Bacteriophage-cocktail hydrogel dressing to prevent multiple bacterial infections and heal diabetic ulcers in mice

Bacteriophage (phage) has been reported to reduce the bacterial infection in delayed-healing wounds and, as a result, aiding in the healing of said wounds. In this study we investigated whether the presence of phage itself could help repair delayed-healing wounds in diabetic mice. Three strains of phage that target Salmonella enterica, Escherichia coli, and Pseudomonas aeruginosa were used. To prevent the phage liquid from running off the wound, the mixture of phage (phage-cocktail) was encapsulated in a porous hydrogel dressing made with three-dimensional printing. The phage-cocktail dressing was tested for its phage preservation and release efficacy, bacterial reduction, cytotoxicity with 3T3 fibroblast, and performance in repairing a sterile full-thickness skin wound in diabetic mice. The phage-cocktail dressing released 1.7%-5.7% of the phages embedded in 24 h, and reduced between 37%-79% of the surface bacteria compared with the blank dressing (p <.05). The phage-cocktail dressing exhibited no sign of cytotoxicity after 3 days (p <.05). In vivo studies showed that 14 days after incision, the full-thickness wound treated with a phage-cocktail dressing had a higher wound healing ratio compared with the blank dressing and control (p <.01). Histological analysis showed that the structure of the skin layers in the group treated with phage-cocktail dressing was restored in an orderly fashion. Compared with the blank dressing and control, the repaired tissue in the phage-cocktail dressing group had new capillary vessels and no sign of inflammation in its dermis, and its epidermis had a higher degree of re-epithelialization (p <.05). The slow-released phage has demonstrated positive effects in repairing diabetic skin wounds.

Arthrospira Enhances Seroclearance in Patients with Chronic Hepatitis B Receiving Nucleos(t)ide Analogue through Modulation of TNF-α/IFN-γ Profile

Chronic hepatitis B (CHB) virus infection, causing immune dysfunction and chronic hepatitis, is one of the leading risk factors for hepatocellular cancer. We investigated how Arthrospira affected hepatitis B surface antigen (HBsAg) reduction in CHB patients under continued nucleos(t)ide analogues (NA). Sixty CHB patients who had been receiving NA for at least one year with undetectable HBV DNA were randomized into three groups: control and oral Arthrospira at 3 or 6 g daily add-on therapy groups. Patients were followed up for 6 months. Oral Arthrospira-diet mice were established to investigate the possible immunological mechanism of Arthrospira against HBV. Within 6 months, mean quantitative HBsAg (qHBsAg) decreased in the oral Arthrospira add-on therapy group. Interestingly, interferon gamma (IFN-γ) increased but TNF-α, interleukin 6 (IL-6), hepatic fibrosis, and steatosis decreased in the add-on groups. In mice, Arthrospira enhanced both innate and adaptive immune system, especially natural killer (NK) cell cytotoxicity, B cell activation, and the interleukin 2 (IL-2), IFN-γ immune response. Arthrospira may modulate IL-2- and TNF-α/IFN-γ-mediated B and T cell activation to reduce HBsAg. Also, Arthrospira has the potential to restore immune tolerance and enhance HBsAg seroclearance in CHB patients through promoting T, B, and NK cell activation.

Percutaneous endoscopic gastrostomy prior to esophagectomy for esophageal cancer - a systematic review and meta-analysis

BACKGROUND

For resectable esophageal cancer (EC), it remains controversial whether to place percutaneous endoscopic gastrostomy (PEG) before the curative surgery to provide nutritional support during the neoadjuvant therapy.

OBJECTIVE

To compare surgical outcomes for patients who received preoperative PEG and those without PEG placement (No-PEG) insertion prior to surgery in a potentially operable EC.

METHODS

A comprehensive literature search was conducted to identify randomized and non-randomized studies comparing PEG and No-PEG groups.

RESULTS

Four retrospective studies with a total number of 1,027 patients were identified and included in this meta-analysis. The differences in anastomotic leakage, anastomotic stricture, morbidity, pulmonary complications, wound infection, and hospital stay were not statistically significant between the two groups. Operation time was significantly shorter in the PEG group. There was no PEG-related gastric conduit failure and no leak from the PEG site in the PEG group.

CONCLUSION

We conclude preoperative PEG for resectable EC is a safe procedure with no adverse effect on the gastric tube construction and anastomosis, it can be selectively inserted for EC patients with marked weight loss and malnutrition or those at risk of developing malnutrition during neoadjuvant therapy.

Locally Applied Stem Cell Exosome-Scaffold Attenuates Nerve Injury-Induced Pain in Rats

Purpose

Nerve injury-induced pain is difficult to treat. In this study, we developed an alginate scaffold with human umbilical cord mesenchymal stem cell exosomes (EX-SC) to treat nerve injury-induced pain.

Materials and Methods

The scaffold was prepared and characterized for its physical traits and biocompatibility. In vitro studies of PC12 and HEK293 cells were used to evaluate the neuroprotective and neurotrophic effects of exosomes. Right L5/6 spinal nerve ligation (SNL) was performed in Sprague-Dawley rats to induce mechanical allodynia and thermal hyperalgesia, evaluated by von Frey hair and radiant heat tests. The EX-SC was wrapped around ligated L5/6 spinal nerves for treatment. Western blotting and immunofluorescence staining were used to evaluate neuron/glial activation, cytokines and neurotrophic factor of affected dorsal root ganglion (DRG).

Results

In cell culture assay, the exosomes induce neurite outgrowth of PC12 cells and protect PC12 and HEK293 cells against formaldehyde acid treatment. On post-ligation day 21, rats receiving EX-SC had significantly higher median (interquartile range) withdrawal threshold and latency [14.1 (13.7-15.5) g, 14.2 (13.7-15.3) s] than saline-SC-treated rats [2.1 (1.7-3.0) g, 2.0 (1.8-2.4) s, P=0.02 and 0.002]. The EX-SC also attenuated SNL-induced up-regulation of c-Fos, GFAP, Iba1, TNF-α and IL-1β, while enhancing the level of IL-10 and GDNF, in the ipsilateral L5/6 DRG. After implantation for 21 days, the EX-SC enhanced the expression of myelin basic protein and IL-10 in injured L5/6 axons.

Conclusion

We demonstrate the EX-SC possesses antinociceptive, anti-inflammation and pro-neurotrophic effects in the SNL pain model. It could be a promising therapeutic alternative for nerve injury-induced pain.

Spontaneous bacterial peritonitis caused by Campylobacter Coli in cirrhotic patient: A rare case report (CARE-compliant)

INTRODUCTION

Spontaneous bacterial peritonitis (SBP) is a fatal infection in patients. It often happens in patients with cirrhosis, cancer or diabetes, and is caused mostly by Enterobacteriaceae. Here we report a rare case of SBP caused by Campylobacter Coli (C coli) infection, which was identified promptly by the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and received adequate therapy sooner after.

PATIENT CONCERNS

In the present study, we reported a 46-year-old male with alcoholic liver cirrhosis (Child-Pugh class C) and type 2 diabetes mellitus presented with a 1-day history of fever and abdominal pain.

DIAGNOSIS

Based on the clinical examinations, the patient was diagnosed with SBP and the pathogen was quickly identified as C coli by the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), a rare causative pathogen of SBP.

INTERVENTIONS

The patient received a 10-day antibiotic treatment with Ciprofloxacin 400 mg every 12 hours, and recovered successfully.

OUTCOMES

The patient had a successful treatment outcome.

CONCLUSION

The study demonstrated a new possible infectious cause of SBP by C Coli, which was rarely seen in liver cirrhosis but mostly found in immunocompromised patients. Thus, it might raise an idea of microorganism screening of broader types that might also induce SBP for immunocompromised patients.

Hydrocele in recurrent acute pancreatitis caused by testicular venous obstruction: A case report of a rare complication (CARE-compliant)

RATIONALE

Scrotal swelling is a rare complication of acute pancreatitis. It had been explained by fluid accumulation in scrotum originated from abdomen. Here we demonstrated a case of recurrent pancreatitis with hydrocele caused by impaired testicular venous drainage.

PATIENT CONCERNS

A 53-year-old man presented with sudden onset epigastric pain after an alcohol binge. Recurrent acute pancreatitis was confirmed by medical history, physical examination, elevated lipase level and abdominal computed tomography (CT) scan. Right scrotal swelling was noticed on the next day.

DIAGNOSIS

The scrotal ultrasonography demonstrated fluid accumulation around the testis and varicocele consistent with scrotal hydrocele. CT scans of the abdomen and pelvis showed encasement of the right testicular vein by pancreatic phlegmon.

INTERVENTIONS

The patient was subject to Nulla per os, hydration, and opioid analgesics for pancreatitis. No intervention was performed for scrotal swelling.

OUTCOMES

Hydrocele gradually resolved along with acute pancreatitis.

LESSONS

Pancreatic phlegmon compromised testicular venous return which led to scrotal hydrocele and posed a threat to fertility. The study has provided a novel pathologic linkage. This complication should be taken into account.

Chronic intrathecal infusion of T-type calcium channel blockers attenuates CaV3.2 upregulation in nerve-ligated rats

OBJECTIVE

T-type channel (TCC) Ca_V3.2 plays a pivotal role in pain transmission. In this study, we examined the effects of intrathecal TCC blockers on Ca_V3.2 expression in a L5/6 spinal nerve ligation (SNL) pain model. The neurotoxicity of TCC blockers were also evaluated.

METHODS

Male Sprague-Dawley rats (200-250 g) were used for right L5/6 SNL to induce neuropathic pain. Intrathecal infusion of saline or TCC blockers [mibefradil (0.7 μg/h) or ethosuximide (60 μg/h)] was started after surgery for 7 days. Fluorescent immunohistochemistry and Western blotting were used to determine the expression pattern and protein level of Ca_V3.2. Hematoxylin-eosin and toluidine blue staining were used to evaluate the neurotoxicity of tested agents.

RESULTS

Seven days after SNL, Ca_V3.2 protein levels were upregulated in ipsi-lateral L5/6 spinal cord and dorsal root ganglia (DRG) in immunofluorescence and Western blotting studies. Compared with the saline-treated group, rats receiving mibefradil or ethosuximide showed significant lower Ca_V3.2 expression in the spinal cord and DRG. No obvious histopathologic change in hematoxylin-eosin and toluidine blue staining were observed in all tested groups.

CONCLUSION

In this study, we demonstrate that SNL-induced Ca_V3.2 upregulation in the spinal cord and DRG was attenuated by intrathecal infusion of mibefradil or ethosuximide. No obvious neurotoxicity effects were observed in all the tested groups. Our data suggest that continuous intrathecal infusion of TCC blockers may be considered as a promising alternative for the treatment of nerve injury-induced pain.

Mutation of a key residue in the type II secretion system ATPase uncouples ATP hydrolysis from protein translocation

Membrane-associated ATPase constitutes an essential element common to all secretion machineries in Gram-negative bacteria. How ATP hydrolysis by these ATPases is coupled to secretion process remains unclear. Here we identified R286 as a key residue in the type II secretion system (T2SS) ATPase XpsE of Xanthomonas campestris that plays a pivotal role in coupling ATP hydrolysis to protein translocation. Mutation of R286 to alanine made XpsE hydrolyse ATP at a rate five times that of the wild-type XpsE. Yet the mutant XpsE(R286A) is non-functional in protein secretion via T2SS. Detailed analyses indicated that the mutant XpsE(R286A) lost the ability co-ordinating the N- and C-domain of XpsE. Without significantly influencing XpsE binding affinity with ATP or its oligomerization, R286A mutation however, caused XpsE lose the ability to associate with the cytoplasmic membrane via XpsL(N). As a consequence, ATP hydrolysis by XpsE was uncoupled from protein secretion. Because R286 is highly conserved among members of the secretion NTPase superfamily, we speculate that its equivalent in other homologues may also play a critical energy coupling role for T2SS, type IV pilus assembly and type IV secretion system.

XpsE oligomerization triggered by ATP binding, not hydrolysis, leads to its association with XpsL

GspE belongs to a secretion NTPase superfamily, members of which are involved in type II/IV secretion, type IV pilus biogenesis and DNA transport in conjugation or natural transformation. Predicted to be a cytoplasmic protein, GspE has nonetheless been shown to be membrane-associated by interacting with the N-terminal cytoplasmic domain of GspL. By taking biochemical and genetic approaches, we observed that ATP binding triggers oligomerization of Xanthomonas campestris XpsE (a GspE homolog) as well as its association with the N-terminal domain of XpsL (a GspL homolog). While isolated XpsE exhibits very low intrinsic ATPase activity, association with XpsL appears to stimulate ATP hydrolysis. Mutation at a conserved lysine residue in the XpsE Walker A motif causes reduction in its ATPase activity without significantly influencing its interaction with XpsL, congruent with the notion that XpsE-XpsL association precedes ATP hydrolysis. For the first time, functional significance of ATP binding to GspE in type II secretion system is clearly demonstrated. The implications may also be applicable to type IV pilus biogenesis.

Structure and function of the XpsE N-terminal domain, an essential component of the Xanthomonas campestris type II secretion system

Secretion of fully folded extracellular proteins across the outer membrane of Gram-negative bacteria is mainly assisted by the ATP-dependent type II secretion system (T2SS). Depending on species, 12-15 proteins are usually required for the function of T2SS by forming a trans-envelope multiprotein secretion complex. Here we report crystal structures of an essential component of the Xanthomonas campestris T2SS, the 21-kDa N-terminal domain of cytosolic secretion ATPase XpsE (XpsEN), in two conformational states. By mediating interaction between XpsE and the cytoplasmic membrane protein XpsL, XpsEN anchors XpsE to the membrane-associated secretion complex to allow the coupling between ATP utilization and exoprotein secretion. The structure of XpsEN observed in crystal form P4(3)2(1)2 is composed of a 90-residue alpha/beta sandwich core domain capped by a 62-residue N-terminal helical region. The core domain exhibits structural similarity with the NifU-like domain, suggesting that XpsE(N) may be involved in the regulation of XpsE ATPase activity. Surprisingly, although a similar core domain structure was observed in crystal form I4(1)22, the N-terminal 36 residues of the helical region undergo a large structural rearrangement. Deletion analysis indicates that these residues are required for exoprotein secretion by mediating the XpsE/XpsL interaction. Site-directed mutagenesis study further suggests the more compact conformation observed in the P4(3)2(1)2 crystal likely represents the XpsL binding-competent state. Based on these findings, we speculate that XpsE might function in T2SS by cycling between two conformational states. As a closely related protein to XpsE, secretion ATPase PilB may function similarly in the type IV pilus assembly.