Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 339
Filtrar
1.
Small ; : e2309528, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38470207

RESUMO

Nanoparticles of a particular, evolutionarily old inorganic polymer found across the biological kingdoms have attracted increasing interest in recent years not only because of their crucial role in metabolism but also their potential medical applicability: it is inorganic polyphosphate (polyP). This ubiquitous linear polymer is composed of 10-1000 phosphate residues linked by high-energy anhydride bonds. PolyP causes induction of gene activity, provides phosphate for bone mineralization, and serves as an energy supplier through enzymatic cleavage of its acid anhydride bonds and subsequent ATP formation. The biomedical breakthrough of polyP came with the development of a successful fabrication process, in depot form, as Ca- or Mg-polyP nanoparticles, or as the directly effective polymer, as soluble Na-polyP, for regenerative repair and healing processes, especially in tissue areas with insufficient blood supply. Physiologically, the platelets are the main vehicles for polyP nanoparticles in the circulating blood. To be biomedically active, these particles undergo coacervation. This review provides an overview of the properties of polyP and polyP nanoparticles for applications in the regeneration and repair of bone, cartilage, and skin. In addition to studies on animal models, the first successful proof-of-concept studies on humans for the healing of chronic wounds are outlined.

2.
J Infect Public Health ; 17(4): 619-623, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38417188

RESUMO

BACKGROUND: Acute gastroenteritis is one of the major causes of morbidity and mortality in young children worldwide. Among these, rotavirus, norovirus, and adenovirus have been reported as the primary viral pathogens associated with the disease. Rapid diagnosis of viral pathogens is crucial when diarrhea outbreaks occur to ensure the timely administration of appropriate treatment and control measures. METHODS: We evaluated three immunochromatographic test kits designed for the detection of norovirus, rotavirus, and adenovirus in 71 stool specimens collected from children with diarrhea who visited clinics in Japan. The first kit is a triplex immunochromatographic test kit designed for simultaneous detections of norovirus, rotavirus, and adenovirus on a single strip (this kit was referred to as IC-A). The other two immunochromatographic test kits are a dual detection kit for rotavirus and adenovirus, and a single detection kit for norovirus (IC-B). The RT-PCR/PCR was used as the gold standard method. RESULTS: The results revealed that both IC-A and IC-B kits exhibited the same level of sensitivity of detection for rotavirus (72.7%) and adenovirus (22.7%), although the detection rate was lower than that of the RT-PCR/PCR method. However, there was a slight difference in the sensitivity of detection for norovirus between IC-A and IC-B, at 86.7% and 93.3%, respectively. The sensitivity of detection for adenovirus of both kits was relatively lower than those of RT-PCR method. This could be due to low viral load of adenovirus in clinical specimens below the detection limit of IC-A and IC-B kits. However, both immunochromatographic test kits (IC-A and IC-B) exhibited 100% specificity for norovirus, rotavirus, and adenovirus. CONCLUSIONS: The triplex immunochromatographic test kit (IC-A) designed for simultaneous detection of norovirus, rotavirus, and adenovirus has been proved to be more practical and convenient than the use of single or dual detection kits with more or less the same sensitivity and specificity of detections.


Assuntos
Infecções por Caliciviridae , Norovirus , Rotavirus , Criança , Humanos , Pré-Escolar , Adenoviridae , Fezes , Diarreia/diagnóstico , Sensibilidade e Especificidade , Infecções por Caliciviridae/diagnóstico
3.
PLoS One ; 19(2): e0298031, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38363743

RESUMO

OBJECTIVE: This study aims to test the association of rest-activity rhythm (intradaily variability and interdaily stability) with all-cause mortality in an older adult cohort in Brazil. It also assesses whether the amount of time spent at each intensity level (i.e., physical activity and nocturnal sleep) interferes with this association. METHODS: This cohort study started in 2014 with older adults (≥60 years). We investigated deaths from all causes that occurred until April 2017. Rest-activity rhythm variables were obtained using accelerometry at baseline. Intradaily variability indicates higher rhythm fragmentation, while interdaily stability indicates higher rhythm stability. Cox proportional-hazard models were used to test the associations controlling for confounders. RESULTS: Among the 1451 older adults interviewed in 2014, 965 presented valid accelerometry data. During the follow-up period, 80 individuals died. After adjusting the analysis for sociodemographic, smoking, morbidity score, and number of medicines, an increase of one standard deviation in interdaily stability decreased 26% the risk of death. The adjustment for total sleep time and inactivity did not change this association. On the other hand, the association was no longer significant after adjusting for overall physical activity and moderate to vigorous physical activity. CONCLUSION: Rest-activity rhythm pattern was not associated with mortality when physical activity was considered, possibly because this pattern could be driven by regular exercise. Promoting physical activity remains a relevant strategy to improve population health.


Assuntos
Ritmo Circadiano , Sono , Humanos , Idoso , Estudos de Coortes , Descanso , Exercício Físico
4.
Int J Nanomedicine ; 19: 1303-1337, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38348175

RESUMO

There is a need for novel nanomaterials with properties not yet exploited in regenerative nanomedicine. Based on lessons learned from the oldest metazoan phylum, sponges, it has been recognized that two previously ignored or insufficiently recognized principles play an essential role in tissue regeneration, including biomineral formation/repair and wound healing. Firstly, the dependence on enzymes as a driving force and secondly, the availability of metabolic energy. The discovery of enzymatic synthesis and regenerative activity of amorphous biosilica that builds the mineral skeleton of siliceous sponges formed the basis for the development of successful strategies for the treatment of osteochondral impairments in humans. In addition, the elucidation of the functional significance of a second regeneratively active inorganic material, namely inorganic polyphosphate (polyP) and its amorphous nanoparticles, present from sponges to humans, has pushed forward the development of innovative materials for both soft (skin, cartilage) and hard tissue (bone) repair. This energy-rich molecule exhibits a property not shown by any other biopolymer: the delivery of metabolic energy, even extracellularly, necessary for the ATP-dependent tissue regeneration. This review summarizes the latest developments in nanobiomaterials based on these two evolutionarily old, regeneratively active materials, amorphous silica and amorphous polyP, highlighting their specific, partly unique properties and mode of action, and discussing their possible applications in human therapy. The results of initial proof-of-concept studies on patients demonstrating complete healing of chronic wounds are outlined.


Assuntos
Polímeros , Polifosfatos , Humanos , Animais , Nanomedicina , Materiais Biocompatíveis , Dióxido de Silício
5.
Sci Rep ; 14(1): 565, 2024 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-38177275

RESUMO

To combat infections, silver was used extensively in biomedical field but there was a need for a capping agent to eliminate its cytotoxic effects. In this study, polymeric calcium polyphosphate was doped by silver with three concentrations 1, 3 or 5 mol.% and were characterized by TEM, XRD, FTIR, TGA. Moreover, cytotoxicity, antibacterial, cell migration and DNA fragmentation assays were done to assure its safety. The results showed that the increase in silver percentage caused an increase in particle size. XRD showed the silver peaks, which indicated that it is present in its metallic form. The TGA showed that thermal stability was increased by increasing silver content. The antibacterial tests showed that the prepared nanoparticles have an antibacterial activity against tested pathogens. In addition, the cytotoxicity results showed that the samples exhibited non-cytotoxic behavior even with the highest doping concentration (5% Ag-CaPp). The cell migration assay showed that the increase in the silver concentration enhances cell migration up to 3% Ag-CaPp. The DNA fragmentation test revealed that all the prepared nanoparticles caused no fragmentation. From the results we can deduce that 3% Ag-CaPp was the optimum silver doped calcium polyphosphate concentration that could be used safely for medical applications.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Prata/farmacologia , Cálcio , Fragmentação do DNA , Extratos Vegetais , Antibacterianos/farmacologia , Cálcio da Dieta , Movimento Celular , Testes de Sensibilidade Microbiana
6.
JMIR Res Protoc ; 13: e42371, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38224475

RESUMO

BACKGROUND: Biphasic calcium phosphates (BCP) may serve as off-the-shelf alternatives for iliac crest-derived autologous bone in alveolar cleft reconstructions. To add osteoinductivity to the osteoconductive BCPs to achieve similar regenerative capacity as autologous bone, a locally harvested buccal fat pad will be mechanically fractionated to generate microfragmented fat (MFAT), which has been shown to have high regenerative capacity due to high pericyte and mesenchymal stem cell content and a preserved perivascular niche. OBJECTIVE: Our primary objectives will be to assess the feasibility and safety of the BCP-MFAT combination. The secondary objective will be efficacy, which will be evaluated using radiographic imaging and histological and histomorphometric evaluation of biopsies taken 6 months postoperatively, concomitant with dental implant placement. METHODS: Eight patients with alveolar cleft (≥15 years) will be included in this prospective, nonblinded, first-in-human clinical study. MFAT will be prepared intraoperatively from the patient's own buccal fat pad. Regular blood tests and physical examinations will be conducted, and any adverse events (AEs) or serious EAs (SAEs) will be meticulously recorded. Radiographic imaging will be performed prior to surgery and at regular intervals after reconstruction of the alveolar cleft with the BCP-MFAT combination. Biopsies obtained after 6 months with a trephine drill used to prepare the implantation site will be assessed with histological and histomorphometric analyses after methylmethacrylate embedding and sectioning. RESULTS: The primary outcome parameter will be safety after 6 months' follow-up, as monitored closely using possible occurrences of SAEs based on radiographic imaging, blood tests, and physical examinations. For efficacy, radiographic imaging will be used for clinical grading of the bone construct using the Bergland scale. In addition, bone parameters such as bone volume, osteoid volume, graft volume, and number of osteoclasts will be histomorphometrically quantified. Recruitment started in November 2019, and the trial is currently in the follow-up stage. This protocol's current version is 1.0, dated September 15, 2019. CONCLUSIONS: In this first-in-human study, not only safety but also the histologically and radiographically assessed regenerative potential of the BCP-MFAT combination will be evaluated in an alveolar cleft model. When an SAE occurs, it will be concluded that the BCP-MFAT combination is not yet safe in the current setting. Regarding AEs, if they do not occur at a higher frequency than that in patients treated with standard care (autologous bone) or can be resolved by noninvasive conventional methods (eg, with analgesics or antibiotics), the BCP-MFAT combination will be considered safe. In all other cases, the BCP-MFAT combination will not yet be considered safe. TRIAL REGISTRATION: Indonesia Clinical Trial Registry INA-EW74C1N; https://tinyurl.com/28tnrr64. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/42371.

7.
Obes Surg ; 33(8): 2620-2624, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37402890

RESUMO

Unknown intestinal rotation anomaly poses a challenge in laparoscopic gastric bypass surgery. We present a case of a patient with intestinal non-rotation that stayed undetected throughout performing a laparoscopic Roux-en-Y gastric bypass. As a result, the alimentary limb was constructed in an anti-peristaltic way, and the whole gastric bypass was located far more distally than usual. Postoperatively, the patient presented with recurring nausea and vomiting. After several diagnostic steps, a computed tomography finally revealed the inadvertently reverse directed gastric bypass and the pre-existing condition of intestinal non-rotation. This was followed by a diagnostic laparoscopy and the reconstruction of the gastric bypass in "mirrored" technique.


Assuntos
Derivação Gástrica , Volvo Intestinal , Laparoscopia , Obesidade Mórbida , Humanos , Derivação Gástrica/métodos , Obesidade Mórbida/cirurgia , Volvo Intestinal/diagnóstico por imagem , Volvo Intestinal/cirurgia , Laparoscopia/métodos
8.
Pharmaceutics ; 15(2)2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36839816

RESUMO

Amorphous calcium carbonate (ACC), precipitated in the presence of inorganic polyphosphate (polyP), has shown promise as a material for bone regeneration due to its morphogenetic and metabolic energy (ATP)-delivering properties. The latter activity of the polyP-stabilized ACC ("ACC∙PP") particles is associated with the enzymatic degradation of polyP, resulting in the transformation of ACC into crystalline polymorphs. In a novel approach, stimulated by these results, it was examined whether "ACC∙PP" also promotes the healing of skin injuries, especially chronic wounds. In in vitro experiments, "ACC∙PP" significantly stimulated the migration of endothelial cells, both in tube formation and scratch assays (by 2- to 3-fold). Support came from ex vivo experiments showing increased cell outgrowth in human skin explants. The transformation of ACC into insoluble calcite was suppressed by protein/serum being present in wound fluid. The results were confirmed in vivo in studies on normal (C57BL/6) and diabetic (db/db) mice. Topical administration of "ACC∙PP" significantly accelerated the rate of re-epithelialization, particularly in delayed healing wounds in diabetic mice (day 7: 1.5-fold; and day 13: 1.9-fold), in parallel with increased formation/maturation of granulation tissue. The results suggest that administration of "ACC∙PP" opens a new strategy to improve ATP-dependent wound healing, particularly in chronic wounds.

9.
Acta Biomater ; 156: 177-189, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-35988660

RESUMO

Understanding the optimal conditions required for bone healing can have a substantial impact to target the problem of non-unions and large bone defects. The combination of bioactive factors, regenerative progenitor cells and biomaterials to form a tissue engineered (TE) complex is a promising solution but translation to the clinic has been slow. We hypothesized the typical material testing algorithm used is insufficient and leads to materials being mischaracterized as promising. In the first part of this study, human bone marrow - derived mesenchymal stromal cells (hBM-MSCs) were embedded in three commonly used biomaterials (hyaluronic acid methacrylate, gelatin methacrylate and fibrin) and combined with relevant bioactive osteogenesis factors (dexamethasone microparticles and polyphosphate nanoparticles) to form a TE construct that underwent in vitro osteogenic differentiation for 28 days. Gene expression of relevant transcription factors and osteogenic markers, and von Kossa staining were performed. In the second and third part of this study, the same combination of TE constructs were implanted subcutaneously (cell containing) in T cell-deficient athymic Crl:NIH-Foxn1rnu rats for 8 weeks or cell free in an immunocompetent New Zealand white rabbit calvarial model for 6 weeks, respectively. Osteogenic performance was investigated via MicroCT imaging and histology staining. The in vitro study showed enhanced upregulation of relevant genes and significant mineral deposition within the three biomaterials, generally considered as a positive result. Subcutaneous implantation indicates none to minor ectopic bone formation. No enhanced calvarial bone healing was detected in implanted biomaterials compared to the empty defect. The reasons for the poor correlation of in vitro and in vivo outcomes are unclear and needs further investigation. This study highlights the discrepancy between in vitro and in vivo outcomes, demonstrating that in vitro data should be interpreted with extreme caution. In vitro models with higher complexity are necessary to increase value for translational studies. STATEMENT OF SIGNIFICANCE: Preclinical testing of newly developed biomaterials is a crucial element of the development cycle. Despite this, there is still significant discrepancy between in vitro and in vivo test results. Within this study we investigate multiple combinations of materials and osteogenic stimulants and demonstrate a poor correlation between the in vitro and in vivo data. We propose rationale for why this may be the case and suggest a modified testing algorithm.


Assuntos
Substitutos Ósseos , Células-Tronco Mesenquimais , Ratos , Humanos , Animais , Coelhos , Osteogênese/fisiologia , Substitutos Ósseos/farmacologia , Substitutos Ósseos/metabolismo , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/metabolismo , Engenharia Tecidual , Diferenciação Celular/fisiologia , Alicerces Teciduais
10.
Front Microbiol ; 14: 1248896, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38274753

RESUMO

Two new caryophyllene-type sesquiterpenes pestalotiopsins U and V (1 and 2) and three known compounds pestalotiopsin B (7), pestaloporinate B (8), and pestalotiopsin C (9) were isolated by the cultivation of the endophytic fungus Pestalotiopsis lespedezae on solid rice medium, while four additional new caryophyllene pestalotiopsins W-Z (3-6) were obtained when 3.5% NaI was added to the fungal culture medium. The structures of the new compounds were determined by HRESIMS and 1D/2D nuclear magnetic resonance data. Compounds 1-9 were tested for cytotoxicity against the mouse lymphoma cell line L5178Y, but only 6 displayed significant activity with an IC50 value of 2.4 µM.

11.
Int J Nanomedicine ; 17: 5825-5850, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36474526

RESUMO

Inorganic polyphosphates (polyP) are long-chain polymers of orthophosphate residues, which, depending on the external conditions, can be present both physiologically and synthetically in either soluble, nanoparticulate or coacervate form. In recent years, these polymers have received increasing attention due to their unprecedented ability to exhibit both morphogenetic and metabolic energy delivering properties. There are no other physiological molecules that contain as many metabolically utilizable, high-energy bonds as polyP, making these polymers of particular medical interest as components of advanced hydrogel scaffold materials for potential applications in ATP-dependent tissue regeneration and repair. However, these polymers show physiological activity only in soluble form and in the coacervate phase, but not as stable metal-polyP nanoparticles. Therefore, understanding the mechanisms of formation of polyP coacervates and nanoparticles as well as their transformations is important for the design of novel materials for tissue implants, wound healing, and drug delivery and is discussed here.


Assuntos
Polifosfatos
12.
Dent Mater ; 38(12): 2014-2029, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36424205

RESUMO

Calcium phosphate (CaP) deposition during bone mineralization starts with the aggregation of Posner's clusters Ca9(PO4)6 into amorphous Ca-phosphate (ACP), which then transforms into crystalline CaP and finally maturates to hydroxyapatite (HA). Using dentin/enamel of human teeth as a model system, we show that the physiological inorganic polymer polyphosphate (polyP), a phosphate donor in mineralization, prevents the transition from amorphous to crystalline CaP at concentrations> 15 wt%. Stabilization of the amorphous phase of CaP by polyP is reversed by hydrolysis of the polymer by alkaline phosphatase (ALP), an enzyme that releases phosphate for mineralization. It is still present in calcified enamel and dentin, as shown here by immunostaining and enzyme activity measurements. The phase transfer into crystalline CaP can be prevented by the ALP inhibitor levamisole. Besides TEM and SEM, the modulating effects of polyP and ALP on the kinetics of the phase transition from amorphous to crystalline CaP are demonstrated and confirmed by XRD and FTIR analyses. Molecular modeling studies show that the polyP chains, due to their dimensions, are able to penetrate into the channels between the Posner molecules, preventing cluster association to ACP and impairing HA crystal formation.


Assuntos
Fosfatos de Cálcio , Polifosfatos , Humanos , Durapatita , Fosfatase Alcalina , Polímeros , Corantes
13.
Mater Today Bio ; 16: 100404, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36065353

RESUMO

Inorganic polyphosphates (polyP) are of increasing medical interest due to their unprecedented ability to exhibit both morphogenetic and ATP-delivering properties. However, these polymers are only physiologically active in the coacervate state, but not as amorphous nanoparticles (NP), the storage form of the polymer. Little is known about the mechanism of formation and interconversion of these two distinct polyP phases in the presence of metal ions. Based on in silico simulation studies, showing a differential clustering of polyP and calcium ions, the pH-dependent NP and coacervate formation of polyP was examined experimentally. Turbidimetric studies showed that Ca-polyP coacervate formation at pH 7 is a slow process compared to NP formation at pH 10. In FTIR spectra, the asymmetric stretching vibration signal of the internal (PO2)- units, which is present in the Ca-polyP coacervate formed at pH 7, disappears in the NP formed at pH 10 using the conventional method (dropping of a CaCl2 solution into a Na-polyP solution). Surprisingly, when reversing the procedure, adding Na-polyP to CaCl2, a coacervate is obtained at both pH 7 and pH 10, as confirmed by SEM and FTIR analyses. The (PO2)- signal also disappears when Ca-polyP-NP are exposed to peptides, leading to the transformation of the NP into the coacervate phase. From these results, a mechanistic model of pH-dependent coacervate and NP formation is proposed that considers not only electrostatic ion-ion but also ion-dipole interactions. Functional studies revealed a delayed polyP release kinetics for Ca-polyP-NP embedded in a hydrogel due to NP/coacervate conversion. Human A549 epithelial cells grown on the coacervate show increased proliferation and ATP production compared to cells cultured on particulate polyP. Ca-polyP NP taken up by endocytosis undergo intracellular coacervate transformation. Understanding the differential expression of the two polyP phases is of functional importance for the potential therapeutic application of this physiological, regeneratively active polymer.

14.
Am J Physiol Gastrointest Liver Physiol ; 323(4): G306-G317, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35916405

RESUMO

The alternative (noncanonical) nuclear factor-κB (NF-κB) signaling pathway predominantly regulates the function of the p52/RelB heterodimer. Germline Nfkb2 deficiency in mice leads to loss of p100/p52 protein and offers protection against a variety of gastrointestinal conditions, including azoxymethane/dextran sulfate sodium (DSS)-induced colitis-associated cancer and lipopolysaccharide (LPS)-induced small intestinal epithelial apoptosis. However, the common underlying protective mechanisms have not yet been fully elucidated. We applied high-throughput RNA-Seq and proteomic analyses to characterize the transcriptional and protein signatures of the small intestinal mucosa of naïve adult Nfkb2-/- mice. Those data were validated by immunohistochemistry and quantitative ELISA using both small intestinal tissue lysates and serum. We identified a B-lymphocyte defect as a major transcriptional signature in the small intestinal mucosa and immunoglobulin A as the most downregulated protein by proteomic analysis in Nfkb2-/- mice. Small intestinal immunoglobulins were dramatically dysregulated, with undetectable levels of immunoglobulin A and greatly increased amounts of immunoglobulin M being detected. The numbers of IgA-producing, cluster of differentiation (CD)138-positive plasma cells were also reduced in the lamina propria of the small intestinal villi of Nfkb2-/- mice. This phenotype was even more striking in the small intestinal mucosa of RelB-/- mice, although these mice were equally sensitive to LPS-induced intestinal apoptosis as their RelB+/+ wild-type counterparts. NF-κB2/p52 deficiency confers resistance to LPS-induced small intestinal apoptosis and also appears to regulate the plasma cell population and immunoglobulin levels within the gut.NEW & NOTEWORTHY Novel transcriptomic analysis of murine proximal intestinal mucosa revealed an unexpected B cell signature in Nfkb2-/- mice. In-depth analysis revealed a defect in the CD38+ B cell population and a gut-specific dysregulation of immunoglobulin levels.


Assuntos
Subunidade p52 de NF-kappa B , Plasmócitos , Animais , Imunoglobulina A/metabolismo , Imunoglobulinas/metabolismo , Mucosa Intestinal/metabolismo , Lipopolissacarídeos/farmacologia , Camundongos , NF-kappa B/metabolismo , Subunidade p52 de NF-kappa B/genética , Subunidade p52 de NF-kappa B/metabolismo , Plasmócitos/metabolismo , Proteômica
15.
Prog Mol Subcell Biol ; 61: 51-82, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35697937

RESUMO

Many pathological conditions are characterized by a deficiency of metabolic energy. A prominent example is nonhealing or difficult-to-heal chronic wounds. Because of their unique ability to serve as a source of metabolic energy, inorganic polyphosphates (polyP) offer the opportunity to develop novel strategies to treat such wounds. The basis is the generation of ATP from the polymer through the joint action of two extracellular or plasma membrane-bound enzymes alkaline phosphatase and adenylate kinase, which enable the transfer of energy-rich phosphate from polyP to AMP with the formation of ADP and finally ATP. Building on these findings, it was possible to develop novel regeneratively active materials for wound therapy, which have already been successfully evaluated in first studies on patients.


Assuntos
Trifosfato de Adenosina , Polifosfatos , Trifosfato de Adenosina/metabolismo , Adenilato Quinase/metabolismo , Fosfatase Alcalina/metabolismo , Humanos , Polifosfatos/metabolismo , Polifosfatos/uso terapêutico , Cicatrização
16.
Prog Mol Subcell Biol ; 61: 83-130, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35697938

RESUMO

In recent years, inorganic polyphosphate (polyP) has attracted increasing attention as a biomedical polymer or biomaterial with a great potential for application in regenerative medicine, in particular in the fields of tissue engineering and repair. The interest in polyP is based on two properties of this physiological polymer that make polyP stand out from other polymers: polyP has morphogenetic activity by inducing cell differentiation through specific gene expression, and it functions as an energy store and donor of metabolic energy, especially in the extracellular matrix or in the extracellular space. No other biopolymer applicable in tissue regeneration/repair is known that is endowed with this combination of properties. In addition, polyP can be fabricated both in the form of a biologically active coacervate and as biomimetic amorphous polyP nano/microparticles, which are stable and are activated by transformation into the coacervate phase after contact with protein/body fluids. PolyP can be used in the form of various metal salts and in combination with various hydrogel-forming polymers, whereby (even printable) hybrid materials with defined porosities and mechanical and biological properties can be produced, which can even be loaded with cells for 3D cell printing or with drugs and support the growth and differentiation of (stem) cells as well as cell migration/microvascularization. Potential applications in therapy of bone, cartilage and eye disorders/injuries and wound healing are summarized and possible mechanisms are discussed.


Assuntos
Polifosfatos , Medicina Regenerativa , Biomimética , Polímeros , Engenharia Tecidual
17.
Prog Mol Subcell Biol ; 61: 145-189, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35697940

RESUMO

Polyanions as polymers carrying multiple negative charges have been extensively studied with regard to their potential antiviral activity. Most studies to date focused on organic polyanionic polymers, both natural and synthetic. The inorganic polymer, polyphosphate (polyP), despite the ubiquitous presence of this molecule from bacteria to man, has attracted much less attention. More recently, and accelerated by the search for potential antiviral agents in the fight against the pandemic caused by the coronavirus SARS-CoV-2, it turned out that polyP disrupts the first step of the viral replication cycle, the interaction of the proteins in the virus envelope and in the cell membrane that are involved in the docking process of the virus with the target host cell. Experiments on a molecular level using the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and the cellular angiotensin converting enzyme 2 (ACE2) receptor revealed that polyP strongly inhibits the binding reaction through an electrostatic interaction between the negatively charged centers of the polyP molecule and a cationic groove, which is formed by positively charged amino acids on the RBD surface. In addition, it was found that polyP, due to its morphogenetic and energy delivering activities, enhances the antiviral host innate immunity defense of the respiratory epithelium. The underlying mechanisms and envisaged application of polyP in the therapy and prevention of COVID-19 are discussed.


Assuntos
Tratamento Farmacológico da COVID-19 , Antivirais/química , Antivirais/uso terapêutico , Humanos , Polieletrólitos , Polímeros , Polifosfatos/química , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus
18.
Biomedicines ; 10(4)2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35453507

RESUMO

The NFκB transcription factors are major regulators of innate immune responses, and NFκB signal pathway dysregulation is linked to inflammatory disease. Here, we utilised bone marrow-derived macrophages from the p65-DsRedxp/IκBα-eGFP transgenic strain to study the functional implication of xenogeneic (human) RelA(p65) protein introduced into the mouse genome. Confocal imaging showed that human RelA is expressed in the cells and can translocate to the nucleus following activation of Toll-like receptor 4. RNA sequencing of lipid A-stimulated macrophages, revealed that human RelA impacts on murine gene transcription, affecting both non-NFκB and NFκB target genes, including immediate-early and late response genes, e.g., Fos and Cxcl10. Validation experiments on NFκB targets revealed markedly reduced mRNA levels, but similar kinetic profiles in transgenic cells compared to wild-type. Enrichment pathway analysis of differentially expressed genes revealed interferon and cytokine signaling were affected. These immune response pathways were also affected in macrophages treated with tumor necrosis factor. Data suggests that the presence of xenogeneic RelA protein likely has inhibitory activity, altering specific transcriptional profiles of key molecules involved in immune responses. It is therefore essential that this information be taken into consideration when designing and interpreting future experiments using this transgenic strain.

19.
Biomedicines ; 10(3)2022 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-35327460

RESUMO

Two biocatalytically produced inorganic biomaterials show great potential for use in regenerative medicine but also other medical applications: bio-silica and bio-polyphosphate (bio-polyP or polyP). Biosilica is synthesized by a group of enzymes called silicateins, which mediate the formation of amorphous hydrated silica from monomeric precursors. The polymeric silicic acid formed by these enzymes, which have been cloned from various siliceous sponge species, then undergoes a maturation process to form a solid biosilica material. The second biomaterial, polyP, has the extraordinary property that it not only has morphogenetic activity similar to biosilica, i.e., can induce cell differentiation through specific gene expression, but also provides metabolic energy through enzymatic cleavage of its high-energy phosphoanhydride bonds. This reaction is catalyzed by alkaline phosphatase, a ubiquitous enzyme that, in combination with adenylate kinase, forms adenosine triphosphate (ATP) from polyP. This article attempts to highlight the biomedical importance of the inorganic polymeric materials biosilica and polyP as well as the enzymes silicatein and alkaline phosphatase, which are involved in their metabolism or mediate their biological activity.

20.
Phytochemistry ; 197: 113124, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35144154

RESUMO

Chemical investigation of the fungal endophyte Pseudopestalotiopsis theae isolated from leaves of Caloncoba welwitschii, collected in Cameroon, resulted in two previously undescribed sulfur-containing xanthone derivatives sydoxanthones D and E, in addition to three previously undescribed monomeric diisoprenyl-cyclohexene-type meroterpenoids biscognienynes D-F and five known natural products. The structures of the undescribed compounds were unambiguously identified by their mass spectra and by extensive 1D and 2D NMR spectroscopic analysis. Mosher's reaction was performed to determine the absolute configuration of sydoxanthones D and E while TDDFT-ECD calculations were used to assign the configuration of biscognienyne D. Biscognienynes B and D showed significant cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values of 7.7 and 6.7 µM and against the human leukemic cell lines HL60, and Hal-01 with IC50 values ranging from 4.3 to 12.1 µM.


Assuntos
Xantonas , Animais , Ascomicetos , Cicloexenos , Camundongos , Estrutura Molecular , Enxofre , Xantonas/química , Xantonas/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA