Combinatorial therapies for spinal cord injury repair

Spinal cord injuries have profound detrimental effects on individuals, regardless of whether they are caused by trauma or non-traumatic events. The compromised regeneration of the spinal cord is primarily attributed to damaged neurons, inhibitory molecules, dysfunctional immune response, and glial scarring. Unfortunately, currently, there are no effective treatments available that can fully repair the spinal cord and improve functional outcomes. Nevertheless, numerous pre-clinical approaches have been studied for spinal cord injury recovery, including using biomaterials, cells, drugs, or technological-based strategies. Combinatorial treatments, which target various aspects of spinal cord injury pathophysiology, have been extensively tested in the last decade. These approaches aim to synergistically enhance repair processes by addressing various obstacles faced during spinal cord regeneration. Thus, this review intends to provide scientists and clinicians with an overview of pre-clinical combinatorial approaches that have been developed toward the solution of spinal cord regeneration as well as update the current knowledge about spinal cord injury pathophysiology with an emphasis on the current clinical management.

Secretome of polarized macrophages:potential for targeting inflammatory dynamics in spinal cord injury

Spinal cord injury(SCI)involves an initial traumatic phase,followed by secondary events such as ischemia,increased blood-spinal cord barrier permeability,ionic disruption,glutamate excitotoxicity,and metabolic alterations.A pe rsistent and exagge rated inflammato ry response within the spinal cord accompanies these events(Lima et al.,2022).The complexity and interplay of these mechanisms exacerbate the initial injury,leading to a degenerative process at the injury site.While the initial trauma is unavoidable,the secondary injury begins within minutes and can last for months,creating an optimal window for therapeutic intervention.

Capsule endoscopy and panendoscopy:A journey to the future of gastrointestinal endoscopy

In 2000,the small bowel capsule revolutionized the management of patients with small bowel disorders.Currently,the technological development achieved by the new models of double-headed endoscopic capsules,as miniaturized devices to evaluate the small bowel and colon[pan-intestinal capsule endoscopy(PCE)],makes this non-invasive procedure a disruptive concept for the management of patients with digestive disorders.This technology is expected to identify which patients will require conventional invasive endoscopic procedures(colonoscopy or balloon-assisted enteroscopy),based on the lesions detected by the capsule,i.e.,those with an indication for biopsies or endoscopic treatment.The use of PCE in patients with inflammatory bowel diseases,namely Crohn’s disease,as well as in patients with iron deficiency anaemia and/or overt gastrointestinal(GI)bleeding,after a non-diagnostic upper endoscopy(esophagogastroduodenoscopy),enables an effective,safe and comfortable way to identify patients with relevant lesions,who should undergo subsequent invasive endoscopic procedures.The recent development of magnetically controlled capsule endoscopy to evaluate the upper GI tract,is a further step towards the possibility of an entirely non-invasive assessment of all the segments of the digestive tract,from mouth-to-anus,meeting the expectations of the early developers of capsule endoscopy.

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.

Highly sensitive ratiometric fluorescent fiber matrices for oxygen sensing with micrometer spatial resolution

Oxygen(O_(2))-sensing matrices are promising tools for the live monitoring of extracellular O_(2) consumption levels in long-term cell cultures.In this study,ratiometric O_(2)-sensing membranes were prepared by electrospinning,an easy,low-cost,scalable,and robust method for fabricating nanofibers.Poly(ε-caprolactone)and poly(dimethyl)siloxane polymers were blended with tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)dichloride,which was used as the O_(2)-sensing probe,and rhodamine B isothiocyanate,which was used as the reference dye.The functionalized scaffolds were morphologically characterized by scanning electron microscopy,and their physicochemical profiles were obtained by Fourier transform infrared spectroscopy,thermogravimetric analysis,and water contact angle measurement.The sensing capabilities were investigated by confocal laser scanning microscopy,performing photobleaching,reversibility,and calibration curve studies toward different dissolved O_(2)(DO)concentrations.Electrospun sensing nanofibers showed a high response to changes in DO concentrations in the physiological-pathological range from 0.5%to 20%and good stability under ratiometric imaging.In addition,the sensing systems were highly biocompatible for cell growth promoting adhesiveness and growth of three cancer cell lines,namely metastatic melanoma cell line SK-MEL2,breast cancer cell line MCF-7,and pancreatic ductal adenocarcinoma cell line Panc-1,thus recreating a suitable biological environment in vitro.These O_(2)-sensing biomaterials can potentially measure alterations in cell metabolism caused by changes in ambient O_(2)content during drug testing/validation and tissue regeneration processes.

Oxygen tension modulates cell function in an in vitro three-dimensional glioblastoma tumor model

Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor progression.However,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor cells.This study reports a three-dimensional(3D)brain tumor model obtained by encapsulating U87MG(U87)cells in a hydrogel containing type I collagen.It also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and migration.Finally,it compares two-dimensional(2D)and 3D cultures.For comparison purposes,cells cultured in flat culture dishes were used as the control(2D model).Cells cultured in the 3D model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2D model.Besides,the two models yielded significantly different cell morphologies.Finally,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3D model.These results indicate that the constructed 3D model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2D culture systems.The developed 3D glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.

Biomaterials and emerging technologies for tissue engineering and in vitro models

The latest advances in the field of biomaterials have opened new avenues for scientific breakthroughs in tissue engineer-ing which greatly contributed for the successful translation of tissue engineering products into the market/clinics.Bio-materials are easily processed to become similar to natural extracellular matrix,making them ideal temporary supports for mimicking the three-dimensional(3D)microenvironment required for maintaining the adequate cell/tissue functions both in vitro and in vivo^([1]).

Combinatorial therapies for spinal cord injury: strategies to induce regeneration

Spinal cord injury(SCI)is a condition without treatment,mainly characterized by the loss of motor and sensory function below the level of injury.This is accompanied by several complications such as cardiac and respiratory compromise,and often patients present psychological ailments associated with the drastic alteration of their normal lifestyle.SCI pathophysiology derives from a massive damage to the spinal cord tissue,which is propagated

Serrated pathway in colorectal carcinogenesis

Serrated adenocarcinoma is a recently described subset of colorectal cancer(CRC),which account for about10%of all CRCs and follows an alternative pathway in which serrated polyps replace the traditional adenoma as the precursor lesion to CRC.Serrated polyps form a heterogeneous group of colorectal lesions that includes hyperplastic polyps(HPs),sessile serrated adenoma(SSA),traditional serrated adenoma(TSA)and mixed polyps.HPs are the most common serrated polyp followed by SSA and TSA.This distinct histogenesis is believed to have a major influence in prevention strategies,patient prognosis and therapeutic impact.Genetically,serrated polyps exhibited also a distinct pattern,with KRAS and BRAF having an important contribution to its development.Two other molecular changes that have been implicated in the serrated pathway include microsatellite instability and the CpG island methylator phenotype.In the present review we will address the current knowledge of serrated polyps,clinical pathological features and will update the most recent findings of its molecular pathways.The understanding of their biology and malignancy potential is imperative to implement a surveillance approach in order to prevent colorectal cancer development.

Endoscopic retrograde cholangiopancreatography for suspected choledocholithiasis: From guidelines to clinical practice

AIM: To study the practical applicability of the American Society for Gastrointestinal Endoscopy guidelines in suspected cases of choledocholithiasis.METHODS: This was a retrospective single center study, covering a 4-year period, from January 2010 to December 2013. All patients who underwent endoscopic retrograde cholangiopancreatography(ERCP) for suspected choledocholithiasis were included. Based on the presence or absence of predictors of choledocholithiasis(clinical ascending cholangitis, common bile duct(CBD) stones on ultrasonography(US), total bilirubin > 4 mg/d L, dilated CBD on US, total bilirubin 1.8-4 mg/d L, abnormal liver function test, age > 55 years and gallstone pancreatitis), patients were stratified in low, intermediate or high risk for choledocholithiasis. For each predictor and risk group we used the χ2 to evaluate the statistical associations with the presence of choledocolithiasis at ERCP. Statistical analysis was performed using SPSS version 21.0. A P value of less than 0.05 was considered statistically significant. RESULTS: A total of 268 ERCPs were performed for suspected choledocholithiasis. Except for gallstone pancreatitis(P = 0.063), all other predictors of cho-ledocholitiasis(clinical ascending cholangitis, P = 0.001; CBD stones on US, P ≤ 0.001; total bilirubin > 4 mg/dL, P = 0.035; total bilirubin 1.8-4 mg/dL, P = 0.001; dilated CBD on US, P ≤ 0.001; abnormal liver function test, P = 0.012; age > 55 years, P = 0.002) showed a statistically significant association with the presence of choledocholithiasis at ERCP. Approximately four fifths of patients in the high risk group(79.8%, 154/193 patients) had confirmed choledocholithiasis on ERCP, vs 34.2%(25/73 patients) and 0(0/2 patients) in the intermediate and low risk groups, respectively. The definition of "high risk group" had a sensitivity of 86%, positive predictive value 79.8% and specificity 56.2% for the presence of choledocholithiasis at ERCP. CONCLUSION: The guidelines should be considered to optimize patients' selection for ERCP. For high risk patients specificity is still low, meaning that some patients perform ERCP unnecessarily.

Characterization of monocarboxylate transporter activity in hepatocellular carcinoma

AIM: To assess the immunoexpression of hypoxia-related markers in samples from cirrhosis and primary and metastatic hepatocellular carcinoma (HCC).

Upper gastrointestinal bleeding risk scores： Who, when andwhy？

Upper gastrointestinal bleeding(UGIB) remains a significant cause of hospital admission. In order to stratify patients according to the risk of the compli-cations, such as rebleeding or death, and to predict the need of clinical intervention, several risk scores have been proposed and their use consistently recommended by international guidelines. The use of risk scoring systems in early assessment of patients suffering from UGIB may be useful to distinguish high-risks patients, who may need clinical intervention and hospitalization, from low risk patients with a lower chance of developing complications, in which management as outpatients can be considered. Although several scores have been published and validated for predicting different outcomes, the most frequently cited ones are the Rockall score and the Glasgow Blatchford score(GBS). While Rockall score, which incorporates clinical and endoscopic variables, has been validated to predict mortality, the GBS, which is based on clinical and laboratorial parameters, has been studied to predict the need of clinical intervention. Despite the advantages previously reported, their use in clinical decisions is still limited. This review describes the different risk scores used in the UGIB setting, highlights the most important research, explains why and when their use may be helpful, reflects on the problems that remain unresolved and guides future research with practical impact.

Natural orifice transluminal endoscopy surgery:A review

Minimally invasive surgery started spreading worldwide in 1987,when the first laparoscopic cholecystectomy was performed.Meanwhile,improvement of endoscopic equipment and instruments allowed gastroenterologists to attempt more aggressive endoluminal interventions,even beyond the wall barrier.The first transgastric peri-toneoscopy,in 2004,brought to light the concept of natural orifice transluminal endoscopic surgery(NOTES).The idea of incisionless surgery is attractive and has become a new goal for both surgeons and other people interested in this field of investigation.The authors present a review of all developments concerning NOTES,including animal studies and human experience.

Mesenchymal stem cells secretome:current trends and future challenges

Mesenchymal stem cells(MSCs)secretome:a good candidate for medical biotechnology?Medical biotechnology is currently defined as the application of biotechnological tools for producing multiple technologies and products to health care,becoming an important bridge between different fields,namely neuroscience,regenerative medicine,pharmacology and bio-engineering(Pham,2018).The use and manipulation of stem cells can potentially represent a medical biotechnology breakthrough that brings regenerative medicine to a new era.Actually,over the last decade,the use of stem cells has remarkably been proposed as a regenerative tool,and within it,MSCs have emerged as a promising therapeutic option.

Finding the solution for incomplete small bowel capsule endoscopy

AIM:To evaluate whether the use of real time viewer(RTV)and administration of domperidone to patients with delayed gastric passage of the capsule could reduce the rate of incomplete examinations(IE)and improve the diagnostic yield of small bowel capsule endoscopy(SBCE).METHODS:Prospective single center interventional study,from June 2012 to February 2013.Capsule location was systematically checked one hour after ingestion using RTV.If it remained in the stomach,the patient received 10 mg domperidone per os and the location of the capsule was rechecked after 30 min.If the capsule remained in the stomach a second dose of10 mg of domperidone was administered orally.After another 30 min the position was rechecked and if the capsule remained in the stomach,it was passed into the duodenum by upper gastrointestinal(GI)endoscopy.The rate of IE and diagnostic yield of SBCE were compared with those of examinations performed before the use of RTV or domperidone in our Department(control group,January 2009-May 2012).RESULTS:Both groups were similar regarding age,sex,indication,inpatient status and surgical history.The control group included 307 patients,with 48(15.6%)IE.The RTV group included 82 patients,with3(3.7%)IE,P=0.003.In the control group,average gastric time was significantly longer in patients with IE than in patients with complete examination of the small bowel(77 min vs 26 min,P=0.003).In the RTV group,the capsule remained in the stomach one hour after ingestion in 14/82 patients(17.0%)vs 48/307(15.6%)in the control group,P=0.736.Domperidone did not significantly affect small bowel transit time(260min vs 297 min,P=0.229).The capsule detected positive findings in 39%of patients in the control group and 49%in the RTV group(P=0.081).CONCLUSION:The use of RTV and selective administration of domperidone to patients with delayed gastric passage of the capsule significantly reduces incomplete examinations,with no effect on small bowel transit time or diagnostic yield.

From regenerative strategies to pharmacological approaches:can we fine-tune treatment for Parkinson's disease?

Parkinson's disease is the second most prevalent neurodegenerative disorder worldwide.Clinically,it is characterized by severe motor complications caused by progressive degeneration of dopaminergic neurons.Current treatment is focused on mitigating the symptoms through the administration of levodopa,rather than on preventing dopaminergic neuronal damage.Therefore,the use and development of neuroprotective/disease-modifying strategies is an absolute need that can lead to promising gains on translational research of Parkinson's disease.For instance,N-acetylcysteine,a natural compound with strong antioxidant effects,has been shown to modulate oxidative stress,preventing dopamine-induced cell death.Despite the evidence of neuroprotective and modulatory effects of this drug,as far as we know,it does not induce per se any regenerative process.Therefore,it would be of interest to combine the latter with innovative therapies that induce dopaminergic neurons repair or even differentiation,as stem cell-based strategies.Stem cells secretome has been proposed as a promising therapeutic approach for Parkinson's disease,given its ability to modulate cell viability/preservation of dopaminergic neurons.Such approach represents a shift in the paradigm,showing that cell-transplantation free therapies based on the use of stem cells secretome may represent a potential alternative for regenerative medicine of Parkinson's disease.Thus,in this review,we address the current understanding of the potential combination of stem cell free-based strategies and neuroprotective/disease-modifying strategies as a new paradigm for the treatment of central nervous system neurodegenerative diseases,like Parkinson's disease.

Relationship between Fusobacterium nucleatum,inflammatory mediators and microRNAs in colorectal carcinogenesis

AIM To examine the effect of Fusobacterium nucleatum(F. nucleatum) on the microenvironment of colonic neoplasms and the expression of inflammatory mediators and microRNAs(miRNAs).METHODS Levels of F. nucleatum DNA, cytokine gene mRNA(TLR2, TLR4, NFKB1, TNF, IL1 B, IL6 and IL8), and potentially interacting miRNAs(miR-21-3p, miR-22-3p, mi R-28-5p, miR-34a-5p, miR-135b-5p) were measured by quantitative polymerase chain reaction(qPCR) TaqMan? assays in DNA and/or RNA extracted from the disease and adjacent normal fresh tissues of 27 colorectal adenoma(CRA) and 43 colorectal cancer(CRC) patients. KRAS mutations were detected by direct sequencing and microsatellite instability(MSI) status by multiplex PCR. Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network.RESULTS Overabundance of F. nucleatum in neoplastic tissue compared to matched normal tissue was detected in CRA(51.8%) and more markedly in CRC(72.1%). We observed significantly greater expression of TLR4, IL1 B, IL8, and miR-135 b in CRA lesions and TLR2, IL1 B, IL6, IL8, mi R-34 a and miR-135 b in CRC tumours compared to their respective normal tissues. Only two transcripts for miR-22 and miR-28 were exclusively downregulated in CRC tumour samples. The mRNA expression of IL1 B, IL6, IL8 and miR-22 was positively correlated with F. nucleatum quantification in CRC tumours. The mRNA expression of miR-135 b and TNF was inversely correlated. The miRNA:mRNA interaction network suggested that the upregulation of miR-34 a in CRC proceeds via a TLR2/TLR4-dependent response to F. nucleatum. Finally, KRAS mutations were more frequently observed in CRC samples infected with F. nucleatum and were associated with greater expression of miR-21 in CRA, while IL8 was upregulated in MSI-high CRC.CONCLUSION Our findings indicate that F. nucleatum is a risk factor for CRC by increasing the expression of inflammatory mediators through a possible mi RNA-mediated activation of TLR2/TLR4.

PillCam~ SB3 capsule: Does the increased frame rate eliminate the risk of missing lesions?

Since its emergence in 2000, small bowel capsule endoscopy(SBCE) has assumed a pivotal role as an investigation method for small bowel diseases. The PillCam SB2-ex offers 12 h of battery time, 4 more than the previous version(SB2). Rahman et al recently found that the PillCam SB2-ex has a significantly increased completion rate, although without higher diagnostic yield, compared with the SB2. We would like to discuss these somewhat surprising results and the new potentialities of the PillCam SB3 regarding the diagnostic yield of small bowel studies. PillCam SB3 offers improved image resolution and faster adaptable frame rate over previous versions of SBCE. We recently compared the major duodenal papilla detection rate obtained with PillCam SB3 and SB2 as a surrogate indicator of diagnostic yield in the proximal small bowel. The PillCam SB3 had a significantly higher major duodenal papilla detection rate than the PillCam SB2(42.7% vs 24%, P = 0.015). Thus, the most recent version of the PillCam capsule, SB3, may increase diagnostic yield, particularly in the proximal segments of the small bowel.

PillCam COLON 2~ in Crohn's disease:A new concept of pan-enteric mucosal healing assessment

AIM: To evaluate mucosal healing in patients with small bowel plus colonic Crohn's disease(CD) with a single non-invasive examination, by using PillCam COLON 2.(PCC2).METHODS: Patients with non-stricturing nonpenetrating small bowel plus colonic CD in sustained corticosteroid-free remission were included. At diagnosis,patients had undergone ileocolonoscopy to identify active CD lesions, such as ulcers and erosions, and small bowel capsule endoscopy to assess the Lewis Score(LS). After ≥ 1 year of follow-up, patients underwent entire gastrointestinal tract evaluation with PCC2. The primary endpoint was assessment of CD mucosal healing, defined as no active colonic CD lesions and LS < 135.RESULTS: Twelve patients were included(7 male;mean age: 32 years), and mean follow-up was 38 mo.The majority of patients(83.3%) received immunosuppressive therapy. Three patients(25%) achieved mucosal healing in both the small bowel and the colon,while disease activity was limited to either the small bowel or the colon in 5 patients(42%). It was possible to observe the entire gastrointestinal tract in 10 of the12 patients(83%) who underwent PCC2.CONCLUSION: Only three patients in sustainedcorticosteroid-free clinical remission achieved mucosal healing in both the small bowel and the colon, highlighting the limitations of clinical assessment when stratifying disease activity, and the need for pan-enteric endoscopy to guide therapeutic modification.

Diagnosis and treatment of iron-deficiency anemia in gastrointestinal bleeding:A systematic review

BACKGROUND Anemia is considered a public health issue and is often caused by iron deficiency.Iron-deficiency anemia(IDA)often originates from blood loss from lesions in the gastrointestinal tract in men and postmenopausal women,and its prevalence among patients with gastrointestinal bleeding has been estimated to be 61%.However,few guidelines regarding the appropriate investigation of patients with IDA due to gastrointestinal bleeding have been published.AIM To review current evidence and guidelines concerning IDA management in gastrointestinal bleeding patients to develop recommendations for its diagnosis and therapy.METHODS Five gastroenterology experts formed the Digestive Bleeding and Anemia Workgroup and conducted a systematic literature search in PubMed and professional association websites.MEDLINE(via PubMed)searches combined medical subject headings(MeSH)terms and the keywords“gastrointestinal bleeding”with“iron-deficiency anemia”and“diagnosis”or“treatment”or“management”or“prognosis”or“prevalence”or“safety”or“iron”or“transfusion”or“quality of life”,or other terms to identify relevant articles reporting the management of IDA in patients over the age of 18 years with gastrointestinal bleeding;retrieved studies were published in English between January 2003 and April 2019.Worldwide professional association websites were searched for clinical practice guidelines.Reference lists from guidelines were reviewed to identify additional relevant articles.The recommendations were developed by consensus during two meetings and were supported by the published literature identified during the systematic search.RESULTS From 494 Literature citations found during the initial literature search,17 original articles,one meta-analysis,and 13 clinical practice guidelines were analyzed.Based on the published evidence and clinical experience,the workgroup developed the following ten recommendations for the management of IDA in patients with gastrointestinal bleeding:(1)Evaluation of hemoglobin and iron status;(2)Laboratory testing;(3)Target treatment population identification;(4)Indications for erythrocyte transfusion;(5)Treatment targets for erythrocyte transfusion;(6)Indications for intravenous iron;(7)Dosages;(8)Monitoring;(9)Indications for intravenous ferric carboxymaltose treatment;and(10)Treatment targets and monitoring of patients.The workgroup also proposed a summary algorithm for the diagnosis and treatment of IDA in patients with acute or chronic gastrointestinal bleeding,which should be implemented during the hospital stay and follow-up visits after patient discharge.CONCLUSION These recommendations may serve as a starting point for clinicians to better diagnose and treat IDA in patients with gastrointestinal bleeding,which ultimately may improve health outcomes in these patients.