A Review of the Role of Bioreactors for iPSCs-Based Tissue-Engineered Articular Cartilage

BACKGROUND

Osteoarthritis (OA) is the most common degenerative joint disease without an ultimate treatment. In a search for novel approaches, tissue engineering (TE) has shown great potential to be an effective way for hyaline cartilage regeneration and repair in advanced stages of OA. Recently, induced pluripotent stem cells (iPSCs) have been appointed to be essential stem cells for degenerative disease treatment because they allow a personalized medicine approach. For clinical translation, bioreactors in combination with iPSCs-engineerd cartilage could match patients needs, serve as platform for large-scale patient specific cartilage production, and be a tool for patient OA modelling and drug screening. Furthermore, to minimize in vivo experiments and improve cell differentiation and cartilage extracellular matrix (ECM) deposition, TE combines existing approaches with bioreactors.

METHODS

This review summarizes the current understanding of bioreactors and the necessary parameters when they are intended for cartilage TE, focusing on the potential use of iPSCs.

RESULTS

Bioreactors intended for cartilage TE must resemble the joint cavity niche. However, recreating human synovial joints is not trivial because the interactions between various stimuli are not entirely understood.

CONCLUSION

The use of mechanical and electrical stimulation to differentiate iPSCs, and maintain and test chondrocytes are key stimuli influencing hyaline cartilage homeostasis. Incorporating these stimuli to bioreactors can positively impact cartilage TE approaches and their possibility for posterior translation into the clinics.

Quantum Sensing for Real-Time Monitoring of Drug Efficacy in Synovial Fluid from Arthritis Patients

Diamond-based T1 relaxometry is a new technique that allows nanoscale magnetic resonance measurements. Here we present its first application in patient samples. More specifically, we demonstrate that relaxometry can determine the free radical load in samples from arthritis patients. We found that we can clearly differentiate between osteoarthritis and rheumatoid arthritis patients in both the synovial fluid itself and cells derived from it. Furthermore, we tested how synovial fluid and its cells respond to piroxicam, a common nonsteroidal anti-inflammatory drug (NSAID). It is known that this drug leads to a reduction in reactive oxygen species production in fibroblast-like synoviocytes (FLS). Here, we investigated the formation of free radicals specifically. While FLS from osteoarthritis patients showed a drastic decrease in the free radical load, cells from rheumatoid arthritis retained a similar radical load after treatment. This offers a possible explanation for why piroxicam is more beneficial for patients with osteoarthritis than those with rheumatoid arthritis.

Friction reducing ability of a poly-l-lysine and dopamine modified hyaluronan coating for polycaprolactone cartilage resurfacing implants

Frictional properties of cartilage resurfacing implants should be sufficiently low to limit damaging of the opposing cartilage during articulation. The present study determines if native lubricious molecule proteoglycan 4 (PRG4) can adsorb onto a layer-by-layer bioinspired coating composed of poly-l-lysine (PLL) and dopamine modified hyaluronic acid (HADN) and thereby can reduce the friction between implant and articular cartilage. An ELISA was developed to quantify the amount of immobilized human recombinant (rh)PRG4 after exposure to the PLL-HADN coating. The effect on lubrication was evaluated by comparing the coefficient of friction (CoF) of bare polycaprolactone (PCL) disks to that of PLL-HADN coated PCL disks while articulated against cartilage using a ring-on-disk geometry and a lubricant solution consisting of native synovial fluid components including rhPRG4. The PLL-HADN coating effectively immobilized rhPRG4. The surface roughness of PCL disks significantly increased while the water contact angle significantly decreased after application of the coating. The average CoF measured during the first minute of bare PCL against cartilage exceeded twice the CoF of the PLL-HADN coated PCL against cartilage. After 60 min, the CoF reached equilibrium values which were still significantly higher for bare PCL compared to coated PCL. The present study demonstrated that PCL can effectively be coated with PLL-HADN. Additionally, this coating reduces the friction between PCL and cartilage when a PRG4-rich lubricant is used, similar to the lubricating surface of native cartilage. This makes PLL-HADN coating a promising application to improve the clinical success of PCL-based cartilage resurfacing implants.

Viscoelastic properties of plasma-agarose hydrogels dictate favorable fibroblast responses for skin tissue engineering applications

Dermal wound healing relies on the properties of the extracellular matrix (ECM). Thus, hydrogels that replicate skin ECM have reached clinical application. After a dermal injury, a transient, biodegradable fibrin clot is instrumental in wound healing. Human plasma, and its main constituent, fibrin would make a suitable biomaterial for improving wound healing and processed as hydrogels albeit with limited mechanical strength. To overcome this, plasma-agarose (PA) composite hydrogels have been developed and used to prepare diverse bioengineered tissues. To date, little is known about the influence of variable agarose concentrations on the viscoelastic properties of PA hydrogels and their correlation to cell biology. This study reports the characterization of the viscoelastic properties of different concentrations of agarose in PA hydrogels: 0 %, 0.5 %, 1 %, 1.5 %, and 2 % (w/v), and their influence on the cell number and mitochondrial activity of human dermal fibroblasts. Results show that agarose addition increased the stiffness, relaxation time constants 1 (τ1) and 2 (τ2), and fiber diameter, whereas the porosity decreased. Changes in cell metabolism occurred at the early stages of culturing and correlated to the displacement of fast (τ1) and intermediate (τ2) Maxwell elements. Fibroblasts seeded in low PA concentrations spread faster during 14 d than cells cultured in higher agarose concentrations. Collectively, these results confirm that PA viscoelasticity and hydrogel architecture strongly influenced cell behavior. Therefore, viscoelasticity is a key parameter in the design of PA-based implants.

Meta-QTLs for multiple disease resistance involving three rusts in common wheat (Triticum aestivum L.)

In wheat, multiple disease resistance meta-QTLs (MDR-MQTLs) and underlying candidate genes for the three rusts were identified which may prove useful for development of resistant cultivars. Rust diseases in wheat are a major threat to global food security. Therefore, development of multiple disease-resistant cultivars (resistant to all three rusts) is a major goal in all wheat breeding programs worldwide. In the present study, meta-QTLs and candidate genes for multiple disease resistance (MDR) involving all three rusts were identified using 152 individual QTL mapping studies for resistance to leaf rust (LR), stem rust (SR), and yellow rust (YR). From these 152 studies, a total of 1,146 QTLs for resistance to three rusts were retrieved, which included 368 QTLs for LR, 291 QTLs for SR, and 487 QTLs for YR. Of these 1,146 QTLs, only 718 QTLs could be projected onto the consensus map saturated with 2, 34,619 markers. Meta-analysis of the projected QTLs resulted in the identification of 86 MQTLs, which included 71 MDR-MQTLs. Ten of these MDR-MQTLs were referred to as the 'Breeders' MQTLs'. Seventy-eight of the 86 MQTLs could also be anchored to the physical map of the wheat genome, and 54 MQTLs were validated by marker-trait associations identified during earlier genome-wide association studies. Twenty MQTLs (including 17 MDR-MQTLs) identified in the present study were co-localized with 44 known R genes. In silico expression analysis allowed identification of several differentially expressed candidate genes (DECGs) encoding proteins carrying different domains including the following: NBS-LRR, WRKY domains, F-box domains, sugar transporters, transferases, etc. The introgression of these MDR loci into high-yielding cultivars should prove useful for developing high yielding cultivars with resistance to all the three rusts.

Differential roles for lysyl oxidase (like), family members in chronic obstructive pulmonary disease; from gene and protein expression to function

Chronic obstructive pulmonary disease (COPD) is characterized by long-term airflow obstruction with cigarette smoke as a key risk factor. Extracellular matrix (ECM) alterations in COPD may lead to small airway wall fibrosis. Altered collagen cross-linking, potentially mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4), orchestrates disturbed ECM homeostasis. In this study, we investigated the effects of smoking status and presence and severity of COPD on LOs gene and protein expression in the airways and the impact of LOs inhibition on airway contraction in an ex vivo mouse model. We used gene expression data from bronchial brushings, airway smooth muscle (ASM) cells in vitro and immunohistochemistry in lung tissue to assess smoke- and COPD-associated differences in LOs gene and protein expression in the small airways. We found higher LOX expression in current- compared to ex-smokers and higher LOXL1 expression in COPD compared to non-COPD patients. LOX and LOXL2 expression were upregulated in COPD ASM cells treated with cigarette smoke extract. LOXL1 and LOXL2 protein levels were higher in small airways from current- compared to non-smokers. In COPD patients, higher LOXL1 and lower LOX protein levels were observed, but no differences for LOXL2, LOXL3, and LOXL4 protein were detected in small airways. Inhibiting LOs activity increased airway contraction in murine lung slices. COPD-associated changes in LOs, in particular LOX and LOXL1, may be related to smoking and contribute to impaired airway function, providing potential novel targets for preventing or treating small airways changes in COPD.

An in vitro model of fibrosis using crosslinked native extracellular matrix-derived hydrogels to modulate biomechanics without changing composition

Extracellular matrix (ECM) is a dynamic network of proteins, proteoglycans and glycosaminoglycans, providing structure to the tissue and biochemical and biomechanical instructions to the resident cells. In fibrosis, the composition and the organization of the ECM are altered, and these changes influence cellular behaviour. Biochemical (i. e. protein composition) and biomechanical changes in ECM take place simultaneously in vivo. Investigating these changes individually in vitro to examine their (patho)physiological effects has been difficult. In this study, we generated an in vitro model to reflect the altered mechanics of a fibrotic microenvironment through applying fibre crosslinking via ruthenium/sodium persulfate crosslinking on native lung ECM-derived hydrogels. Crosslinking of the hydrogels without changing the biochemical composition of the ECM resulted in increased stiffness and decreased viscoelastic stress relaxation. The altered stress relaxation behaviour was explained using a generalized Maxwell model. Fibre analysis of the hydrogels showed that crosslinked hydrogels had a higher percentage of matrix with a high density and a shorter average fibre length. Fibroblasts seeded on ruthenium-crosslinked lung ECM-derived hydrogels showed myofibroblastic differentiation with a loss of spindle-like morphology together with greater α-smooth muscle actin (α-SMA) expression, increased nuclear area and circularity without any decrease in the viability, compared with the fibroblasts seeded on the native lung-derived ECM hydrogels. In summary, ruthenium crosslinking of native ECM-derived hydrogels provides an exciting opportunity to alter the biomechanical properties of the ECM-derived hydrogels while maintaining the protein composition of the ECM to study the influence of mechanics during fibrotic lung diseases. STATEMENT OF SIGNIFICANCE: Fibrotic lung disease is characterized by changes in composition and excessive deposition of extracellular matrix (ECM). ECM fibre structure also changes due to crosslinking, which results in mechanical changes. Separating the changes in composition and mechanical properties has been difficult to date. In this study, we developed an in vitro model that allows alteration of the mechanical changes alone by applying fibre crosslinking in native lung ECM-derived hydrogels. Characterisations of the crosslinked hydrogels indicated the model mimicked mechanical properties of fibrotic lung tissue and reflected altered fibre organisation. This ECM-based fibrosis model provides a method to preserve the native protein composition while altering the mechanical properties providing an important tool, not only for lung but also other organ fibrosis.

Clinical Profile and Prevalence of H Pylori, Iga-Ttg, and Spectrum of Duodenal Abnormalities in Non Ulcer Dyspepsia

The Rome IV criterion for a diagnosis of NUD is chronic or recurrent epigastric pain within the last 3 months and an onset of symptoms at least 6 months prior to presentation. The term functional Dyspepsia and idiopathic dyspepsia are often used as well. Symptoms include ulcer-like dyspepsia; gastroparetic-like (nausea, early satiety, and post-prandial pain), and undifferentiated. Pathogenesis of NUD is not completely known yet. Several mechanisms have been proposed to be responsible for these symptoms. Although there is strong evidence of an association between H. pylori infection and NUD, Celiac Disease and NUD. Being a tropical country, the prevalence of infections is parasitic cause. Dyspepsia is likely to be more in India. However, the present data from India as scares in literature. Hence the present study was planned to decipher the clinical profile, prevalence of H. pylori, IgA tTG, spectrum of duodenal biopsy abnormalities in NUD patients.

MATERIAL

This Descriptive Observational study was carried out in the Gastro Enterology center in GOI research institute from August 2020 to March 2021. Initially, 200 dyspepsia patients were selected. 50 patients were excluded due to various reasons. Finally, 150 patients who met the Rome 4 criteria for NUD/Functional Dyspepsia were recruited. The inclusion criteria were patients above 18 years of age, dyspepsia for >/- 6 months, and no evidence of underlying malignancy, pan gastritis, previous gastric ulcers, and pancreatitis. The patients underwent routine blood investigations like haemogram and biochemistry, Rapid Urease Test (RUT), Upper Gastro-Intestinal Endoscopy, Duodenal Biopsy, and Serum IgA-tTG antibody.

OBSERVATION

The mean age was 46.3 yrs. +/- 14.12 yrs, of which 49.3% were females and 50.70% were males. The prevalence of Epigastric Pain Syndrome (EPS) was found in 37.3%, Post Prandial Distress Syndrome (PDS) in 30.7%, and 32% had both EPS+PDS. 38% of the NUD patients were positive on Rapid Urease Test (RUT) suggesting H. pylori infection. 88.7% of NUD patients were IgA-tTG antibody negative and 11.3% serologically positive. The Duodenal biopsy was normal in 48% of patients, 21.3% had mild inflammation/duodenitis, 8% chronic duodenitis and 22.7% had various grades of Celiac Disease (as per Marsh Grading). These 22.7% showing evidence of Celiac Disease on histopathological examination showed Marsh Grade 1 in 12.7%, Grade-2 in 2%, Grade 3A in 6.7%, and Grade 3B in 1.3%. Only 17.6% of biopsy positive had IgA-tTG antibody positivity but only 4% of total cases were positive for both biopsy and IgA-tTG antibody (p-value 0.05). Eosinophilic infiltration in duodenum common in NUD patients. It was observed that 17.33% (26/150) NUD patients had duodenal eosinophilia. Further, look for the association of duodenal eosinophilia with various diseases. 33.33% (19/57) H. pylori patients had duodenal eosinophilia with p-value < 0.001. It was also observed that 7.52% (7/93) others like normal individual, Chronic duodenitis, mild inflammation/ duodenitis had Duodenal eosinophilia.

CONCLUSION

The prevalence of H. pylori and IgA-tTG antibodies in non-ulcer dyspepsia patients was 38% and 11.3% respectively. The spectrum of Duodenum biopsy abnormalities in NUD patients included mild inflammation/ duodenitis, Chronic duodenitis, and Celiac Disease. 22.7% of NUD patients had various degrees of celiac disease morphology on D2 biopsy and only 17.6% of these biopsy positive patients were positive for IgA-tTG. Only 4% of total NUD patients were positive for both biopsy and IgA-tTG antibody labeled as Celiac Disease (CeD). There is a significant association between H. pylori and duodenal eosinophilia.

Dopamine-conjugated hyaluronic acid delivered via intra-articular injection provides articular cartilage lubrication and protection

Due to its high molecular weight and viscosity, hyaluronic acid (HA) is widely used for viscosupplementation to provide joint pain relief in osteoarthritis. However, this benefit is temporary due to poor adhesion of HA on articular surfaces. In this study, we therefore conjugated HA with dopamine to form HADN, which made the HA adhesive while retaining its viscosity enhancement capacity. We hypothesized that HADN could enhance cartilage lubrication through adsorption onto the exposed collagen type II network and repair the lamina splendens. HADN was synthesized by carbodiimide chemistry between hyaluronic acid and dopamine. Analysis of Magnetic Resonance (NMR) and Ultraviolet spectrophotometry (Uv-vis) showed that HADN was successfully synthesized. Adsorption of HADN on collagen was demonstrated using Quartz crystal microbalance with dissipation (QCM-D). Ex vivo tribological tests including measurement of coefficient of friction (COF), dynamic creep, in stance (40 N) and swing (4 N) phases of gait cycle indicated adequate protection of cartilage by HADN with higher lubrication compared to HA alone. HADN solution at the cartilage-glass sliding interface not only retains the same viscosity as HA and provides fluid film lubrication, but also ensures better boundary lubrication through adsorption. To confirm the cartilage surface protection of HADN, we visualized cartilage wear using optical coherence tomography (OCT) and atomic force microscopy (AFM).

Lectin-Functionalized Polyethylene Glycol for Relief of Mucosal Dryness

The importance of lubrication between oral surfaces provided by the salivary film is most acutely apparent when it is disrupted, a prevalent consequence of salivary gland hypofunction experienced with aging, a symptom of certain diseases, or a side effect of some medical interventions. Sufferers report difficulty with speech and oral food processing and collectively is detrimental to quality of life. Polyethylene glycol (PEG) is widely employed as a successful biocompatible boundary lubricant in engineering and biomedical applications. It is hypothesized that the immobilization of PEG to biological materials such as oral epithelial cells and tissue can mimic the salivary film and provide durable relief from the symptoms of mucosal dryness. To do so, PEG is functionalized with a sugar binding lectin (wheat germ agglutinin) to enhance epithelial adhesion through lectin-sugar interactions. Retention and lubricity are characterized on an ex vivo oral tissue tribology rig. WGA-PEG coats and retains on mucin films, oral epithelial cells, and porcine tongue tissue, and offers sustained reduction in coefficient of friction (COF). WGA-PEG could be developed into a useful topical treatment for reducing oral friction and the perception of dry mouth.

Nonviral Expression of LL-37 in a Human Skin Equivalent to Prevent Infection in Skin Wounds

Inefficient autologous tissue recovery in skin wounds increases the susceptibility of patients to infections caused by multidrug resistant microorganisms, resulting in a high mortality rate. Genetic modification of skin cells has become an important field of study because it could lead to the construction of more functional skin grafts, through the overexpression of antimicrobial peptides that would prevent early contamination and infection with bacteria. In this study, we produce and evaluate human skin equivalents (HSEs) containing transfected human primary fibroblasts and keratinocytes by polyplexes to express the antimicrobial peptide LL-37. The effect of LL-37 on the metabolic activity of normal HSEs was evaluated before the construction of the transfected HSEs, and the antimicrobial efficacy against Pseudomonas aeruginosa and Staphylococcus aureus was evaluated. Subsequently, the levels of LL-37 in the culture supernatants of transfected HSEs, as well as the local expression, were determined. It was found that LL-37 treatment significantly promoted the cellular proliferation of HSEs. Furthermore, HSEs that express elevated levels of LL-37 were shown to possess histological characteristics close to the normal skin and display enhanced antimicrobial activity against S. aureus in vitro. These findings demonstrate that HSEs expressing LL-37 through nonviral modification of skin cells are a promising approach for the prevention of bacterial colonization in wounds.

Lubricating properties of chewing stimulated whole saliva from patients suffering from xerostomia

OBJECTIVES

The study aimed to quantify the lubricating properties of chewing stimulated whole saliva from healthy controls (n = 22), from patients suffering from primary Sjögren's syndrome (n = 37) and from patients undergoing head-and-neck radiotherapy (n = 34).

MATERIALS AND METHODS

All participants had to complete the Xerostomia Inventory questionnaire to score dry mouth sensation. Lubrication was measured using an ex vivo tongue-enamel friction system in terms of Relief and Relief period. MUC5b and total protein concentrations of the saliva samples were measured by an enzyme-linked immunosorbent assay and a bicinchoninic acid assay, respectively.

RESULTS

Relief of Sjögren's patients' saliva and post-irradiation patients' saliva was similar compared with healthy controls, but saliva from post-irradiation patients lubricated significantly better than saliva from Sjögren's patients. The Relief period was similar between the three groups. The Relief and Relief period were higher for saliva samples post-irradiation compared to pre-irradiation. MUC5b and total protein concentrations were comparable in all groups. MUC5b and total protein output were significantly lower in patients subjected to radiotherapy compared to saliva from healthy controls and pre-irradiation patients. MUC5b concentrations positively correlated with lubricating properties of post-irradiation patient saliva.

CONCLUSIONS

The lubricating properties of patient saliva were not any worse than healthy controls. Lower flow rate leads to lower availability of saliva in the oral cavity and decreases the overall output of protein and MUC5b, which might result in an insufficient replenishing of the mucosal salivary film.

CLINICAL RELEVANCE

An insufficient replenishing might underlie the sensation of a dry mouth and loss of oral function.

Examining the uptake and bioaccumulation of molybdenum nanoparticles and their effect on antioxidant activities in growing rice seedlings

The synthesized α-MoO₃ and MoS₂ NPs had nanosheet and nanoflower-like structures with crystallite size of 21.34 nm and 4.32 nm, respectively. The uptake, bioaccumulation, and impact of these two Mo-NPs were studied in rice (Oryza sativa L) cv. HUR 3022 seedlings exposed to 100, 500, and 1000 ppm concentrations in hydroponics for 10 days in the growth medium. The uptake of α-MoO₃ and MoS₂ NPs by rice exposed to 100 ppm concentrations of NPs led to the accumulation of 7.32 ppm/4.55 ppm and 1.84 ppm/1.19 ppm in roots/shoots, respectively, as compared to controls. Unlike MoO₃, more accumulation of MoS₂ in roots reflect less translocation of this NP from roots to shoots. Results suggest tissue-specific distribution of NPs in rice seedlings. The increased growth and elevated protein levels in rice seedlings at 100 ppm concentrations of nanoparticles imply a stimulation in the repair mechanism at low doses indicating hormesis. MoS₂ NPs treatments led to increased chlorophyll a levels suggesting it to be non-compromising with photosynthetic process in rice. The high malondialdehyde levels and altered activities of antioxidant enzymes GPX, APX, and CAT in rice seedlings exposed to α-MoO₃ or MoS₂ NPs indicate oxidative imbalance. Between α-MoO₃ and MoS₂ NPs, the former shows toxic effects as reflected from the decreased levels of photosynthetic pigments at all concentrations; however, an activation of chloroplast ROS detoxification is evident in the presence of MoS₂ NPs. The BCF > 1 for both α-MoO₃ and MoS₂ NPs and TF of 0.6-2.0 and 0.42-0.65 suggest the latter to be more environmentally safe. In conclusion, a100 ppm MoS₂ NPs concentration has low translocation and less accumulation with no significant impact on growth of rice cv. HUR 3022 seedlings and appears to be environmentally safe for future applications.

Biotribological properties of xerostomia patient saliva and its enhancement

The study aimed to quantify the lubricating properties of chewing stimulated whole saliva from healthy controls (n=22), from patients suffering from primary Sjögren’s syndrome (n=37) and from patients undergoing head-and-neck radiotherapy (n=34). Materials and Methods All participants had to complete the Xerostomia Inventory questionnaire to score dry mouth sensation. Lubrication was measured using an ex vivo tongue-enamel friction system in terms of Relief and Relief period. MUC5b and total protein concentrations of the saliva samples were measured by an enzyme-linked immunosorbent assay and a bicinchoninic acid assay, respectively. Results Relief of Sjögren’s patients saliva and post-irradiation patients saliva was similar compared with healthy controls, but saliva from post-irradiation patients lubricated significantly better than saliva from Sjögren’s patients. The Relief period was similar between the three groups. The Relief and Relief period were higher for saliva samples post-irradiation compared to pre-irradiation. MUC5b and total protein concentrations were comparable in all groups. MUC5b and total protein output were significantly lower in patients subjected to radiotherapy compared to saliva from healthy controls and pre-irradiation patients. MUC5b concentrations positively correlated with lubricating properties of post-irradiation patient saliva. Conclusions The lubricating properties of patient saliva were not any worse than healthy controls. Lower flow rate leads to lower availability of saliva in the oral cavity and decreases the overall output of protein and MUC5b, which might result in an insufficient replenishing of the mucosal salivary film. Clinical Relevance An insufficient replenishing might underlie the sensation of a dry mouth and loss of oral function. In the talk I will explain biomaterials related strategies, yet ex vivo, to enhance salivary lubrication despite of low flowrates.

Chemical and mechanical influence of root canal irrigation on biofilm removal from lateral morphological features of simulated root canals, dentine discs and dentinal tubules

Aim

To investigate the anti‐biofilm efficacy of irrigation using a simulated root canal model, the chemical effect of irrigants against biofilms grown on dentine discs and their impact on biofilm viscoelasticity, the efficacy of the irrigants in decontaminating infected dentinal tubules and the capacity of bacteria to regrow.

Methodology

Biofilm removal, viscoelastic analysis of remaining biofilms and bacterial viability were evaluated using a simulated root canal model with lateral morphological features, dentine discs and a dentinal tubule model, respectively. Experiments were conducted using a two‐phase irrigation protocol. Phase 1: a modified salt solution (RISA) and sodium hypochlorite (NaOCl) were used at a low flow rate to evaluate the chemical action of the irrigants. Ultrasonic activation (US) of a chemically inert solution (buffer) was used to evaluate the mechanical efficacy of irrigation. Phase 2: a final irrigation with buffer at a high flow rate was performed for all groups. Optical coherence tomography (OCT), low load compression testing (LLCT) and confocal scanning laser microscopy analysis were used in the different models. One‐way analysis of variance (anova) was performed for the OCT and LLCT analysis, whilst Kruskal–Wallis and Wilcoxon ranked tests for the dentinal tubule model.

Results

US and high flow rate removed significantly more biofilm from the artificial lateral canal. For biofilm removal from the artificial isthmus, no significant differences were found between the groups. Within‐group analysis revealed significant differences between the steps of the experiment, with the exception of NaOCl. For the dentine discs, no significant differences regarding biofilm removal and viscoelasticity were detected. In the dentinal tubule model, NaOCl exhibited the greatest anti‐biofilm efficacy.

Conclusions

The mechanical effect of irrigation is important for biofilm removal. An extra high flow irrigation rate resulted in greater biofilm removal than US in the artificial isthmus. The mechanical effect of US seemed to be more effective when the surface contact biofilm–irrigant was small. After the irrigation procedures, the remaining biofilm could survive after a 5‐day period. RISA and NaOCl seemed to alter post‐treatment remaining biofilms.

Biofilm removal from a simulated isthmus and lateral canal during syringe irrigation at various flow rates: a combined experimental and Computational Fluid Dynamics approach

Aim

(i) To quantify biofilm removal from a simulated isthmus and a lateral canal in an artificial root canal system during syringe irrigation with NaOCl at different concentrations and delivered at various flow rates (ii) to examine whether biofilm removal is further improved by a final high‐flow‐rate rinse with an inert irrigant following irrigation with NaOCl. (iii) to simulate the irrigant flow in these areas using a computer model (iv) to examine whether the irrigant velocity calculated by the computer model is correlated to biofilm removal.

Methodology

Ninety‐six artificial root canals with either a simulated isthmus or lateral canal were used. A dual‐species in vitro biofilm was formed in these areas using a Constant Depth Film Fermenter. NaOCl at various concentrations (2, 5 and 10%) or adhesion buffer (control) was delivered for 30 s by a syringe and an open‐ended needle at 0.033, 0.083, or 0.166 mL s⁻¹ or passively deposited in the main root canal (phase 1). All specimens were subsequently rinsed for 30 s with adhesion buffer at 0.166 mL s⁻¹ (phase 2). The biofilm was scanned by Optical Coherence Tomography to determine the percentage of the remaining biofilm. Results were analysed by two 3‐way mixed‐design ANOVAs (α = 0.05). A Computational Fluid Dynamics model was used to simulate the irrigant flow inside the artificial root canal system.

Results

The flow rate during phase 1 and additional irrigation during phase 2 had a significant effect on the percentage of the remaining biofilm in the isthmus (P = 0.004 and P < 0.001). Additional irrigation during phase 2 also affected the remaining biofilm in the lateral canal significantly (P ≤ 0.007) but only when preceded by irrigation at medium or high flow rate during phase 1. The effect of NaOCl concentration was not significant (P > 0.05). Irrigant velocity in the isthmus and lateral canal increased with increasing flow rate and it was substantially correlated to biofilm removal from those areas.

Conclusions

The irrigant flow rate affected biofilm removal in vitro more than NaOCl concentration. Irrigant velocity predicted by the computer model corresponded with the pattern of biofilm removal from the simulated isthmus and lateral canal.

Genome-wide analysis of H3K4me3 and H3K27me3 modifications due to Lr28 for leaf rust resistance in bread wheat (Triticum aestivum)

Present study revealed a complex relationship among histone H3 methylation (examined using H3K4/K27me3 marks), cytosine DNA methylation and differential gene expression during Lr28 mediated leaf rust resistance in wheat. During the present study, genome-wide histone modifications were examined in a pair of near isogenic lines (NILs) (with and without Lr28 in the background of cv. HD2329). The two histone marks used included H3K4me3 (an activation mark) and H3K27me3 (a repression mark). The results were compared with levels of expression (using RNA-seq) and DNA methylation (MeDIP) data obtained using the same pair of NILs. Some of the salient features of the present study include the following: (i) large scale differential binding sites (DBS) were available for only H3K4me3 in the susceptible cultivar, but for both H3K4me3 and H3K27me3 in its resistant NIL; (ii) DBSs for H3K27me3 mark were more abundant (> 80%) in intergenic regions, whereas DBSs for H3K4me3 were distributed in all genomic regions including exons, introns, intergenic, TTS (transcription termination sites) and promoters; (iii) fourteen (14) genes associated with DBSs showed co-localization for both the marks; (iv) only a small fraction (7% for H3K4me3 and 12% for H3K27me3) of genes associated with DBSs matched with the levels of gene expression inferred from RNA-seq data; (v) validation studies using qRT-PCR were conducted on 26 selected representative genes; results for only 11 genes could be validated. The proteins encoded by important genes involved in promoting infection included domains generally carried by R gene proteins such as Mlo like protein, protein kinases and purple acid phosphatase. Similarly, proteins encoded by genes involved in resistance included those carrying domains for lectin kinase, R gene, aspartyl protease, etc. Overall, the results suggest a very complex network of downstream genes that are expressed during compatible and incompatible interactions; some of the genes identified during the present study may be used in future validation studies involving RNAi/overexpression approaches.

Next Generation Salivary Lubrication Enhancer Derived from Recombinant Supercharged Polypeptides for Xerostomia

Insufficient retention of water in adsorbed salivary conditioning films (SCFs) because of altered saliva secretion can lead to oral dryness (xerostomia). Patients with xerostomia sometimes are given artificial saliva, which often lacks efficacy because of the presence of exogenous molecules with limited lubrication properties. Recombinant supercharged polypeptides (SUPs) improve salivary lubrication by enhancing the functionality of endogenously available salivary proteins, which is in stark contrast to administration of exogenous lubrication enhancers. This novel approach is based on establishing a layered architecture enabled by electrostatic bond formation to stabilize and produce robust SCFs in vitro. Here, we first determined the optimal molecular weight of SUPs to achieve the best lubrication performance employing biophysical and in vitro friction measurements. Next, in an ex vivo tongue-enamel friction system, stimulated whole saliva from patients with Sjögren syndrome was tested to transfer this strategy to a preclinical situation. Out of a library of genetically engineered cationic polypeptides, the variant SUP K108cys that contains 108 positive charges and two cysteine residues at each terminus was identified as the best SUP to restore oral lubrication. Employing this SUP, the duration of lubrication (Relief Period) for SCFs from healthy and patient saliva was significantly extended. For patient saliva, the lubrication duration was increased from 3.8 to 21 min with SUP K108cys treatment. Investigation of the tribochemical mechanism revealed that lubrication enhancement is because of the electrostatic stabilization of SCFs and mucin recruitment, which is accompanied by strong water fixation and reduced water evaporation.

Correction to: Dry mouth: saliva substitutes which adsorb and modify existing salivary condition films improve oral lubrication

After publication of this paper, the authors observed that that figure 6 appears before figure 5.

The influence of time and irrigant refreshment on biofilm removal from lateral morphological features of simulated root canals

Aim

To evaluate the effect of irrigant refreshment and exposure time of a 2% sodium hypochlorite solution (NaOCl) on biofilm removal from simulated lateral root canal spaces using two different flow rates.

Methodology

A dual‐species biofilm was formed by a Constant Depth Film Fermenter (CDFF) for 96 h in plug inserts with anatomical features resembling an isthmus or lateral canal‐like structures. The inserts were placed in a root canal model facing the main canal. NaOCl 2% and demineralized water (control group) were used as irrigant solutions. Both substances were applied at a flow rate of 0.05 and 0.1 mL s⁻¹. The samples were divided into three groups with zero, one or two refreshments in a total exposure time of 15 min. A three‐way analysis of variance (anova) was performed to investigate the interaction amongst the independent variables and the effect of consecutive irrigant refreshment on percentage of biofilm removal. A Tukey post hoc test was used to evaluate the effect of each independent variable on percentage biofilm removal in the absence of statistically significant interactions.

Results

For the lateral canal, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time (P = 0.005). There was no significant effect in biofilm removal between the consecutive irrigant refreshments measured in the same biofilm. For the isthmus, NaOCl removed significantly more biofilm irrespective of the number of refreshments and exposure time; both NaOCl and a high flow rate removed significantly more biofilm when the exposure time was analysed (P = 0.018 and P = 0.029, respectively). Evaluating the effect of consecutive irrigant refreshment on the same biofilm, 2% NaOCl, 0.1 mL s⁻¹ flow rate and one or two refreshments removed significant more biofilm (P = 0.04, 0.034 and 0.003, <0.001, respectively).

Conclusions

In this model, refreshment did not improve biofilm removal from simulated lateral root canal spaces. NaOCl removed more biofilm from the lateral canal‐ and isthmus‐like structure. A higher flow rate removed significantly more biofilm from the isthmus‐like structure. There was always remaining biofilm left after the irrigation procedures.

Molecular and Biomechanical Clues From Cardiac Tissue Decellularized Extracellular Matrix Drive Stromal Cell Plasticity

Decellularized-organ-derived extracellular matrix (dECM) has been used for many years in tissue engineering and regenerative medicine. The manufacturing of hydrogels from dECM allows to make use of the pro-regenerative properties of the ECM and, simultaneously, to shape the material in any necessary way. The objective of the present project was to investigate differences between cardiovascular tissues (left ventricle, mitral valve, and aorta) with respect to generating dECM hydrogels and their interaction with cells in 2D and 3D. The left ventricle, mitral valve, and aorta of porcine hearts were decellularized using a series of detergent treatments (SDS, Triton-X 100 and deoxycholate). Mass spectrometry-based proteomics yielded the ECM proteins composition of the dECM. The dECM was digested with pepsin and resuspended in PBS (pH 7.4). Upon warming to 37°C, the suspension turns into a gel. Hydrogel stiffness was determined for samples with a dECM concentration of 20 mg/mL. Adipose tissue-derived stromal cells (ASC) and a combination of ASC with human pulmonary microvascular endothelial cells (HPMVEC) were cultured, respectively, on and in hydrogels to analyze cellular plasticity in 2D and vascular network formation in 3D. Differentiation of ASC was induced with 10 ng/mL of TGF-β1 and SM22α used as differentiation marker. 3D vascular network formation was evaluated with confocal microscopy after immunofluorescent staining of PECAM-1. In dECM, the most abundant protein was collagen VI for the left ventricle and mitral valve and elastin for the aorta. The stiffness of the hydrogel derived from the aorta (6,998 ± 895 Pa) was significantly higher than those derived from the left ventricle (3,384 ± 698 Pa) and the mitral valve (3,233 ± 323 Pa) (One-way ANOVA, p = 0.0008). Aorta-derived dECM hydrogel drove non-induced (without TGF-β1) differentiation, while hydrogels derived from the left ventricle and mitral valve inhibited TGF-β1-induced differentiation. All hydrogels supported vascular network formation within 7 days of culture, but ventricular dECM hydrogel demonstrated more robust vascular networks, with thicker and longer vascular structures. All the three main cardiovascular tissues, myocardium, valves, and large arteries, could be used to fabricate hydrogels from dECM, and these showed an origin-dependent influence on ASC differentiation and vascular network formation.

Dry mouth: saliva substitutes which adsorb and modify existing salivary condition films improve oral lubrication

Objectives

The aims of this study are to assess different saliva substitutes for their efficacy to lubricate the oral cavity, and to relate this oral lubrication to the ability of saliva substitutes to adsorb on and change the structure of the existing salivary conditioning film (SCF).

Materials and methods

Quartz crystal microbalance with dissipation was used to study the capability of saliva substitutes to interact with natural SCF and the ability to change the secondary SCF (S-SCF). A tongue-enamel friction system mimicking xerostomic conditions was used to assess the relief and relief period expected from these substitutes under set circumstances.

Results

Saliva Orthana spray, Biotène spray and Gum Hydral gel had an immediate effect on a SCF, increasing its structural softness. BioXtra gel, Biotène gel, Gum Hydral gel and Glandosane spray changed the S-SCF by increasing salivary protein adsorption, while others showed no sign of interaction. With respect to relief, only 2 out of the 16 saliva substitutes tested (Saliva Orthana spray and Gum Hydral gel) performed better than water. Overall, relief period correlated positively to structural softness change, whereas a positive correlation was seen between relief and mass adsorption.

Conclusions

The majority of saliva substitutes did not adsorb on the SCF, thus did not enhance lubrication. Only saliva substitutes containing carrageenan, carboxymethylcellulose, pig gastric mucin, xanthan gum and carbomer performed better in enhancing oral lubrication.

Clinical relevance

This objective assessment will help clinicians and patients make better choice of saliva substitutes. This study provides a scientific basis for future improvement in saliva substitutes.

Human lung extracellular matrix hydrogels resemble the stiffness and viscoelasticity of native lung tissue

Chronic lung diseases such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are associated with changes in extracellular matrix (ECM) composition and abundance affecting the mechanical properties of the lung. This study aimed to generate ECM hydrogels from control, severe COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) IV], and fibrotic human lung tissue and evaluate whether their stiffness and viscoelastic properties were reflective of native tissue. For hydrogel generation, control, COPD GOLD IV, and fibrotic human lung tissues were decellularized, lyophilized, ground into powder, porcine pepsin solubilized, buffered with PBS, and gelled at 37°C. Rheological properties from tissues and hydrogels were assessed with a low-load compression tester measuring the stiffness and viscoelastic properties in terms of a generalized Maxwell model representing phases of viscoelastic relaxation. The ECM hydrogels had a greater stress relaxation than tissues. ECM hydrogels required three Maxwell elements with slightly faster relaxation times (τ) than that of native tissue, which required four elements. The relative importance (R_i) of the first Maxwell element contributed the most in ECM hydrogels, whereas for tissue the contribution was spread over all four elements. IPF tissue had a longer-lasting fourth element with a higher R_i than the other tissues, and IPF ECM hydrogels did require a fourth Maxwell element, in contrast to all other ECM hydrogels. This study shows that hydrogels composed of native human lung ECM can be generated. Stiffness of ECM hydrogels resembled that of whole tissue, while viscoelasticity differed.

Cardiovascular complications and its relationship with functional outcomes in Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is a monophasic disease characterized by acute polyradiculoneuropathy.

AIM

This study investigated cardiovascular complications in patients with GBS and their relationship with outcomes.

DESIGN AND METHODS

We included 96 patients, who were diagnosed with GBS according to Brighton case definitions. All enrolled patients were evaluated according to a predetermined algorithm, which included nerve conduction studies, cerebrospinal fluid analysis, electrocardiography, 2D echo, cardiac markers and autonomic function testing.

RESULTS

We enrolled a total of 96 patients. The mean age of patients was 35.75 ± 17.66 years. Furthermore, 54.2% of patients developed cardiovascular complications, of which changes in electrocardiography (ECG) findings (50%), hypertension (28.12%), labile hypertension (12.5), tachycardia (26.04), bradycardia (13.54%) and a fluctuating heart rate (HR) (11.46) were common. Other cardiovascular complications seen in GBS patients were increased pro-BNP (26.04%), raised troponin T levels (3.12%), acute coronary syndrome (2.08%), heart failure (2.08%) and abnormal 2D echo findings (8.33%). The results of the univariate analysis revealed that a history of preceding infection, a Medical Research Council sum score, neck muscle weakness, facial nerve involvement, bulbar involvement, respiratory failure, cardiovascular complications, autonomic dysfunction, acute motor sensory axonal neuropathy subtype and baseline Hughes score were significantly (P < 0.005) associated with poor outcomes. However, none of these factors were found to be independently associated with poor outcomes in the multivariate analysis.

CONCLUSION

A considerable number of patients with GBS developed cardiovascular complications and it needs attention.

Role of Vascular Ultrasound in Cases of Lower Limb Hyperpigmentation

Background

Hyperpigmentation remains an important finding in cases of venous insufficiency and peripheral arterial disease (PAD) among the vascular causes.

Aims

This study aimed at finding the presence of arterial and/or venous insufficiency in patients of lower leg hyperpigmentation by using vascular ultrasound (US).

Materials and Methods

Fifty patients of lower leg pigmentation were included in the study. The detailed history, general physical examination, and laboratory investigations were done. Color Doppler ultrasonography was performed to check for venous insufficiency/PADs. Qualitative variables were correlated using chi-square test/Fisher's exact test. P < 0.05 was considered statistically significant.

Results

The mean age of the patients was 44.32 ± 14.16 years. Four patterns of skin changes were seen - reticulate macular, diffuse macular, lipodermatosclerosis and ulcer. Thirty-five (70%) patients had no visible varicose vein while 15 (30%) had visible varicose vein. In patients with visible varicose vein, color Doppler showed signs of venous insufficiency in all patients, but in cases of no visible varicose vein, color Doppler showed signs of venous insufficiency in 19 (54.28%) patients and showed no signs of venous insufficiency in others (P = 0.78). Only 1 (2%) patient showed atherosclerotic changes in both anterior tibial arteries.

Conclusion

All patients with lower leg pigmentation with or without visible varicose vein should undergo vascular US to rule out any venous insufficiency.

Brucellosis in India: results of a collaborative workshop to define One Health priorities

Brucellosis is an important zoonosis worldwide. In livestock, it frequently causes chronic disease with reproductive failures that contribute to production losses, and in humans, it causes an often-chronic febrile illness that is frequently underdiagnosed in many low- and middle-income countries, including India. India has one of the largest ruminant populations in the world, and brucellosis is endemic in the country in both humans and animals. In November 2017, the International Livestock Research Institute invited experts from government, national research institutes, universities, and different international organizations to a one-day meeting to set priorities towards a "One Health" control strategy for brucellosis in India. Using a risk prioritization exercise followed by discussions, the meeting agreed on the following priorities: collaboration (transboundary and transdisciplinary); collection of more epidemiological evidence in humans, cattle, and in small ruminants (which have been neglected in past research); Economic impact studies, including cost effectiveness of control programmes; livestock vaccination, including national facilities for securing vaccines for the cattle population; management of infected animals (with the ban on bovine slaughter, alternatives such as sanctuaries must be explored); laboratory capacities and diagnostics (quality must be assured and better rapid tests developed); and increased awareness, making farmers, health workers, and the general public more aware of risks of brucellosis and zoonoses in general. Overall, the meeting participants agreed that brucellosis control will be challenging in India, but with collaboration to address the priority areas listed here, it could be possible.

Chemical efficacy of several NaOCl concentrations on biofilms of different architecture: new insights on NaOCl working mechanisms

AIM

To investigate the anti-biofilm efficacy and working mechanism of several NaOCl concentrations on dual-species biofilms of different architecture as well as the changes induced on the architecture of the remaining biofilms.

METHODOLOGY

Streptococcus oralis J22 and Actinomyces naeslundii T14V-J1 were co-cultured under different growth conditions on saliva-coated hydroxyapatite discs. A constant-depth film fermenter (CDFF) was used to grow steady-state, four-day mature biofilms (dense architecture). Biofilms were grown under static conditions for 4 days within a confined space (less dense architecture). Twenty microlitres of buffer, 2-, 5-, and 10% NaOCl were applied statically on the biofilms for 60 s. Biofilm disruption and dissolution, as well as bubble formation, were evaluated with optical coherence tomography (OCT). The viscoelastic profile of the biofilms post-treatment was assessed with low load compression testing (LLCT). The bacteria/extracellular polysaccharide (EPS) content of the biofilms was examined through confocal laser scanning microscopy (CLSM). OCT, LLCT and CLSM data were analysed through one-way analysis of variance (ANOVA) and Tukey's HSD post-hoc test. Linear regression analysis was performed to test the correlation between bubble formation and NaOCl concentration. The level of significance was set at a < 0.05.

RESULTS

The experimental hypothesis according to which enhanced biofilm disruption, dissolution and bubble formation were anticipated with increasing NaOCl concentration was generally confirmed in both biofilm types. Distinct differences between the two biofilm types were noted with regard to NaOCl anti-biofilm efficiency as well as the effect that the several NaOCl concentrations had on the viscoelasticity profile and the bacteria/EPS content. Along with the bubble generation patterns observed, these led to the formulation of a concentration and biofilm structure-dependent theory of biofilm removal.

CONCLUSIONS

Biofilm architecture seems to be an additional determining factor of the penetration capacity of NaOCl, and consequently of its anti-biofilm efficiency.

Study of interleukin-6 and interleukin-8 levels in patients with neurological manifestations of dengue

Context:

Pro-inflammatory markers play a key role in the pathogenesis of various Flavivirus infection.

Aim:

In this study, we evaluated the role of these markers in neurological manifestations of dengue.

Settings and Designs:

Consecutive dengue cases with different neurological manifestations who presented between August 2012 and July 2014 were studied in hospital-based case–control study.

Materials and Methods:

Interleukin (IL-6) and IL-8 level were measured in serum and cerebrospinal fluid (CSF) of dengue cases with different neurological manifestations and also in age- and sex-matched controls. Level was analyzed with various parameters and outcomes.

Statistical Analysis:

Statistical analysis was done using SPSS version 16.0 by applying appropriate statistical methods. P < 0.05 considered statistically significant.

Results:

Out of the 40 enrolled cases of dengue with neurological manifestations, 29 had central nervous system and 11 had peripheral nervous system (CNS/PNS) manifestations. In CNS group, both IL-6 and IL-8 (CSF and serum) were significantly elevated (P < 0.001), whereas CSF IL-6 (P = 0.008), serum IL-6 (P = 0.001), and serum IL-8 (P = 0.005) were significantly elevated in PNS group. CSF IL-6, serum IL-6, and IL-8 were significantly elevated in poor outcome patients in CNS group (P < 0.05). CSF IL-6 and IL-8 were significantly elevated in CSF dengue positive cases as compared to CSF negative patients (P < 0.05). Cytokine level was not significantly correlated with neuroimaging abnormality in CNS group. Nine patients died and the remainder recovered.

Conclusion:

Elevated level of IL-6 and IL-8 is associated with different neurological manifestations and poor outcome, but whether they are contributing to neuropathogenesis or simply a correlate of severe disease remains to be determined.

Bioactive Silk Coatings Reduce the Adhesion of Staphylococcus aureus while Supporting Growth of Osteoblast-like Cells

Orthopedic and dental implants are associated with a substantial risk of failure due to biomaterial-associated infections and poor osseointegration. To prevent such outcomes, a coating can be applied on the implant to ideally both reduce the risk of bacterial adhesion and support establishment of osteoblasts. We present a strategy to construct dual-functional silk coatings with such properties. Silk coatings were made from a recombinant partial spider silk protein either alone (silk_wt) or fused with a cell-binding motif derived from fibronectin (FN-silk). The biofilm-dispersal enzyme Dispersin B (DspB) and two peptidoglycan degrading endolysins, PlySs2 and SAL-1, were produced recombinantly. A sortase recognition tag (SrtTag) was included to allow site-specific conjugation of each enzyme onto silk_wt and FN-silk coatings using an engineered variant of the transpeptidase Sortase A (SrtA*). To evaluate bacterial adhesion on the samples, Staphylococcus aureus was incubated on the coatings and subsequently subjected to live/dead staining. Fluorescence microscopy revealed a reduced number of bacteria on all silk coatings containing enzymes. Moreover, the bacteria were mobile to a higher degree, indicating a negative influence on the bacterial adhesion. The capability to support mammalian cell interactions was assessed by cultivation of the osteosarcoma cell line U-2 OS on dual-functional surfaces, prepared by conjugating the enzymes onto FN-silk coatings. U-2 OS cells could adhere to silk coatings with enzymes and showed high spreading and viability, demonstrating good cell compatibility.

Penetration and Accumulation of Dendrons with Different Peripheral Composition in Pseudomonas aeruginosa Biofilms

Multidrug resistant bacterial infections threaten to become the number one cause of death by the year 2050. Development of antimicrobial dendritic polymers is considered promising as an alternative infection control strategy. For antimicrobial dendritic polymers to effectively kill bacteria residing in infectious biofilms, they have to penetrate and accumulate deep into biofilms. Biofilms are often recalcitrant to antimicrobial penetration and accumulation. Therefore, this work aims to determine the role of compact dendrons with different peripheral composition in their penetration into Pseudomonas aeruginosa biofilms. Red fluorescently labeled dendrons with pH-responsive NH₃⁺ peripheral groups initially penetrated faster from a buffer suspension at pH 7.0 into the acidic environment of P. aeruginosa biofilms than dendrons with OH or COO^- groups at their periphery. In addition, dendrons with NH₃⁺ peripheral groups accumulated near the top of the biofilm due to electrostatic double-layer attraction with negatively charged biofilm components. However, accumulation of dendrons with OH and COO^- peripheral groups was more evenly distributed across the depth of the biofilms than NH₃⁺ composed dendrons and exceeded accumulation of NH₃⁺ composed dendrons after 10 min of exposure. Unlike dendrons with NH₃⁺ groups at their periphery, dendrons with OH or COO^- peripheral groups, lacking strong electrostatic double-layer attraction with biofilm components, were largely washed-out during exposure to PBS without dendrons. Thus, penetration and accumulation of dendrons into biofilms is controlled by their peripheral composition through electrostatic double-layer interactions, which is an important finding for the further development of new antimicrobial or antimicrobial-carrying dendritic polymers.

Ophthalmological manifestation in patients of tuberculous meningitis

BACKGROUND

Vision impairment, blindness in particular is a devastating complication in patients with tuberculous meningitis. However, information regarding ophthalmological manifestation and its impact on vision is sparse in the literature. This study evaluated the spectrum of ophthalmological manifestations in tuberculous meningitis, including retinal nerve fiber layer thickness assessment by optic coherence tomography and its correlation with visual and clinical outcome.

METHODS

This was a prospective observational study done from October 2015 to March 2017. Consecutive patients of tuberculous meningitis, diagnosed as per consensus case definition were included in the study. The patients were divided into two categories: uncomplicated and complicated tuberculous meningitis. Clinical evaluation, cerebrospinal fluid examination and contrast enhanced MRI of brain was done. Detailed ophthalmological evaluation including optic coherence tomography was done in all patients. All the patients were followed for 6 months. The primary outcome was blindness or low vision after 6 months. The secondary outcome was death or severe disability after 6 months. It was defined as modified Barthel index (MBI) ≤ 12 at 6 months (including disability plus death). Appropriate statistical analysis was done.

RESULTS

Out of 101 patients of tuberculous meningitis, 47 patients of TBM belonged to uncomplicated category, while 54 patients were of complicated group. The visual impairment was present in 24 out of 101 (23.76%) patients out of which 20 (19.8%) patients had low vision while 4 (3.96%) had blindness. The visual impairment was more evident in complicated group, low vision 0.03 (1.2-31.5). The most common abnormality on fundus examination was papilledema (22.8%). The complicated group had more incidence <0.0001 (19.6-48). Optic atrophy was found in three patients while choroid tubercles were found in eight patients (all complicated TBM group). RNFL thinning was noted in 10 patients in both the eyes. On univariate analysis, presence of diplopia at baseline, impairment of color vision at baseline, visual impairment at baseline, cranial nerve VIth involvement, optic atrophy and papilledema at baseline, RNFL thinning, abnormal VEP and baseline MBI were associated with poor visual outcome. On multivariate analysis, none of the factors were found to be independently associated with poor visual outcome. On univariate analysis, many factors including baseline MRC staging, altered sensorium, seizure, hemiparesis, basal exudates, infarcts, optochiasmaticarachnoiditis, visual impairment at baseline were found to be associated with poor clinical outcome at 6 months. On multivariate analysis, presence of seizure (P = 0.047, odds ratio = 78.59, 95% confidence interval (1.07-578.72)) was the only factor found to be independently associated with poor outcome.

CONCLUSION

Wide spectrum of ophthalmological manifestation was observed in patients of tuberculous meningitis. The visual impairment was more evident in complicated tuberculous meningitis. Ophthalmological findings like optic atrophy, papilledema and RNFL thinning were associated with poor visual outcome on univariate but not multivariate analysis. Visual impairment at baseline, among other factors was associated with poor clinical outcome on univariate analysis, whereas seizure was the only factor independently associated with poor outcome on multivariate analysis.

Characterization of the in vitro, ex vivo, and in vivo Efficacy of the Antimicrobial Peptide DPK-060 Used for Topical Treatment

Antimicrobial peptides, also known as host defense peptides, have recently emerged as a promising new category of therapeutic agents for the treatment of infectious diseases. This study evaluated the preclinical in vitro, ex vivo, and in vivo antimicrobial activity, as well as the potential to cause skin irritation, of human kininogen-derived antimicrobial peptide DPK-060 in different formulations designed for topical delivery. We found that DPK-060 formulated in acetate buffer or poloxamer gel caused a marked reduction of bacterial counts of Staphylococcus aureus in vitro (minimum microbicidal concentration <5 μg/ml). We also found that DPK-060 in poloxamer gel significantly suppressed microbial survival in an ex vivo wound infection model using pig skin and in an in vivo mouse model of surgical site infection (≥99 or ≥94% reduction in bacterial counts was achieved with 1% DPK-060 at 4 h post-treatment, respectively). Encapsulation of DPK-060 in different types of lipid nanocapsules or cubosomes did not improve the bactericidal potential of the peptide under the applied test conditions. No reduction in cell viability was observed in response to administration of DPK-060 in any of the formulations tested. In conclusion, the present study confirms that DPK-060 has the potential to be an effective and safe drug candidate for the topical treatment of microbial infections; however, adsorption of the peptide to nanocarriers failed to show any additional benefits.

Adipose tissue-derived extracellular matrix hydrogels as a release platform for secreted paracrine factors

Fat grafting is an established clinical intervention to promote tissue repair. The role of the fat's extracellular matrix (ECM) in regeneration is largely neglected. We investigated in vitro the use of human adipose tissue‐derived ECM hydrogels as release platform for factors secreted by adipose‐derived stromal cells (ASCs). Lipoaspirates from nondiabetic and diabetic donors were decellularized. Finely powdered acellular ECM was evaluated for cell remainders and DNA content. Acellular ECM was digested, and hydrogels were formed at 37°C and their viscoelastic relaxation properties investigated. Release of ASC‐released factors from hydrogels was immune assessed, and bio‐activity was determined by fibroblast proliferation and migration and endothelial angiogenesis. Acellular ECM contained no detectable cell remainders and negligible DNA contents. Viscoelastic relaxation measurements yielded no data for diabetic‐derived hydrogels due to gel instability. Hydrogels released several ASC‐released factors concurrently in a sustained fashion. Functionally, released factors stimulated fibroblast proliferation and migration as well as angiogenesis. No difference between nondiabetic and diabetic hydrogels in release of factors was measured. Adipose ECM hydrogels incubated with released factors by ASC are a promising new therapeutic modality to promote several important wound healing‐related processes by releasing factors in a controlled way.

Influence of doping ion, capping agent and pH on the fluorescence properties of zinc sulfide quantum dots: Sensing of Cu2+ and Hg2+ ions and their biocompatibility with cancer and fungal cells

Herein, a facile one-pot synthetic method was explored for the fabrication of glutathione capped Mn²⁺ doped‑zinc sulphide quantum dots (GSH-Mn²⁺-ZnS QDs) for both fluorescent detection of Cu²⁺ and Hg²⁺ ions and for fluorescence imaging of two cancer (RIN5F and MDAMB231) and fungal (Rhizopus oryzae) cells. Particularly, doping of Mn²⁺ into ZnS QDs nanocrystal structure resulted a great improvement in the fluorescence properties of ZnS QDs. The emission peak of undoped ZnS QDs was found at 447 nm, which is due to the large number of surface defects in the ZnS QDs nanostructures. Under identical conditions, there is a good linear relationship between the quenching of fluorescence intensity and analytes (Cu²⁺ and Hg²⁺ ions) concentration in the range of 0.005 to 0.2 mM and of 0.025 to 0.4 mM for Cu²⁺ and Hg²⁺ ions, respectively. The GSH-Mn²⁺-ZnS QDs exhibit least cytotoxicity against RIN5F and MDAMB231 cells, demonstrating the multifunctional applications in sensing of metal ions and biocompatibility towards cancer (RIN5F and MDAMB231) and fungal (Rhizopus oryzae) cells.

Further studies on sugar transporter (SWEET) genes in wheat (Triticum aestivum L.)

SWEET proteins represent one of the largest sugar transporter family in the plant kingdom and play crucial roles in plant development and stress responses. In the present study, a total of 108 TaSWEET genes distributed on all the 21 wheat chromosomes were identified using the latest whole genome sequence (as against 59 genes reported in an earlier report). These 108 genes included 14 of the 17 types reported in Arabidopsis and also included three novel types. Tandem duplications (22) and segmental duplications (5) played a significant role in the expansion of TaSWEET family. A number of cis-elements were also identified in the promoter regions of TaSWEET genes, indicating response of TaSWEET genes during development and also during biotic/abiotic stresses. The TaSWEET proteins carried 4-7 trans-membrane helices (TMHs) showing diversity in structure. Phylogenetic analysis using SWEET proteins of wheat and 8 other species gave four well-known clusters. Expression analysis involving both in silico and in planta indicated relatively higher expression of TaSWEET genes in water/heat sensitive and leaf rust resistant genotypes. The results provided insights into the functional role of TaSWEETs in biotic and abiotic stresses, which may further help in planning strategies to develop high yielding wheat varieties tolerant to environmental stresses.

Antimicrobial synergy of monolaurin lipid nanocapsules with adsorbed antimicrobial peptides against Staphylococcus aureus biofilms in vitro is absent in vivo

Bacterial infections are mostly due to bacteria in their biofilm-mode of growth, while penetrability of antimicrobials into infectious biofilms and increasing antibiotic resistance hamper infection treatment. In-vitro, monolaurin lipid nanocapsules (ML-LNCs) carrying adsorbed antimicrobial peptides (AMPs) displayed synergistic efficacy against planktonic Staphylococcus aureus, but it has not been demonstrated, neither in-vitro nor in-vivo, that such ML-LNCs penetrate into infectious S. aureus biofilms and maintain synergy with AMPs. This study investigates the release mechanism of AMPs from ML-LNCs and possible antimicrobial synergy of ML-LNCs with the AMPs DPK-060 and LL-37 against S. aureus biofilms in-vitro and in a therapeutic, murine, infected wound-healing model. Zeta potentials demonstrated that AMP release from ML-LNCs was controlled by the AMP concentration in suspension. Both AMPs demonstrated no antimicrobial efficacy against four staphylococcal strains in a planktonic mode, while a checkerboard assay showed synergistic antimicrobial efficacy when ML-LNCs and DPK-060 were combined, but not for combinations of ML-LNCs and LL-37. Similar effects were seen for growth reduction of staphylococcal biofilms, with antimicrobial synergy persisting only for ML-LNCs at the highest level of DPK-060 or LL-37 adsorption. Healing of wounds infected with bioluminescent S. aureus Xen36, treated with ML-LNCs alone, was faster when treated with PBS, while AMPs alone did not yield faster wound-healing than PBS. Faster, synergistic wound-healing due to ML-LNCs with adsorbed DPK-060, was absent in-vivo. Summarizing, antimicrobial synergy of ML-LNCs with adsorbed antimicrobial peptides as seen in-vitro, is absent in in-vivo healing of infected wounds, likely because host AMPs adapted the synergistic role of the AMPs added. Thus, conclusions regarding synergistic antimicrobial efficacy, should not be drawn from planktonic data, while even in-vitro biofilm data bear little relevance for the in-vivo situation.

H3K4/K9 acetylation and Lr28-mediated expression of six leaf rust responsive genes in wheat (Triticum aestivum)

Development of leaf rust-resistant cultivars is a priority during wheat breeding, since leaf rust causes major losses in yield. Resistance against leaf rust due to Lr genes is partly controlled by epigenetic modifications including histone acetylation that is known to respond to biotic/abiotic stresses. In the present study, enrichment of H3K4ac and H3K9ac in promoters of six defense responsive genes (N-acetyltransferase, WRKY 40, WRKY 70, ASR1, Peroxidase 12 and Sarcosine oxidase) was compared with their expression in a pair of near-isogenic lines (NILs) for the gene Lr28 following inoculation with leaf rust pathotype '77-5'; ChIP-qPCR was used for this purpose. The proximal and distal promoters of these genes contained a number of motifs that are known to respond to biotic stresses. The enrichment of two acetylation marks changed with passage of time; changes in expression of two of the six genes (N-acetyltransferase and peroxidase12), largely matched with changes in H3K4/H3K9 acetylation patterns of the two promoter regions. For example, enrichment of both the marks matched with higher expression of N-acetyltransferase gene in susceptible NIL and the deacetylation (H3K4ac) largely matched with reduced gene expression in resistant NIL. In peroxidase12, enrichment of H3K4ac and H3K9ac largely matched with higher expression in both the NILs. In the remaining four genes, changes in H3 acetylation did not always match with gene expression levels. This indicated complexity in the regulation of the expression of these remaining four genes, which may be controlled by other epigenetic/genetic regulatory mechanisms that need further analysis.