Beneficiary Effect of Fibrin Glue on Healing of Ileoileal Anastomoses in Rats

BACKGROUND/AIM

Intestinal anastomosis' integrity is crucial in surgery. This study aimed to investigate whether fibrin glue (FG) (a fibrin sealant containing human factor XII and fibrinogen) has a positive effect on the healing and the integrity of the ileoileal anastomosis in rats.

MATERIALS AND METHODS

Twenty Wistar rats underwent enterotomy, ileoileal anastomosis and divided into four groups (A: complete anastomosis-no FG, B: complete anastomosis-FG, C: incomplete anastomosis-no FG, D: incomplete anastomosis-FG). Data included leak, adhesions, bursting pressure of the anastomosis, neoangiogenesis, and hydroxyproline levels.

RESULTS

Angiogenesis was significantly higher in group B compared to group A (p=0.019). There were no significant differences between groups A and B regarding adhesions, hydroxyproline, and bursting pressure (p=0.500, p=0.158 and p=0.829, respectively). Hydroxyproline levels were higher in group D compared to C, but did not reach significance (p=0.098).

CONCLUSION

Fibrin glue has a positive effect on ileoileal anastomoses. It is not entirely clear whether this effect is due to mechanical support or to the facilitation of the healing process or both. Further research is needed before FG can be applied to humans.

Growth Rate and Bone Hydroxyproline Concentration in Turkeys Fed with a Silage-Composed Diet Modified with Different Diet Cation-Anion Differences (DCADs)

Simple Summary

In this study, we point to the possibility of using dietary cation–anion difference manipulation to improve growth rates and bone condition, especially in the last phase of poultry turkey husbandry, when birds have many bone abnormalities.

Abstract

Our goal was to determine the responses of body weight (BW) and bone hydroxyproline (Hyp) concentration in turkeys fed a corn silage (CS) diet with different values of dietary cation–anion differences (DCADs). The turkeys (n = 90) were divided into five groups and fed as follows: group A (control)—standard diet (SD) (60%) plus CS (40%); group B—SD (60%), CS (40%) plus 240 g of CaCl₂ per 100 kg of diet; group C—SD (60%), CS (40%) plus 480 g of CaCl₂ per 100 kg of diet; group D—SD (60%), CS (40%) plus 240 g of NaHCO₃ per 100 kg of diet; group E—SD (60%), CS (40%) plus 480 g NaHCO₃ per 100 kg of diet. The addition of a lesser amount of CaCl₂ lowered the DCAD, which ranged between 52.5 ± 4.19 and 91.14 ± 3.14 mEq/kg DM. An increased content of CaCl₂ led to high negative values of DCAD. NaHCO₃ supplemented in both doses resulted in a significant elevation of DCAD. Compared to each experimental group, feeding birds with a diet supplemented only with CS resulted in a lower BW. Addition of CaCl₂ or NaHCO₃ to the diet improved BW, but only CaCl₂ addition enhanced the bone Hyp amount. In conclusion, we suggest that an anionic diet with low DCAD can prevent bone abnormalities in large turkeys, especially in the final course of production.

HIF-1α Hydroxyprolines Modulate Oxygen-Dependent Protein Stability Via Single VHL Interface With Comparable Effect on Ubiquitination Rate

The basic molecular mechanism underlying mammalian oxygen-dependent regulation of hypoxia-inducible factor (HIF) via the von Hippel-Lindau E3 ubiquitin ligase is well established. The principal step in this critical cellular process is the hydroxylation of either or both of the two conserved proline residues P402 and P564 within the oxygen-dependent degradation domain (ODD) of HIF-1α subunit via prolyl hydroxylases, which is necessary for binding VHL. However, the significance of the two prolines has remained unclear considering that only one hydroxyproline is sufficient for the recruitment of VHL. Here, we show using biophysical analyses that both hydroxyprolines bind to the same interface on VHL with similar affinity; VHL binding affinity to HIF-1α ODD remains relatively unchanged regardless of whether the ODD contains one or two hydroxyprolines; ODD with two hydroxyprolines can accommodate two VHLs; and the rate of in vitro ubiquitination of ODD with one hydroxyproline via VHL E3 ligase is comparable to the rate observed with ODD containing two hydroxyprolines. However, the two hydroxyprolines show distinct contributions to the intracellular stability of HIF-1α ODD. These results demonstrate for the first time that the graduated HIF-1α stability profile observed over a range of oxygen tension is not attributed to the binding of or ubiquitination via VHL per se, but is likely due to the preceding events such as the efficacy of oxygen-dependent prolyl hydroxylase-mediated hydroxylation of HIF-1α.

The Major Peanut Allergen Ara h 2 Produced in Nicotiana benthamiana Contains Hydroxyprolines and Is a Viable Alternative to the E. Coli Product in Allergy Diagnosis

Peanut allergy is a potentially life-threatening disease that is mediated by allergen-specific immunoglobulin E (IgE) antibodies. The major peanut allergen Ara h 2, a 2S albumin seed storage protein, is one of the most dangerous and potent plant allergens. Ara h 2 is posttranslationally modified to harbor four disulfide bridges and three hydroxyprolines. These hydroxyproline residues are required for optimal IgE-binding to the DPYSPOHS motifs representing an immunodominant IgE epitope. So far, recombinant Ara h 2 has been produced in Escherichia coli, Lactococcus lactis, Trichoplusia ni insect cell, and Chlamydomonas reinhardtii chloroplast expression systems, which were all incapable of proline hydroxylation. However, molecular diagnosis of peanut allergy is performed using either natural or E. coli-produced major peanut allergens. As IgE from the majority of patients is directed to Ara h 2, it is of great importance that the recombinant Ara h 2 harbors all of its eukaryotic posttranslational modifications. We produced hydroxyproline-containing and correctly folded Ara h 2 in the endoplasmic reticulum of leaf cells of Nicotiana benthamiana plants, using the plant virus-based magnICON® transient expression system with a yield of 200 mg/kg fresh biomass. To compare prokaryotic with eukaryotic expression methods, Ara h 2 was expressed in E. coli together with the disulfide-bond isomerase DsbC and thus harbored disulfide bridges but no hydroxyprolines. The recombinant allergens from N. benthamiana and E. coli were characterized and compared to the natural Ara h 2 isolated from roasted peanuts. Natural Ara h 2 outperformed both recombinant proteins in IgE-binding and activation of basophils via IgE cross-linking, the latter indicating the potency of the allergen. Interestingly, significantly more efficient IgE cross-linking by the N. benthamiana-produced allergen was observed in comparison to the one induced by the E. coli product. Ara h 2 from N. benthamiana plants displayed a higher similarity to the natural allergen in terms of basophil activation due to the presence of hydroxyproline residues, supporting so far published data on their contribution to the immunodominant IgE epitope. Our study advocates the use of N. benthamiana plants instead of prokaryotic expression hosts for the production of the major peanut allergen Ara h 2.

Biochemical and physicochemical indicators of the quality of milk and meat obtained from cows with brucellosis

Background and Aim:

Brucellosis is a disease occurring worldwide. Although it is mainly a cattle disease, it is extremely dangerous for humans. Milk and meat can be contaminated with Brucella. The present study aims to examine the biochemical and physicochemical indicators of the quality of milk and meat obtained from cows positively reacting to brucellosis in comparison with healthy animals.

Materials and Methods:

Two groups of cattle meat samples (four muscles from different parts of the carcass) were obtained during slaughter at a specialized meat processing plant, and milk samples were examined from healthy animals (10 cows) and from cows positively responding to brucellosis (10 cows). For the milk samples, federal standards (GOST 32915-2014 and GOST 25179-2014) and an atomic absorption spectrometer “Kvant-Z ETA” were used. To evaluate the chemical composition of the meat, the “Clover” apparatus and a tissue grinder (SM-3) were used.

Results:

In the meat of cows that positively responded to brucellosis, compared with that of healthy animals, the amount of dry matter decreased by 1.2 times, amino ammonia nitrogen by 1.01 times, proteins by 1.2 times, fat by 1.28 times, volatile fatty acids by 1.09 times, tryptophan by 1.25 times, oxyproline by 1.14 times, and protein quality indicator by 1.21 times.

Conclusion:

Despite the severity of brucellosis in cattle, the biochemical and physicochemical indicators of the quality of milk and meat obtained from the healthy and contaminated animals vary, although insignificantly.

Epigenomic and transcriptional profiling identifies impaired glyoxylate detoxification in NAFLD as a risk factor for hyperoxaluria

Epigenetic modifications (e.g. DNA methylation) in NAFLD and their contribution to disease progression and extrahepatic complications are poorly explored. Here, we use an integrated epigenome and transcriptome analysis of mouse NAFLD hepatocytes and identify alterations in glyoxylate metabolism, a pathway relevant in kidney damage via oxalate release-a harmful waste product and kidney stone-promoting factor. Downregulation and hypermethylation of alanine-glyoxylate aminotransferase (Agxt), which detoxifies glyoxylate, preventing excessive oxalate accumulation, is accompanied by increased oxalate formation after metabolism of the precursor hydroxyproline. Viral-mediated Agxt transfer or inhibiting hydroxyproline catabolism rescues excessive oxalate release. In human steatotic hepatocytes, AGXT is also downregulated and hypermethylated, and in NAFLD adolescents, steatosis severity correlates with urinary oxalate excretion. Thus, this work identifies a reduced capacity of the steatotic liver to detoxify glyoxylate, triggering elevated oxalate, and provides a mechanistic explanation for the increased risk of kidney stones and chronic kidney disease in NAFLD patients.

Arginine Supplementation Promotes Extracellular Matrix and Metabolic Changes in Keratoconus

Keratoconus (KC) is a common corneal ectatic disease that affects 1:500–1:2000 people worldwide and is associated with a progressive thinning of the corneal stroma that may lead to severe astigmatism and visual deficits. Riboflavin-mediated collagen crosslinking currently remains the only approved treatment to halt progressive corneal thinning associated with KC by improving the biomechanical properties of the stroma. Treatments designed to increase collagen deposition by resident corneal stromal keratocytes remain elusive. In this study, we evaluated the effects of arginine supplementation on steady-state levels of arginine and arginine-related metabolites (e.g., ornithine, proline, hydroxyproline, spermidine, and putrescine) and collagen protein expression by primary human corneal fibroblasts isolated from KC and non-KC (healthy) corneas and cultured in an established 3D in vitro model. We identified lower cytoplasmic arginine and spermidine levels in KC-derived constructs compared to healthy controls, which corresponded with overall higher gene expression of arginase. Arginine supplementation led to a robust increase in cytoplasmic arginine, ornithine, and spermidine levels in controls only and a significant increase in collagen type I secretion in KC-derived constructs. Further studies evaluating safety and efficacy of arginine supplementation are required to elucidate the potential therapeutic applications of modulating collagen deposition in the context of KC.

Effect of Vitamin B2-Deficient Diet on Hydroxyproline- or Obesity-Induced Hyperoxaluria in Mice

SCOPE

Hyperoxaluria is a major cause of kidney stone disease. Around half of the oxalate in mammals is supplied from the diet and the other half is endogenously synthesized from glyoxylate. Reduction of hepatic glycolate oxidase (GO) activity is one approach to reduce endogenous production of oxalate. However, there are currently few effective dietary approaches to reduce hepatic GO activity.

METHODS AND RESULTS

In the present study, it is investigated whether restriction of dietary vitamin B2 (VB2) can reduce hepatic GO activity and oxalate excretion in mice with hyperoxaluria induce by hydroxyproline (Hyp) or obesity. It is found that VB2 restriction significantly reduces hepatic GO activity in both the Hyp- and obesity-induced model of hyperoxaluria in mice. However, VB2 restriction reduces urinary oxalate excretion only in the Hyp-treated mice and not the obese mice. This difference could be due to the contribution of endogenous oxalate production that manifests as increased hepatic GO activity in Hyp-treated mice but not obese mice.

CONCLUSION

Together these results suggest that VB2 restriction could be a new dietary approach to improve hyperoxaluria when endogenous production of oxalate is increased.

Green synthesized silver nanoparticles (AgNPs) from Parrotiopsis jacquemontiana (Decne) Rehder leaf extract and its biological activities

Parrotiopsis jacquemontiana (Decne) Rehder aqueous extract of leaf was used for biosynthesis of AgNPs and characterized through UV-Visible spectroscopy, X-ray diffraction, Fourier-transform-infrared, diffraction light scattering, and scanning electron microscope analysis. Moderate to strong antioxidant activity during in vitro antioxidant assays for scavenging of 2,2-diphenyl-1-picryl hydrazyl (DPPH), hydroxyl (OH), nitric oxide (NO) radicals, iron chelation, and inhibition of β-carotene bleaching was recorded with minimum IC₅₀ value (27.70 ± 2.67 μg/ml) calculated for OH radicals. The AgNPs were evaluated against six multidrug resistant human bacterial strains and minimum inhibitory concentration (MIC) along with minimum bactericidal concentration (MBC) values was determined and all were found remarkably susceptible. The bacterial strain Staphylococcus aureus was the most susceptible with MIC = 5 μg/ml and MBC = 10 μg/ml. Among six fungal strains, Fumigatus esculentum was the most susceptible with MIC and MBC of 10 μg/ml. 3-(4,5-Dimethylthiazol-2 yl)-2,5-diphenyltetrazolium bromide (MTT) screening assay against cancer cell lines (HCCLM3, HEPG2, MDA-MB 231, and MCF-7) revealed the least IC₅₀ values against HCCLM3 (74.20 ± 5.04) and MCF-7 (91.90 ± 1.17). While no cytotoxicity against normal cell lines; LO2 and MCF-10a was recorded. Parrotiopsis jacquemontiana silver nanoparticles (PJAgNPs) significantly (p > .001) prevented the migration of HCCLM3 cells in a dose-dependent style, relative to control. The wound healing potential of AgNPs in rat was found higher (p < .05) for wound contraction rates, hydroxyproline content, hemostatic and re-epithelization and regeneration efficiency in comparison to the reference group.

Design, Synthesis, and Biochemical Evaluation of Alpha-Amanitin Derivatives Containing Analogs of the trans-Hydroxyproline Residue for Potential Use in Antibody-Drug Conjugates

Alpha-amanitin, an extremely toxic bicyclic octapeptide extracted from the death-cap mushroom, Amanita phalloides, is a highly selective allosteric inhibitor of RNA polymerase II. Following on growing interest in using this toxin as a payload in antibody-drug conjugates, herein we report the synthesis and biochemical evaluation of several new derivatives of this toxin to probe the role of the trans-hydroxyproline (Hyp), which is known to be critical for toxicity. This structure activity relationship (SAR) study represents the first of its kind to use various Hyp-analogs to alter the conformational and H-bonding properties of Hyp in amanitin.

Oxidative Stress and Musculoskeletal Pain in University Students with Generalized Joint Hypermobility: A Case-Control Study

Objective

The current case–control study aimed to evaluate generalized joint hypermobility (GJH) and its association with pain intensity, cellular oxidative stress, and collagen-associated disorders in university students aged 18–25 years old.

Background

Joint hypermobility has been recognized in healthy subjects and people who are carriers of cellular disorders in connective tissues. Cellular tissue oxidative stress and collagen-associated disorders were shown to be associated with joint hypermobility (JH).

Materials and Methods

A total of 300 university students aged 18–25 years were randomly invited from different medical and science faculties in Mansoura university, Mansoura, Egypt to participate in this case–control study. Only 280 university students who had no exclusion criteria like chronic health problems, physical disability, musculoskeletal disorders, and body mass index (BMI) of ≥25 underwent an initial clinical interview and Beighton scoring as measures of GJH. Pain intensity, physical activity, oxidative stress parameters; TAC, TOC, OSI, and collagen-associated parameters; cellular prolidase activity and hydroxyproline were evaluated by using a prevalidated questionnaire, colorimetric, and immunoassay techniques.

Results

GJH was significantly reported in 57.1% of the study population, and most of them are females. Compared to men, females with GJH showed poor physical activity, lower TAC, and significantly higher levels of TOC, OSI, cellular prolidase activity, and hydroxyproline. Based on our findings, a high Beighton score is closely related to the tissue levels of prolidase, hydroxyproline, antioxidant activity, pain intensity, and poor physical activity in the female with GJH compared to men.

Conclusion

GJH was significantly reported in 57.1% of the study population, and most of them are females. The incidence of GJH showed to be associated with poor physical activity, abnormal cellular oxidative stress, and collagen abnormalities measured by significant increase in change in cellular prolidase activity and hydroxyproline.

Oral Administration of Aloe vera Ameliorates Wound Healing through Improved Angiogenesis and chemotaxis in Sprague Dawley Rats

BACKGROUND

Aloe vera has been reported as a topical antibiotic and healing agent for wounds, but advantages of oral administration and mechanisms of wound healing have not been reported. Present study focuses on the evaluation of effects of oral administration of Aloe vera for excisional cutaneous wounds in Sprague Dawley rats.

METHODS

Sprague Dawley (SD) rats were inflicted with excisional wounds and were either treated with Aloe vera orally (Aloe vera) or kept untreated (wound). In contrast, healthy rats were kept as control group. Wound area was measured from day 7th to day 21st. Collagen content was estimated by hydroxyproline assay. Histology was analysed by hematoxylin and eosin staining. Angiogenesis was observed by indirect ELISA for Insulin like Growth Factor (IGF-1) and Vascular Endothelial Growth Factor (VEGF) protein from skin, serum and bone marrow. Chemotaxis was evaluated by RT-PCR analysis for Stromal cell-Derived Factor-1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR-4) from skin and bone marrow.

RESULTS

Aloe vera healed wounds earlier than untreated rats with gradual improvement in wound areas and collagen content. Aloe vera also improved the expression of IGF-1 and VEGF in skin and bone marrow indicating an improvement in angiogenesis. RT- PCR analysis showed increased expression of genes for chemotaxis (SDF-1 and CXCR-4) in skin and bone marrow.

CONCLUSION

Aloe vera improves healing by increasing collagen content, improving angiogenesis and chemotaxis.

Green synthesized AgNPs from Periploca hydaspidis Falc. and its biological activities

Characterization of bio-synthesized silver nanoparticles (AgNPs) using Periploca hydaspidis (PHAgNPs) whole plant extract for the first time via UV-Visible spectroscopy, XRD, FTIR, DLS, and SEM analysis techniques was done. A rich variety of phytochemicals in P. hydaspidis aqueous extract (PHA) functioned as possible reducing and capping agents for AgNPs synthesis. In vitro antioxidant activities (DPPH, Iron chelating, Hydroxyl ion, Nitric oxide, and β-carotene bleaching assays) of PHAgNPs revealed least IC₅₀ values especially in hydroxyl ion (39.08 ± 0.88 μg/mL) and nitric oxide (37.53 ± 2.24 μg/mL) scavenging assays relative to standard controls (ascorbic acid, rutin, and gallic acid) and PHA. In addition, visible inhibition zone diameters were formed around discs against all pathogenic microbial strains including multi-drug resistant strains (MDR's). MIC and MBC/MFC were depicted least in PHAgNPs with maximum bactericidal/fungicidal effects. MTT assay displayed a significant antiproliferative potential of PHAgNPs against HCCLM3, MCF-7, MDA-MB 231, and HEPG2 cancer cell lines, where least IC₅₀ values were recorded against HEPG2 (12.97 ± 0.04 μg/mL) and MCF-7 (5.73 ± 0.22 μg/mL). Furthermore, PHAgNPs considerably (p > 0.001) prevented the migration of MCF-7 cancer cells in vitro whereas in in vivo wound healing assay, faster skin regeneration, and epithelization in wound biopsies was observed via histological analysis. PHAgNPs treated group rats significantly increased (p < 0.05) the wound contraction rate, hydroxyproline content and hemostatic potential compared to control and PHA-treated groups.

Acidified Nitrite Accelerates Wound Healing in Type 2 Diabetic Male Rats: A Histological and Stereological Evaluation

Impaired skin nitric oxide production contributes to delayed wound healing in type 2 diabetes (T2D). This study aims to determine improved wound healing mechanisms by acidified nitrite (AN) in rats with T2D. Wistar rats were assigned to four subgroups: Untreated control, AN-treated control, untreated diabetes, and AN-treated diabetes. AN was applied daily from day 3 to day 28 after wounding. On days 3, 7, 14, 21, and 28, the wound levels of vascular endothelial growth factor (VEGF) were measured, and histological and stereological evaluations were performed. AN in diabetic rats increased the numerical density of basal cells (1070 ± 15.2 vs. 936.6 ± 37.5/mm³) and epidermal thickness (58.5 ± 3.5 vs. 44.3 ± 3.4 μm) (all p < 0.05); The dermis total volume and numerical density of fibroblasts at days 14, 21, and 28 were also higher (all p < 0.05). The VEGF levels were increased in the treated diabetic wounds at days 7 and 14, as was the total volume of fibrous tissue and hydroxyproline content at days 14 and 21 (all p < 0.05). AN improved diabetic wound healing by accelerating the dermis reconstruction, neovascularization, and collagen deposition.

Alterations in serum amino acid profiles in children with attention deficit/hyperactivity disorder

The objective of the present study was to evaluate the circulating serum amino acid levels in children with attention deficit/hyperactivity disorder (ADHD). A total of 71 children with untreated ADHD and 31 neurotypical controls aged 7-14 years old were examined. Serum amino acid levels were evaluated using high-performance liquid chromatography (HPLC) with UV-detection. Laboratory quality control was performed with reference materials of human plasma amino acid levels. The obtained data demonstrated that children with ADHD were characterized by 29, 10 and 20% lower serum histidine (His), glutamine (Gln) and proline (Pro) levels compared with neurotypical children, respectively. In contrast, circulating aspartate (Asp), glutamate (Glu) and hydroxyproline (Hypro) levels exceeded the respective control values by 7, 7 and 42%. Correspondingly, the Gln-to-Glu and Pro-to-Hypro ratios were 28% and 49%, respectively, lower in ADHD cases compared with the controls. Total Gln/Glu levels were also significantly lower in ADHD patients. No significant group differences were observed between the groups in the other amino acids analyzed, including phenylalanine. Multiple linear regression analysis revealed significant associations between circulating serum Gln, lysine (Lys) (both negative) and Glu (positive) levels with total ADHD Rating Scale-IV scores. The observed alterations in Pro/Hypro and Gln/Glu levels and ratios are likely associated with the coexisting connective tissue pathology and alterations in glutamatergic neurotransmission in ADHD, respectively. Altered circulating levels of His, Lys and Asp may also be implicated in ADHD pathogenesis. However, further in vivo and in vitro studies are required in order to investigate the detailed mechanisms linking amino acid metabolism with ADHD pathogenesis.

Contribution of Inhibitory Metabolites and Competition for Nutrients to Colonization Resistance against Clostridioides difficile by Commensal Clostridium

Clostridioides difficile is an anaerobic pathogen that causes significant morbidity and mortality. Understanding the mechanisms of colonization resistance against C. difficile is important for elucidating the mechanisms by which C. difficile is able to colonize the gut after antibiotics. Commensal Clostridium play a key role in colonization resistance. They are able to modify bile acids which alter the C. difficile life cycle. Commensal Clostridium also produce other inhibitory metabolites including antimicrobials and short chain fatty acids. They also compete with C. difficile for vital nutrients such as proline. Understanding the mechanistic effects that these metabolites have on C. difficile and other gut pathogens is important for the development of new therapeutics against C. difficile infection (CDI), which are urgently needed.

Relationship between calcification, atherosclerosis and matrix proteins in the human aorta

INTRODUCTION

Extracellular matrix (ECM) proteins have been associated with atherosclerotic complications, such as plaque rupture, calcification and aneurysm. It is not clear what role different types of collagen play in the pathomechanism of atherosclerosis. The aim of the study was to analyze the content of elastin and major types of collagen in the aortic wall and how they associated are with course of atherosclerosis.

MATERIAL AND METHODS

In this work we present six biochemical parameters related to ECM proteins and collagen-specific amino acids (collagen type I, III, and IV, elastin, proline and hydroxyproline) analyzed in 106 patients' aortic wall specimens characterized by different degree of atherosclerosis. Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC/ESI-MS/MS), ELISA and immunohistochemical methods were used. The severity of atherosclerosis was assessed on the six-point scale of the American Heart Association, taking into account the number and location of foam cells, the presence of a fatty core, calcium deposits and other characteristic atherosclerotic features.

RESULTS

The results show that there is a relationship between the content of collagen-specific amino acids and development of atherosclerosis. The degree of atherosclerotic lesions was negatively correlated with the content of proline, hydroxyproline and the ratio of these two amino acids. Calcium deposits and surrounding tissue were compared and it was demonstrated that the ratio of type I collagen to type III collagen was higher in the aortic tissue than in aortic calcification areas, while the ratio of collagen type III to elastin was smaller in the artery than in the calcium deposits.

CONCLUSIONS

We suggest that increase in collagen type III presence in the calcification matrix may stem from disorders in the structure of the type I and III collagen fibers. These anomalous fibers are likely to favor accumulation of the calcium salts, an important feature of the process of atheromatosis.

Bone need not remain an elephant in the room for radiocarbon dating

Radiocarbon (¹⁴C) analysis of skeletal remains by accelerator mass spectrometry is an essential tool in multiple branches of science. However, bone ¹⁴C dating results can be inconsistent and not comparable due to disparate laboratory pretreatment protocols that remove contamination. And, pretreatments are rarely discussed or reported by end-users, making it an 'elephant in the room' for Quaternary scientists. Through a questionnaire survey, I quantified consensus on the reliability of collagen pretreatments for ¹⁴C dating across 132 experts (25 countries). I discovered that while more than 95% of the audience was wary of contamination and would avoid gelatinization alone (minimum pretreatment used by most ¹⁴C facilities), 52% asked laboratories to choose the pretreatment method for them, and 58% could not rank the reliability of at least one pretreatment. Ultrafiltration was highly popular, and purification by XAD resins seemed restricted to American researchers. Isolating and dating the amino acid hydroxyproline was perceived as the most reliable pretreatment, but is expensive, time-consuming and not widely available. Solid evidence supports that only molecular-level dating accommodates all known bone contaminants and guarantees complete removal of humic and fulvic acids and conservation substances, with three key areas of progress: (i) innovation and more funded research is required to develop affordable analytical chemistry that can handle low-mass samples of collagen amino acids, (ii) a certification agency overseeing dating-quality control is needed to enhance methodological reproducibility and dating accuracy among laboratories, and (iii) more cross-disciplinary work with better ¹⁴C reporting etiquette will promote the integration of ¹⁴C dating across disciplines. Those developments could conclude long-standing debates based on low-accuracy data used to build chronologies for animal domestications, human/megafauna extirpations and migrations, archaeology, palaeoecology, palaeontology and palaeoclimate models.

Investigating the efficacy and safety of mineral smectite granules on wound healing

Mineral smectite granules have traditionally been used for diarrhea and gastrointestinal bleeding; however, the wound healing ability of mineral smectite granules has not been investigated in detail. Therefore, the present study explored the efficacy and safety of mineral smectite granules on wound healing. An excision wound rat model was established. The experimental group was treated with smectite granules, the positive control group was treated with starch and the blank control group was left untreated. Wound closure rates, wound healing times and histopathological analysis were compared among the three groups. The mechanism underlying the effects of mineral smectite granules on wound healing was assessed by performing picrosirius red staining and immunohistochemical staining and measuring hydroxyproline content. Based on wound closure rates, wound healing times and histopathological analysis, the results indicated that rats treated with smectite granules displayed increased wound healing efficacy compared with the other two groups. Investigation of the underlying mechanism suggested that mineral smectite granules could promote wound healing by inducing collagen fiber synthesis and increasing the number of neovessels. The present study indicated the efficacy and safety of mineral smectite granules on wound healing and provided a theoretical basis for its application in a clinical setting.

Three Decades of Advances in Arabinogalactan-Protein Biosynthesis

Arabinogalactan-proteins (AGPs) are a large, complex, and highly diverse class of heavily glycosylated proteins that belong to the family of cell wall hydroxyproline-rich glycoproteins. Approximately 90% of the molecules consist of arabinogalactan polysaccharides, which are composed of arabinose and galactose as major sugars and minor sugars such as glucuronic acid, fucose, and rhamnose. About half of the AGP family members contain a glycosylphosphatidylinositol (GPI) lipid anchor, which allows for an association with the outer leaflet of the plasma membrane. The mysterious AGP family has captivated the attention of plant biologists for several decades. This diverse family of glycoproteins is widely distributed in the plant kingdom, including many algae, where they play fundamental roles in growth and development processes. The journey of AGP biosynthesis begins with the assembly of amino acids into peptide chains of proteins. An N-terminal signal peptide directs AGPs toward the endoplasmic reticulum, where proline hydroxylation occurs and a GPI anchor may be added. GPI-anchored AGPs, as well as unanchored AGPs, are then transferred to the Golgi apparatus, where extensive glycosylation occurs by the action of a variety glycosyltransferase enzymes. Following glycosylation, AGPs are transported by secretory vesicles to the cell wall or to the extracellular face of the plasma membrane (in the case of GPI-anchored AGPs). GPI-anchored proteins can be released from the plasma membrane into the cell wall by phospholipases. In this review, we present an overview of the accumulated knowledge on AGP biosynthesis over the past three decades. Particular emphasis is placed on the glycosylation of AGPs as the sugar moiety is essential to their function. Recent genetics and genomics approaches have significantly contributed to a broader knowledge of AGP biosynthesis. However, many questions remain to be elucidated in the decades ahead.

The glucose-sensing transcription factor ChREBP is targeted by proline hydroxylation

Cellular energy demands are met by uptake and metabolism of nutrients like glucose. The principal transcriptional regulator for adapting glycolytic flux and downstream pathways like de novo lipogenesis to glucose availability in many cell types is carbohydrate response element-binding protein (ChREBP). ChREBP is activated by glucose metabolites and post-translational modifications, inducing nuclear accumulation and regulation of target genes. Here we report that ChREBP is modified by proline hydroxylation at several residues. Proline hydroxylation targets both ectopically expressed ChREBP in cells and endogenous ChREBP in mouse liver. Functionally, we found that specific hydroxylated prolines were dispensable for protein stability but required for the adequate activation of ChREBP upon exposure to high glucose. Accordingly, ChREBP target gene expression was rescued by re-expressing WT but not ChREBP that lacks hydroxylated prolines in ChREBP-deleted hepatocytes. Thus, proline hydroxylation of ChREBP is a novel post-translational modification that may allow for therapeutic interference in metabolic diseases.

Comparison of Dietary Oils with Different Polyunsaturated Fatty Acid n-3 and n-6 Content in the Rat Model of Cutaneous Wound Healing

Dietary supplementation with polyunsaturated fatty acids (PUFA) n-3 can affect cutaneous wound healing; however, recent findings demonstrate the variable extent of their influence on the quality of healing. Here, we compare the effect of several dietary oils, containing different levels of PUFA n-3 and PUFA n-6, on wound healing in the rat model. Rats were fed the feed mixture with 8% palm oil (P), safflower oil (S), fish oil (F) or Schizochytrium microalga extract (Sch) and compared to the animals fed by control feed mixture (C). Dorsal full-thickness cutaneous excisions were performed after 52 days of feeding and skin was left to heal for an additional 12 days. Histopathological analysis of skin wounds was performed, including immune cells immunolabeling and the determination of hydroxyproline amount as well as gene expression analyses of molecules contributing to different steps of the healing. Matrix-assisted-laser-desorption-ionization mass-spectrometry-imaging (MALDI-MSI) was used to determine the amount of collagen α-1(III) chain fragment in healing samples. Treatment by Schizochytrium extract resulted in decrease in the total wound area, in contrast to the safflower oil group where the size of the wound was larger when comparing to control animals. Diet with Schizochytrium extract and safflower oils displayed a tendency to increase the number of new vessels. The number of MPO-positive cells was diminished following any of oil treatment in comparison to the control, but their highest amount was found in animals with a fish oil diet. On the other hand, the number of CD68-positive macrophages was increased, with the most significant enhancement in the fish oil and safflower oil group. Hydroxyproline concentration was the highest in the safflower oil group but it was also enhanced in all other analyzed treatments in comparison to the control. MALDI-MSI signal intensity of a collagen III fragment decreased in the sequence C > S > Sch > P > F treatment. In conclusion, we observed differences in tissue response during healing between dietary oils, with the activation of inflammation observed following the treatment with oil containing high eicosapentaenoic acid (EPA) level (fish oil) and enhanced healing features were induced by the diet with high content of docosahexaenoic acid (DHA, Schizochytrium extract).

Liver Biopsy Hydroxyproline Content Is a Diagnostic for Hepatocellular Carcinoma in Murine Models of Nonalcoholic Steatohepatitis

There is increasing evidence that nonalcoholic steatohepatitis (NASH) is a risk factor for hepatocellular carcinoma (HCC) in the absence of cirrhosis, a phenomenon termed noncirrhotic HCC. Early diagnosis of HCC is critical to a favorable prognosis. We tested the hypothesis that hydroxyproline content of liver biopsy samples is diagnostic for HCC in murine models of NASH induced by diet or by diet and chemicals. The training set comprised mice fed a standard diet or a fast-food diet with or without administration of thioacetamide. At harvest, livers from the modified diet cohort exhibited NASH with a subset of NASH livers exhibiting HCC. Hydroxyproline content was measured in liver biopsy samples with tissue in the NASH+HCC cohort sampled from the remote, nontumor parenchyma. Plotting the receiver operating characteristics (ROC) with hydroxyproline as the continuous variable against the absence or presence of HCC yielded an area under ROC of 0.87, a threshold of >0.18 μg hydroxyproline/mg liver and sensitivity of 91% with a specificity of 83.3%. The use of liver hydroxyproline content as a diagnostic for HCC in a test set comprising healthy, NASH and NASH+HCC livers proved 87% accurate.

Multi-omics Analysis Reveals Adipose-tumor Crosstalk in Patients with Colorectal Cancer

Obesity and obesity-driven cancer rates are continuing to rise worldwide. We hypothesize that adipocyte-colonocyte interactions are a key driver of obesity-associated cancers. To understand the clinical relevance of visceral adipose tissue in advancing tumor growth, we analyzed paired tumor-adjacent visceral adipose, normal mucosa, and colorectal tumor tissues as well as presurgery blood samples from patients with sporadic colorectal cancer. We report that high peroxisome proliferator-activated receptor gamma (PPARG) visceral adipose tissue expression is associated with glycoprotein VI (GPVI) signaling-the major signaling receptor for collagen-as well as fibrosis and adipogenesis pathway signaling in colorectal tumors. These associations were supported by correlations between PPARG visceral adipose tissue expression and circulating levels of plasma 4-hydroxyproline and serum intercellular adhesion molecule 1 (ICAM1), as well as gene set enrichment analysis and joint gene-metabolite pathway results integration that yielded significant enrichment of genes defining epithelial-to-mesenchymal transition-as in fibrosis and metastasis-and genes involved in glycolytic metabolism, confirmed this association. We also reveal that elevated prostaglandin-endoperoxide synthase 2 (PTGS2) colorectal tumor expression is associated with a fibrotic signature in adipose-tumor crosstalk via GPVI signaling and dendritic cell maturation in visceral adipose tissue. Systemic metabolite and biomarker profiling confirmed that high PTGS2 expression in colorectal tumors is significantly associated with higher concentrations of serum amyloid A and glycine, and lower concentrations of sphingomyelin, in patients with colorectal cancer. This multi-omics study suggests that adipose-tumor crosstalk in patients with colorectal cancer is a critical microenvironment interaction that could be therapeutically targeted.See related spotlight by Colacino et al., p. 803.

Down-Regulation of Collagen Hydroxylation in Colorectal Liver Metastasis

Collagen is significantly upregulated in colorectal liver metastasis (CRLM) compared to liver tissue. Expression levels of specific collagen types in CRLM resemble those in colorectal cancer (CRC) and colon tissue. We investigated whether the collagen hydroxylation pattern from the primary tumor also migrates with the metastatic tumor. The degree of collagen alpha-1(I) hydroxylation in colon, CRC, liver, and CRLM tissue of the same individuals (n = 14) was studied with mass spectrometry. The degree of hydroxylation was investigated in 36 collagen alpha-1(I) peptides, covering 54% of the triple helical region. The degree of hydroxylation in liver tissue was similar to that in colon tissue. The overall degree of hydroxylation was significantly lower (9 ± 14%) in CRC tissue and also significantly lower (12 ± 22%) in CRLM tissue compared to colon. Furthermore, eleven peptides with a specific number of hydroxylations are significantly different between CRLM and liver tissue; these peptides could be candidates for the detection of CRLM. For one of these eleven peptides, a matching naturally occurring peptide in urine has been identified as being significantly different between patients suffering from CRLM and healthy controls. The hydroxylation pattern in CRLM resembles partly the pattern in liver, primary colorectal cancer and colon.