Validación de un método mul-tirresiduo para la determinación de medicamentos veterinarios en trucha y langostino

Este estudio se realizó con el objetivo de desarrollar y validar un método para la determinación de 30 medicamentos veterinarios en muestras de trucha y langostino. El método utiliza extracción en fase sólida dispersiva (dSPE) con C18 y detección por cromatografía líquida acoplada a espectrometría de masas. Se determinó linealidad, veracidad (porcentaje de recuperación), repetitividad y reproducibilidad intralaboratorio (porcentaje de desviación estándar relativa (% RSD)), límites de detección (LoD), límites de cuantificación (LoQ), selectividad e incertidumbre. La recuperación varió de 70 a 120% y la repetibilidad y la reproducibilidad fueron menores de 20% de la desviación estándar relativa. La selectividad fue adecuada, sin picos interferentes. Las relaciones iónicas cumplieron con los criterios de confirmación. Los coeficientes de determinación (R2) fueron mayores de 0,99, con excepción de la sulfaquinoxalina en langostino (R2 = 0,97). Los LoD y los LoQ variaron entre 0,6 µg/kg y 12,8 µg /kg y los valores de incertidumbre entre 6 µg/kg y 49 µg/ kg. Se analizaron adicionalmente 6 muestras de diferentes mercados de Lima y se detectaron trazas de algunos medicamentos incluidos en el ensayo. El método es adecuado para el análisis de residuos de medicamentos veterinarios y se recomienda su aplicación en los programas nacionales de monitoreo de la inocuidad de truchas y langostinos provenientes de acuicultura.

The study was aimed at developing and validate an analysis method to determine residues of 30 veterinary drugs in rainbow trout and shrimp specimens. The method involves extraction in dispersive solid phase with C18 and the subsequent detection through liquid chromatography coupled to mass spectrometry. Validation was done through determination of linearity, trueness (% of recovery), repeatability and intralaboratory reproducibility, limits of detection (LoD), limits of quantification (LoQ) selectivity and uncertainty. Recovery ranged from 70 to 120% and repeatability and intralaboratory reproducibility were lower than 20%. Selectivity was adequate, without interference peaks. Likewise, the ionic relationships met the confirmation criteria. The linearity was adequate, with determination coefficients (R2) above 0.99, except for sulfaquinolaxin in shrimp specimens (R2 = 0,97). LoD and LoQ varied from 0,6 µg /kg to 12,8 µg / kg. Limits of uncertainty ranged from 6 µg /kg to 49 µg /kg. The method was used to analyze 6 samples from different markets in Lima (Peru), identifying traces of some drugs included in the study. Our results show that the method is adequate for the analysis of veterinary drug residues and allow us to recommend its application in national monitoring programs, to assess the safety of rainbow trout and shrimp specimens from aquaculture.

O estudo foi realizado com o objetivo de desenvolver e validar um método para a determinação de 30 medicamentos veterinários, em amostras de truta e camarão. O método utiliza extração dispersiva em fase sólida com C18 e detecção por cromatografia líquida acoplada à espectrometria de massas. Foram determinados a linearidade, a veracidade (recuperação percentual), a repetibilidade, a reprodutibilidade intra-laboratorial, os limites de detecção (LoD) e de quantificação (LoQ), a linearidade, a selectividade e a incerteza. A recuperação variou de 70 a 120%, a repetibilidade e reprodutibilidade estiveram abaixo do 20% do desvio padrão relativo. A selectividade fio adequada, sem picos de interferentes. As proporções de íons atenderam aos critérios de confirmação. Os coeficientes de determinação (R2) foram superiores a 0,99, com excepção da sulfanoxalina em camarão (R2 = 0,97). LoD e LoQ variavam entre 0,6 µg /kg e 12,8 µg /kg e valores de incerteza entre 6 µg /kg e 49 µg / kg. Seis amostras de mercados do Lima foram adicionalmente analisadas e foram detectados vestígios de alguns medicamentos incluídos no estudo. O método é adequado para o análise de resíduos de medicamentos veterinários e sua aplicação é recomendada em programas nacionais de controlo da segurança da truta e do camarão provenientes da aquicultura.

Blood lead levels in Peruvian adults are associated with proximity to mining and DNA methylation.

BACKGROUND: Inorganic lead (Pb) is common in the environment, and is toxic to neurological, renal, and cardiovascular systems. Pb exposure influences the epigenome with documented effects on DNA methylation (DNAm). We assessed the impact of low levels of Pb exposure on DNAm among non-miner individuals from two locations in Peru: Lima, the capital, and Cerro de Pasco, a highland mining town, to study the effects of Pb exposure on physiological outcomes and DNAm. METHODS: Pb levels were measured in whole blood (n = 305). Blood leukocyte DNAm was determined for 90 DNA samples using the Illumina MethylationEPIC chip. An epigenome-wide association study was performed to assess the relationship between Pb and DNAm. RESULTS: Individuals from Cerro de Pasco had higher Pb than individuals from Lima (p-value = 2.00E-16). Males had higher Pb than females (p-value = 2.36E-04). Pb was positively associated with hemoglobin (p-value = 8.60E-04). In Cerro de Pasco, blood Pb decreased with the distance from the mine (p-value = 0.04), and association with soil Pb was approaching significance (p-value = 0.08). We identified differentially methylated positions (DMPs) associated with genes SOX18, ZMIZ1, and KDM1A linked to neurological function. We also found 45 differentially methylated regions (DMRs), seven of which were associated with genes involved in metal ion binding and nine to neurological function and development. CONCLUSIONS: Our results demonstrate that even low levels of Pb can have a significant impact on the body including changes to DNAm. We report associations between Pb and hemoglobin, Pb and distance from mining, and between blood and soil Pb. We also report associations between loci- and region-specific DNAm and Pb.

Drivers of the progress achieved by Peru in reducing childhood diarrhoea mortality: a country case study.

BACKGROUND: Childhood diarrhoea mortality has declined substantially in Peru in recent decades. We documented trends in childhood diarrhoea mortality from 1980 to 2015, along with trends in coverage of diarrhoea-related interventions and risk factors, to identify the main drivers of mortality reduction. METHODS: We conducted desk reviews on social determinants, policies and programmes, and diarrhoea-related interventions implemented during the study period. We reviewed different datasets on child mortality, and on coverage of diarrhoea-related interventions. We received input from individuals familiar with implementation of diarrhoea-related policies and programmes. We used the Lives Saved Tool (LiST) to help explain the reasons for the decline in diarrhoea mortality from 1980 to 2015 and to predict additional reduction with further scale up of diarrhoea-related interventions by 2030. RESULTS: In Peru under-five diarrhoea mortality declined from 23.3 in 1980 to 0.8 per 1000 livebirths in 2015. The percentage of under-five diarrhoea deaths as related to total under-five deaths was reduced from 17.8% in 1980 to 4.9% in 2015. Gross domestic product increased and poverty declined from 1990 to 2015. Access to improved water increased from 56% in 1986 to 79.3% in 2015. Oral rehydrating salts (ORS) use during an episode of diarrhoea increased from 3.6% in 1986 to 32% in 2015. Vertical programmes focused on diarrhoea management with ORS were implemented successfully in the 1980s and 1990s, and were replaced by integrated crosscutting interventions since the early 2000s. LiST analyses showed that about half (53.9%) of the reduction in diarrhoea mortality could be attributed to improved water, sanitation and hygiene, 25.0% to direct diarrhoea interventions and 21.1% to nutrition. The remaining mortality could be reduced by three-quarters by 2030 with improved diarrhoea treatment and further with enhanced breastfeeding practices and reduction in stunting. LiST does not take into account the role of social determinants. CONCLUSIONS: The reduction of diarrhoeal under-five mortality in Peru can be explained by a combination of factors, including improvement of social determinants, child nutrition, diarrhoea treatment with ORS and prevention with rotavirus vaccine and increased access to water and sanitation. The already low rate of diarrhoea mortality could be further reduced by a number of interventions, especially additional use of ORS and zinc for diarrhoea treatment. Peru is a remarkable example of a country that was able to reduce childhood diarrhoea mortality by implementing interventions through vertical programmes initially, and afterwards through implementation of integrated multisectoral packages targeting prevalent illnesses and multi-causal problems like stunting.

Association of EGLN1 gene with high aerobic capacity of Peruvian Quechua at high altitude.

Highland native Andeans have resided at altitude for millennia. They display high aerobic capacity (VO2max) at altitude, which may be a reflection of genetic adaptation to hypoxia. Previous genomewide (GW) scans for natural selection have nominated Egl-9 homolog 1 gene (EGLN1) as a candidate gene. The encoded protein, EGLN1/PHD2, is an O2 sensor that controls levels of the Hypoxia Inducible Factor-α (HIF-α), which regulates the cellular response to hypoxia. From GW association and analysis of covariance performed on a total sample of 429 Peruvian Quechua and 94 US lowland referents, we identified 5 EGLN1 SNPs associated with higher VO2max (L⋅min-1 and mL⋅min-1⋅kg-1) in hypoxia (rs1769793, rs2064766, rs2437150, rs2491403, rs479200). For 4 of these SNPs, Quechua had the highest frequency of the advantageous (high VO2max) allele compared with 25 diverse lowland comparison populations from the 1000 Genomes Project. Genotype effects were substantial, with high versus low VO2max genotype categories differing by ∼11% (e.g., for rs1769793 SNP genotype TT = 34.2 mL⋅min-1⋅kg-1 vs. CC = 30.5 mL⋅min-1⋅kg-1). To guard against spurious association, we controlled for population stratification. Findings were replicated for EGLN1 SNP rs1769793 in an independent Andean sample collected in 2002. These findings contextualize previous reports of natural selection at EGLN1 in Andeans, and support the hypothesis that natural selection has increased the frequency of an EGLN1 causal variant that enhances O2 delivery or use during exercise at altitude in Peruvian Quechua.

Understanding drivers of domestic public expenditure on reproductive, maternal, neonatal and child health in Peru at district level: an ecological study.

BACKGROUND: Peru has increased substantially its domestic public expenditure in maternal and child health. Peruvian departments are heterogeneous in contextual and geographic factors, underlining the importance of disaggregated expenditure analysis up to the district level. We aimed to assess possible district level factors influencing public expenditure on reproductive, maternal, neonatal and child health (RMNCH) in Peru. METHODS: We performed an ecological study in 24 departments, with specific RMNCH expenditure indicators as outcomes, and covariates of different hierarchical dimensions as predictors. To account for the influence of variables included in the different dimensions over time and across departments, we chose a stepwise multilevel mixed-effects regression model, with department-year as the unit of analysis. RESULTS: Public expenditure increased in all departments, particularly for maternal-neonatal and child health activities, with a different pace across departments. The multilevel analysis did not reveal consistently influential factors, except for previous year expenditure on reproductive and maternal-neonatal health. Our findings may be explained by a combination of inertial expenditure, a results-based budgeting approach to increase expenditure efficiency and effectiveness, and by a mixed-effects decentralization process. Sample size, interactions and collinearity cannot be ruled out completely. CONCLUSIONS: Public district-level RMNCH expenditure has increased remarkably in Peru. Evidence on underlying factors influencing such trends warrants further research, most likely through a combination of quantitative and qualitative approaches.

Enabling reproductive, maternal, neonatal and child health interventions: Time trends and driving factors of health expenditure in the successful story of Peru.

We compared expenditure trends for reproductive, maternal, neonatal and child health (RMNCH) with trends in RMNCH service coverage in Peru. We used National Health Accounts data to report on total health expenditure by source; the Countdown database for trends in external funding to RMNCH, and Ministry of Finance data for trends in domestic funding to RMNCH. We undertook over 170 interviews and group discussions to explore factors explaining expenditure trends. We describe trends in total health expenditure and RMNCH expenditure in constant 2012 US$ between 1995 and 2012. We estimated expenditure to coverage ratios. There was a substantial increase in domestic health expenditure over the period. However, domestic health expenditure as share of total government spending and GDP remained stable. Out-of-pocket health spending (OOPS) as a share of total health expenditure remained above 35%, and increased in real terms. Expenditure on reproductive health per woman of reproductive age varied from US$ 1.0 in 2002 to US$ 6.3 in 2012. Expenditure on maternal and neonatal health per pregnant woman increased from US$ 34 in 2000 to US$ 512 in 2012, and per capita expenditure on under-five children increased from US$ 5.6 in 2000 to US$ 148.6 in 2012. Increased expenditure on RMNCH reflects a greater political support for RMNCH, along with greater emphasis on social assistance, family planning, and health reforms targeting poor areas, and a recent emphasis on antipoverty and crosscutting equitable policies and programmes focused on nutrition and maternal and neonatal mortality. Increasing domestic RMNCH expenditure likely enabled Peru to achieve substantial health gains. Peru can provide useful lessons to other countries struggling to achieve sustained gains in RMNCH by relying on their own health financing.

Factors behind the success story of under-five stunting in Peru: a district ecological multilevel analysis.

BACKGROUND: Stunting prevalence in children less than 5 years has remained stagnated in Peru from 1992 to 2007, with a rapid reduction thereafter. We aimed to assess the role of different predictors on stunting reduction over time and across departments, from 2000 to 2012. METHODS: We used various secondary data sources to describe time trends of stunting and of possible predictors that included distal to proximal determinants. We determined a ranking of departments by annual change of stunting and of different predictors. To account for variation over time and across departments, we used an ecological hierarchical approach based on a multilevel mixed-effects regression model, considering stunting as the outcome. Our unit of analysis was one department-year. RESULTS: Stunting followed a decreasing trend in all departments, with differing slopes. The reduction pace was higher from 2007-2008 onwards. The departments with the highest annual stunting reduction were Cusco (-2.31%), Amazonas (-1.57%), Puno (-1.54%), Huanuco (-1.52%), and Ancash (-1.44). Those with the lowest reduction were Ica (-0.67%), Ucayali (-0.64%), Tumbes (-0.45%), Lima (-0.37%), and Tacna (-0.31%). Amazon and Andean departments, with the highest baseline poverty rates and concentrating the highest rural populations, showed the highest stunting reduction. In the multilevel analysis, when accounting for confounding, social determinants seemed to be the most important factors influencing annual stunting reduction, with significant variation between departments. CONCLUSIONS: Stunting reduction may be explained by the adoption of anti-poverty policies and sustained implementation of equitable crosscutting interventions, with focus on poorest areas. Inclusion of quality indicators for reproductive, maternal, neonatal and child health interventions may enable further analyses to show the influence of these factors. After a long stagnation period, Peru reduced dramatically its national and departmental stunting prevalence, thanks to a combination of social determinants and crosscutting factors. This experience offers useful lessons to other countries trying to improve their children's nutrition.

Examining national and district-level trends in neonatal health in Peru through an equity lens: a success story driven by political will and societal advocacy.

BACKGROUND: Peru has impressively reduced its neonatal mortality rate (NMR). We aimed, for the period 2000-2013, to: (a) describe national and district NMR variations over time; (b) assess NMR trends by wealth quintile and place of residence; (c) describe evolution of mortality causes; (d) assess completeness of registered mortality; (e) assess coverage and equity of NMR-related interventions; and (f) explore underlying driving factors. METHODS: We compared national NMR time trends from different sources. To describe NMR trends by wealth quintiles, place of residence and districts, we pooled data on births and deaths by calendar year for neonates born to women interviewed in multiple surveys. We disaggregated coverage of NMR-related interventions by wealth quintiles and place of residence. To identify success factors, we ran regression analyses and combined desk reviews with qualitative interviews and group discussions. RESULTS: NMR fell by 51 % from 2000 to 2013, second only to Brazil in Latin America. Reduction was higher in rural and poorest segments (52 and 58 %). District NMR change varied by source. Regarding cause-specific NMRs, prematurity decreased from 7.0 to 3.2 per 1,000 live births, intra-partum related events from 2.9 to 1.2, congenital abnormalities from 2.4 to 1.8, sepsis from 1.9 to 0.8, pneumonia from 0.9 to 0.4, and other conditions from 1.2 to 0.7. Under-registration of neonatal deaths decreased recently, more in districts with higher development index and lower rural population. Coverage of family planning, antenatal care and skilled birth attendance increased more in rural areas and in the poorest quintile. Regressions did not show consistent associations between mortality and predictors. During the study period social determinants improved substantially, and dramatic out-of-health-sector and health-sector changes occurred. Rural areas and the poorest quintile experienced greater NMR reduction. This progress was driven, within a context of economic growth and poverty reduction, by a combination of strong societal advocacy and political will, which translated into pro-poor implementation of evidence-based interventions with a rights-based approach. CONCLUSIONS: Although progress in Peru for reducing NMR has been remarkable, future challenges include closing remaining gaps for urban and rural populations and improving newborn health with qualified staff and intermediate- and intensive-level health facilities.

Pregnancy at high altitude in the Andes leads to increased total vessel density in healthy newborns.

The developing human fetus is able to cope with the physiological reduction in oxygen supply occurring in utero. However, it is not known if microvascularization of the fetus is augmented when pregnancy occurs at high altitude. Fifty-three healthy term newborns in Puno, Peru (3,840 m) were compared with sea-level controls. Pre- and postductal arterial oxygen saturation (SpO2) was determined. Cerebral and calf muscle regional tissue oxygenation was measured using near infrared spectroscopy (NIRS). Skin microcirculation was noninvasively measured using incident dark field imaging. Pre- and postductal SpO2 in Peruvian babies was 88.1 and 88.4%, respectively, which was 10.4 and 9.7% lower than in newborns at sea level (P < 0.001). Cerebral and regional oxygen saturation was significantly lower in the Peruvian newborns (cerebral: 71.0 vs. 74.9%; regional: 68.5 vs. 76.0%, P < 0.001). Transcutaneously measured total vessel density in the Peruvian newborns was 14% higher than that in the newborns born at sea level (29.7 vs. 26.0 mm/mm(2); P ≤ 0.001). This study demonstrates that microvascular vessel density in neonates born to mothers living at high altitude is higher than that in neonates born at sea level.

Vascular endothelial growth factor-A is associated with chronic mountain sickness in the Andean population.

A study of chronic mountain sickness (CMS) with a candidate gene--vascular endothelial growth factor A (VEGFA)--was carried out in a Peruvian population living at high altitude in Cerro de Pasco (4380 m). The study was performed by genotyping of 11 tag SNPs encompassing 2.2 kb of region of VEGFA gene in patients with a diagnosis of CMS (n = 131; 49.1 ± 12.7 years old) and unrelated healthy controls (n = 84; 47.2 ± 13.4 years old). The VEGFA tag SNP rs3025033 was found associated with CMS (p < 0.05), individuals with AG genotype have 2.5 more risk of CMS compared to those with GG genotype (p < 0.02; OR, 2.54; 95% CI: 1.10-5.88). Pairwise Fst and Nei's distance indicate genetic differentiation between Cerro de Pasco population and HapMap3 population (Fst > 0.36, p < 0.01), suggesting selection is operating on the VEGF gene. Our results suggest that VEGFA is associated with CMS in long-term residents at high altitude in the Peruvian Andes.

Prevalence, clinical profile, iron status, and subject-specific traits for excessive erythrocytosis in andean adults living permanently at 3,825 meters above sea level.

BACKGROUND: Excessive erythrocytosis (EE) is a prevalent condition in populations living at high altitudes (> 2,500 m above sea level). Few large population-based studies have explored the association between EE and multiple subject-specific traits including oxygen saturation, iron status indicators, and pulmonary function. METHODS: We enrolled a sex-stratified and age-stratified sample of 1,065 high-altitude residents aged ≥ 35 years from Puno, Peru (3,825 m above sea level) and conducted a standardized questionnaire and physical examination that included spirometry, pulse oximetry, and a blood sample for multiple clinical markers. Our primary objectives were to estimate the prevalence of EE, characterize the clinical profile and iron status indicators of subjects with EE, and describe subject-specific traits associated with EE. RESULTS: Overall prevalence of EE was 4.5% (95% CI, 3.3%-6.0%). Oxygen saturation was significantly lower among EE than non-EE group subjects (85.3% vs 90.1%, P < .001) but no difference was found in iron status indicators between both groups (P > .09 for all values). In multivariable logistic regression, we found that age ≥ 65 years (OR = 2.45, 95% CI, 1.16-5.09), male sex (3.86, 1.78-9.08), having metabolic syndrome (2.66, 1.27-5.75) or being overweight (5.20, 1.95-16.77), pulse oximetry < 85% (14.90, 6.43-34.90), and % predicted FVC < 80% (13.62, 4.40-41.80) were strongly associated with EE. Attributable fractions for EE were greatest for being overweight (26.7%), followed by male sex (21.5%), pulse oximetry < 85% (16.4%), having metabolic syndrome (14.4%), and % predicted FVC < 80% (9.3%). CONCLUSIONS: We found a lower prevalence of EE than in previous reports in the Peruvian Andes. Although the presence of hypoxemia and decreased vital capacity were strongly associated with excessive erythrocytosis, being overweight or having metabolic syndrome were associated with an important fraction of cases in our study population.

Regulation of hepcidin expression at high altitude.

Enhanced erythropoietic drive and iron deficiency both influence iron homeostasis through the suppression of the iron regulatory hormone hepcidin. Hypoxia also suppresses hepcidin through a mechanism that is unknown. We measured iron indices and plasma hepcidin levels in healthy volunteers during a 7-day sojourn to high altitude (4340 m above sea level), with and without prior intravenous iron loading. Without prior iron loading, a rapid reduction in plasma hepcidin was observed that was almost complete by the second day at altitude. This occurred before any index of iron availability had changed. Prior iron loading delayed the decrease in hepcidin until after the transferrin saturation, but not the ferritin concentration, had normalized. We conclude that hepcidin suppression by the hypoxia of high altitude is not driven by a reduction in iron stores.

Intravenous iron supplementation may protect against acute mountain sickness: a randomized, double-blinded, placebo-controlled trial.

Acute mountain sickness (AMS) is a common and disabling condition that occurs in healthy individuals ascending to high altitude. Based on the ability of iron to influence cellular oxygen sensing pathways, we hypothesized that iron supplementation would protect against AMS. To examine this hypothesis, 24 healthy sea-level residents were randomized to receive either intravenous iron(III)-hydroxide sucrose (200 mg) or saline placebo, before ascending rapidly to Cerro de Pasco, Peru (4340 m). The Lake Louise scoring system was used to assess incidence and severity of AMS at sea level and on the first full day at altitude. No significant difference in absolute AMS score was detected between the two groups either at baseline or at high altitude. However, the mean increase in AMS score was 65% smaller in the iron group than in the saline group (p<0.05), and the change in AMS score correlated negatively with the change in ferritin (R=-0.43; p<0.05). Hematocrit and arterial oxygen saturation were unaffected by iron. In conclusion, this preliminary randomized, double-blinded, placebo-controlled trial suggests that intravenous iron supplementation may protect against the symptoms of AMS in healthy volunteers.

Effects of iron supplementation and depletion on hypoxic pulmonary hypertension: two randomized controlled trials.

CONTEXT: Hypoxia is a major cause of pulmonary hypertension in respiratory disease and at high altitude. Recent work has established that the effect of hypoxia on pulmonary arterial pressure may depend on iron status, possibly acting through the transcription factor hypoxia-inducible factor, but the pathophysiological and clinical importance of this interaction is unknown. OBJECTIVE: To determine whether increasing or decreasing iron availability modifies altitude-induced hypoxic pulmonary hypertension. DESIGN, SETTING, AND PARTICIPANTS: Two randomized, double-blind, placebo-controlled protocols conducted in October-November 2008. In the first protocol, 22 healthy sea-level resident men (aged 19-60 years) were studied over 1 week of hypoxia at Cerro de Pasco, Peru (altitude 4340 m). In the second protocol, 11 high-altitude resident men (aged 30-59 years) diagnosed with chronic mountain sickness were studied over 1 month of hypoxia at Cerro de Pasco, Peru. INTERVENTION: In the first protocol, participants received intravenous infusions of Fe(III)-hydroxide sucrose (200 mg) or placebo on the third day of hypoxia. In the second protocol, patients underwent staged isovolemic venesection of 2 L of blood. Two weeks later, patients received intravenous infusions of Fe(III)-hydroxide sucrose (400 mg) or placebo, which were subsequently crossed over. MAIN OUTCOME MEASURE: Effect of varying iron availability on pulmonary artery systolic pressure (PASP) assessed by Doppler echocardiography. RESULTS: In the sea-level resident protocol, approximately 40% of the pulmonary hypertensive response to hypoxia was reversed by infusion of iron, which reduced PASP by 6 mm Hg (95% confidence interval [CI], 4-8 mm Hg), from 37 mm Hg (95% CI, 34-40 mm Hg) to 31 mm Hg (95% CI, 29-33 mm Hg; P = .01). In the chronic mountain sickness protocol, progressive iron deficiency induced by venesection was associated with an approximately 25% increase in PASP of 9 mm Hg (95% CI, 4-14 mm Hg), from 37 mm Hg (95% CI, 30-44 mm Hg) to 46 mm Hg (95% CI, 40-52 mm Hg; P = .003). During the subsequent crossover period, no acute effect of iron replacement on PASP was detected. CONCLUSION: Hypoxic pulmonary hypertension may be attenuated by iron supplementation and exacerbated by iron depletion. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00952302.

Pulmonary pressure and cardiac function in chronic mountain sickness patients.

BACKGROUND: Chronic mountain sickness (CMS) is characterized by a loss of adaptation to hypoxia in high-altitude (HA) dwellers. Chronic hypoxemia, excessive erythrocytosis and frequently pulmonary hypertension (PH), which may lead to cardiac failure, develop in patients. We sought to assess the determinants of cardiac function in CMS patients with hypoxia-induced PH. METHODS: Fifteen healthy men living at sea level (SL) were compared to 15 healthy men living at HA and 55 patients with CMS from Cerro de Pasco, Peru (altitude, 4,300 m). Pulmonary pressures and cardiac function were estimated by echocardiography. RESULTS: None of the subjects had overt cardiac failure symptoms. CMS patients exhibited elevated mean pulmonary pressures as assessed by high-tricuspid pressure gradients (CMS patients, 34 +/- 10 mm Hg; HA subjects, 25 +/- 4 mm Hg [p = 0.002]; and SL subjects, 19 +/- 3 mm Hg [p < 0.001]). They also showed right ventricular (RV) dilation (mean end-diastolic RV area: CMS patients, 17 +/- 2 cm(2); HA subjects, 13 +/- 2 cm(2); SL subjects, 12 +/- 2 cm(2); p < 0.001) but did not display impaired systolic ventricular function. However, the RV Tei index was increased in CMS and HA subjects (CMS patients, 0.56 +/- 0.15; HA subjects, 0.52 +/- 0.12; SL subjects, 0.21 +/- 0.12; p < 0.001). CONCLUSION: Despite obvious pulmonary arterial hypertension and right heart dilation, CMS patients did not show any symptom or echocardiographic parameter of heart failure. TRIAL REGISTRATION: ClinicalTrials.gov. Identifier: NCT00424970.

Abnormal energy regulation in early life: childhood gene expression may predict subsequent chronic mountain sickness.

BACKGROUND: Life at altitude depends on adaptation to ambient hypoxia. In the Andes, susceptibility to chronic mountain sickness (CMS), a clinical condition that occurs to native highlanders or to sea level natives with prolonged residence at high altitude, remains poorly understood. We hypothesized that hypoxia-associated gene expression in children of men with CMS might identify markers that predict the development of CMS in adults. We assessed distinct patterns of gene expression of hypoxia-responsive genes in children of highland Andean men, with and without CMS. METHODS: We compared molecular signatures in children of highland (HA) men with CMS (n = 10), without CMS (n = 10) and in sea level (SL) children (n = 20). Haemoglobin, haematocrit, and oxygen saturation were measured. Gene expression in white cells was assessed at HA and then, in the same subjects, within one hour of arrival at sea level. RESULTS: HA children showed higher expression levels of genes regulated by HIF (hypoxia inducible factor) and lower levels of those involved in glycolysis and in the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase kinase 1(PDK1) and HIF prolyl hydroxylase 3 (HPH3) mRNA expressions were lowest in children of CMS fathers at altitude. At sea level the pattern of gene expression in the 3 children's groups was indistinguishable. CONCLUSION: The molecular signatures of children of CMS patients show impaired adaptation to hypoxia. At altitude children of CMS fathers had defective coupling between glycolysis and mitochondria TCA cycle, which may be a key mechanism/biomarker for adult CMS. Early biologic markers of disease susceptibility in Andeans might impact health services and social planning.

Effect of acetazolamide on ventilatory response in subjects with chronic mountain sickness.

Although the effects of acetazolamide (ACZ) on ventilation during acute mountain sickness are well known, there are no studies assessing its effect on ventilatory response in chronic hypoxia. We studied this effect in patients with chronic mountain sickness (CMS). Subjects with CMS, living permanently at 4300 m, were assigned in a randomized, double-blind study to 250 mg/day (n=9) or to 500 mg/day (n=9) of ACZ. Resting end-tidal PET(O2) and end-tidal PET(CO2) were measured before and after 3 weeks of acetazolamide. Ventilatory responses were evaluated by the determination of sensitivity to hypoxia and to CO2. After treatment ventilatory response to hypoxia increased, resting PET(CO2) decreased, and ACZ caused a leftward shift in the position, but not a change in the slope of the ventilation (VE) versus PET(CO2) relationship. There were no differences between the two doses used. ACZ administration provides a beneficial effect on respiratory function of high altitude natives with CMS and thus it can be an effective therapy for the disease.

Adaptation and mal-adaptation to ambient hypoxia; Andean, Ethiopian and Himalayan patterns.

The study of the biology of evolution has been confined to laboratories and model organisms. However, controlled laboratory conditions are unlikely to model variations in environments that influence selection in wild populations. Thus, the study of "fitness" for survival and the genetics that influence this are best carried out in the field and in matching environments. Therefore, we studied highland populations in their native environments, to learn how they cope with ambient hypoxia. The Andeans, African highlanders and Himalayans have adapted differently to their hostile environment. Chronic mountain sickness (CMS), a loss of adaptation to altitude, is common in the Andes, occasionally found in the Himalayas; and absent from the East African altitude plateau. We compared molecular signatures (distinct patterns of gene expression) of hypoxia-related genes, in white blood cells (WBC) from Andeans with (n = 10), without CMS (n = 10) and sea-level controls from Lima (n = 20) with those obtained from CMS (n = 8) and controls (n = 5) Ladakhi subjects from the Tibetan altitude plateau. We further analyzed the expression of a subset of these genes in Ethiopian highlanders (n = 8). In all subjects, we performed the studies at their native altitude and after they were rendered normoxic. We identified a gene that predicted CMS in Andeans and Himalayans (PDP2). After achieving normoxia, WBC gene expression still distinguished Andean and Himalayan CMS subjects. Remarkably, analysis of the small subset of genes (n = 8) studied in all 3 highland populations showed normoxia induced gene expression changes in Andeans, but not in Ethiopians nor Himalayan controls. This is consistent with physiologic studies in which Ethiopians and Himalayans show a lack of responsiveness to hypoxia of the cerebral circulation and of the hypoxic ventilatory drive, and with the absence of CMS on the East African altitude plateau.