ARTICLE | doi:10.20944/preprints202203.0034.v1
Subject: Life Sciences, Biochemistry Keywords: Hemopexin; Hemoglobin; protein-protein binding; hemin
Online: 2 March 2022 (06:56:02 CET)
Abstract: Background: Hemopexin (Hx) is a plasma glycoprotein that scavenges heme (Fe(III) protoporphyrin IX), Hx have important implication in hemolytic disorders and hemorrhagic condition because the release of hemoglobin increase labile heme, which is potentially toxic producing oxidative stress. Hx has been considered for therapeutic use and diagnostics. In this work, we analyzed and mapped interaction sequences of Hx with hemin and hemoglobin (2) Methods: Spot-synthesis technique was used to map human hemopexin (P02790) binding to hemin and human hemoglobin, a library of 15 amino acid peptides with a 10-amino acid overlap was designed to represent the entire coding region (aa 1-462) of hemopexin and synthesized onto cellulose membranes. In silico approach was performed to analyze amino acid frequency in identified interaction regions, and molecular docking was applied for protein-protein interaction (3) Results: Seven linear peptide sequences in Hx were identified to bind hemin (H1-H7), and five were described for Hb (Hb1-Hb5) interaction, with just two sequences shared between hemin and Hb. Amino acid composition of identified sequences demonstrated that Histidine residues are relevant for heme binding, H105, H293, H373, H400, H429, and H462 was distributed in H1-H7 peptide sequences, but other residues may also play an important role. Molecular docking analysis demonstrated Hx association with the β-chain of Hb, with several hot spot amino acids that coordinated interaction. (4) Conclusions: This study highlights new insights on Hx-hemin binding motifs and protein-protein interactions with Hb. Binding sequences and identified specific peptides can be used for therapeutic purposes and diagnostics, as hemopexin is under investigation to treat different diseases, and there is an urgent need for diagnostics of labile heme for monitoring hemolysis.
ARTICLE | doi:10.20944/preprints202209.0246.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: hemoglobin; monocytes; overall survival; prostate cancer; radiotherapy
Online: 16 September 2022 (10:11:15 CEST)
The prognostic value of inflammatory indices such as absolute monocyte count (AMC) has been a subject of interest in recent prostate cancer (PCa) literature, while hemoglobin concentration (HGB) has been recognized as a survival factor in castration-resistant metastatic prostate cancer, but its value remains unclear in localized disease. The aim of this study was to test the prognostic value of these two simple and inexpensive biomarkers for survival based on a cohort of 1016 patients treated with primary radiotherapy and androgen deprivation therapy for localized or locally advanced intermediate- or high-risk PCa. Complete survival data was available for all cases based on the National Cancer Registry with a median observation time of 120 months (IQR 80.9-144.7). Missing blood test data were supplemented using the Nearest Neighbor Imputation, and the Cox proportional hazards regression model was used for analysis. The median age was 68.8 years (IQR 63.3-73.5). The five-year overall survival was 82.8%, and 508 patients were alive at the time of analysis. The median time between blood tests and the first day of radiotherapy was 6 days (IQR 0-19). HGB (p = 0.009) and AMC (p = 0.003) were independent prognostic factors for survival, along with age, ISUP Grade Group, clinical T stage and maximum PSA concentration. The study demonstrated that HGB and AMC can be useful biomarkers for overall survival in patients treated with radiotherapy for localized intermediate- or high-risk PCa.
Subject: Life Sciences, Genetics Keywords: Sickle cell disease; genetic disorder; fetal hemoglobin; hemoglobinopathy; Tanzania
Online: 20 September 2019 (11:47:39 CEST)
Sickle cell disease (SCD) is a blood disorder caused by a point mutation on the beta globin gene resulting in the synthesis of abnormal hemoglobin. Fetal hemoglobin (HbF) reduces disease severity, but the levels vary from one individual to another. Most research has focused on common variants which differ across populations and hence do not fully account for HbF variation. To investigate rare and common variants influencing HbF levels in SCD, we performed targeted next generation sequencing covering exonic and other significant fetal hemoglobin-associated loci, including BCL11A, MYB, HOXA9, HBB, HBG1, HBG2, CHD4, KLF1, MBD3, ZBTB7A and PGLYRP1. Results revealed a range of functionally relevant genetic variants. Notably, there were significantly more deletions in individuals with high HbF levels (11% vs 0.9%). We identified frameshift deletion in individuals with high HbF levels and frameshift insertions in individuals with low HbF. CHD4 and MBD3 genes, interacting in the same sub-network, were identified to have a significant number of pathogenic or non-synonymous mutations in individuals with low HbF levels, suggesting an important role of epigenetic pathways in the regulation of HbF synthesis. This study provides new insights in selecting essential variants associated with extreme HbF levels in SCD.
ARTICLE | doi:10.20944/preprints202205.0364.v1
Subject: Life Sciences, Molecular Biology Keywords: Hemoglobin switch; BGLT3-lncRNA expression; chromatin conformation; LRF/ZBTB7A overexpression
Online: 26 May 2022 (10:39:49 CEST)
Hemoglobin switch from fetal (HbF) to adult (HbA) has been studied intensively as an essential model for gene’s expression regulation, but also as a beneficial therapeutic approach for β-hemoglobinopathies, towards the objective of reactivating HbF. Transcription factor LRF (Leukemia/lymphoma-related), encoded from ZBTB7A gene has been implicated in fetal hemoglobin silencing, though has a wide range of functions that have not been fully clarified. We thus established LRF/ZBTB7A-overexpressing and ZBTB7A-knockdown K562 (human erythroleukemia cell line) clones and hemoglobin production was evaluated pre- and post-induction. Related effects on the process of hemoglobin switch from fetal to adult were also assessed. Transgenic K562 clones were further developed and studied under the influence of epigenetic chromatin regulators, such as DNA methyl transferase 3 (DNMT3) and Histone Deacetylase 1 (HDAC1), to evaluate LRF’s potential disturbance upon aberrant epigenetic background and provide valuable information of the preferable epigenetic frame, in which LRF unfolds its action on the β-type globin’s expression. ChIP-seq analysis demonstrated that LRF binds το γ-globin genes (HBG2/1) and apparently associates BCL11A for their silencing, but also, during erythropoiesis induction LRF binds BGLT3 gene promoting BGLT3-lncRNA production through the γ-δ intergenic region of β-type globin’s locus, triggering the transcriptional events from γ- to β-globin switch.
REVIEW | doi:10.20944/preprints202012.0522.v1
Subject: Chemistry, Analytical Chemistry Keywords: sickle cell disease; hemoglobin; oxidative stress; antioxidants; red blood cells
Online: 21 December 2020 (12:09:09 CET)
Sickle cell disease (SCD) is the most common hereditary disorder of hemoglobin (Hb) that affects approximately a millions people worldwide. It is characterized by a single nucleotide substitution on the β-globin gene, leading to the production of abnormal sickle hemoglobin with multi-system consequences. Mutated Hb leads to profound changes in: i) red blood cell metabolism and physiology; ii) endothelial signaling; and iii) immune response. Oxidative stress is an important hallmark of SCD. It plays a key role in the pathophysiology of hemolysis, vessel occlusion and the following organ damage in sickle cell patients. For this reason, reactive oxidizing species and the (end)-products of their oxidative reactions have been proposed as markers of both tissue pro-oxidant status and disease severity. Although more studies are needed to clarify their role, antioxidant agents have been shown to be effective in reducing pathological consequences of the disease by preventing oxidative damage in SCD, i.e. by decreasing the oxidant formation or repairing the induced damage. An improved understanding of oxidative stress will lead to targeted antioxidant therapies that should prevent or delay the development of organ complications in this patient population.
ARTICLE | doi:10.20944/preprints201904.0088.v1
Subject: Life Sciences, Other Keywords: Near Infrared Spectroscopy (NIRS); oxygen consumption; hemoglobin; myoglobin; skeletal muscle
Online: 8 April 2019 (11:28:43 CEST)
NIRS uses the relative absorption of light at 850nm and 760nm, to determine skeletal muscle oxygen saturation. Previous studies have used the ratio of both signals to report muscle oxygen saturation. Purpose: To evaluate the different approaches used to represent muscle oxygen saturation, and to evaluate the pulsations of the O2heme and Heme signal. Method: Twelve participants, ages 20-29years were tested on the forearm flexor muscles using continuous wave NIRS at rest. Measurements were taken during 2-3mins rest, during physiological calibration (5-minuts Ischemia) and during reperfusion. Results: There was a significant difference in pulse size between O2heme and Heme signal at the three locations (p < 0.05). Resting oxygen saturation was 58.8+9.2%, 69.6+3.9%, and 89.2+6.9% when calibrated using O2heme, TSI, and Heme, respectively. Conclusion: The difference in magnitude of O2heme and Heme pulse with each heartbeat might suggest different anatomical locations of these signals, which propose calibrating with just one of the signals instead of the ratio of both. Calculations of physiological calibration must account for increased blood volume in the tissue, because of the changes in blood volume which appear to be primarily from the O2heme signal. Resting oxygen levels calibrated with Heme agrees with theoretical oxygen saturation.
ARTICLE | doi:10.20944/preprints202204.0301.v1
Subject: Biology, Other Keywords: glucose metabolism disorders; circadian clocks; sleep; blood glucose; glycated hemoglobin H1Ac
Online: 29 April 2022 (11:38:26 CEST)
Background: Evidence supports a causal relationship between circadian disturbance and impaired glucose homeostasis. Method: To determine the effect of a nursing educational intervention on improving healthy sleep, a parallel, open-label clinical trial in subjects with Impaired Fasting Glucose (IFG) or Type 2 Diabetes Mellitus (T2DM) and 18 and older was performed. Study variables were sex, age, fasting glucose, glycated hemoglobin A1c (HbA1c), Pittsburgh Sleep Quality Index (PSQI), sleep duration and efficiency, BMI, antidiabetic treatment and diet and physical exercise. An individual informative educational intervention was carried out following a bidirectional feedback method. It was intended to develop skills to improve sleep through 9 simple tips. An analysis of covariance was performed on all the mean centered outcome variables controlling for the respective baseline scores. Results: After the intervention, in the experimental group, PSQI dropped, the duration and quality of sleep increased. Further, a decrease in fasting glucose and in HbA1c levels was observed. Conclusion: The proposed intervention has proven to be effective to improve sleep quality, time, and efficiency and in only 3 months, to achieve a decrease in fasting glucose and HbA1c levels. These findings support the importance of sleep and circadian rhythms education focused on improving in T2DM or IFG.
ARTICLE | doi:10.20944/preprints202112.0475.v1
Subject: Life Sciences, Biochemistry Keywords: heme distortion; pocket rigidity; protein environment; hemoglobin; myoglobin; MD simulation; ONIOM
Online: 29 December 2021 (23:52:57 CET)
Heme is located in the active site of proteins and has diverse and important biological functions, such as electron transfer and oxygen transport and/or storage. The distortion of heme porphyrin is considered an important factor for the diverse functions of heme because it correlates with the physical properties of heme, such as oxygen affinity and redox potential. Therefore, clarification of the relationship between heme distortion and the protein environment is crucial in protein science. Here, we analyzed the fluctuation in heme distortion in the protein environment for hemoglobin and myoglobin using molecular dynamics (MD) simulations and quantum mechanical (QM) calculations. We also investigated the protein structures of hemoglobin and myoglobin stored in Protein Data Bank and found that heme is distorted along the doming mode, which correlates with its oxygen affinity, more prominently in the protein environment than in the isolated state, and the magnitude of distortion is different between hemoglobin and myoglobin. This tendency was also observed in the results of MD simulations and QM calculations. These results suggest that heme distortion is affected by its protein environment and fluctuates around its fitted conformation, leading to physical properties that are appropriate for protein functions.
HYPOTHESIS | doi:10.20944/preprints202206.0409.v1
Subject: Life Sciences, Genetics Keywords: Non random mutation; interaction-based evolution; hemoglobin S; directed mutation; parallelism; genome organization
Online: 29 June 2022 (14:56:32 CEST)
Recent results have shown that the human malaria-resistant hemoglobin S mutation originates de novo more frequently in the gene and in the population where it is of adaptive significance, namely, in the hemoglobin subunit beta gene compared to the non-resistant but otherwise identical 20A>T mutation in the hemoglobin subunit delta gene, and in sub-Saharan Africans, who have been subject to intense malarial pressure for many generations, compared to Northern Europeans, who have not. This finding raises a fundamental challenge to the traditional notion of accidental mutation. Here we address this finding with the replacement hypothesis, according to which pre-existing genetic interactions can lead directly and mechanistically to mutations that simplify and replace them. Thus, a gradual evolutionary process under selection can hone in on interactions of importance for the currently evolving adaptations, from which large-effect mutations follow that are relevant to these adaptations. We exemplify this hypothesis using multiple types of mutation, including gene fusion mutations, gene duplication mutations, A>G mutations in RNA-edited sites and transcription-associated mutations, and place it in the broader context of a system-level view of mutation origination called Interaction-based Evolution. Potential consequences include that similarity of mutation pressures may contribute to parallel evolution in genetically related species, that the evolution of genome organization may be driven by mutational mechanisms, that transposable element movements may also be explained by replacement, and that long-term directional mutational responses to specific environmental pressures are possible. Such responses need to be further tested by future studies in natural and artificial settings.
ARTICLE | doi:10.20944/preprints202208.0225.v1
Subject: Life Sciences, Other Keywords: hemoglobin; iron nutrition status; metabolic syndrome; metabolic disorders; observational study; Taiwanese Han Chinese; European White
Online: 12 August 2022 (04:03:24 CEST)
Iron overnutrition has been implicated with higher risk of developing metabolic and cardiovascular diseases, including metabolic syndrome (MetS), while iron deficiency anemia exacerbates many underlying chronic conditions. Hemoglobin (Hb) concentration in the blood, which reflects a major functional iron (i.e., heme iron) in the body, may serve as a surrogate of iron nutrition status. We conducted sex-specific observational association studies where we carefully titrated the association between Hb deciles and MetS and its components among the Taiwanese Han Chinese (HC) from the Taiwan Biobank and Europeans of White ancestry from the UK Biobank, representing two large ethnicities. Our data show that at higher-than-normal levels of Hb, increasing deciles of Hb concentration were significantly associated with MetS across all sex subgroups in both ethnicities, with the highest deciles resulting in up to three times greater risks than the reference group [Taiwanese HC: OR=3.17 (95% CI, 2.75-3.67) for Hb >16.5 g/dL in men, OR=3.11 (2.78-3.47) for Hb >14.5 g/dL in women; European Whites: OR=1.89 (1.80-1.98) for Hb >16.24 g/dL in men, OR=2.35 (2.24-2.47) for Hb >14.68 g/dL in women]. The association between stronger risks and increasing Hb deciles was similarly observed with all metabolic components except diabetes. Here we found that both the highest Hb decile groups and contrarily the lowest ones, with respect to the reference, were associated with higher odds of diabetes in both ethnic groups [e.g., Taiwanese HC men: OR=1.64 (1.33-2.02) for Hb >16.5 g/dL, OR=1.71 (1.39-2.10) for Hb <13.5 g/dL; European Whites women: OR=1.39 (1.26-1.45) for Hb >14.68 g/dL, OR=1.81 (1.63-2.01) for Hb <12.39 g/dL]. These findings confirm that elevated Hb concentrations, a potential indicator of iron overnutrition, may play a role in the pathophysiology of MetS and metabolic components.
ARTICLE | doi:10.20944/preprints201701.0126.v1
Subject: Biology, Animal Sciences & Zoology Keywords: anemia; iron deficiency; pregnancy; serum ferritin; mean corpuscular volume (mcv); mean corpuscular hemoglobin (MCH); Northern Pakistan
Online: 27 January 2017 (03:46:07 CET)
Abstract: The aim of this study was to find out the incidence of anemia in pregnant women of Swat District; to analyze the iron variations and its dietary effects.Data were collected during the periods of January – September 2016. The study of samples comprised of 250 pregnant women in the different trimester. Blood sample from each woman was collected and full blood count (FBC) was conducted through Mindray BC-3000 plus hem analyzer for all pregnant individuals. Confirmed anemic cases were then examined for IDA with serum ferritin, serum iron, total iron binding capacity (TIBC) through Randox kit and serum transferrin saturation was estimated by formula (serum ferritin saturation =serum iron ×100/TIBC). The total number of participants in the first trimester were 50, among them 26 women were suffer from iron deficiency anemia (IDA) with 52% weightage of prevalence rate, (mean Hb concentration 9.602 ± 0.87 g/dl). The rates of IDA were 63.3%; ( mean Hb concentration 8.48 ± 1.24 g/dl) and 54%; ( mean Hb concentration 9.18 ± 1.28 g/dl), among 150 and 50 participants in the second and third trimester, respectively. A significant correlation was found between serum ferritin and Hb, serum ferritin against MCV and serum ferritin against MCH. The high prevalence of anemia was found 78.2% in the age group from 26-30 followed by 78.2% in the age group 36-40 years compared to those of other age groups in the second trimester. In this study the prevalence of IDA in third trimester is lower compared to first and second trimester.
ARTICLE | doi:10.20944/preprints202111.0028.v1
Subject: Medicine & Pharmacology, Nursing & Health Studies Keywords: pregnant mothers, physical activity; maternal wellbeing; antenatal mothers; newborn outcomes; m-health; low birth weight; small for gestation; gestation age; hemoglobin
Online: 1 November 2021 (17:50:14 CET)
Maternal and child nutrition has been a critical component of health, sustainable development, and progress in low- and middle-income countries (LMIC). While a decrement in maternal mortality is an important indicator, simply surviving pregnancy and childbirth does not imply better maternal health. One of the fundamental obligations of nations under international human rights law is to enable mothers and teenage girls to endure pregnancy and delivery as an aspect of their enjoyment of reproductive and sexual health and rights and live a dignified life. The aim of this study was to discover the correlation between the Maternal Observation and Motivation (MOM) program and m-Health support for maternal and newborn health. A Comparative study was done among 109 pregnant mothers (study group-94; control group-102 mothers) with not less than 20 weeks of gestation. Maternal outcomes such as Hb, weight gain and newborn results like birth weight and crown- heel length was obtained on the baseline, 28 and 36 weeks of gestation. Other secondary data collected were abortion, stillbirth, low birth weight, major congenital malformations, twin or triplet pregnancies, physical activity and maternal wellbeing. The MOM intervention included initial face to face education, three in-person visits and eight virtual health coaching by WhatsApp. The baseline data on Hb of the mothers show that 31(32.98%) vs 27(28.72%) of the study and control group had anaemia, which improved to 27.66% and 14.98% among study group mothers at 28 and 36 weeks of gestation (p<0.001). The weight gain (p< 0.001), level of physical activity (p< 0.001), and maternal wellbeing (p< 0.01) also had significant differences after the Intervention. Even after controlling for potentially confounding variables, the maternal food practices regression model revealed that birth weight was directly correlated with consumption of milk (p 0.001), fruits (p 0.01), and green vegetables (p 0.05).As per the physical activity and maternal wellbeing regression model, the birth weight and crown heel length were strongly related with the physical activity and maternal wellbeing of mothers at 36 weeks of gestation (p <0.05). Combining the MOM intervention with standard antenatal care is a safe and effective way to improve maternal welfare while upholding pregnant mothers' human rights.
CONCEPT PAPER | doi:10.20944/preprints202106.0486.v1
Subject: Medicine & Pharmacology, Allergology Keywords: high altitude, chronic hypobaric hypoxia, physiologic adaptation, travel to high altitude cities, high altitude physiology, pulmonary hypertension, lung disease, hemoglobin, tolerance to hypoxia, oxygen content.
Online: 18 June 2021 (15:22:04 CEST)
Acute high altitude illnesses are of great concern for physicians and people traveling to high altitude. High Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad which involves the Pneumo-Dynamic Pump (Ventilation), the Hemo-Dynamic Pump (Heart and circulation), and Hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The increased hemoglobin at high altitude reduces the percentage of dissolved oxygen in the arterial oxygen content with respect to sea level. At high altitude, the acid-base balance must be adequately interpreted using the high altitude Van-Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude the more tolerance to hypoxia. All organisms adapt physiologically and optimally to a high-altitude environment to survive. Reduction of pulmonary hypertension in HAPE through oxygen administration results in a favorable outcome.