Browsing by Autor "Ricardo Amaru"

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Acute promyelocytic leukemia incidence in Andean highlanders with the NFKB1 haplotype (rs230511)
(Elsevier BV, 2025) Ricardo Amaru; Victor R. Gordeuk; Julieta Luna; Edgar Teddy Quispe Soto; Silvia Mancilla; Javier Valencia; Luis Felipe Mamani; Daniela Patón; Ariel Amaru
Abstract Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML), characterized by the oncogenic fusion protein PML-RARα, which results from the t(15;17) chromosomal translocation. APL accounts for approximately 4-10% of AML cases worldwide. The median age at diagnosis falls around the fifth decade of life, with a slight male predominance (PMID: 39682277). The PML-RARα fusion protein plays an essential role in the pathogenesis of APL by enhancing hypoxia-inducible factor (HIF)-driven transcriptional activity. PML-RARα acts as a transcriptional co-activator of HIF-α, amplifying HIF-mediated transcription independently of PML protein inhibition. This activation is unique to APL-specific fusion proteins; it is absent in other AML subtypes. The interaction of PML-RARα and HIF factors significantly influences disease progression and relapse. (PMID: 24711541). Transcriptomic analyses of APL cells reveal enrichment of NF-κB signaling pathways among differentially expressed genes, particularly those involved in cancer pathways. This suggests that NFKB1 contributes to the proliferative and survival signaling in APL cells (Villiers W, Nat. Commun, 2023). However, PML-RARα disrupts NF-κB activity by inhibiting phosphorylation and DNA binding of the NF-κB p65 subunit, suppressing NF-κB target gene expression. This disruption contributes to leukemogenesis through impaired differentiation and altered transcriptional regulation (Ahmed A, Sci.rep, March 2017). The incidence of APL varies across geographic regions and ethnic groups. Higher frequencies have been observed in Latin American populations compared to North America and Europe. These disparities suggest that genetic and environmental factors contribute to differences in disease distribution and outcomes (PMID: 12935956) and currently, there are no published data directly comparing APL incidence between populations living at sea level and those residing at high altitudes. We investigated the proportion of AML cases diagnosed as APL in Bolivian Andean highlanders residing at 4000 m, a population characterized by elevated HIF-α expression and a predominant NFKB1 haplotype rs230511 (95%) that results in a non-functional NFKB1 protein. We then compared the proportion of APL cases from Bolivian populations living at 2000m and 400 m. We analyzed 1,273 AML diagnoses from January 2000 to June 2025, grouped by altitude of residence: 406 at 4,000 m (mean age 37 years), 412 at 2,000 m (mean age 41 years), and 455 at 400 m (mean age 28 years). The overall mean age at AML diagnosis was 35 ± 25 years, with a male predominance of 54%. Among the total AML cases, 140 (11.0%) were identified as APL. We compared the proportion of AML cases classified as APL across three altitudes: at 4,000 m, 38 of 406 AML cases (9.4%) were APL; at 2,000 m, 46 of 412 cases (11.2%); and at 400 m, 56 of 455 cases (12.3%). There was a trend toward a lower proportion of APL cases at 4,000 m compared to 2,000 m and 400 m, although this difference was not statistically significant (P = 0.17). The age distribution of APL cases was as follows: 1-17 years, 44 cases (31.4%); 18-39 years, 59 cases (41.7%); 40–59 years, 30 cases (21.4%); and ≥60 years, 7 cases (5.0%). The age of AML patients was significantly lower at 400 m compared to the higher altitudes, whereas the proportion of males did not differ significantly by altitude. ConclusionsThe APL tends to decrease with increasing altitude, consistent with genetic adaptations in high-altitude Andean populations (~4000 m) involving increased HIF activity and a specific NFKB1 haplotypeThe 25-year incidence of APL was significantly lower in the La Paz population at 4000 m compared to populations at lower elevations (P &lt; 0.020).Individuals younger than 40 years are disproportionately affected, representing 73.1% of APL cases. The increased incidence in younger age groups does not vary by altitude, suggesting that genetic factors may predominantly drive this demographic pattern.Investigating genetic adaptations in high-altitude populations could offer novel insights into APL pathobiology and therapeutic strategies.
Allogeneic Hematopoietic Progenitor Cell from Peripheral Whole Blood in Acute Myeloid Leukemia
(Elsevier BV, 2024) Ricardo Amaru; Reyna Mamani; Jeaneth Velarde; Mireya Carrasco; Edgar Teddy Quispe Soto; Silvia Mancilla; Juan Carlos Valencia; Daniela Patón; Ariel Amaru
Acute Myeloid Leukemia (AML) standard treatment involves initial induction therapy administrating two cycles of the 3+7 protocol (3 days anthracycline + 7 days cytarabine), and post-remission therapy of 3 cycles of high-dose cytarabine. The 5-year overall survival is 20 % (PMID: 33734442). During prolonged aplasia, infections and hemorrhages can cause treatment failure and death (PMID: 32236160). That is why transfusions of allogeneic hematopoietic progenitor cells (Allo-HPC) from whole peripheral blood to reduce the time of aplasia and complications were of interest. We studied 6 patients (3 males, 3 females) with AML (M1, M2), average age 35 years (18-60 years), who received Allo-HPC from whole peripheral blood during aplasia after each 3+7 regimen. The transfusion was performed at day 14 (day 12-16) post-regimen, when patients had neutrophils &lt;100/ul (0-100/ul). Regarding donors, one corresponded to HLA identical sibling, and 5 to haploidentical (2 fathers, 2 mothers and 1 brother), they received G-CSF 300 μg subcutaneously every 12 hours over 3 days, then 450 ml phlebotomy was performed. Phlebotomy displayed median WBC 27,310/ul, neutrophils 21,830/ul, CD34+ cells 9/ul, hemoglobin 14.8 g/dl, and platelets 218,000/ul. Thus, whole peripheral blood obtained was transfused through patients' CVC after premedication with dexamethasone 8 mg and metamizole 1 g. FISH (Y chromosome, Vysis CEP-Y DYZ1) and RT-PCR (HUMARA gene) studies were performed for chimerism analysis. Recovery of neutrophils &gt;500/ul was observed at day 9 and platelets &gt;20,000/ul at day 6. One case of cutaneous rush was observed as an adverse event. MRD after each cycle reflected 0.01% average. Three patients remain alive with follow-up of 4 years, 5 years and 1 year respectively. Two patients relapsed and died during 1year follow-up. One patient developed optic neuritis and did not receive high-dose cytarabine therapy, relapsed and died after 6 months. None of the patients presented acute or chronic GVHD. Regarding the results of chimerism, one male patient (1year follow-up) showed mixed chimera by FISH (Y=95%) and by RT-PCR (HUMARA gene), such studies were still in progress in the other two women patients. Contrasting patients who received Allo-HPC from the ones who do not, statistically differences were found in neutrophils recovery and hospital staying, the former displayed 9 + 3 days vs 14 + 4 days (p=0.008) and 19 +5 days vs 25 + 4 days (p=0.009) respectively, infections also decreased from 83% to 25%. Transfusion of Allogeneic Hematopoietic Progenitor Cell from Peripheral whole blood reduces the duration of aplasia, infections, inpatient stays, and increases survival.
ALTAS DOSIS DE COBALAMINA Y ÁCIDO FÓLICO EN EL TRATAMIENTO DE LEUCOPENIAS POST COVID-19
(2021) Ricardo Amaru; Mireya Carrasco; Jeaneth Velarde; Reyna Mamani; Daniela Patón; Julieta Luna
Alteraciones en el patrón de apoptosis de células precursoras de eritrocitos en mujeres postmenopáusicas con eritrocitosis patológica de la altura
(2000) Adelis Arias; Ricardo Amaru; Pilar Navia; Gloria Rodrigo; R Peñaloza; G Torrez; A Vázquez; H Cuevas
ALTERACIONES HEMATOLÓGICAS EN GESTANTES CON COVID-19 RESIDENTES EN LA ALTURA
(2021) Gunder Aguirre; Carlos Urquieta; Edgar Chávez; Yuri Perez; Bianca Anahi Tarqui; Daniela Patón; Ricardo Amaru
Andean Aymara Enriched Genetic Variants Are Beneficial to High Altitude Adaptation of Andean Quechuas Living at 5000 m
(Elsevier BV, 2022) Ricardo Amaru; Emerson Cayo; Julieta Luna; Teddy Quispe; Josef T. Prchal; Jihyun Song
Populations living at high altitude developed distinct evolutionary genetic adaptations allowing them to exist in extreme hypobaric hypoxia condition. Tibetans and Andean highlanders (Aymaras and Quechuas) have inhabited regions over ~4000 m for 44,000 and 14,000 years, respectively (PMID: 28448578, 25342802). Unlike other high-altitude populations, such as Tibetans, Andeans' Aymaras and Quechuas have higher hemoglobin levels. Tibetan genomic analyses revealed evolutionary selected genetic signatures EPAS1, EGLN1 and PKLR genes (PMID:25129147; Song, ASH 2018). However non-DenisovanEPAS1 variants (rs13005507 and rs142764723) are present in Aymaras and Quechuas, and ~56% of Aymaras have Tibetan PKLR variants (Song, ASH 2018). Our whole genome study found that most Aymara evolutionary-enriched genes (BRNIP3, NOS2, SH2B1, and TBX5) are associated with cardiopulmonary development but not with hemoglobin levels (PMID: 29100088); different genomic selection was reported in Andean Quechuas (PMID:23954164). We then found previously unreported Aymara enriched NFKB1 single nucleotide polymorphisms (SNP) by integrative analysis of the Aymaras' genome and transcriptome, this SNP is also enriched in Quechuas but to the lesser degree. Decreased NFKB1 results in increased NF-kB levels leading to NF-kB driven increased inflammation as well as increased HIFs activity (PMID: 26513405) and is associated with high hemoglobin and inflammatory protein and transcript levels in Aymaras (Song, ASH 2018). We studied the presence of Aymara enriched SNPs in Quechua, one of Andean population living in Chorolque (5000 m) and their association with phenotypes at high altitude. We genotyped 5 Aymara enriched SNPs and PKLR (Table) in Quechuas (45 men, 14 women) living in Chorolque (5000 m) mining district, Potosi-Bolivia. All men were smokers while none of women were smokers. We also measured laboratory phenotypes leukocytes, platelets, lymphocytes, monocytes, neutrophils, as well as hemoglobin dissociation p50, SpO2, lactose, hemoglobin and hematocrit to study if genetic variants play a role in changes in these phenotypes. All Aymara enriched allele frequencies in Quechuas were lower than in Aymaras (Table). The allele frequencies of BRINP3, SH2B1, TBX5 in Quechuas were significantly different from those in Aymara, suggesting that Quechuas share some but not all genetic background with Aymaras. Since all men were smokers, we tested smoking effect on these phenotypes. Except hemoglobin and hematocrit levels, other phenotypes were comparable to women without smoking history. BRINP3 SNP positively correlated with SpO2 levels (r=0.2252, p=0.0893), suggesting that this SNP may have a role in delivery oxygen to tissue. PKLR SNP is associated with decreased levels of pyruvate kinase transcript levels, leading to increase 2,3 DPG and shifting hemoglobin dissociation curve to the right (increase of p50) (Song, ASH 2018). However, in these subjects, we did not find association in p50 but positive correlation with SpO2 (r=0.3423, p=0.0082). It suggests that presence of BRINP3 and PKLR SNPs is beneficial to live at low oxygen tension by delivering more oxygen to tissues. Total leukocytes, lymphocytes, and neutrophils were negatively correlated with NFKB1 SNP (r=-0.2349, r=-0.281, and r=-0.1725, respectively) which differed from our previous study of Aymaras at La Paz, suggesting that Quechuas may have different mechanisms in responding to inflammation from Aymaras. None of SNPs were associated with hematocrit and hemoglobin levels in men; however, we could not exclude effect of smoking. In females, NOS2 SNP were positively correlated with both hemoglobin and hematocrit (r=0.5513, p=0.0246). NO (nitric oxide) synthesized by NOS2 inhibits erythropoiesis (PMID: 18282521), suggesting that NOS2 SNP may decrease NO production resulting in inducing erythropoiesis in Quechuas. We conclude that while Quechuas and Aymaras share some genetic variants, but they differ in degree of selection for these SNPs. BRINP3 and PKLR SNPs are helpful to transfer more oxygen to tissues at high altitude. NFKB1 SNPs` inverse correlation with immune cells may provide protective functions in response to increased inflammation at high altitude (PMID: 26855492). Decreased NO production by NOS2 SNP may augment erythropoiesis in Quechuas, resulting in their higher hemoglobin and hematocrit at high altitude compared to Europeans. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal
Andean high-altitude dwellers with the NFKB1 haplotype (rs230511) are protected from acute mountain sickness
(Elsevier BV, 2025) Ricardo Amaru; Javier Valencia; Edgar Teddy Quispe Soto; Emerson Cayo; Julieta Luna; Daniela Patón; Victor R. Gordeuk; Josef T. Prchal; Jihyun Song
Abstract Acute Mountain Sickness (AMS) occurs with rapid ascent to high altitudes (&gt;2,500m), where air and oxygen pressures are lower than at sea level. AMS symptoms are headache, loss of appetite, nausea, dizziness, insomnia, fatigue and chest tightness, but severe AMS can progress to cerebral edema or pulmonary edema (PMID:26294748). Hypoxia at high altitude activates inflammatory pathways in which NF-κB signaling plays a central role. Severe hypoxia (1–3% O2) induces NF-κB-driven production of inflammatory mediators, connecting hypoxia-induced stress mediated by hypoxia-inducible factors (HIFs) with NF-κB. HIFs are also involved in responses that increase pulmonary vascular permeability, pulmonary hypertension, and edema (PMIDs:11441701;3410239;18641050). HIFs increase blood-brain barrier permeability, a central feature of high-altitude cerebral edema (PMID:33856254). NFKB1 is part of NF-κB complex and modulates NF-κB activity. NFKB1 also augments activity of HIFs. In our study of evolutionary adaptation to extreme high altitude of Andean native Aymara who have higher hemoglobin than Europeans living at the same high-altitude (PMIDs: 24039843; 29100088), we reported that the evolutionary selected T allele of NFKB1 rs230511 haplotype is linked to previously unreported alternate splicing of NFKB1, including skipping exon 4, exon 5, or both exons 4 and 5. It is present in ~90% of Aymara, but it also exists at lower frequency in Europeans, Asians and Hispanics (~30%). These alternatively spliced NFKB1 transcripts result in partial or complete loss of NFKB1 protein expression. This Aymara NFKB1haplotype is associated with increased baseline expression of inflammatory and HIF-regulated genes and correlates with those Aymara having high hemoglobin. However, under inflammatory stress, it has the opposite effect: nuclear translocation of NF-kB protein is attenuated, resulting in reduced expression of inflammatory, HIF-regulated, and prothrombotic genes (PMID:39971917). Since the incidence of AMS in the Aymara population is 0.6 % (Viruez, Horiz Med [Lima] 2020; 20(3): e943), which is markedly lower than the 1.7 % observed in non-Aymara at the same altitude (Castellanos, Correo Científico Médico 2022; 26), we hypothesized that rs230511-T is also associated with a protective role for AMS in Aymara. We studied 35 Bolivian Aymara in LaPaz (altitude of 4000 meters) who relocated to lower altitudes (&lt;400 m) for 1 month to 5 years and then returned to 4000 m and developed AMS. Among 35 subjects, 10 participants- 5 women (age 29±14 years) and 5 men (age 39±8 years)- without a history of medical comorbidities (except for one having history of gout) developed AMS. The 25 subjects who did not develop AMS served as controls (7 women, age 40±14 years and 18 men, age 38±11 years). All participants were genotyped for the NFKB1(rs230511) and NOS2 (rs34913965) variants; NOS2 was included due to a potential relationship with AMS (PMID:29100088). Among the subjects who developed AMS, the allele frequencies for the Aymara-enrichedNFKB1 variant were C:0.75 and T:0.25, compared to C:0.0 and T:1.0 in the control group (p&lt;0.0001). The genotype frequencies were CC:50%, CT:50% and TT:0% in the AMS group and CC:0%, CT:0% and TT:100% in the control group (p&lt;0.0001). For the NOS2 C/T haplotype variant, analysis of 7 AMS patients revealed that allele frequencies (T-Aymara enriched allele PMID:29100088) were C:0.14 and T:0.86, compared to C:0.1 and T:0.9 in the control group (p=0.5146). The genotype frequencies were CC:0%, CT:29%, and TT:71% in the AMS group, but CC:4%, CT:12%, and TT:84% in the control group (p=0.011). We classified AMS severity as severe (4 patients admitted to the intensive care unit), moderate (2 patients hospitalized), and mild (4 patients managed at home). Two patients with severe AMS who developed both pulmonary and cerebral edema had an Aymara NFKB1 allele frequency of C: 1.0 and T: 0.0, a 100% CC genotype. Our findings suggest that the presence of the Aymara evolutionary selected NFKB1 haplotype protects from developing AMS, whereas its absence (CC genotype) increases the likelihood of development of severe AMS. The CT genotype of NOS2 variant may also provide some protective effect. Larger cohorts and functional assays are needed to validate these associations and to further explore the molecular mechanisms by which the NFKB1 and NOS2 variants contribute to protection against AMS.
Atorvastan, Apsirin and Hydorxyurea for an Effective and Low-Cost Treatment in High-Risk Polycythemia Vera
(European Medical Journal, 2022) Ricardo Amaru; Mireya Carrasco; Victor R. Gordeuk; Teddy Quispe; Silvia Mancilla; Daniela Patón; Ariel Amaru
Introduction: Polycythemia vera (PV) treatment focuses on preventing thrombotic events and delaying transformation to myelofibrosis or leukaemia. According to risk stratification, low-risk patients require therapeutic phlebotomy combined with acetylsalicylic acid, whilst the treatment of high-risk patients with PV relies on cytoreductive therapies, employing hydroxyurea (HU), ruxolitinib, or interferons. However, in low- and middle-income countries, the availability and cost of these drugs poses a challenge in treating high-risk patients, so optimising existing resources is required. Method: A prospective longitudinal study aimed to investigate the combination of atorvastatin (ATV), aspirin, and low-dose HU as a therapeutic strategy to treat PV in high-risk patients. The study evaluated the effect of statins on erythroid colony proliferation in vitro, as well as the applicability of ATV (20 mg/day), acetylsalicylic acid (100 mg/day), and hydroxiurea (500 mg/day) in high-risk patients with PV from La Paz, Bolivia, residing at 3,600 metres above sea level. Results: Simvastatin (3.5 μm) inhibited UKE-1 cell (JAK2V617F mutated) proliferation at 33%, and burstforming unit-erythroid colonies from patients with PV at 61%. Patients receiving ATV, aspirin, and low-dose HU displayed a good response and adequate tolerance to treatment (13-years follow-up). No patients experienced myelofibrosis or transformation to leukaemia, and no severe adverse events were observed. Conclusions: This accessible, effective, and low-cost therapeutic strategy could improve adherence to treatment and the overall survival of high-risk patients with PV in resource-limited countries.
Bolivian Aymara Natives with Chronic Mountain Sickness Have Autonomous BFU-E Growth
(Elsevier BV, 2015) Ricardo Amaru; Ariel Amaru; Hortensia Miguez; Torres Gina; Josué Mamani; Oscar Vera; Heriberto Cuevas; Josef T. Prchal; Jaroslav F. Prchal
Abstract Background Erythrocytosis / polycythemia is divided into primary and secondary. Primary polycythemia can be either acquired; i.e. polycythemia vera (PV) due to somatic JAK2 mutation, or congenital due to germ-line DNA changes (erythropoietin (EPO) receptor and VHL mutations in Chuvash polycythemia). These mutations are expressed within erythroid progenitors, drive increased erythropoiesis and are detected by hypersensitive or autonomous EPO BFU-E responses. In contrast, secondary erythrocytosis (SE), such as seen with cardiopulmonary pathologies, is driven by the circulating EPO. Chronic mountain sickness (CMS) is characterized by high altitude pathological erythrocytosis and by cognitive and neurological impairments. CMS is found in subjects living in high altitude (2500 meters and higher). In La Paz, Bolivia, (3600m) there is 7% incidence of CMS erythrocytosis. Some human populations (Tibetans, Andean Quechuas and Aymaras, and Ethiopians) are adapted to very high altitudes and their adapted phenotypes and, in some instances, evolutionarily selected haplotypes, have been reported. Whole genome was evaluated in Andeans and two genes, SENP1 and ANP32D were found to be evolutionarily selected and correlated with presence or absence of erythrocytosis. The genes down-regulation in hypoxia had survival benefit in Drosophila ortholog (1).SENP1 desumoylate GATA-1 and other regulatory proteins and is critical for definitive erythropoiesis (2,3). Here we evaluated native Aymara La Paz dwellers with three types of polycythemia: CMS, SE secondary to cardiopulmonary disease, and PV, by clinical studies and by in vitro evaluation of erythroid progenitors, and compared them to non-polycythemic subjects. Patients and Methods Complete blood count was performed by automatic hematologic counter (Micro 60, USA). Serum EPO was measured by Elisa (R&D System, USA) and JAK2V617F mutation analysis by PCR assay. Erythroid progenitors were isolated by density gradient centrifugation and cultured in methylcellulose medium with and without EPO (Stem Cell technologies, Canada) at 370 C and 5 % CO2. BFU-E colonies reading was carried out according to standardized criteria at 7 and 14 days. Results Table. Normal Control(n=10) CMS (n=15) Secondary Erythrocytosis(n=10) PolycythemiaVera (n=5) 1.Gender M/F 10/0 15/0 10/0 3/2 Age (range) 42 (40-47) 48 (29-58) 53 (34-72) 67 (42-74) Hb g/dl (SD) 16.2 (+ 0.9) 20.3 (+ 0.9) 22.8 (+ 1.4) 20.0 (+ 2.5) Ret % (SD) 1.3 (+ 0.1) 2.9 (+ 1.3) 3.6 (+ 1.2) 2.1 (+ 0.3) WBC /ul (SD) 6300 (+ 1600) 7200 (+ 1900) 6600 (+ 1700) 16600 (+ 4800) PLT 103 ul (SD) 273 (+ 80) 229 (+ 58) 193 (+ 54) 604 (+ 177) sEPO mUI/ml (SD) 10.0 (+ 3.9) 10.5 (+ 2.2) 82.9 (+ 30.4) 3.0 (+ 1.2) JAK2 V617F, No. (%) 0 (0) 0 (0) 0 (0) 100 Apoptosis Normal Delayed Normal Delayed BFU-E: EEC 0 (0-0) 10 (2-25) 0 (0-0) 45 (25-70) References: 1. Yu L et al. J Exp Med., 2010, 207:1183. 2. Sharma D et al. Cell Report, 2013, 3:1640. 3. Zhou D et al. Am J Hum Genet. 2013, 93:452. 4. Kapralova K et al. Blood. 2014,123:391 Conclusions a) Endogenous erythroid colony (EEC) are present in Aymaras with CMS, indicating primary polycythemia. b) Endogenous EECs are higher in PV than in CMS. c) CMS subjects have normal serum EPO levels. d) The role of SENP1, and hypoxia-regulated RUNX1 and NF-E2 (4) that promote erythropoiesis, is being interrogated in native erythroid cells. e) It remains to be determined if the autonomous BFU-E growth is specific for Aymara's CMS or present in CMS individuals of other ethnicities. Disclosures No relevant conflicts of interest to declare.
Características bio-celulares de las leucemias agudas en Bolivia y su diversidad en relación con otros países: Reporte de 100 casos de leucemias agudas
(2001) Ricardo Amaru; R Peñaloza; G Torres; A Vásquez; Nicolás Espejo Yaksic; Hugo A Míguez; Mónica Lizett Perez Limachi; Zaida Patiño; Luis Flores Morillas; Homero Cuevas
DNA-UMSAgen, EXTRACCIÓN DE DNA GENÓMICO PARA DIAGNÓSTICO MOLECULAR: MÉTODO RÁPIDO Y ECONÓMICO
(2006) Ricardo Amaru; Hortencia Miguez; Rosario Peñaloza; Gina Torres; Julio Silvestre; Heriberto Cuevas
Do Andean Aymara High‐Altitude–Enriched Genetic Variants Protect Europeans Against Acute Mountain Sickness?
(Wiley, 2026) Josef T. Prchal; M. Burtscher; Soo Jin Kim; Maria Wille; Ricardo Amaru; Jihyun Song
The authors declare no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analyzed during the current study.
Do Andean Aymaras' Evolutionary Selected Genes to High Altitude Hypoxia Also Influence Hemoglobin Concentration of Europeans and Their Acute Hypoxia Responses?
(Elsevier BV, 2022) Divya Sundar; Grace Min; Martin Burtscher; Ricardo Amaru; Maria Wille; Soo Jin Kim; Josef T. Prchal; Jihyun Song
The major regulation of hemoglobin levels (Hb) is hypoxia regulated by hypoxia inducible factors (HIFs). Some mutations of hypoxia sensing pathway increase HIFs and cause erythrocytosis (PMID: 23733342). Some high-altitude dwellers developed beneficial genomic evolution, facilitating their existence in high altitude hypoxia. Tibetans have been exposed to longer evolutionary selection than Andeans for approximately 44,000 and 14,000 years, respectively (PMID: 28448578, 25342802). This evolutionary pressure accounted for unique Tibetan haplotypes; it decreased HIFs activity and lowered Hb (PMID: 25129147). In contrast, Andean natives, Quechuas and Aymaras underwent different evolutionary adaptations to environmental hypoxia developinghigh Hb. We previously studied Aymaras at high-altitude and identified their evolutionary selected genes. The 5 most selected genes - BRINP3, NOS2, TBX5,SH2B1, and PYGM have some roles in cardiopulmonary development, but their functional consequences are unknown. None of these 5 highly selected Aymara genes are correlated with their Hb levels (PMID: 29100088). The single nucleotide polymorphisms (SNPs) of these genes also exist in Europeans, although in much lower frequency (Table). In contrast, NFKB1 rs230511 (allele frequency: 88% of Aymaras) underwent lower selection, but was still significant and correlated with the elevated hemoglobin in Aymaras (Song, ASH2018). It is also present in Europeans but at lower gene frequency (38%). NFKB1 is an inhibitor of NF-kB. Our previous analysis of differential exon usage of Aymara transcriptome found two previously unreported alternative splice transcripts of NFKB1 with exons 4 or 5 skipped transcripts. These transcripts correlated with Aymara enriched NFKB1 rs230511 and resulted in non-functional truncated-NFKB1 protein. Decreased NFKB1 results in increased NF-kB levels leading to NF-kB driven increased inflammation as well as increased HIFs activity (PMID: 26513405). Here, we interrogated associations among 6 Aymara hypoxia selected SNPs with physiological changes akinwith being rapidly exposed to hypobaric hypoxia (equivalent to 4500m) (Table). We isolated DNA from plasma 79 young and fit Austrian volunteers before and after exposure to hypoxia. Mean age was 26 ± 5.4 years (female = 34, male = 40 ). Their physiological responses to acute hypoxia were monitored at specific time intervals (0hr, 3hr, 6hr). These intervals included heart rate, systolic and diastolic blood pressures, oxygen saturation SpO2 and SaO2, PaCO2, blood pH, lactate and parameters of acute mountain sickness by Lake Louis score(PMID: 29583031). Their baseline Hb levels were also measured. These parameters were correlated with their 6 Aymara-enriched SNP. The Hb was only significantly higher in females with Aymara selected NFKB1 rs230511 by T test (p= 0.0163) and by Bartlett's test at p=0.017. Other SNPs have reached statistical significance in correlation with physiological parameters corresponding to acute hypoxic exposure. NOS2 rs34913975 correlated negatively with SpO2 (p= 0.0451), systolic blood pressure (p=0.0307) and diastolic blood pressure (p=0.0388), while SH2B1 rs 12448902 negatively correlated with SpO2 in heterozygotes (p=0.0068, ). The PYGM rs487105 correlated with systolic blood pressure (p=0.0095), and heart rate p=0.0442. However, some of these associations revealed trends for correlation.Since several Aymara-enriched SNPs had low allele frequency in Europeans, some correlations may not have reached enough statistical significance. A larger cohort may be needed for evaluation. In contrast, NFKB1 rs230511 correlated in females with higher Hb, but also with several other physiological responses to acute hypoxia in this cohort. It correlated positively with SpO2, systolic blood pressure (p=0.0041) and diastolic blood pressure (p=0.0114) while negatively with PaCO2 (p=0.0487) and Lake Louis score(p=0.0184). We conclude that the evolutionary-selected genes to chronic environmental hypoxia in Aymaras appear to also have function in Europeans. NFKB1 rs230511 has a significant association with higher Hb in the European females and is beneficial in some physiological responses to acute hypoxia. DS and GM contributed equally in this abstract. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal
ERITROCITOSIS PATOLÓGICA DE ALTURA: CARACTERIZACIÓN BIOLÓGICA, DIAGNÓSTICO Y TRATAMIENTO
(2013) Ricardo Amaru; Hortencia Miguez; Rosario Peñaloza; Gina Torres; Oscar Vera; Jeaneth Velarde; Nelly Huarachi; Reyna Mamani; Heriberto Cuevas
Erythroid and Cardiovascular High Altitude-Selected Haplotypes in Andean Aymaras and Tibetans
(Elsevier BV, 2017) Ricardo Amaru; Jihyun Song; N. Scott Reading; Victor R. Gordeuk; Teddy Quispe; Lorna G. Moore; Rasmus Nielsen; Josef T. Prchal
Abstract Humans migrating out of Africa encountered new conditions, including living at high altitude. Tibetans and Andean Aymaras have inhabited regions of 4,000 meters or more for ~44,000 and 14,000 years respectively (Hu et al, PLoS Genet 2017, Rademaker et al, Science 2014). There is a distinct difference in erythroid phenotypes: Aymaras are polycythemic at high altitude, while most Tibetans are not. Mutations providing an advantage in highlanders will improve fitness under hypoxic conditions,including modulation of erythropoiesis through the hypoxia-inducible factor (HIF) pathway. There are few shared, naturally-selected gene regions in Aymaras and Tibetans and these have different phenotypic associations (Bigham et al, Am J Hum Biol 2013). Aymara high-altitude selected haplotypes have not been published. Tibetan EPAS 1 (encoding HIF2a protein) haplotypes in part originated from ancient Denisovans and entered the Tibetan genome through introgression (Huerta-Sanchez et al, Nature 2014). Tibetan variant prolyl hydroxylase 2 (PHD2), a negative regulator of HIFs encoded by EGLN1 gene, encodes in cis both PHD2D4E and PHD2C127S which together have increased activity in hypoxia (Lorenzo et al, Nature Genetics 2014) and, together with a Tibetan EPAS 1 haplotype, protects from high altitude polycythemia (Tashi et al, JMM 2017). We and others previously identified other Tibetans haplotypes that are not unique but are enriched in Tibetans, including a “Tibetan” haplotype of PKLR encoding liver- and red cell-specific pyruvate kinase (PK) (Simonson et al, Science 2010, and Yi et al, Science 2010). We studied Tibetan-enriched haplotypes of EGLN1, EPAS1 and PKLR in 72 Bolivian Andean Aymaras, all residing at 4,000 m, and compared them with 347 Tibetans living at altitudes of 200 m and 4,300 m (Table). We genotyped PHD2D4E and PHD2C127S variants of EGLN1 and 10 Tibetan specific single nucleotide polymorphisms (SNPs) of EPAS1, 5 Denisovan and 5 non-Denisovan, each under different linkage disequilibrium (Hu et all, PLoS Genet 2017), 7 Tibetan enriched PKLR SNPs, and searched for Aymara selected variants by whole genome sequencing. The prevalence of the Tibetan-selected EGLN1 and EPAS1 haplotypes increased with increasing altitude of residence in Tibetans, suggesting a continuous evolutionary advantage (Tashi et al, JMM 2017). Aymaras did not have the PHD2D4E haplotype, and PHD2C127S was found at lower prevalence in heterozygote form. Aymaras shared two of five non-Denisovan EPAS1 SNPs selected in Tibetans; one, rs130005507 G allele, had a similar prevalence to Tibetans, but another, rs142764723 C allele, had a lower prevalence. We report that >90% of Tibetans and ~50% of Aymaras, but only ~10% of Europeans, have the “Tibetan ” PKLR haplotype. Aymara females with homozygous PKLR haplotypes have lower hemoglobins than heterozygotes (p=0.022). Further, the PKLR transcript in reticulocytes decreases with increasing altitude and this progressive decrease is even more pronounced in the “Tibetan” haplotype. We found Aymaras' selected haplotypes encoding BRINP3, NOS2, TBX5 ; these genes are associated with cardiovascular development and function but not hypoxia sensing. They are not enriched in Tibetans. We conclude that Aymara highlanders do not have the Tibetan PHD2D4E mutation or Denisovan-like EPAS1 variants. Furthermore, they share only two of five Tibetan non- Denisovan EPAS1 variants. The absence of these variants in Aymaras supports that Tibetan and Aymara high altitude inhabitants do not have the same ancestry, that they developed different evolutionary adaptations (Bigham et al, Am J Hum Biol 2013), and that Tibetans' EGLN1 and EPAS1 mutations are unique to that part of the world. We hypothesize that decreased PK enzyme activity would be expected to increase 2,3-diphosphoglycerate (2,3-DPG) (as is shown in people with PK enzyme deficiency) and thus be beneficial to high altitude adaptation by progressively augmenting tissue oxygen delivery with increasing altitude. Based on its association with lower hemoglobin in Aymara females, the selected “Tibetan” PKLR haplotype, present in about half of Aymaras, may contribute to their hypoxic adaptation. Additional evaluation of evolutionary selected genes including PKLR, BRINP3, NOS 2, and TBX5 and their functional consequences are in progress with Aymaras living at El Alto (4,150 m), Cochabamba (2,500 m) and Santa Cruz, (416m), Bolivia. Download : Download high-res image (320KB) Download : Download full-size image Disclosures No relevant conflicts of interest to declare.
Erythroid Leukemia Is Increased at High Altitude (4000 m)
(Elsevier BV, 2024) Ricardo Amaru; Maria Julieta Luna Leyza; Luis Felipe Mamani; Silvia Mancilla; Daniela Patón; Juan Carlos Valencia; Mireya Carrasco; Ariel Amaru
Acute erythroid leukemia (AEL) also known as pure erythroid leukemia (PEL) from the 2016 WHO update (PMID: 35264503; Wang, Am J Hematol. 2017; 92: 292-296) is a rare and unique subtype of acute myeloid leukemia (AML). It is characterized by immature erythroid precursors predominance with a high frequency of gains and amplifications involving EPOR/JAK2 (PMID: 35839275) and phosphorylation of ERK1/2 by inhibiting Fli-1 Promoter Activity (Min Mo, Catalysts, 2022. 13.1:84). AEL accounts for 1% of AML cases and can evolve from prior myelodysplastic syndrome or develop de novo, it is typically observed in adults with a median age ranging 66-68 years, and of dismal prognosis (&lt;6 months overall median survival) (PMID: 36323674). Its distinction attributes to erythroblastic proliferation (&gt;80%), pancytopenia, and extensive bone marrow involvement by proerythroblasts (≥30%). Common immunophenotype markers include CD105, CD34, CD71, CD36, CD235 (Wang, Am J Hematol. 2017). Moreover, it has been reported that hypoxia influences the development of erythroleukemia through various mechanisms, including promoting erythroid differentiation, inducing hemoglobin production, defining cell heterogeneity, regulating erythropoiesis, and influencing the bone marrow microenvironment (PMID: 33675821; 17255519). Regardingly, an overexpression of HIFs is related with a bad prognosis in AML (PMID: 25687039), HIF-1α is involved in cancer early stages, whereas HIF-2α in the later stages (PMID: 29753878). HIF-2a expression plays an important role in regulating proliferation in erythroleukemia cells under hypoxia (PMID: 26898802). Thus, we aimed to search for the hematologic and immunophenotypic characteristics of AEL cases among all AML diagnoses at high altitude. We retrospectively analyzed cases of AML diagnosed in Bolivia from the period of May 2019 to April 2024 considering the different altitudes 4000m (n=68), 2000m (n=62), and 400m (n=71), and gathered a comprehensive account of hematologic, bone marrow morphology, and immunophenotypic features. Among AML cases (n=201), 13 cases of AEL were identified which corresponded to 6.5 %. Interestingly, AEL cases at 4000 m accounted for 13.2 % (female 2, male 7, median age 54 years), and this was significantly higher (p=0.02) when compared to cases at 2000 m representing 3.2 % (female 1, male 1, median age 75 years) or at 400 m with 2.8 % (female 2, median age 52 years). Hematologic indices displayed mean Hb 7.3 g/dl, WBC: 11515/ul and Plt: 127154/ul. Bone marrow findings reflected &gt; 80% of prominent erythroid precursors with large irregular nuclei, dispersed chromatin, 1 to 3 elongated nucleoli, deeply basophilic cytoplasm, and an intense mitotic activity. Immunophenotypic features revealed CD34, CD71, CD105, CD36 and CD235 regarding erythroid clonality. AEL incidence is increased at high altitude, reflects intriguingly morphology and hematological characteristics. This increase may be due to the increase in HIF and Epo at high altitude, since the barometric pressure (462 mmHg) and the oxygen level in the air (14%) at high altitude are low. So, further studies elucidating the genetic mechanism involved are of interest.
FILTRO DE AGUA EN LA PREPARACIÓN DE QUIMIOTERAPIA PARA OPTIMIZAR LA BIOSEGURIDAD
(2016) Jeaneth Velarde; Reyna Mamani; Nelly Guarachi; Teddy Quispe; Ricardo Amaru; Heriberto Cuevas
FRECUENCIA DE TRANSCRITOS BCR/ABL P210 EN 272 PACIENTES CON LEUCEMIA MIELOIDE CRÓNICA (LMC) EN BOLIVIA
(2016) Ariel Amaru Calzada; Jose Masias; Eduardo Ustarez; German Choque; Rosario Peñaloza; Silvia Mansilla; Ricardo Amaru
Hematopoietic Progenitor Cells From Patients with Chronic Mountain Sickness Lack the JAK2V617F Mutation, Show Hypersensitivity to Erythropoietin and Are Inhibited by Statins.
(Elsevier BV, 2009) Ricardo Amaru; Martin Villarroel; Hortencia Miguez; Rosario Peñaloza; Gina Torres; Tiziano Barbui; Josée Golay; Alessandro Rambaldi
Abstract Abstract 1894 Poster Board I-917 Background Chronic Mountain Sickness (CMS) is a clinical entity that occurs in native or long-life residents above 2500 meters of altitude. The disease is characterized by massive erythrocytosis, hyperviscosity syndrome (headache, dyspnea and cyanosis) severe hypoxemia and cardiopulmonary symptoms. The etiology is unknown and no association has been found with Erythropoietin (EPO), Epo receptor (EpoR), Hypoxia Inducible Factor 1a (HIF-1a), von Hippel Lindau (VHL), as well as PHD1, PHD2, PHD3 or PTEN genes. Therapy relies on phlebotomy and oxygen support. Acetazolamide, Medroxyprogesterone and Enalapril have also been tested, but their use has not been largely implemented. Since HMG-CoA inhibitors such as farnesyltransferase inhibitors (Larghero, Blood 2005) may inhibit the in vitro autonomous erythropoiesis of polycythemia vera patients, we studied in CMS the therapeutic potential of statins that have similar pharmacologic activity. Patients and Methods Normal controls (NC, n= 10) and patients were native Bolivians from the city of La Paz, Bolivia (3600–4000 mt altitude). The diagnosis of CMS (n=15) was made according to the consensus statement on this disease (Leon-Velarde, 2005). The diagnosis of Polycythemia Vera (PV, n= 5) or secondary erythrocytosis (SE, n= 10) was done according to WHO criteria or established clinical guidelines. Serum Erythropoietin (sEpo) was assessed by chemiluminescent assay. Burst forming units-erythroid (BFU-E) assay was performed by plating 105 BM mononuclear cells in methylcellulose with or without recombinant human rhEpo (2IU/ml) and Simvastatin (20 mM). Evaluation of apoptosis by Annexin V/7-AAD and JAK2V617F mutational analyses were performed as described (Guerini et al, Leukemia 2008). Results CMS patients (median age 48 years, range 29–58) had median values of hemoglobin and hematocrit (Hb 20.3 gr/dl, range: 19.1–22 and Hct, 62%) significantly higher than observed in NC (Hb 16.2 gr/dl, range 14.8–16.5 and Htc 52%), respectively (p< 0.001) and significantly lower than SE patients (Hb: 22.8 gr/dl, range 20.2–25 and Htc: 71%), (p<0.001). Hb and Hct were not different in CMS and PV patients (p= 0.875). In CMS sEpo values (median 22 mIU/mL, range: 16.1–45.1) were significantly higher compared to NC (median 10.7 mIU/mL, range 7–18.8) (p<0.001) and lower compared to SE patients (median 82.9 mIU/mL, range 44.8–135) (p<0.001); as expected, PV patients showed very low sEpo levels (median 3 mIU/ml, range 2.5–5.2). The JAK2V617F mutation analysis proved negative in all NC, CMS and SE patients and positive in PV. In the absence of exogenous rhEpo, a median of 0, 10, 0, 45 BFU-E colonies were obtained from NC, CMS, SE and PV patients. When rhEpo was added, 21, 40, 47 and 130 BFU-E were counted, respectively; this difference was significant when comparing NC and PV to CMS (p<0.001; p< 0.001 respectively), but not in the case of SE vs. CMS (p= 0.227). Interestingly, in PV and CMS patients, BFU-E colonies remain remarkably viable between day 14–21 while viability declined rapidly in NC and SE colonies after day 14. The prolonged viability and higher sensitivity to rhEpo of BFU-E obtained from CMS and PV erythroid progenitors was also confirmed by plating BM mononuclear cells with suboptimal doses of rhEpo (0.03 to 1 IU/ml). Moreover, when simvastatin (20 μM) was added in vitro to rhEpo driven BFU-E colonies, it induced a median inhibition of 29% in NC as compared to 37, 56 and 44 in CMS, SE and PV (p <0.013: p<0.001; p<0.001, respectively). Finally, 11 CMS patients who had a concomitant hypercholesterolemia (median cholesterol level 238 mg/dl, range 206– 310) had the opportunity to be treated with statins (atorvastatin, 20–40 mg/day). Before starting treatment with atorvastatin, all patients, who had median Hb and Htc values of 19.9 gr/dl and 63 % respectively, performed phlebotomy. After a median follow up of 18 months with atorvastatin, the median Hb and Htc values were 17.1 gr/dl and 54.6 %, respectively. The need of phlebotomy was apparently reduced, from 4–6 sessions/year to 1. Conclusions Our results underline that a) hematopoietic progenitor cells from CMS patients may promote an autonomous erythroid colony growth and show hypersensitivity to hrEpo b) statins may induce in vitro a significant inhibition of this accelerated erythropoiesis so that they could play a therapeutic role in the treatment of this and other chronic myeloproliferative disorders. Disclosures: No relevant conflicts of interest to declare.
High altitude genetic adaptation in Tibetans: No role of increased hemoglobin–oxygen affinity
(Elsevier BV, 2014) Tsewang Tashi; Tang Feng; Parvaiz A Koul; Ricardo Amaru; Dottie Hussey; Felipe Lorenzo; Ri‐Li Ge; Josef T. Prchal