Prácticas culturales en la lactancia materna. Revisión integrativa. / Cultural Practices In Breastfeeding: Integrative Review

Introducción: Existen muchas culturas con sus propias creencias y costumbres con respecto a la lactancia materna. Estas costumbres pueden ser correctas o incorrectas, por tanto, el profesional debe hacer uso de la interculturalidad. Objetivo: Describir y analizar las prácticas culturales en la lactancia materna. Método: Revisión Integrativa de la literatura en las bases de datos: Scielo, ScienceDirect, PubMed, SpringerLink y BVS. Resultados: Los 16 artículos seleccionados, se analizaron en 5 categorías: Prácticas culturales que deben reestructurarse, razones para la introducción de otros alimentos, prácticas culturales que deben acomodarse, prácticas culturales que pueden mantenerse, influencia sociocultural. Conclusión: Existen prácticas culturales que deben reestructurarse (uso del agua, leche de vaca, cabra, mantequilla antes de los 6 meses de edad); otras que deben acomodarse (descarte del calostro) y otras que deben mantenerse (uso de alimentos que mejoran la producción láctea). Las personas cercanas a la madre (sus madres y suegras) son las que más influyen; por ello, lo que debe procurar el profesional de la salud, es ejecutar acciones interinstitucionales dirigidas a la promoción de la lactancia materna, con un enfoque intercultural. (AU)

Introduction: There are many cultures with their own beliefs and customs regarding breastfeeding. These customs can be correct or incorrect, therefore, the professional must make use of interculturality. Objective: Describe and analyze cultural practices in breastfeeding. Method: Integrative review of the literature in the databases: Scielo, ScienceDirect, PubMed, SpringerLink and BVS. Results: The 16 selected articles were analyzed in 5 categories: Cultural practices that must be restructured, reasons for the introduction of other foods, cultural practices that must be accommodated, cultural practices that can be maintained, sociocultural influence. Conclusion: There are cultural practices that must be restructured (use of water, cow's milk, goat's milk, butter before 6 months of age); others that must be accommodated (discarding colostrum) and others that must be maintained (use of foods that improve milk production). People close to the mother (her mothers and mothers-in-law) are the most influential; Therefore, what the health professional must seek is to execute inter-institutional actions aimed at promoting breastfeeding, with an intercultural approach. (AU)

Inhibition of phosphate transport by NAD+/NADH brush border membrane vesicles.

Nicotinamide is an important regulator of Pi homeostasis after conversion into NAD+/NADH. In this work, we have studied the classical inhibition of Pi transport by these compounds in the brush border membrane vesicles (BBMV) of rat kidney and rat intestine, and we examined the effects in opossum kidney (OK) cells and in phosphate transporter-expressing Xenopus laevis oocytes. In BBMV, NAD+ required preincubation at either room temperature or on ice to inhibit Pi uptake in BBMV. However, no effects were observed in the known Slc34 or Slc20 Pi transporters expressed in Xenopus oocytes, in OK cells, or in isolated rat cortical nephron segments. In BBMV from jejunum or kidney cortex, the inhibition of Pi transport was specific, dose-related, and followed a competitive inhibition pattern, as shown by linear transformation and nonlinear regression analyses. A Ki value of 538 µM NAD+ in kidney BBMV was obtained. Ribosylation inhibitors and ribosylation assays revealed no evidence that this reaction was responsible for inhibiting Pi transport. An analysis of the persistence of NAD+/NADH revealed a half-life of just 2 min during preincubation. Out of several metabolites of NAD degradation, only ADP-ribose was able to inhibit Pi uptake. Pi concentration also increased during 30 min of preincubation, up to 0.67 mM, most likely as a metabolic end product. In conclusion, the classical inhibition of Pi transport by NAD+/NADH in BBMV seems to be caused by the degradation metabolites of these compounds during the preincubation time.

The presence of an embryo affects day 14 uterine transcriptome depending on the nutritional status in sheep. b. Immune system and uterine remodeling.

Transcriptomics and bioinformatics were used to investigate the potential interactions of undernutrition and the presence of the conceptus at the time of maternal recognition of pregnancy on uterine immune system and remodeling. Adult Rasa Aragonesa ewes were allocated to one of two planes of nutrition for 28 days: maintenance energy intake (control; 5 cyclic, 6 pregnant ewes) providing 7.8 MJ of metabolisable energy and 0.5 maintenance intake (undernourished; 6 cyclic, 7 pregnant ewes) providing 3.9 MJ of metabolisable energy per ewe. Uterine gene expression was measured using Agilent 15 K Sheep Microarray chip on day 14 of estrus or pregnancy. Functional bioinformatics analyses were performed using PANTHER (Protein ANalysis THrough Evolutionary Relationships) Classification System. Pregnancy affected the expression of 18 genes in both control and undernourished ewes, underscoring the relevance for embryo-maternal interactions. Immune system evidenced by classical interferon stimulated genes were activated in control and -in a lesser extent-in undernourished pregnant vs cyclic ewes. Genes involved in uterine remodeling such as protein metabolism were also upregulated with the presence of an embryo in control and undernourished ewes. However, relevant genes for the adaptation of the uterus to the embryo were differentially expressed between pregnant vs cyclic ewes both in control and undernourished groups. Undernutrition alone led to an overall weak activation of immune system pathways both in cyclic and pregnant ewes. Data revealed that cellular and immune adaptations of the uterus to pregnancy are dependent on the nutritional status.

Effects of oral exposure to arsenite on arsenic metabolism and transport in rat kidney.

Nephrotoxicity is within the recognized toxic effects of arsenic. In this study we assessed the effect of arsenite on the renal capacity to metabolize and handle arsenicals in rats exposed to drinking water with 0, 1, 5, or 10 ppm sodium arsenite for ten days. Arsenite treatment did not affect the gene expression of the main enzyme catalyzing methylation of arsenite, As3mt, while it reduced the expression of GSTO1 mRNA and protein. Arsenite decreased the expression of Aqp3, Mrp1, Mrp4, and Mdr1b (i.e., transporters and channels used by arsenic), but not that of Aqp7, Glut1, Mrp2, and Mdr1a. The protein abundance of AQP3 was also reduced by arsenite. Arsenite increased urinary NGAL and FABP3 and decreased Klotho plasma levels, without alteration of creatinine, which evidenced early tubular damage. Renal Klotho mRNA and protein expressions were also downregulated, which may exacerbate renal damage. No effect was observed in selected miRNAs putatively associated with renal injury. Plasma PTH and FGF23 were similar between groups, but arsenite decreased the renal expression of Fgfr1 mRNA. In conclusion, exposure to arsenite alters the gene expression of proteins involved in the cellular handling of arsenical species and elicits tubular damage.

The embryo affects day 14 uterine transcriptome depending on nutritional status in sheep. a. Metabolic adaptation to pregnancy in nourished and undernourished ewes.

This study investigated the effects of undernutrition and the presence of the conceptus at the time of maternal recognition of pregnancy on the expression of uterine indicators of metabolism in ewes. Adult Rasa Aragonesa ewes were allocated to one of two planes of nutrition for 28 days: maintenance energy intake (control; 5 cyclic and 6 pregnant ewes) providing 7.8 MJ of metabolisable energy, and 0.5 maintenance intake (undernourished; 6 cyclic and 7 pregnant ewes) providing 3.9 MJ of metabolisable energy per ewe. RNA from intercaruncular uterine tissue was harvested at slaughter on Day 14 of estrous cycle or pregnancy, and hybridized to the Agilent 15K Sheep Microarray chip. Functional bioinformatics analyses were performed using PANTHER (Protein ANalysis THrough Evolutionary Relationships) Classification System. The presence of the embryo upregulated expression of genes encoding peptide and monocarboxylate transporters regardless of nutritional treatment, although the degree of gene expression was lower in undernourished ewes. Genes encoding enzymes involved in glycolysis were downregulated both in pregnant control and undernourished ewes, probably as a compensatory mechanism for the increased glucose transport to the uterus. Compared with control cyclic ewes, control pregnant ewes had greater expression of genes involved in oxidation of fatty acids, suggesting increased uterine energy demands. This was not observed in undernourished pregnant animals when compared to undernourished cyclic ewes; nevertheless, those animals had lower uterine expression of enzymes involved in fatty acid biosynthesis. The presence of the embryo upregulated genes involved in electron transport probably as a result of increased energy demands for pregnancy. Overall, the data indicate that depending on the nutritional status of ewe, pregnancy alters gene expression of metabolic pathways related to energy generation in the uterus. An impairment in nutrient transport and metabolism in the uterus of pregnant undernourished ewes may explain the greater embryo mortality associated with undernutrition.

Several phosphate transport processes are present in vascular smooth muscle cells.

We have studied inorganic phosphate (Pi) handling in rat aortic vascular smooth muscle cells (VSMC) using 32P-radiotracer assays. Our results have revealed a complex set of mechanisms consisting of 1) well-known PiT1/PiT2-mediated sodium-dependent Pi transport; 2) Slc20-unrelated sodium-dependent Pi transport that is sensitive to the stilbene derivatives 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 4-acetamido-4-isothiocyanostilbene-2,2-disulfonate (SITS); 3) a sodium-independent Pi uptake system that is competitively inhibited by sulfate, bicarbonate, and arsenate and is weakly inhibited by DIDS, SITS, and phosphonoformate; and 4) an exit pathway from the cell that is partially chloride dependent and unrelated to the known anion-exchangers expressed in VSMC. The inhibitions of sodium-independent Pi transport by sulfate and of sodium-dependent transport by SITS were studied in greater detail. The maximal inhibition by sulfate was similar to that of Pi itself, with a very high inhibition constant (212 mM). SITS only partially inhibited sodium-dependent Pi transport, but the Ki was very low (14 µM). Nevertheless, SITS and DIDS did not inhibit Pi transport in Xenopus laevis oocytes expressing PiT1 or PiT2. Both the sodium-dependent and sodium-independent transport systems were highly dependent on VSMC confluence and on the differentiation state, but they were not modified by incubating VSMC for 7 days with 2 mM Pi under nonprecipitating conditions. This work not only shows that the Pi handling by cells is highly complex but also that the transport systems are shared with other ions such as bicarbonate or sulfate.NEW & NOTEWORTHY In addition to the inorganic phosphate (Pi) transporters PiT1 and PiT2, rat vascular smooth muscle cells show a sodium-dependent Pi transport system that is inhibited by DIDS and SITS. A sodium-independent Pi uptake system of high affinity is also expressed, which is inhibited by sulfate, bicarbonate, and arsenate. The exit of excess Pi is through an exchange with extracellular chloride. Whereas the metabolic effects of the inhibitors, if any, cannot be discarded, kinetic analysis during initial velocity suggests competitive inhibition.

Substrates and inhibitors of phosphate transporters: from experimental tools to pathophysiological relevance.

The control of inorganic phosphate homeostasis is mediated through the activity of sodium-coupled Pi transporters located in the intestine, kidneys, and bone. To study these transporters in either the native tissue or after heterologous expression, it is very important to use specific inhibitors of the studied transporter, in order to know the corresponding relevance in the total Pi uptake and to differentiate from the activity of other transporters. Inhibitors are also necessary as drugs for treating Pi homeostasis disorders. Under normal physiological conditions, the renal and intestinal excretion of Pi matches dietary intestinal absorption, but when the number of non-functional nephrons increase in chronic kidney disease and end-stage renal disease, the excretion of surplus Pi is progressively impaired, thereby increasing the risk of hyperphosphatemia and Pi toxicity. When the compensatory mechanisms that increase Pi excretion fail, Pi toxicity can only be prevented by reducing the intestinal absorption of Pi through phosphate binders that reduced the free Pi concentration in the lumen, and inhibitors of intestinal Pi transporters and of the paracellular absorption route. Although many potentially interesting inhibitors have been reported to date, only a few are available for experimental purposes, and even fewer have been used in independent clinical trials. In this review, we summarize the different groups of compounds reported to date as inhibitors of Pi transport. To help understand and characterize the inhibition mechanisms, we also summarize the kinetic analysis approaches and screening methods that could be applied.

Influences of nutrition and metabolism on reproduction of the female ruminant.

Beef cows and ewes grazing native pastures are exposed to cycles of undernutrition that reflect the seasonal variations of biomass production. In grazing dairy cows, the physiological undernutrition during early lactation due to increased demands for lactation and low dry matter intake is exacerbated by the need to get sufficient intake from pasture and the extra grazing energy costs. Undernutrition has profound impacts on reproduction by affecting multiple reproductive processes at different levels of the reproductive axis. The objective of this paper is to review the influence of undernutrition on reproductive events of the adult female ruminant, with emphasis on both grassland and mixed rain-fed grazing farming systems. The comparative endocrinology and reproductive biology among ewes, beef and dairy cows may provide a comprehensive knowledge of the metabolic and reproductive adaptation to feed restriction. Understanding the critical underlying physiological mechanisms by which nutrition affects reproduction is the base of focus feeding strategy to improve the reproductive performance of the female ruminant.

Identifying early pathogenic events during vascular calcification in uremic rats.

Vascular calcification in chronic kidney disease is a very complex process traditionally explained in multifactorial terms. Here we sought to clarify relevance of the diverse agents acting on vascular calcification in uremic rats and distinguish between initiating and complicating factors. After 5/6 nephrectomy, rats were fed a 1.2% phosphorus diet and analyzed at different time points. The earliest changes observed in the aortic wall were noticed 11 weeks after nephrectomy: increased Wnt inhibitor Dkk1 mRNA expression and tissue non-specific alkaline phosphatase (TNAP) expression and activity. First deposits of aortic calcium were observed after 12 weeks in areas of TNAP expression. Increased mRNA expressions of Runx2, BMP2, Pit1, Pit2, HOXA10, PHOSPHO1, Fetuin-A, ANKH, OPN, Klotho, cathepsin S, MMP2, and ENPP1 were also found after TNAP changes. Increased plasma concentrations of activin A and FGF23 were observed already at 11 weeks post-nephrectomy, while plasma PTH and phosphorus only increased after 20 weeks. Plasma pyrophosphate decreased after 20 weeks, but aortic pyrophosphate was not modified, nor was the aortic expression of MGP, Msx2, several carbonic anhydrases, osteoprotegerin, parathyroid hormone receptor-1, annexins II and V, and CD39. Thus, increased TNAP and Dkk1 expression in the aorta precedes initial calcium deposition, and this increase is only preceded by elevations in circulating FGF23 and activin A. The expression of other agents involved in vascular calcification only changes at later stages of chronic kidney disease, in a complex branching pattern that requires further clarification.

Failure to establish and maintain a pregnancy in undernourished recipient ewes is associated with a poor endocrine milieu in the early luteal phase.

Embryos from undernourished and control donor ewes were transferred to undernourished and control recipient ewes. Progesterone and metabolic hormones were investigated in recipient ewes to determine their association with pregnancy success. Forty-five donor and 52 recipient Rasa Aragonesa ewes were fed 1.5 (control group; donor n=20; recipient n=25) or 0.5 (low group; donor n=25; recipient n=27) times the daily requirements for maintenance from the onset of estrous synchronization treatment to embryo collection and transfer. The embryos were collected 7days after the onset of estrus (day 0), and two good-quality embryos were transferred into each recipient ewe. The percentage of pregnant ewes on day 18 and 40 did not differ between the two groups, although the recipient undernourished ewes tended to have greater late embryonic mortality (from days 18-40) than the control recipient ewes (P=0.11). No effect of the nutrition of the donor was found. Recipients that became pregnant had a higher ovulation rate than non-pregnant ewes (P=0.02). Undernourished ewes had lower plasma insulin concentrations than control ewes (P=0.03), and those that suffered late embryo mortality (from days 18-40) tended to have lower insulin and progesterone concentrations than their counterparts that remained pregnant (P=0.06 and P=0.07, respectively). In this study, pregnancy in control and undernourished recipient ewes was not associated with the origin of the embryo (undernourished and control donors). In conclusion, failure to establish and maintain a pregnancy was associated with lower progesterone and insulin levels one week after estrus in recipient ewes.

Critical Parameters of the In Vitro Method of Vascular Smooth Muscle Cell Calcification.

BACKGROUND: Vascular calcification (VC) is primarily studied using cultures of vascular smooth muscle cells. However, the use of very different protocols and extreme conditions can provide findings unrelated to VC. In this work we aimed to determine the critical experimental parameters that affect calcification in vitro and to determine the relevance to calcification in vivo. EXPERIMENTAL PROCEDURES AND RESULTS: Rat VSMC calcification in vitro was studied using different concentrations of fetal calf serum, calcium, and phosphate, in different types of culture media, and using various volumes and rates of change. The bicarbonate content of the media critically affected pH and resulted in supersaturation, depending on the concentration of Ca2+ and Pi. Such supersaturation is a consequence of the high dependence of bicarbonate buffers on CO2 vapor pressure and bicarbonate concentration at pHs above 7.40. Such buffer systems cause considerable pH variations as a result of minor experimental changes. The variations are more critical for DMEM and are negligible when the bicarbonate concentration is reduced to ». Particle nucleation and growth were observed by dynamic light scattering and electron microscopy. Using 2mM Pi, particles of ~200nm were observed at 24 hours in MEM and at 1 hour in DMEM. These nuclei grew over time, were deposited in the cells, and caused osteogene expression or cell death, depending on the precipitation rate. TEM observations showed that the initial precipitate was amorphous calcium phosphate (ACP), which converts into hydroxyapatite over time. In blood, the scenario is different, because supersaturation is avoided by a tightly controlled pH of 7.4, which prevents the formation of PO43--containing ACP. CONCLUSIONS: The precipitation of ACP in vitro is unrelated to VC in vivo. The model needs to be refined through controlled pH and the use of additional procalcifying agents other than Pi in order to reproduce calcium phosphate deposition in vivo.

Joining time-resolved thermometry and magnetic-induced heating in a single nanoparticle unveils intriguing thermal properties.

Whereas efficient and sensitive nanoheaters and nanothermometers are demanding tools in modern bio- and nanomedicine, joining both features in a single nanoparticle still remains a real challenge, despite the recent progress achieved, most of it within the last year. Here we demonstrate a successful realization of this challenge. The heating is magnetically induced, the temperature readout is optical, and the ratiometric thermometric probes are dual-emissive Eu(3+)/Tb(3+) lanthanide complexes. The low thermometer heat capacitance (0.021·K(-1)) and heater/thermometer resistance (1 K·W(-1)), the high temperature sensitivity (5.8%·K(-1) at 296 K) and uncertainty (0.5 K), the physiological working temperature range (295-315 K), the readout reproducibility (>99.5%), and the fast time response (0.250 s) make the heater/thermometer nanoplatform proposed here unique. Cells were incubated with the nanoparticles, and fluorescence microscopy permits the mapping of the intracellular local temperature using the pixel-by-pixel ratio of the Eu(3+)/Tb(3+) intensities. Time-resolved thermometry under an ac magnetic field evidences the failure of using macroscopic thermal parameters to describe heat diffusion at the nanoscale.

Effect of water fluoridation on the development of medial vascular calcification in uremic rats.

Public water fluoridation is a common policy for improving dental health. Fluoride replaces the hydroxyls of hydroxyapatite, thereby improving the strength of tooth enamel, but this process can also occur in other active calcifications. This paper studies the effects of water fluoridation during the course of vascular calcification in renal disease. The effect of fluoride was studied in vitro and in vivo. Rat aortic smooth muscle cells were calcified with 2mM Pi for 5 days. Fluoride concentrations of 5-10 µM--similar to those found in people who drink fluoridated water--partially prevented calcification, death, and osteogene expression in vitro. The anticalcifying mechanism was independent of cell activity, matrix Gla protein, and fetuin A expressions, and it exhibited an IC50 of 8.7 µM fluoride. In vivo, however, fluoridation of drinking water at 1.5mg/L (concentration recommended by the WHO) and 15 mg/L dramatically increased the incipient aortic calcification observed in rats with experimental chronic kidney disease (CKD, 5/6-nephrectomy), fed a Pi-rich fodder (1.2% Pi). Fluoride further declined the remaining renal function of the CKD animals, an effect that most likely overwhelmed the positive effect of fluoride on calcification in vitro. Ultrastructural analysis revealed that fluoride did not modify the Ca/P atomic ratio, but it was incorporated into the lattice of in vivo deposits. Fluoride also converted the crystallization pattern from plate to rode-like structures. In conclusion, while fluoride prevents calcification in vitro, the WHO's recommended concentrations in drinking water become nephrotoxic to CKD rats, thereby aggravating renal disease and making media vascular calcification significant.

Arsenic increases Pi-mediated vascular calcification and induces premature senescence in vascular smooth muscle cells.

Several mechanisms have been proposed to explain the vascular toxicity of arsenic. Some of them are described in this work, such as stress-induced premature senescence (SIPS), dedifferentiation, and medial vascular calcification, and they all affect vascular smooth muscle cells (VSMC). Rat aortic VSMC were treated with 1-100 µM of either sodium arsenate (As(V)), sodium arsenite (As(III)), monomethylarsonic acid, or dimethylarsinic acid. None of the treatments induced VSMC calcification in the presence of 1mM inorganic phosphate (Pi), but 1 µM As(III) did increase calcification when induced with 2.5mM Pi. A lactate dehydrogenase assay revealed that this increase was explained by a rise in cytotoxicity due to simultaneous incubation with 1 µM As(III) and 2.5mM Pi. This calcification increase was also observed in the aortas of a vascular calcification model: 5/6 nephrectomized rats fed with a high Pi diet and treated with vitamin D(3). Several known mechanisms that might explain arsenic toxicity in our experimental model were discarded: apoptosis, oxidative stress, and inflammasome activation. Nevertheless, both senescence-associated ß-galactosidase activity and p21 expression were increased by As(III), which reveals the induction of SIPS. As(III) also caused dedifferentiation of VSMC, as shown by the reduced expression of the VSMC markers SM22α and calponin. Senescence and gene expression were also observed in the aortas of healthy rats treated with 50 ppm As(V) in drinking water for 1 month. In conclusion, both premature senescence in aortic VSMC with phenotypic dedifferentiation and the increase of Pi-induced calcification are novel mechanisms of arsenic vasculotoxicity.

Nuclear DNA typing from ancient teeth.

Because of the adverse effects that diagenesis exert on ancient skeletal remains, DNA from these samples is often compromised to the point where genetic typing can be challenging. Nevertheless, robust and reliable methods are currently available to allow successful genotyping of ancient specimens. Here we report nuclear DNA-based methods and typing strategies used to analyze 2 human skeletons from a medieval burial. Reliable DNA nuclear profiles were obtained from teeth, whereas mitochondrial DNA analyses in bones were inconclusive. A complete nuclear mini short tandem repeat profile was obtained from a well-preserved premolar, but only a partial one from the femur. Increasing the sensitivity of the polymerase chain reaction system allowed a full profile from the latter, but the presence of artifacts reinforced the idea that the interpretation of this kind of analysis must be performed with caution. The results presented here also indicate that DNA from dental pieces can be better preserved than from bones, even in the case of well-preserved long bones with thick cortical tissue such as the femurs, and have a better chance of successful genetic typing, probably because of the high degree of protection conferred to the DNA by the enamel.

Mitochondrial diversity in Amerindian Kichwa and Mestizo populations from Ecuador.

This study presents mitochondrial DNA (mtDNA) data from 107 unrelated individuals from two of the major ethnic groups in Ecuador: Amerindian Kichwas (n = 65) and Mestizos (n = 42). We characterized the diversity of the matrilineal lineages of these Ecuadorian groups by analyzing the entire mtDNA control region. Different patterns of diversity were observed in the two groups as result of the unique historical and demographic events which have occurred in each population. Higher genetic diversity values were obtained for the Mestizo group than for the Amerindian group. Interestingly, only Native American lineages were detected in the two population samples, but with differences in the haplogroup distribution: Kichwa (A, 49%; B, 3%; C, 8%; and D, 40%) and Mestizo (A, 33%; B, 33%; C, 10%; and D, 24%). Analysis of the complete mtDNA control region proved to be useful to increase the discrimination power between individuals who showed common haplotypes in HVSI and HVSII segments; and added valuable information to the phylogenetic interpretation of mtDNA haplotypes.

Genetic analysis of 7 medieval skeletons from the Aragonese Pyrenees.

AIM: To perform a genetic characterization of 7 skeletons from medieval age found in a burial site in the Aragonese Pyrenees. METHODS: Allele frequencies of autosomal short tandem repeats (STR) loci were determined by 3 different STR systems. Mitochondrial DNA (mtDNA) and Y-chromosome haplogroups were determined by sequencing of the hypervariable segment 1 of mtDNA and typing of phylogenetic Y chromosome single nucleotide polymorphisms (Y-SNP) markers, respectively. Possible familial relationships were also investigated. RESULTS: Complete or partial STR profiles were obtained in 3 of the 7 samples. Mitochondrial DNA haplogroup was determined in 6 samples, with 5 of them corresponding to the haplogroup H and 1 to the haplogroup U5a. Y-chromosome haplogroup was determined in 2 samples, corresponding to the haplogroup R. In one of them, the sub-branch R1b1b2 was determined. mtDNA sequences indicated that some of the individuals could be maternally related, while STR profiles indicated no direct family relationships. CONCLUSIONS: Despite the antiquity of the samples and great difficulty that genetic analyses entail, the combined use of autosomal STR markers, Y-chromosome informative SNPs, and mtDNA sequences allowed us to genotype a group of skeletons from the medieval age.

Reconstructing the population history of Nicaragua by means of mtDNA, Y-chromosome STRs, and autosomal STR markers.

Before the arrival of the Spaniards in Nicaragua, diverse Native American groups inhabited the territory. In colonial times, Native Nicaraguan populations interacted with Europeans and slaves from Africa. To ascertain the extent of this genetic admixture and provide genetic evidence about the origin of the Nicaraguan ancestors, we analyzed the mitochondrial control region (HVSI and HVSII), 17 Y chromosome STRs, and 15 autosomal STRs in 165 Mestizo individuals from Nicaragua. To carry out interpopulation comparisons, HVSI sequences from 29 American populations were compiled from the literature. The results reveal a close relationship between Oto-manguean, Uto-Aztecan, Mayan groups from Mexico, and a Chibchan group to Nicaraguan lineages. The Native American contribution to present-day Nicaraguan Mestizos accounts for most of the maternal lineages, whereas the majority of Nicaraguan Y chromosome haplogroups can be traced back to a West Eurasian origin. Pairwise Fst distances based on Y-STRs between Nicaragua and European, African and Native American populations show that Nicaragua is much closer to Europeans than the other populations. Additionally, admixture proportions based on autosomal STRs indicate a predominantly Spanish contribution. Our study reveals that the Nicaraguan Mestizo population harbors a high proportion of European male and Native American female substrate. Finally, the amount of African ancestry is also interesting, probably because of the contribution of Spanish conquerors with North African genetic traces or that of West African slaves.