers. Further investigation and optimization are still required before application in the field.

Guar meal diets as an alternative approach to inducing molt and improving Salmonella enteritidis resistance in late-phase laying hens

Induced molting of laying hens is a practice used by commercial egg producers to increase the productive lifetime of their flock. However, the conventional method of inducing molt, which involves removal of feed, water, or both as well as a reduction in photoperiod to less than a natural day has drawn criticism due to animal welfare and food safety concerns. The objective of this study was to explore the efficacy of diets containing high levels of guar meal (GM) in inducing molt and reducing susceptibility to Salmonella Enteritidis colonization in late-phase laying hens. Late-phase (68 wk old) Lohmann laying hens were either full-fed standard laying hen diets (nonmolted control), induced to molt by feed withdrawal, or full-fed standard laying hen diets containing 20% GM with or without 250 units/kg of mannanase Hemicell supplementation. On the fourth day of treatment, all hens were orally challenged with SE (1.65 x 10(7) cfu). Hens were killed and evaluated for Salmonella colonization and differences in organ weights 5 d postinoculation. Salmonella Enteritidis present in crop, liver, ovary, and cecal contents were significantly reduced by feeding GM with enzyme supplementation compared with feed withdrawal hens. No significant differences were observed in reproductive tract weights of molted groups, although a difference in liver weight was detected. Results indicate that feeding diets containing 20% GM are as effective as complete feed withdrawal with respect to inducing molt with the added benefit of improved resistance to Salmonella Enteritidis colonization and translocation.

Impact of activated vitamin D and race on survival among hemodialysis patients

Contrary to most examples of disparities in health outcomes, black patients have improved survival compared with white patients after initiating hemodialysis. Understanding potential explanations for this observation may have important clinical implications for minorities in general. This study tested the hypothesis that greater use of activated vitamin D therapy accounts for the survival advantage observed in black and Hispanic patients on hemodialysis. In a prospective cohort of non-Hispanic white (n = 5110), Hispanic white (n = 979), and black (n = 3214) incident hemodialysis patients, higher parathyroid hormone levels at baseline were the primary determinant of prescribing activated vitamin D therapy. Median parathyroid hormone was highest among black patients, who were most likely to receive activated vitamin D and at the highest dosage. One-year mortality was lower in black and Hispanic patients compared with white patients (16 and 16 versus 23%; P < 0.01), but there was significant interaction between race and ethnicity, activated vitamin D therapy, and survival. In multivariable analyses of patients treated with activated vitamin D, black patients had 16% lower mortality compared with white patients, but the difference was lost when adjusted for vitamin D dosage. In contrast, untreated black patients had 35% higher mortality compared with untreated white patients, an association that persisted in several sensitivity analyses. In conclusion, therapy with activated vitamin D may be one potential explanation for the racial differences in survival among hemodialysis patients. Further studies should determine whether treatment differences based on biologic differences contribute to disparities in other conditions.

Postprandial mineral metabolism and secondary hyperparathyroidism in early CKD

Normophosphatemia and normocalcemia are maintained in chronic kidney disease (CKD) by increased levels of fibroblast growth factor-23 (FGF-23) and parathyroid hormone (PTH), but the stimuli for secretion of these hormones in early CKD are incompletely understood. Most human physiologic studies have focused on random or fasting measurements of phosphorus, calcium, FGF-23, and PTH, but in this study, the hypothesis was that measurements in the postprandial state may reveal intermittent stimuli that lead to increased FGF-23 and PTH levels. The 4-h postprandial response in 13 patients with CKD and fasting normophosphatemia and normocalcemia (mean GFR 41 +/- 8 ml/min per m(2)) was compared with 21 healthy volunteers. Compared with healthy subjects, fasting patients with CKD had significantly higher levels of FGF-23 and fractional excretion of phosphorus; lower fractional excretion of calcium; and no difference in serum calcium, phosphorus, and PTH levels. After standardized meals, urinary phosphorus excretion in both groups increased despite unchanged serum phosphorus and FGF-23 levels. Postprandial urinary calcium excretion also increased in both groups, and this was accompanied by significantly reduced serum calcium and increased PTH levels in patients with CKD only; therefore, FGF-23 does not seem to be an acute postprandial regulator of phosphaturia in CKD or in health, but inappropriate postprandial calciuria with episodic, relative hypocalcemia may represent a previously unreported mechanism of secondary hyperparathyroidism in CKD.

Continuous measurement of dissolved sulfide in sewer systems

Sulfides are particularly problematic in the sewage industry. Hydrogen sulfide causes corrosion of concrete infrastructure, is dangerous at high concentrations and is foul smelling at low concentrations. Despite the importance of sulfide monitoring there is no commercially available system to quantify sulfide in waste water. In this article we report on our use of an in situ spectrometer to quantify bisulfide in waste water and additional analysis with a pH probe to calculate total dissolved sulfide. Our results show it is possible to use existing commercially available and field proven sensors to measure sulfide to mg/l levels continuously with little operator intervention and no sample preparation.

Nosocomial spread of Pseudomonas aeruginosa producing the metallo-β-lactamase VIM-2 in a Spanish hospital: clinical and epidemiological implications

Thirty-four isolates of pan-resistant Pseudomonas aeruginosa producing VIM-2 metallo-beta-lactamase (MBL) were detected at a university hospital in Spain (July 2004-September 2006). Eleven (32%) patients had clinically significant infections, and three (27%) of these patients died. A single clone of MBL-producing P. aeruginosa was identified by pulsed-field gel electrophoresis. A cluster of isolates associated with the vascular surgery ward involved ten patients and appeared as a series of low-grade, sustained and misdiagnosed endemic infections in the hospital. The identification of MBL-positive P. aeruginosa should be considered mandatory in the surveillance of pan-resistant P. aeruginosa and requires a high index of suspicion in the context of endemic infections with a low attack rate.

Use of guar by-products in high-production laying hen diets

A 5x5 Latin square experiment was conducted to evaluate the effect of feeding low concentrations of guar germ or a combination of guar germ and hull (guar meal) in high-production laying hen diets. A total of 125 Lohmann laying hens (21 wk old) of similar BW were randomly assigned to 5 blocks. Each block was divided into 5 experimental units, consisting of 5 hens per unit. Hens were fed either a nonguar control diet, or 1 of 4 diets containing either 2.5 or 5% guar germ, or 2.5 or 5% guar meal over a 20-wk trial period (five 4-wk periods). No significant differences were observed when feeding either 2.5 or 5% guar germ or meal (P>0.05) on hen-day egg production or feed consumption. Significant differences in egg weight, total egg mass per hen, and feed conversion ratio were detected in hens fed 2.5% guar meal, whereas they remained unchanged for diets containing either level of guar germ or 5% guar meal. Feeding either level of guar germ or guar meal did not affect shell quality (shell thickness, egg breaking force, and specific gravity), Haugh units, or egg yolk color (L*, a*, b*). The results showed that both guar germ and guar meal can be fed to high-production laying hens at up to 5% without adverse effects on laying hen performance.

Vitamin D levels and early mortality among incident hemodialysis patients

Vitamin D deficiency is associated with cardiovascular disease, the most common cause of mortality in hemodialysis patients. To investigate the relation between blood levels of 25-hydroxyvitamin D (25D) and 1,25-dihydroxyvitamin D (1,25D) with hemodialysis outcomes, we measured baseline vitamin D levels in a cross-sectional analysis of 825 consecutive patients from within a prospective cohort of incident US hemodialysis patients. Of these patients, 78% were considered vitamin D deficient with 18% considered severely deficient. Calcium, phosphorus, and parathyroid hormone levels correlated poorly with 25D and 1,25D concentrations. To test the association between baseline vitamin D levels and 90-day mortality, we selected the next 175 consecutive participants who died within 90 days and compared them to the 750 patients who survived in a nested case-control analysis. While low vitamin D levels were associated with increased mortality, significant interaction was noted between vitamin D levels, subsequent active vitamin D therapy, and survival. Compared to patients with the highest 25D or 1,25D levels who received therapy, untreated deficient patients were at significantly increased risk for early mortality. Our study shows that among incident hemodialysis patients, vitamin D deficiency is common, correlates poorly with other components of mineral metabolism and is associated with increased early mortality.

Imatinib (I) compared to I + cytarabine (Ara-C) for the frontline treatment of chronic phase (CP) chronic myeloid leukemia (CML)

7048

Background: Imatinib is now worldwide accepted as the standard frontline therapy of CP CML. Regardless of their impressive clinical results and low toxicity profile, a small proportion of CP CML patients could develop primary or secondary resistance. Main objective of present trial was to increase the hematological (HR) and major cytogenetical responses (MCR) with the addition of Ara-C to standard doses of I as a frontline therapy of CP CML. Methods: on September, 2003 we began this multicentric, phase III randomized, clinical trial, comparing I (400 mg/day) vs I (400 mg/day) plus subcutaneous Ara-C (10 mg/m2/day, for 10 days/monthly cycles), doses could be adjusted due to tolerance and toxicity. Inclusion criteria: newly diagnosed CP CML, not elective to allogeneic transplant. Primary endpoint was the acquisition and time to acquisition of HR, MCR by conventional criteria. Secondary endpoints were main toxicities, dead to progression and overall survival. Results: 61 patients were randomized with median follow-up of 850 days (range 85–1151) for entire group. Table 1 shows results for both treatment arms. Table 1 Both treatment arms were well tolerated and the toxicity profile was low and manageable. Statistical analysis (chi- square, paired T-student, Log-rank survival analysis) did not show significant differences among treatment arms. Conclusions: The addition of cytarabine to conventional I doses on frontline therapy CP CML does not produce significant benefit on HR or MHR. Larger I doses or other therapeutic options should be explored.

[Table: see text] [Table: see text]

Oral anticoagulant treatment: risk factors involved in 500 intracranial hemorrhages

Intracranial bleeding is the most severe complication caused by anticoagulant or antiplatelet treatment. The increasing use of this therapy, especially in older people, makes the balance between clinical benefit and bleeding risk an important consideration. A retrospective study of all consecutive 500 intracranial hemorrhages in the West Valladolid area, approximately 220,000 people, during the period 1998 to 2004, was performed. In relation to mortality, predisposing conditions were included, such as age, antithrombotic treatment, arterial hypertension, cancer, blood diseases, vascular malformations, and traumatisms. The incidence of intracranial hemorrhage was 310 per 100,000 per year with a mortality of 30%. Higher mortality was found in antiplatelet-treated patients (44.9%) than in anticoagulated patients (31.1%). This may be related to a different mean age of 78 vs. 71 years. Arterial hypertension was the most frequent risk factor (45.1% in nontreated patients, 60% anticoagulated, and 75.5% antiplatelet). The relative risk of intracranial bleeding in anticoagulated patients was 11.2 (p < 0.001) with an incidence of 0.03% and a median of 14 months since treatment began. The median INR was 3.3. In 40% of the patients the previous five controls were in range. Strict consideration of indications criteria joined to a better control of risk factors may avoid intracranial bleeding episodes.

Post-transplant hypophosphatemia: Tertiary 'Hyper-Phosphatoninism'?

Hypophosphatemia is a common complication of kidney transplantation. Tertiary hyperparathyroidism has long been thought to be the etiology, but hypophosphatemia can occur despite low parathyroid hormone (PTH) levels and can persist after high PTH levels normalize. Furthermore, even in the setting of normal allograft function, hypophosphatemia, and hyperparathyroidism, calcitriol levels remain inappropriately low following transplantation, suggesting that mechanisms other than PTH contribute. Fibroblast growth factor-23 (FGF-23) induces phosphaturia, inhibits calcitriol synthesis, and accumulates in chronic kidney disease. We performed a prospective, longitudinal study of 27 living donor transplant recipients to test the hypotheses that excessive FGF-23 accounts for hypophosphatemia and decreased calcitriol levels following kidney transplantation. Hypophosphatemia <2.5 mg/dl developed in 85% of subjects, including one who had previously undergone parathyroidectomy; 37% developed phosphate < or =1.5 mg/dl. The mean pre-transplant FGF-23 level was 1,218+/-542 RU/ml. Within the first week following transplantation, mean levels decreased to 557+/-579 RU/ml, which were still above normal. FGF-23 was independently associated with serum phosphate (P < 0.01), urinary excretion of phosphate (P < 0.01), and calcitriol levels (P < 0.01); PTH was not independently associated with any of these parameters. We calculated area under the curve for FGF-23 and PTH between the pre- and first post-transplant levels as a summary measure of early exposure to these phosphaturic hormones. An area under the FGF-23 curve greater than the median was associated with a relative risk of developing hypophosphatemia < or =1.5 mg/dl of 5.3 (P = 0.02) compared with lower levels. Increased area under the PTH curve was not associated with greater risk of hypophosphatemia. Excessive FGF-23 exposure in the early post-transplant period appears to be more strongly associated with post-transplant hypophosphatemia than PTH.

Helicobacter pylori outer membrane proteins and gastroduodenal disease

BACKGROUND AND AIMS

A number of Helicobacter pylori outer membrane proteins (OMPs) undergo phase variations. This study examined the relation between OMP phase variations and clinical outcome.

METHODS

Expression of H pylori BabA, BabB, SabA, and OipA proteins was determined by immunoblot. Multiple regression analysis was performed to determine the relation among OMP expression, clinical outcome, and mucosal histology.

RESULTS

H pylori were cultured from 200 patients (80 with gastritis, 80 with duodenal ulcer (DU), and 40 with gastric cancer). The most reliable results were obtained using cultures from single colonies of low passage number. Stability of expression with passage varied with OipA > BabA > BabB > SabA. OipA positive status was significantly associated with the presence of DU and gastric cancer, high H pylori density, and severe neutrophil infiltration. SabA positive status was associated with gastric cancer, intestinal metaplasia, and corpus atrophy, and negatively associated with DU and neutrophil infiltration. The Sydney system underestimated the prevalence of intestinal metaplasia/atrophy compared with systems using proximal and distal corpus biopsies. SabA expression dramatically decreased following exposure of H pylori to pH 5.0 for two hours.

CONCLUSIONS

SabA expression frequently switched on or off, suggesting that SabA expression can rapidly respond to changing conditions in the stomach or in different regions of the stomach. SabA positive status was inversely related to the ability of the stomach to secrete acid, suggesting that its expression may be regulated by changes in acid secretion and/or in antigens expressed by the atrophic mucosa.

Atrophic gastritis in young children and adolescents

BACKGROUND

Helicobacter pylori associated gastric cancer arises via a multistage process, with atrophic gastritis being the precursor lesion. Helicobacter pylori is typically acquired in childhood, yet little is known of the prevalence of atrophic gastritis in childhood.

AIM

To study atrophic gastritis among children from countries with high gastric cancer incidence.

METHODS

Sections from topographically mapped gastric biopsy specimens from children undergoing clinically indicated endoscopy in Korea and Colombia were evaluated using visual analogue scales. Atrophy was defined as loss of normal glandular components, including replacement with fibrosis, intestinal metaplasia (IM), and/or pseudopyloric metaplasia of the corpus (identified by the presence of pepsinogen I in mucosa that was topographically corpus but phenotypically antrum).

RESULTS

One hundred and seventy three children, 58 from Korea (median age, 14 years) and 115 from Colombia (median age, 13 years), were studied. Helicobacter pylori was present in 85% of Colombian children versus 17% of Korean children (p<0.01). Atrophic mucosa near the antrum-corpus border was present in 16% of children, primarily as pseudopyloric metaplasia (31%, IM; 63%, pseudopyloric metaplasia; 6%, both). The median age of children with corpus atrophy was 15 (range, 7-17) years.

CONCLUSION

Gastric atrophy occurs in H pylori infected children living in countries with high gastric cancer incidence. Identification and characterisation of the natural history of H pylori gastritis requires targeted biopsies to include the lesser and greater curve of the corpus, starting just proximal to the anatomical antrum-corpus junction, in addition to biopsies targeting the antrum and cardia.

Fibroblast growth factor-23 mitigates hyperphosphatemia but accentuates calcitriol deficiency in chronic kidney disease

Hyperphosphatemia, calcitriol deficiency, and secondary hyperparathyroidism (SHPT) are common complications of chronic kidney disease (CKD). Fibroblast growth factor-23 (FGF-23) is a novel phosphaturic hormone that also inhibits renal 1alpha-hydroxylase activity and thus may be involved in the pathogenesis of SHPT. Several hypotheses were tested: that FGF-23 increases as renal function declines; is linearly associated with serum phosphate levels; is associated with increased phosphaturia independent of parathyroid hormone (PTH); and is associated with decreased calcitriol levels independent of renal function, hyperphosphatemia, and vitamin D stores. FGF-23, PTH, 25(OH)D3, calcitriol, calcium, phosphate, and urinary fractional excretion of phosphate (Fe(PO4)) were measured in 80 CKD patients. Multiple linear regression was used to test the hypotheses. FGF-23 and PTH were inversely associated with estimated GFR (eGFR), whereas calcitriol levels were linearly associated with eGFR. Hyperphosphatemia and hypocalcemia were present in only 12 and 6% of patients, respectively, all of whose eGFR was <30. Increased Fe(PO4) was associated with decreased eGFR, and both increased FGF-23 and PTH were independently associated with increased Fe(PO4). Increased FGF-23 and decreased 25(OH)D3 were independent predictors of decreased calcitriol, but the effects on calcitriol levels of renal function itself and hyperphosphatemia were completely extinguished by adjusting for FGF-23. It is concluded that FGF-23 levels increase early in CKD before the development of serum mineral abnormalities and are independently associated with serum phosphate, Fe(PO4), and calcitriol deficiency. Increased FGF-23 may contribute to maintaining normal serum phosphate levels in the face of advancing CKD but may worsen calcitriol deficiency and thus may be a central factor in the early pathogenesis of SHPT.

CagA in Barrett's oesophagus in Colombia, a country with a high prevalence of gastric cancer

BACKGROUND

In the USA, atrophic gastritis and gastric cancer are rare, whereas gastro-oesophageal reflux disease (GERD) is common. Infection with Helicobacter pylori, especially a CagA positive strain, is unusual in patients with GERD/Barrett's oesophagus in the USA.

AIM

To examine the relation between Barrett's oesophagus and CagA positive H pylori in Colombia, a country with a high prevalence of CagA positive H pylori associated atrophic gastritis and gastric cancer.

METHODS

Helicobacter pylori and CagA status was determined among Colombian patients with long segment Barrett's oesophagus and a control group with simple H pylori gastritis. Helicobacter pylori status was determined using a triple stain and CagA status was determined by immunohistochemistry using a specific rabbit anti-CagA serum.

RESULTS

Gastric and oesophageal mucosal biopsies were obtained from 51 patients--39 men (mean age, 57.8 years; SD, 13.1) and 12 women (mean age, 51.8 years; SD, 14.4)--with documented long segment Barrett's oesophagus. The results were compared with 24 Colombian patients with H pylori gastritis without oesophageal disease. Thirty two patients with Barrett's oesophagus had active H pylori infection. CagA status was evaluated in a subset of 23 H pylori infected patients with Barrett's oesophagus, and was positive in eight of these patients compared with 19 of 24 controls (p = 0.01).

CONCLUSIONS

Although most Colombian patients with Barrett's oesophagus had H pylori infection, CagA positive infections were unusual. These data illustrate how consistent corpus inflammation reduces acid secretion, which prevents Barrett's oesophagus among those with abnormal gastro-oesophageal reflux barriers.

Geographic differences in the distribution of intestinal metaplasia in duodenal ulcer patients

OBJECTIVE

A strong correlation exists between atrophic gastritis and the intestinal type of gastric carcinoma. Duodenal ulcer disease characteristically has an antral predominant gastritis and a lower risk for gastric cancer. The aim of this study was to investigate the extent and distribution of intestinal metaplasia in duodenal ulcer in countries differing in gastric cancer incidence.

METHODS

Topographically mapped gastric biopsy specimens (median 11) were obtained from patients with duodenal ulcer in four countries (Korea, Colombia, USA, and South Africa). Sections were stained with a triple stain and evaluated for Helicobacter pylori (H. pylori), active inflammation, and intestinal metaplasia.

RESULTS

One hundred and sixty-five patients with duodenal ulcer were examined (29 from Korea, 52 from Colombia, 62 from the USA, and 22 from South Africa). The percentage of biopsies with intestinal metaplasia was significantly greater in Korean patients (86%) compared with that in other countries (50%) (p = 0.0004). Intestinal metaplasia was most prevalent in the antrum lesser curve and greater curve, and the body lesser curve. Intestinal metaplasia was present in the gastric corpus of 38% of duodenal ulcer patients from Korea compared with an average of 10% elsewhere (p = 0.018). No differences were observed in the density or distribution of H. pylori infection or in the degree of active gastritis between countries.

CONCLUSIONS

Although antral predominant gastritis is the prevalent pattern of gastritis in duodenal ulcer, intestinal metaplasia in the gastric corpus may be found with geographic differences. These findings suggest that duodenal ulcer and gastric cancer are not mutually exclusive diseases but are rather ends of the spectrum of H. pylori infection.

Topographic patterns of intestinal metaplasia and gastric cancer

OBJECTIVE

The role of intestinal metaplasia in gastric oncogenesis has been demonstrated by both cross-sectional and longitudinal studies. This study was designed to determine whether, in a population at high risk for gastric cancer, different topographical patterns and phenotypes of intestinal metaplasia were associated with different degrees of cancer risk.

METHODS

A total of 68 Colombian patients with gastric cancer and 67 controls with nonulcer dyspepsia were studied by an extensive biopsy protocol. Intestinal metaplasia was assessed semiquantitatively by histology and was characterized histochemically. In both patients and controls, the Spearman's correlation test was applied to the test if the gastric distribution of metaplastic lesions resulted in specific topographical patterns associated with different risks for cancer.

RESULTS

Four topographical patterns of intestinalization emerged: 1) "Focal," in 14 cancer patients and 16 controls; 2) "Antrum-predominant," in seven cancer patients and six controls; 3) "Magenstrasse" (involving the lesser curvature from cardia to pylorus) in 25 cancer patients and four controls. This pattern was associated with higher cancer risk (OR = 5.7; 95% CI: 1.3-26) than were the two less extensive patterns; and 4) "Diffuse," involving essentially the entire gastric mucosa with the exception of the fundus, was unique to 13 cancer patients. The OR for cancer was 12.2; 95% CI: 2.0-72.9. Incomplete-type metaplasia significantly correlated with the extent of total metaplasia and was also associated with greater cancer risk.

CONCLUSIONS

In a population with high risk for gastric cancer, the extension of intestinal metaplasia correlates with the extent of its "incomplete" phenotype and is significantly associated with increased cancer risk. Both the extent and location of intestinal metaplasia along the lesser curvature (from the cardia to the prepyloric zones) identify patients with the highest cancer risk.

Molecular identification of main cellular lineages as a tool for the classification of gastric cancer

Gastric carcinomas (GC) are heterogeneous tumors comprising variable amounts of cells of different lineage phenotype, including gastric mucous cells (surface--SMC or gland--GMC) and intestinal cells (IC). The evaluation of tumor behavior has classically depended on strictly morphological classifications of tumors. Microsatellite instability (MSI) is frequently detected in GC, but whether MSI affects all gastric cellular lineages or exclusively occurs in unique cellular lineages in GC is not known. The aims of this study were to test a combination of anti-mucin antibodies to classify gastric cancer into predominant cell lineage phenotype and to determine whether MSI in GC is associated with particular cellular tumor phenotypes. Fifty-five GC were immunophenotyped with antibodies specific for SMC, GMC, or IC. DNA was extracted from tumor and non-neoplastic gastric tissues and amplified with 5 microsatellite markers. A mixed cellular pattern was the most frequent phenotype of GC (61%) and was seen in both glandular (63%) and diffuse (58%)-type tumors. No significant difference in the rate of MSI was found in tumors with predominant gastric, intestinal or mixed phenotype. However, tumors with null or low-level expression of cellular lineage differentiation markers displayed MSI more frequently than tumors with high-level expression (40% v 20%). In conclusion, different gastric carcinoma cell lineage patterns can be easily identified with the 3 immunohistochemical markers used in this study. The 3 main cellular lineage components of gastric cancer can be similarly affected by microsatellite instability, consistent with the notion that MSI is an early event in gastric carcinogenesis.

Molecular epidemiology of Helicobacter pylori: separation of H. pylori from East Asian and non-Asian countries

The predominant H. pylori strain circulating among geographic locations differs with regard to the genomic structure. This study determined whether structural subtypes of the cagA 3' repeat region could be used to identify the population of origin of H. pylori isolates. We examined 600 cagA-positive H. pylori (Colombia, 100; USA, 100; France, 100; Canada, 20; Italy, 20; Korea, 100; Japan, 100; Hong Kong, 20; Taiwan, 20; Vietnam, 20). The cagA 3' region was amplified by PCR using primers specific to Japanese and Western 3' cagA gene sequences. PCR using Japanese cagA primers resulted in PCR products in 99-6 % of strains from East Asia but no non-Asian strains. Conversely, PCR using Western cagA primers resulted in amplicons in 100% of non-Asian strains, and only one from East Asia. cagA genotyping is useful for molecular epidemiological studies as strains can be completely separated by differences in the cagA 3' region.

Marked differences in the frequency of microsatellite instability in gastric cancer from different countries

OBJECTIVE

Previous studies have reported variable rates of microsatellite instability (MSI) in gastric cancer. We investigated the frequency of MSI in invasive gastric carcinoma of patients from three geographic regions.

METHODS

Genomic DNA from gastric cancer and nontumor tissue from 22 Korean, 20 Colombian, and 26 U.S. patients was amplified with five microsatellite markers.

RESULTS

MSI was more frequently seen in gastric cancer from Korea, affecting 50% of patients, in contrast with gastric cancers from the U.S. (7%) and Colombia (15%) (p = 0.003 and p = 0.03, respectively). MSI at one locus was significantly more frequent in gastric cancer from individuals >65 yr (p = 0.01). MSI was similarly associated with both diffuse and intestinal types of gastric cancer.

CONCLUSIONS

MSI affects the two major histological types of gastric cancer, and was more frequent in gastric cancer from Korea than in the other countries, suggesting that the relative importance of different pathways of gastric carcinogenesis may vary in diverse regions of the world.

The differential diagnosis of early gastric mucosa-associated lymphoma: polymerase chain reaction and paraffin section immunophenotyping

The distinction between benign florid lymphoid hyperplasia and low-grade gastric mucosal-associated lymphoid tissue (MALT) lymphoma may be a challenge. The presence of monoclonal B cells in Helicobacter pylori-chronic active gastritis has suggested that polymerase chain reaction (PCR) data should be viewed with caution. We investigated the reliability of PCR versus immunophenotyping in diagnosing early gastric MALT lymphoma. We studied 1511 biopsies from eight patients with high-grade primary gastric lymphoma, 25 with low-grade MALT lymphoma, 32 with atypical lymphoid infiltrates, and 39 with Helicobacter pylori-chronic active gastritis. Paraffin sections from all cases were stained with antibodies to CD20, CD3, AE1/AE3, kappa and lambda. PCR was performed on paraffin sections using the primer set VH-FR3/J(H). Using histopathology as the gold standard in diagnosis, we confirmed monoclonality in 22 of 25 MALT lymphomas (88%); a clonal band was found in 38% (15 of 39) of patients with chronic active gastritis. An immunophenotype pattern with predominance of CD20-positive cells in lymphocytic infiltrates was associated with monoclonality in 92% of cases. The presence of an enlarged irregular mantle zone was found in both monoclonal and polyclonal areas. An equal prevalence of B and T cells in lymphocytic infiltrates was associated with a polyclonal pattern in 24 of 31 cases (77%). Immunostaining of sIg (kappa and lambda) was difficult in paraffin sections and convincing proof of monoclonality was not obtained. Lymphoepithelial lesions were infrequent in gastric biopsies and their presence was highlighted with keratin stains. Because monoclonal B cells are observed in Helicobacter pylori-associated gastritis, the correct interpretation of clonality by PCR remains unclear. Paraffin section IHC using CD20 and CD3 is especially useful to confirm the diagnosis of gastric MALT lymphoma.

Relationship between the cagA 3' repeat region of Helicobacter pylori, gastric histology, and susceptibility to low pH

BACKGROUND & AIMS

The variation in size of Helicobacter pylori CagA is related to repeat sequences in the 3' region of the cagA gene. We investigated whether structural subtypes of the cagA 3' region are associated with presentation of the infection or to susceptibility to acid.

METHODS

We examined 319 cagA-positive H. pylori isolates: 84 isolates from Bogota, Colombia; 83 from Houston, Texas; 24 from Siena, Italy; and 128 from Seoul, Korea. The cagA 3' region was amplified by polymerase chain reaction. Gastric histology and susceptibility to pH 3 were evaluated in relation to the number of cagA repeat regions.

RESULTS

Strains with more than three repeat regions were associated with significantly higher scores for gastric mucosal atrophy and intestinal metaplasia than those with fewer repeat regions. H. pylori strains with three repeat regions were also significantly more susceptible to pH 3 than isolates with fewer repeat regions.

CONCLUSIONS

H. pylori strains with more than three repeat regions in the 3' region of the cagA gene are associated with enhanced histological injury and with reduced survival in acidic conditions. It is hypothesized that these variants arise within the stomach.

Relationship between Helicobacter pylori iceA, cagA, and vacA status and clinical outcome: studies in four different countries

There is continuing interest in identifying Helicobacter pylori virulence factors that might predict the risk for symptomatic clinical outcomes. It has been proposed that iceA and cagA genes are such markers and can identify patients with peptic ulcers. We compared H. pylori isolates from four countries, looking at the cagA and vacA genotypes, iceA alleles, and presentation of the infection. We used PCR to examine iceA, vacA, and cagA status of 424 H. pylori isolates obtained from patients with different clinical presentations (peptic ulcer, gastric cancer, and atrophic gastritis). The H. pylori isolates examined included 107 strains from Bogota, Colombia, 70 from Houston, Tex., 135 from Seoul, Korea, and 112 from Kyoto, Japan. The predominant genotype differed among countries: the cagA-positive iceA1 vacA s1c-m1 genotype was predominant in Japan and Korea, the cagA-positive iceA2 vacA s1b-m1 genotype was predominant in the United States, and the cagA-positive iceA2 vacA s1a-m1 genotype was predominant in Colombia. There was no association between the iceA, vacA, or cagA status and clinical outcome in patients in the countries studied. iceA status shows considerable geographic differences, and neither iceA nor combinations of iceA, vacA, and cagA were helpful in predicting the clinical presentation of an H. pylori infection.

Microflora of gastric biopsies from patients with duodenal ulcer and gastric cancer: a comparative study of patients from Korea, Colombia, and the United States

It remains unclear why the spectrum of H. pylori-related diseases differs among different geographic regions. We examined the non-H. pylori contamination rates of the stomach in patients with duodenal ulcer or gastric adenocarcinoma from three different regions with different spectra of H. pylori-related diseases. Gastric biopsies were cultured from patients with duodenal ulcer or histologically proven gastric cancer from Seoul, Korea; Bogota, Colombia; and Houston, Texas. The frequency of non-H. pylori contamination was tallied in relation to the clinical diagnosis. Cultures from 247 duodenal ulcer patients and 165 patients with gastric cancer had bacterial growth. H. pylori was isolated from 207 (73.7%) patients with duodenal ulcer and 90 (47.1%) patients with gastric cancer (P < 0.001). In patients with duodenal ulcer (DU) or gastric cancer (GC), the rate of positive cultures for H. pylori were not statistically different (P > 0.143 for DU, P > 0.190 for GC) between regions. The frequency of isolation ranged from 69% to 79% for DU patients and from 39% to 50% for gastric cancer patients. Non-H. pylori bacterial contamination was found more frequently (63%) in Colombian duodenal ulcer patients compared to 30% ulcer patients from the United States or Korea (P < 0.001). Non-H. pylori growth occurred in 50.8-75.5% of cancer patients and was significantly lower in US patients than in patients from either Colombia or Korea (P < 0.01). The geographic location as well as disease status affects the rate of H. pylori recovery and non-H. pylori contamination of the stomach and may play a role in the geographic differences in manifestation of H. pylori infection. The fact that the proportion of gastric cancer patients in the United States with non-H. pylori contamination was significantly less than that of Korea or Colombia shows that the notion of an almost universal increase in gastric microbial content in gastric adenocarcinoma should be reconsidered.

Takayasu arteritis in Colombia

Takayasu arteritis has been recognized in Colombia just recently, and so far we do not have any report concerning its presentation here. In this first report, some issues related to the presentation of the disease are indicated and compared with those found in the medical literature. No differences were found in age and sex. Most of the cases were diagnosed during an inactive phase of the disease with advanced manifestations due to vascular lesion which suggests the existence of some genetic factor influencing such a presentation, or may be the consequence of a delay in diagnosing the disease during initial and active stages due to not suspecting it. Comparing the vessels which are affected among other races and countries, we can find both differences and similarities. With the purpose of discovering the demographic, clinical, angiographic and laboratorial characteristics of Takayasu arteritis in Colombia, the present study was carried out by studying 35 clinical cases in different medical centers of the country.