Effects of nonnutritive sugar inclusion in laboratory diets and attracticidal spheres on survivorship and mobility of 2 Dipteran species, Rhagoletis pomonella (Diptera: Tephritidae) and Drosophila suzukii (Diptera: Drosophilidae)

Native apple maggot fly, Rhagoletis pomonella, and invasive spotted-wing drosophila, Drosophila suzukii, are key pests of apple and small fruit, respectively, in the United States. Both species are typically managed with standard insecticide applications. However, interest in alternative strategies that result in insecticide reductions has led to evaluations of nonnutritive sugars as toxicants for Drosophila species and development of attracticidal spheres for both species. Here, we evaluated the survivorship of R. pomonella and D. suzukii when provided with standard diets that substituted saccharin, sucralose, aspartame, erythritol, dextrose, or mannitol for the sucrose component and compared them with standard diets and water-only controls for up to 15 days. Presence of erythritol and mannitol significantly decreased survivorship of R. pomonella and erythritol significantly decreased the survivorship of D. suzukii. However, mobility trials following a 2 h exposure to aqueous solutions of each sugar treatment resulted in no strong impact on either species. Survivorship after 30 min exposure to erythritol or mannitol alone, or in combination with varying concentrations of sucrose (serving as a phagostimulant) at 30 min and 24 h were evaluated for both species. Only D. suzukii survivorship was affected with decreased survivorship on erythritol:sucrose solutions of 20:0% and 15:5% for 24 h. Based on all results, erythritol appeared most promising, and was integrated into attracticidal spheres as a toxicant but even at the highest concentration, survivorship remained unaffected for either species, thus making this nonnutritive sugar impractical and ineffective as a toxicant substitute in attracticidal spheres.

Effects of intratesticular injection of hypertonic mannitol and saline on the quality of donkey sperm, indicators of oxidative stress and testicular tissue pathology

OBJECTIVES

The aim of the present study was to examine donkey sperm quality after intratesticular injection of hypertonic mannitol (HM) and saline (HS).

METHODS

Randomly assigned to five treatment groups were 15 adult male donkeys: (1) Control group (no treatment), (2) Surgery group (surgical castration for testosterone control), (3) NS group (normal saline intratesticular injection), (4) HS group (hypertonic saline), and (5) HM group. We injected 20 mL per testicle. We took 5 mL blood from all donkeys before injection. Castration was performed under general anesthesia 60 days later. Samples included blood and testicular tissue. Total motility (TM), progressive motility (PM), movementy features, DNA damage, morphology, viability, and plasma membrane functionality were evaluated. Hormone analyses, histomorphometric studies and oxidative stress indices including total antioxidant capacity (TAC), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and NADP+/NADPH were evaluated. Apoptosis, pyroptosis-related Bax, Caspase-1, GSDMD, and Bcl-2 expression were also assessed.

RESULTS

In HS and HM groups, testosterone, epididymal sperm count, motility, viability, and plasma membrane functionality dropped while sperm DNA damage increased. HS and HM groups had significantly lower histomorphometric parameters, TAC, GPx, SOD, GSH, and Bcl-2 gene expression. MDA, NADP+/NADPH, Bax, Caspase-1, and GSDMD gene expression were substantially higher in the HS and HM groups than in the control group.

CONCLUSIONS

Toxic effects of hypertonic saline and mannitol on reproductive parameters were seen following, hence, they might be considered as a good chemical sterilizing treatment in donkeys.

Improved cardioprotective effect of 3-nitro-N-methyl salicylamide solution after a prolonged preservation time of rat heart

Ischemic reperfusion injury, caused by oxidative stress during reperfusion, is an inevitable outcome of organ transplantation, especially when the organ preservation time is prolonged. Prolonged ischaemic preservation is a valuable technique for improving the success of organ transplantation, but numerous challenges remain. 3-nitro-N-methyl salicylamide (3-NNMS), an inhibitor of mitochondrial electron transport chain complex III, can be used to reduce reactive oxygen species production during blood reperfusion by slowing the electron flow rate of the respiratory chain. Based on this property, a novel preservation solution was developed for the preservation of isolated rat heart and its cardioprotective effect was investigated during an 8-h cold ischaemia preservation time for the first time. For comparison, 3-NNMS was also included in the histidine-tryptophan-ketoglutarate (HTK) solution. Compared to HTK, HTK supplemented with 3-NNMS significantly improved the heart rate of isolated rat hearts after 8 h of cold storage. Both 3-NNMS solution and HTK supplemented with 3-NNMS solution decreased cardiac troponin T and lactate dehydrogenase levels in perfusion fluid and reduced reactive oxygen species and malondialdehyde levels in the myocardium. The 3-NNMS also maintained the membrane potential of myocardial mitochondria and significantly increased superoxide dismutase levels. These results showed that the new 3-NNMS solution can protect mitochondrial and cardiomyocyte function by increasing antioxidant capacity and reducing oxidative stress in cryopreserved rat hearts during a prolonged preservation time, resulting in less myocardial injury and better heart rate.

Quercetin Improves Barrier Properties in Porcine Small Intestine but Not in Peyer's Patches

Peyer's patches (PPs) are part of the gut-associated lymphatic tissue (GALT) and represent the first line of the intestinal immunological defense. They consist of follicles with lymphocytes and an overlying subepithelial dome with dendritic cells and macrophages, and they are covered by the follicle-associated epithelium (FAE). A sealed paracellular pathway in the FAE is crucial for the controlled uptake of luminal antigens. Quercetin is the most abundant plant flavonoid and has a barrier-strengthening effect on tight junctions (TJs), a protein complex that regulates the paracellular pathway. In this study, we aimed to analyze the effect of quercetin on porcine PPs and the surrounding villus epithelium (VE). We incubated both tissue types for 4 h in Ussing chambers, recorded the transepithelial electrical resistance (TEER), and measured the unidirectional tracer flux of [3H]-mannitol. Subsequently, we analyzed the expression, protein amount, and localization of three TJ proteins, claudin 1, claudin 2, and claudin 4. In the PPs, we could not detect an effect of quercetin after 4 h, neither on TEER nor on the [3H]-mannitol flux. In the VE, quercetin led to a higher TEER value, while the [3H]-mannitol flux was unchanged. The pore-forming claudin 2 was decreased while the barrier-forming claudin 4 was increased and the expression was upregulated. Claudin 1 was unchanged and all claudins could be located in the paracellular membrane by immunofluorescence microscopy. Our study shows the barrier-strengthening effect of quercetin in porcine VE by claudin 4 upregulation and a claudin 2 decrease. Moreover, it underlines the different barrier properties of PPs compared to the VE.

Mannitol inhibits the proliferation of neural stem cell by a p38 mitogen-activated protein kinase-dependent signaling pathway

PURPOSE

Mannitol is one of the first-line drugs for reducing cerebral edema through increasing the extracellular osmotic pressure. However, long-term administration of mannitol in the treatment of cerebral edema triggers damage to neurons and astrocytes. Given that neural stem cell (NSC) is a subpopulation of main regenerative cells in the central nervous system after injury, the effect of mannitol on NSC is still elusive. The present study aims to elucidate the role of mannitol in NSC proliferation.

METHODS

C57 mice were derived from the animal house of Zunyi Medical University. A total of 15 pregnant mice were employed for the purpose of isolating NSCs in this investigation. Initially, mouse primary NSCs were isolated from the embryonic cortex of mice and subsequently identified through immunofluorescence staining. In order to investigate the impact of mannitol on NSC proliferation, both cell counting kit-8 assays and neurospheres formation assays were conducted. The in vitro effects of mannitol were examined at various doses and time points. In order to elucidate the role of Aquaporin 4 (AQP4) in the suppressive effect of mannitol on NSC proliferation, various assays including reverse transcription polymerase chain reaction, western blotting, and immunocytochemistry were conducted on control and mannitol-treated groups. Additionally, the phosphorylated p38 (p-p38) was examined to explore the potential mechanism underlying the inhibitory effect of mannitol on NSC proliferation. Finally, to further confirm the involvement of the p38 mitogen-activated protein kinase-dependent (MAPK) signaling pathway in the observed inhibition of NSC proliferation by mannitol, SB203580 was employed. All data were analyzed using SPSS 20.0 software (SPSS, Inc., Chicago, IL). The statistical analysis among multiple comparisons was performed using one-way analysis of variance (ANOVA), followed by Turkey's post hoc test in case of the data following a normal distribution using a Shapiro-Wilk normality test. Comparisons between 2 groups were determined using Student's t-test, if the data exhibited a normal distribution using a Shapiro-Wilk normality test. Meanwhile, data were shown as median and interquartile range and analyzed using the Mann-Whitney U test, if the data failed the normality test. A p < 0.05 was considered as significant difference.

RESULTS

Primary NSC were isolated from the mice, and the characteristics were identified using immunostaining analysis. Thereafter, the results indicated that mannitol held the capability of inhibiting NSC proliferation in a dose-dependent and time-dependent manner using cell counting kit-8, neurospheres formation, and immunostaining of Nestin and Ki67 assays. During the process of mannitol suppressing NSC proliferation, the expression of AQP4 mRNA and protein was downregulated, while the gene expression of p-p38 was elevated by reverse transcription polymerase chain reaction, immunostaining, and western blotting assays. Subsequently, the administration of SB203580, one of the p38 MAPK signaling pathway inhibitors, partially abrogated this inhibitory effect resulting from mannitol, supporting the fact that the p38 MAPK signaling pathway participated in curbing NSC proliferation induced by mannitol.

CONCLUSIONS

Mannitol inhibits NSC proliferation through downregulating AQP4, while upregulating the expression of p-p38 MAPK.

Morphology as indicator of adaptive changes of model tissues in osmotically and chemically changing environments

We investigate the formation and maintenance of the homeostatic state in the case of 2D epithelial tissues following an induction of hyperosmotic conditions, using media enriched with 80 to 320 mOsm of mannitol, NaCl, and urea. We characterise the changes in the tissue immediately after the osmotic shock, and follow it until the new homeostatic state is formed. We characterise changes in cooperative motility and proliferation pressure in the tissue upon treatment with the help of a theoretical model based on the delayed Fisher-Kolmogorov formalism, where the delay in density evolution is induced by the the finite time of the cell division. Finally we explore the adaptation of the homeostatic tissue to highly elevated osmotic conditions by evaluating the morphology and topology of cells after 20 days in incubation. We find that hyperosmotic environments together with changes in the extracellular matrix induce different mechanical states in viable tissues, where only some remain functional. The perspective is a relation between tissue topology and function, which could be explored beyond the scope of this manuscript. Experimental investigation of morphological effect of change of osmotic conditions on long-term tissue morphology and topology Effect of osmotic changes on transient tissue growth behaviour Analysis of recovery process of tissues post-osmotic-shock Toxicity limits of osmolytes in mid- to long-term tissue evolution Tissue adaptation to physiological changes in environment Long-term tissue stabilisation under altered osmotic conditions.

Defining the contractile prostanoid component in hyperosmolar-induced bronchoconstriction in human small airways

Exercise-induced bronchoconstriction (EIB) is thought to be triggered by increased osmolarity at the airway epithelium. The aim of this study was to define the contractile prostanoid component of EIB, using an ex vivo model where intact segments of bronchi (inner diameter 0.5-2 mm) isolated from human lung tissue and subjected to mannitol. Exposure of bronchial segments to hyperosmolar mannitol evoked a contraction (64.3 ± 3.5 %) which could be prevented either by elimination of mast cells (15.8 ± 4.3 %) or a combination of cysteinyl leukotriene (cysLT1), histamine (H1) and thromboxane (TP) receptor antagonists (11.2 ± 2.3 %). Likewise, when antagonism of TP receptor was exchanged for inhibition of either cyclooxygenase-1 (8 ± 2.5 %), hematopoietic prostaglandin (PG)D synthase (20.7 ± 5.6 %), TXA synthase (14.8 ± 4.9 %), or the combination of the latter two (12.2 ± 4.6 %), the mannitol-induced contraction was prevented, suggesting that the TP-mediated component is induced by PGD2 and TXA2 generated by COX-1 and their respective synthases.

Extracellular Perinexal Separation Is a Principal Determinant of Cardiac Conduction

BACKGROUND

Cardiac conduction is understood to occur through gap junctions. Recent evidence supports ephaptic coupling as another mechanism of electrical communication in the heart. Conduction via gap junctions predicts a direct relationship between conduction velocity (CV) and bulk extracellular resistance. By contrast, ephaptic theory is premised on the existence of a biphasic relationship between CV and the volume of specialized extracellular clefts within intercalated discs such as the perinexus. Our objective was to determine the relationship between ventricular CV and structural changes to micro- and nanoscale extracellular spaces.

METHODS

Conduction and Cx43 (connexin43) protein expression were quantified from optically mapped guinea pig whole-heart preparations perfused with the osmotic agents albumin, mannitol, dextran 70 kDa, or dextran 2 MDa. Peak sodium current was quantified in isolated guinea pig ventricular myocytes. Extracellular resistance was quantified by impedance spectroscopy. Intercellular communication was assessed in a heterologous expression system with fluorescence recovery after photobleaching. Perinexal width was quantified from transmission electron micrographs.

RESULTS

CV primarily in the transverse direction of propagation was significantly reduced by mannitol and increased by albumin and both dextrans. The combination of albumin and dextran 70 kDa decreased CV relative to albumin alone. Extracellular resistance was reduced by mannitol, unchanged by albumin, and increased by both dextrans. Cx43 expression and conductance and peak sodium currents were not significantly altered by the osmotic agents. In response to osmotic agents, perinexal width, in order of narrowest to widest, was albumin with dextran 70 kDa; albumin or dextran 2 MDa; dextran 70 kDa or no osmotic agent, and mannitol. When compared in the same order, CV was biphasically related to perinexal width.

CONCLUSIONS

Cardiac conduction does not correlate with extracellular resistance but is biphasically related to perinexal separation, providing evidence that the relationship between CV and extracellular volume is determined by ephaptic mechanisms under conditions of normal gap junctional coupling.

Genome-Wide Analysis of Stress-Responsive Genes and Alternative Splice Variants in Arabidopsis Roots under Osmotic Stresses

Plant roots show distinct gene-expression profiles from those of shoots under abiotic stress conditions. In this study, we performed mRNA sequencing (mRNA-Seq) to analyze the transcriptional profiling of Arabidopsis roots under osmotic stress conditions-high salinity (NaCl) and drought (mannitol). The roots demonstrated significantly distinct gene-expression changes from those of the aerial parts under both the NaCl and the mannitol treatment. We identified 68 closely connected transcription-factor genes involved in osmotic stress-signal transduction in roots. Well-known abscisic acid (ABA)-dependent and/or ABA-independent osmotic stress-responsive genes were not considerably upregulated in the roots compared to those in the aerial parts, indicating that the osmotic stress response in the roots may be regulated by other uncharacterized stress pathways. Moreover, we identified 26 osmotic-stress-responsive genes with distinct expressions of alternative splice variants in the roots. The quantitative reverse-transcription polymerase chain reaction further confirmed that alternative splice variants, such as those for ANNAT4, MAGL6, TRM19, and CAD9, were differentially expressed in the roots, suggesting that alternative splicing is an important regulatory mechanism in the osmotic stress response in roots. Altogether, our results suggest that tightly connected transcription-factor families, as well as alternative splicing and the resulting splice variants, are involved in the osmotic stress response in roots.

Effectiveness of curcumin-based antimicrobial photodynamic therapy against Staphylococcus aureus

PURPOSE

This study investigated the effectiveness of curcumin-based antimicrobial photodynamic therapy (aPDT) against Staphylococcus aureus (S. aureus), the causative agent of ventilator-associated pneumonia.

METHODS

Curcumin was added to S. aureus culture medium at concentrations of 25, 2.5, and 0.25 µM. After 60 min (20-25°C), each culture was irradiated for 1 and 3 min, and viable bacteria were counted. Curcumin (25 µM) was also added to a bacterial suspension with D-mannitol and sodium azide; microbial counts were determined after irradiation for 3 min.

RESULTS

S. aureus was significantly reduced in the 1-min (P = 0.043) and 3-min (P = 0.011) irradiation groups in comparison to the 0-min irradiation group with 25 µM curcumin. No significant differences were observed between the curcumin alone group and the curcumin plus D-mannitol or sodium azide group.

CONCLUSION

The findings of this study indicate that prolonged exposure (≥1 min) of S. aureus to LED in 25 μM curcumin solution induces cell wall injury. Curcumin-based aPDT as an adjunct to conventional oral care, employing existing dentistry equipment, offers a promising approach that does not rely on antimicrobial drugs or allows the emergence of resistant bacterial strains. This suggests its potential role in future strategies aimed at preventing ventilator-associated pneumonia.

A novel ABA-insensitive mutant in Arabidopsis reveals molecular network of ABA-induced anthocyanin accumulation and abiotic stress tolerance

Abscisic acid (ABA) plays primary regulatory roles in abiotic stress tolerance and seed germination. Here, we report a unique novel Arabidopsis abscisic acid-insensitive mutant, abr (abscisic acid resistance), which was able to germinate in medium containing high ABA concentrations and tolerant to abiotic stress tolerance. We observed that abr mutant accumulated more anthocyanins by ABA treatment than did the wild type (WT). Dimethylthiourea (DMTU, an H₂O₂ scavenger) was effective in inhibiting ABA-induced anthocyanins accumulation. RNA-seq showed that the expression of anthocyanins synthesis, antioxidant enzyme and stress-related genes were specifically increased in ABA-treated abr seedlings, suggesting that the abr mutation affects stress response as well as ABA responses. Interestingly, seedlings accumulating anthocyanins exhibited more tolerance to mannitol and NaCl compared to wild type. We propose that ABA-induced H₂O₂ generation triggers the foliar anthocyanins accumulation, which, in turn, enhances the abiotic stress tolerance in abr mutant.

Functional proteomics identify mannitol metabolism in serum resistance and therapeutic implications in Vibrio alginolyticus

Serum resistance is recognized as one of the most important pathogenic traits of bacterial pathogens, and no control measure is available. Based on our previous discovery that pathogenic Escherichia coli represses glycine, serine, and threonine metabolism to confer serum resistance and that the reactivation of this pathway by exogenous glycine could restore serum sensitivity, we further investigate the mechanism underlying the action of glycine in Vibrio alginolyticus. Thus, V. alginolyticus is treated with glycine, and the proteomic change is profiled with tandem mass tag-based quantitative proteomics. Compared to the control group, glycine treatment influences the expression of a total of 291 proteins. Among them, a trap-type mannitol/chloroaromatic compound transport system with periplasmic component, encoded by N646_0992, is the most significantly increased protein. In combination with the pathway enrichment analysis showing the altered fructose and mannitol metabolism, mannitol has emerged as a possible metabolite in enhancing the serum killing activity. To demonstrate this, exogenous mannitol reduces bacterial viability. This synergistic effect is further confirmed in a V. alginolyticus-Danio rerio infection model. Furthermore, the mechanism underlying mannitol-enabled serum killing is dependent on glycolysis and the pyruvate cycle that increases the deposition of complement components C3b and C5b-9 on the bacterial surface, whereas inhibiting glycolysis or the pyruvate cycle significantly weakened the synergistic effects and complement deposition. These data together suggest that mannitol is a potent metabolite in reversing the serum resistance of V. alginolyticus and has promising use in aquaculture.

Comparative analysis of stress-induced calcium signals in the crop species barley and the model plant Arabidopsis thaliana

BACKGROUND

Plants are continuously exposed to changing environmental conditions and biotic attacks that affect plant growth. In crops, the inability to respond appropriately to stress has strong detrimental effects on agricultural production and yield. Ca²⁺ signalling plays a fundamental role in the response of plants to most abiotic and biotic stresses. However, research on stimulus-specific Ca²⁺ signals has mostly been pursued in Arabidopsis thaliana, while in other species these events are little investigated .

RESULTS

In this study, we introduced the Ca²⁺ reporter-encoding gene APOAEQUORIN into the crop species barley (Hordeum vulgare). Measurements of the dynamic changes in [Ca²⁺]_cyt in response to various stimuli such as NaCl, mannitol, H₂O₂, and flagellin 22 (flg22) revealed the occurrence of dose- as well as tissue-dependent [Ca²⁺]_cyt transients. Moreover, the Ca²⁺ signatures were unique for each stimulus, suggesting the involvement of different Ca²⁺ signalling components in the corresponding stress response. Alongside, the barley Ca²⁺ signatures were compared to those produced by the phylogenetically distant model plant Arabidopsis. Notable differences in temporal kinetics and dose responses were observed, implying species-specific differences in stress response mechanisms. The plasma membrane Ca²⁺ channel blocker La³⁺ strongly inhibited the [Ca²⁺]_cyt response to all tested stimuli, indicating a critical role of extracellular Ca²⁺ in the induction of stress-associated Ca²⁺ signatures in barley. Moreover, by analysing spatio-temporal dynamics of the [Ca²⁺]_cyt transients along the developmental gradient of the barley leaf blade we demonstrate that different parts of the barley leaf show quantitative differences in [Ca²⁺]_cyt transients in response to NaCl and H₂O₂. There were only marginal differences in the response to flg22, indicative of developmental stage-dependent Ca²⁺ responses specifically to NaCl and H₂O₂.

CONCLUSION

This study reveals tissue-specific Ca²⁺ signals with stimulus-specific kinetics in the crop species barley, as well as quantitative differences along the barley leaf blade. A number of notable differences to the model plants Arabidopsis may be linked to different stimulus sensitivity. These transgenic barley reporter lines thus present a valuable tool to further analyse mechanisms of Ca²⁺ signalling in this crop and to gain insights into the variation of Ca²⁺-dependent stress responses between stress-susceptible and -resistant species.

Prolonged Hyperglycemia Causes Visual and Cognitive Deficits in Danio rerio

The present study induced prolonged hyperglycemia (a hallmark symptom of Type 2 diabetes [T2DM]) in Danio rerio (zebrafish) for eight or twelve weeks. The goal of this research was to study cognitive decline as well as vision loss in hyperglycemic zebrafish. Fish were submerged in glucose for eight or twelve weeks, after which they were assessed with both a cognitive assay (three-chamber choice) and a visual assay (optomotor response (OMR)). Zebrafish were also studied during recovery from hyperglycemia. Here, fish were removed from the hyperglycemic environment for 4 weeks after either 4 or 8 weeks in glucose, and cognition and vision was again assessed. The 8- and 12-week cognitive results revealed that water-treated fish showed evidence of learning while glucose- and mannitol-treated fish did not within the three-day testing period. OMR results identified an osmotic effect with glucose-treated fish having significantly fewer positive rotations than water-treated fish but comparable rotations to mannitol-treated fish. The 8- and 12-week recovery results showed that 4 weeks was not enough time to fully recovery from the hyperglycemic insult sustained.

Transcription factor TERF1 promotes seed germination under osmotic conditions by activating gibberellin acid signaling

Seed germination is the first step of seedling establishment, which is particularly sensitive to drought stress. Elucidating the mechanism regulating seed germination under drought stress is of great importance. We showed that overexpressing Tomato Ethylene Responsive Factor 1 (TERF1), an ERF transcription factor in the ethylene signaling pathway, significantly reduced seed sensitivity to mannitol treatment during seed germination. Germination assay demonstrated that TERF1 could activate gibberellin acid (GA) signaling pathway independent on GA metabolism during germination. By comparative transcriptome analysis (mannitol vs normal germination condition, mannitol vs mannitol plus paclobutrazol (PAC, an inhibitor of GA biosynthesis)) we identified the genes regulated by TERF1 specifically under mannitol treatment and confirmed that TERF1 could activate GA signaling pathway independent on GA metabolism, which were consistent with the germination assay with mannitol and mannitol plus PAC treatment. Based on sugar, gene expression and germination analysis we proved that TERF1 promoted seed germination through glucose signaling pathway mediated by GA. Thus our study provides an underlying mechanism for activating GA signaling pathway by TERF1 during seed germination under osmotic conditions.

Differential sensitivity of metabolic pathways in sugar beet roots to combined salt, heat, and light stress

Plants in nature commonly encounter combined stress scenarios. The response to combined stressors is often unpredictable from the response to single stresses. To address stress interference in roots, we applied salinity, heat, and high light to hydroponically grown sugar beet. Two main patterns of metabolomic acclimation were apparent. High salt of 300 mM NaCl considerably lowered metabolite amounts, for example, those of most amino acids, γ-amino butyric acid (GABA), and glucose. Very few metabolites revealed the opposite trend with increased contents at high salts, mostly organic acids such as citric acid and isocitric acid, but also tryptophan, tyrosine, and the compatible solute proline. High temperature (31°C vs. 21°C) also frequently lowered root metabolite pools. The individual effects of salinity and heat were superimposed under combined stress. Under high light and high salt conditions, there was a significant decline in root chloride, mannitol, ribulose 5-P, cysteine, and l-aspartate contents. The results reveal the complex interaction pattern of environmental parameters and urge researchers to elaborate in much more detail and width on combinatorial stress effects to bridge work under controlled growth conditions to growth in nature, and also to better understand acclimation to the consequences of climate change.

Melatonin in preservation solutions prevents ischemic injury in rat kidneys

Transplantation is lifesaving and the most effective treatment for end-stage organ failure. The transplantation success depends on the functional preservation of organs prior to transplantation. Currently, the University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) are the most commonly used preservation solutions. Despite intensive efforts, the functional preservation of solid organs prior to transplantation is limited to hours. In this study, we modified the UW solution containing components from both the UW and HTK solutions and analyzed their tissue-protective effect against ischemic injury. The composition of the UW solution was changed by reducing hydroxyethyl starch concentration and adding Histidine/Histidine-HCl which is the main component of HTK solution. Additionally, the preservation solutions were supplemented with melatonin and glucosamine. The protective effects of the preservation solutions were assessed by biochemical and microscopical analysis at 2, 10, 24, and 72 h after preserving the rat kidneys with static cold storage. Lactate dehydrogenase (LDH) activity in preservation solutions was measured at 2, 10, 24, and 72. It was not detectable at 2 h of preservation in all groups and 10 h of preservation in modified UW+melatonin (mUW-m) and modified UW+glucosamine (mUW-g) groups. At the 72nd hour, the lowest LDH activity (0.91 IU/g (0.63–1.17)) was measured in the mUW-m group. In comparison to the UW group, histopathological damage score was low in modified UW (mUW), mUW-m, and mUW-g groups at 10, 24, and 72 hours. The mUW-m solution at low temperature was an effective and suitable solution to protect renal tissue for up to 72 h.

Effects of α2-adrenoceptor stimulation on luminal alkalinisation and net fluid flux in rat duodenum

The sympathetic nervous system is highly involved in the regulation of gastrointestinal functions such as luminal alkalinisation and fluid absorption. However, the exact mechanisms are not clear. This study aimed to delineate how α₂-adrenergic receptor stimulation reduces duodenal luminal alkalinisation and induces net fluid absorption. This was tested by perfusing the duodenum of anesthetized rats with isotonic solutions devoid of Cl^- and/or Na⁺, in the absence and presence of the α₂-adrenoceptor agonist clonidine. The clonidine was also studied in rats treated with dimethylamiloride (a Na⁺/H⁺ exchange inhibitor), vasoactive intestinal peptide, and the nicotinic receptor antagonist hexamethonium. Clonidine reduced luminal alkalinisation and induced net fluid absorption. The Cl^--free solution decreased luminal alkalinisation and abolished net fluid absorption, but did not prevent clonidine from doing so. Both the Na⁺-free solution and luminal dimethylamiloride increased luminal alkalinisation and abolished net fluid absorption, effects counteracted by clonidine. The NaCl-free solution (D-mannitol) did not affect luminal alkalinisation, but reduced net fluid absorption. Clonidine reduced luminal alkalinisation and induced net fluid absorption in rats perfused luminally with mannitol. However, clonidine did not affect the vasoactive intestinal peptide-induced increase in luminal alkalinisation or fluid secretion. Pre-treatment with hexamethonium abolished the effects of clonidine on luminal alkalinisation and net fluid flux. In summary, our in vivo experiments showed that clonidine-induced reduction in luminal alkalinisation and induction of net fluid absorption was unrelated to luminal Na⁺ and Cl^-, or to apical Na⁺/H⁺ or Cl^-/HCO₃^- exchangers. Instead, clonidine seems to exert its effects via suppression of nicotinic receptor-activated acetylcholine secretomotor neurons.

Gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill against ethanol-induced gastric ulcer in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The use of mushrooms in medicine is quite old and the first report about the use of genus Agaricus in treatment of ulcers occurred in Byzantine period. This mushroom is widely consumed as food, tea, food supplements, as well as nutraceutical and cosmeceutical applications, being cultivated and appreciated in several countries such as Brazil, Korea, Japan and China.

AIM OF THE STUDY

This study aimed to characterize the chemical profile and the potential gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill (HEAb).

MATERIALS AND METHODS

The extract was chemically characterized by elemental analysis, UPLC-QTOF-MS^E, Nuclear Magnetic Resonance (NMR) and high-performance liquid chromatography (HPLC) techniques to elucidate the metabolites present in the extract. The quantification of phenolic compounds and the in vitro antioxidant activities were performed and the gastroprotective effect of this extract was evaluated against ethanol-induced gastric ulcer model. HEAb was administered by gavage at 5, 25 and 50 mg kg^-1 and N-acetylcysteine at 300 mg kg^-1 (positive control). Furthermore, the pathways of nitric oxide (NO), Cyclic Guanylate Monophosphate (cGMP), prostaglandins (PGs) and the involvement of ATP-sensitive K⁺ Channels were modulated.

RESULTS

Mannitol, malic acid, pyroglutamic acid, L-agaritine and L-valine were putatively identified by UPLC-QTOF-MS^E in HEAb. In addition, it was possible to identify mannitol by the intense signals in the NMR spectra, being still quantified as the main compound in the extract by HPLC. The contents of total phenols and flavonoids corroborated with the good antioxidant activity of HEAb. This study observed that HEAb at 25 and 50 mg kg^-1 had gastroprotection effect demonstrated by the reduction of histopathological parameters and the reduction of mastocytosis in the stomach of mice.

CONCLUSIONS

In this study was possible to conclude that HEAb has gastroprotective effect related to the involvement of NO and PG pathways in the ethanol-induced gastric ulcer model in mice.

Single-Cell Analysis of CHO Cells Reveals Clonal Heterogeneity in Hyperosmolality-Induced Stress Response

Hyperosmolality can occur during industrial fed-batch cultivation processes of Chinese hamster ovary (CHO) cells as highly concentrated feed and base solutions are added to replenish nutrients and regulate pH values. Some effects of hyperosmolality, such as increased cell size and growth inhibition, have been elucidated by previous research, but the impact of hyperosmolality and the specific effects of the added osmotic-active reagents have rarely been disentangled. In this study, CHO cells were exposed to four osmotic conditions between 300 mOsm/kg (physiologic condition) and 530 mOsm/kg (extreme hyperosmolality) caused by the addition of either high-glucose-supplemented industrial feed or mannitol as an osmotic control. We present novel single-cell cultivation data revealing heterogeneity in mass gain and cell division in response to these treatments. Exposure to extreme mannitol-induced hyperosmolality and to high-glucose-oversupplemented feed causes cell cycle termination, mtDNA damage, and mitochondrial membrane depolarization, which hints at the onset of premature stress-induced senescence. Thus, this study shows that both mannitol-induced hyperosmolality (530 mOsm/kg) and glucose overfeeding induce severe negative effects on cell growth and mitochondrial activity; therefore, they need to be considered during process development for commercial production.

[Evaluation of the results of sodium fumarate, furosemide, and mannitol on the initiation and outcome of renal warm ischemia in an experimental study]

While performing surgical treatment of the localized form of renal cell cancer by means of open or laparoscopic partial nephrectomy, renal warm ischemia is an important issue. Using renal warm ischemia allows to prevent parenchymal bleeding, to optimize conditions for resection of the tumor and to increase significantly the efficiency of hemostasis. However, an important problem is the probability of ischemic hypoxic damage of the remaining part of the kidney tissue during renal warm ischemia and renal functional impairment in the postoperative period.

AIM

To compare nephroprotective activity of sodium fumarate, mannitol and furosemide using experimental model of 30- and 60-minute renal warm ischemia in rabbits.

MATERIALS AND METHODS

The experiments were carried out on 360 conventional male-rabbits of the "Chinchilla" breed weighed 2,6+/-0,3 kg which were allocated into 10 groups. The control group No1 included intact animals, the control group No2 included the rabbits in which renal artery was not clamped. For the animals from the trial groups (No3-No10) the experimental model of 30- and 60-minute renal warm ischemia was used. In groups No3 and No4 no drugs were provided. Other rabbits undergone renal warm ischemia with a protection by sodium fumarate (groups No5 and No6 - 1,5 ml/kg IV), lasix (groups No7 and No8 - 3,0 mg/kg IV) and mannitol (No9 and No10 - 1,0 g/kg IV). The influence of renal warm ischemia on the renal tissue ultrastructure and the levels of NGAL, Cystatin-C and creatinine in blood and urine were studied.

RESULTS

During experimental pharmacologically uncorrected 30-minute renal warm ischemia in animals, edema of the terminal part of microvilli of the proximal tubules epithelium, an increase of lysosome number in the hyaloplasm of epithelial cells, appearance of flaky content of medium electronic density in the lumens of distal tubules and collecting tubules, as well as sharp peak-like increase of NGAL and cystatin-C in blood and urine were observed. Increasing the time of ischemia up to 60 minutes was accompanied by more severe disturbances. In groups where sodium fumarate, lasix and mannitol were used the observed ultrastructural disturbances were expressed to lesser extent, whereas sodium fumarate demonstrated the best nephroprotective activity. After using mannitol the severity of disturbances was less than in the groups where mannitol, lasix or sodium fumarate were not given. Lasix and sodium salt of fumaric acid showed a higher nephroprotective activity. The best results were received in the animals received sodium fumarate.

CONCLUSIONS

The studied drugs provided a nephroprotective effect regarding ischemia of rabbit kidney. The effect of sodium fumarate was the most pronounced, followed by furosemide and, to a lesser extent, mannitol. Use of sodium fumarate allows to protect and stimulate the kidney tissue effectively during oxygen deprivation under ischemic state.

Metabolism-mediated mechanisms underpin the differential stomatal speediness regulation among ferns and angiosperms

Recent results suggest that metabolism-mediated stomatal closure mechanisms are important to regulate differentially the stomatal speediness between ferns and angiosperms. However, evidence directly linking mesophyll metabolism and the slower stomatal conductance (g_s ) in ferns is missing. Here, we investigated the effect of exogenous application of abscisic acid (ABA), sucrose and mannitol on stomatal kinetics and carried out a metabolic fingerprinting analysis of ferns and angiosperms leaves harvested throughout a diel course. Fern stomata did not respond to ABA in the time period analysed. No differences in the relative decrease in g_s was observed between ferns and the angiosperm following provision of sucrose or mannitol. However, ferns have slower g_s responses to these compounds than angiosperms. Metabolomics analysis highlights that ferns have a higher accumulation of secondary rather than primary metabolites throughout the diel course, with the opposite being observed in angiosperms. Our results indicate that metabolism-mediated stomatal closure mechanisms underpin the differential stomatal speediness regulation among ferns and angiosperms, in which the slower stomatal closure in ferns is associated with the lack of ABA-responsiveness, to a reduced capacity to respond to mesophyll-derived sucrose and to a higher carbon allocation toward secondary metabolism, which likely modulates both photosynthesis-g_s and growth-stress tolerance trade-offs.

Role of cassava CC-type glutaredoxin MeGRXC3 in regulating sensitivity to mannitol-induced osmotic stress dependent on its nuclear activity

BACKGROUND

We previously identified six drought-inducible CC-type glutaredoxins in cassava cultivars, however, less is known about their potential role in the molecular mechanism by which cassava adapted to abiotic stress.

RESULTS

Herein, we investigate one of cassava drought-responsive CC-type glutaredoxins, namely MeGRXC3, that involved in regulation of mannitol-induced inhibition on seed germination and seedling growth in transgenic Arabidopsis. MeGRXC3 overexpression up-regulates several stress-related transcription factor genes, such as PDF1.2, ERF6, ORA59, DREB2A, WRKY40, and WRKY53 in Arabidopsis. Protein interaction assays show that MeGRXC3 interacts with Arabidopsis TGA2 and TGA5 in the nucleus. Eliminated nuclear localization of MeGRXC3 failed to result mannitol-induced inhibition of seed germination and seedling growth in transgenic Arabidopsis. Mutation analysis of MeGRXC3 indicates the importance of conserved motifs for its transactivation activity in yeast. Additionally, these motifs are also indispensable for its functionality in regulating mannitol-induced inhibition of seed germination and enhancement of the stress-related transcription factors in transgenic Arabidopsis.

CONCLUSIONS

MeGRXC3 overexpression confers mannitol sensitivity in transgenic Arabidopsis possibly through interaction with TGA2/5 in the nucleus, and nuclear activity of MeGRXC3 is required for its function.

Microtubule organization changes severely after mannitol and n-butanol treatments inducing microspore embryogenesis in bread wheat

BACKGROUND

A mannitol stress treatment and a subsequent application of n-butanol, known as a microtubule-disrupting agent, enhance microspore embryogenesis (ME) induction and plant regeneration in bread wheat. To characterize changes in cortical (CMT) and endoplasmic (EMT) microtubules organization and dynamics, associated with ME induction treatments, immunocytochemistry studies complemented by confocal laser scanning microscopy (CLSM) were accomplished. This technique has allowed us to perform advanced 3- and 4D studies of MT architecture. The degree of MT fragmentation was examined by the relative fluorescence intensity quantification.

RESULTS

In uni-nucleated mannitol-treated microspores, severe CMT and EMT fragmentation occurs, although a complex network of short EMT bundles protected the nucleus. Additional treatment with n-butanol resulted in further depolymerization of both CMT and EMT, simultaneously with the formation of MT aggregates in the perinuclear region. Some aggregates resembled a preprophase band. In addition, a portion of the microspores progressed to the first mitotic division during the treatments. Bi-nucleate pollen-like structures showed a high MT depolymerization after mannitol treatment and numerous EMT bundles around the vegetative and generative nuclei after n-butanol. Interestingly, bi-nucleate symmetric structures showed prominent stabilization of EMT.

CONCLUSIONS

Fragmentation and stabilization of microtubules induced by mannitol- and n-butanol lead to new configurations essential for the induction of microspore embryogenesis in bread wheat. These results provide robust insight into MT dynamics during EM induction and open avenues to address newly targeted treatments to induce ME in recalcitrant species.

Mediation of the Cardioprotective Effects of Mannitol Discovered, with Refutation of Common Protein Kinases

The osmodiuretic agent Mannitol exerts cardioprotection against ischemia and reperfusion (I/R) injury when applied as a pre- and/or postconditioning stimulus. Previously, we demonstrated that these properties are mediated via the activation of mitochondrial ATP-sensitive potassium (mK_ATP) channels. However, considering Mannitol remains in the extracellular compartment, the question arises as to which receptor and intracellular signaling cascades are involved in myocardial protection by the osmodiuretic substance. Protein kinase B (Akt) and G (PKG), as part of the reperfusion injury salvage kinase (RISK) and/or endothelial nitric oxide (eNOS)/PKG pathway, are two well-investigated intracellular targets conferring myocardial protection upstream of mitochondrial potassium channels. Adenosine receptor subtypes have been shown to trigger different cardioprotective pathways, for example, the reperfusion injury. Further, Mannitol induces an increased activation of the adenosine 1 receptor (A1R) in renal cells conferring its nephroprotective properties. Therefore, we investigated whether (1) Akt and PKG are possible signaling targets involved in Mannitol-induced conditioning upstream of the mK_ATP channel and/or whether (2) cardioprotection by Mannitol is mediated via activation of the A1R. All experiments were performed on male Wistar rats in vitro employing the Langendorff isolated heart perfusion technique with infarct size determination as the primary endpoint. To unravel possible protein kinase activation, Mannitol was applied in combination with the Akt (MK2206) or PKG (KT5823) inhibitor. In further groups, an A1R blocker (DPCPX) was given with or without Mannitol. Preconditioning with Mannitol (Man) significantly reduced the infarct size compared to the control group. Co-administration of the A1R blocker DPXPC fully abolished myocardial protection of Mannitol. Interestingly and in contrast to the initial hypothesis, neither administration of the Akt nor the PKG blocker had any impact on the cardioprotective properties of Mannitol-induced preconditioning. These results are quite unexpected and show that the protein kinases Akt and PKG—as possible targets of known protective signaling cascades—are not involved in Mannitol-induced preconditioning. However, the cardioprotective effects of Mannitol are mediated via the A1R.

Genome-Wide Comprehensive Analysis of the GASA Gene Family in Populus

Gibberellic acid-stimulated Arabidopsis (GASA) proteins, as cysteine-rich peptides (CRPs), play roles in development and reproduction and biotic and abiotic stresses. Although the GASA gene family has been identified in plants, the knowledge about GASAs in Populus euphratica, the woody model plant for studying abiotic stress, remains limited. Here, we referenced the well-sequenced Populus trichocarpa genome, and identified the GASAs in the whole genome of P. euphratica and P. trichocarpa. 21 candidate genes in P. trichocarpa and 19 candidate genes in P. euphratica were identified and categorized into three subfamilies by phylogenetic analysis. Most GASAs with signal peptides were located extracellularly. The GASA genes in Populus have experienced multiple gene duplication events, especially in the subfamily A. The evolution of the subfamily A, with the largest number of members, can be attributed to whole-genome duplication (WGD) and tandem duplication (TD). Collinearity analysis showed that WGD genes played a leading role in the evolution of GASA genes subfamily B. The expression patterns of P. trichocarpa and P. euphratica were investigated using the PlantGenIE database and the real-time quantitative PCR (qRT-PCR), respectively. GASA genes in P. trichocarpa and P. euphratica were mainly expressed in young tissues and organs, and almost rarely expressed in mature leaves. GASA genes in P. euphratica leaves were also widely involved in hormone responses and drought stress responses. GUS activity assay showed that PeuGASA15 was widely present in various organs of the plant, especially in vascular bundles, and was induced by auxin and inhibited by mannitol dramatically. In summary, this present study provides a theoretical foundation for further research on the function of GASA genes in P. euphratica.

Danhong injection enhances the therapeutic effect of mannitol on hemispheric ischemic stroke by ameliorating blood-brain barrier disruption

Mannitol, a representative of hyperosmolar therapy, is indispensable for the treatment of malignant cerebral infarction, but its therapeutic effect is limited by its exacerbation of blood-brain barrier (BBB) disruption. This study was to explore whether Danhong injection (DHI), a standardized product extracted from Salvia miltiorrhiza Bunge and Carthamus tinctorius L., inhibits the destructive effect of mannitol on BBB and thus enhancing the treatment of hemispheric ischemic stroke. SD rats were subjected to pMCAO followed by intravenous bolus injections of mannitol with/without DHI intervention. Neurological deficit score, brain edema, infarct volume at 24 h after MCAO and histopathology, microvascular ultrastructure, immunohistochemistry and immunofluorescence staining of endothelial cell junctions, energy metabolism in the ischemic penumbra were assessed. Intravenous mannitol after MCAO resulted in a decrease in 24 h mortality and cerebral edema, whereas no significant benefit on neurological deficits, infarct volume and microvascular ultrastructure. Moreover, mannitol led to the loss of endothelial integrity, manifested by the decreased expression of occludin, junctional adhesion molecule-1 (JAM-1) and zonula occluden-1 (ZO-1) and the discontinuity of occludin staining around the periphery of endothelial cells. Meanwhile, after mannitol treatment, energy-dependent vimentin and F-actin, ATP content, and ATP5D expression were down-regulated, while MMP2 and MMP9 expression increased in the ischemic penumbra. All the insults after mannitol treatment were attenuated by addition of intravenous DHI. The results suggest DHI as a potential remedy to attenuate mannitol-related BBB disruption, and the potential of DHI to upregulate energy metabolism and inhibit the activity of MMPs is likely attributable to its effects observed.

Effects of osmolality on the expression of brain aquaporins in AQP11-null mice

Water transport in the brain is tightly controlled by blood-brain-barrier (BBB) composed of capillary endothelial cells expressing AQP1/AQP11 and glial foot processes expressing AQP4. Here we examined each AQP mRNA expression in acute hyponatremic and hypernatremic mouse models of wild type (WT) and AQP11 KO mice (KO). The expressions of AQP1, AQP4 and AQP11 mRNAs were quantified by real-time qRT-PCR analysis of whole brain RNA. Acute hyponatremia enhanced AQP4 expression without changing AQP1 expression in KO, whereas it did not change the expression of all AQPs in WT. On the other hand, acute hypernatremia increased AQP4 but decreased AQP1 expression by half in KO, whereas it decreased AQP1 and AQP11 by half without changing AQP4 expression in WT. Enhanced AQP4 expression by osmotic challenges with sodium in KO seems to be a compensation for the loss of AQP11. A stronger hypertonic stimulation with mannitol decreased all AQPs by 30-80% in WT. Since AQP4 plays an important role in the regulation of brain edema at BBB, the results suggest that AQP11 may also be involved in the osmotic regulation of the brain.

A bamboo leaf-specific aquaporin gene PePIP2;7 is involved in abiotic stress response

PePIP2;7, a leaf-specific aquaporin gene in bamboo, is upregulated under abiotic stresses. Overexpressing PePIP2;7 confers abiotic stresses tolerance in transgenic Arabidopsis plant and yeast. Aquaporins (AQPs) participate in the regulation of water balance in plants. However, the function of AQPs in bamboo remains unclear. Here, PePIP2;7 was identified as a leaf-specific aquaporin gene in moso bamboo based on the expression analysis of transcriptome data and PCR. In situ hybridization further indicated that PePIP2;7 was mainly expressed in mesophyll cells of mature leaves, while in immature leaves it was dominant in blade edge cells followed by mesophyll cells. Interestingly, PePIP2;7 was strongly expressed in the mesophyll cells near bulliform cells of immature leaves, suggesting that PePIP2;7 might function in water transport and contribute to leaf unfolding. The transient expression assay showed that PePIP2;7 was a plasma membrane intrinsic protein. Furthermore, PePIP2;7 was upregulated under abiotic stresses such as high light, drought, and NaCl. Compared with Col-0, transgenic Arabidopsis plants overexpressing PePIP2;7 had better seed germination rate, longer taproot length, higher SOD activity, and lower MDA content under abiotic stresses. Besides, yeasts expressing PePIP2;7 also had higher tolerance to stress compared to the control. Taken together, our results show that PePIP2;7 is leaf-specific and involved in stress response, which provides new insights into aquaporin function in bamboo.

Montanide™ ISA 763A VG and ISA 761 VG induce different immune pathway responses in rainbow trout (Oncorhynchus mykiss) when used as adjuvant for an Aeromonas salmonicida bacterin

Adjuvants are the helper substances that increase vaccine efficacy by enhancing the potency and longevity of specific immune responses to antigens. Most existing fish vaccines are presented in the form of oil-based emulsions delivered by intraperitoneal injection. The characterization of their mode of action is a valuable aid to future vaccine development, particularly for the potential identification and stimulation of specific immunological pathways related to the desired protective response. This study characterized the expression of selected immune-related genes in the peritoneal cavity, head kidney and spleen following the administration of two adjuvanted-bacterial vaccines thought to induce humoral (Montanide™ ISA 763A VG) or humoral and cell mediated (Montanide™ ISA 761 VG) immune responses, to determine if differences in responsiveness are readily apparent. The most informative site was the spleen, where Montanide™ ISA 763A VG + bacterin gave rise to upregulation of genes driving T-cell/lymphoid responses, namely IL-2, IL-15 and IL-21. This combined with upregulation of IFNγ1 and IFNγ2, IL-4/13B2, p35A1 and p40 (B1 and C) indicated that the induction of Th1 and possibly Th2 immunity was occurring in fish vaccinated with this adjuvant. Perhaps the most intriguing finding was the lack of a detectable Th1 response in fish given Montanide™ ISA 761 VG + bacterin, suggesting some other arm of the immune system is activated to give protection. Whatever the reason for the different responses detected, it is clear from the present study that the adjuvant used has a major impact on the responses elicited. Since these differences are readily detectable it allows, in principle, their use to help select the most appropriate adjuvants for inclusion into fish vaccines, where the type of response elicited may need to be tailored to a particular pathogen to confer protection.

Therapeutic doses of acetaminophen with co-administration of cysteine and mannitol during early development result in long term behavioral changes in laboratory rats

Based on several lines of evidence, numerous investigators have suggested that acetaminophen exposure during early development can induce neurological disorders. We had previously postulated that acetaminophen exposure early in life, if combined with antioxidants that prevent accumulation of NAPQI, the toxic metabolite of acetaminophen, might be innocuous. In this study, we administered acetaminophen at or below the currently recommended therapeutic dose to male laboratory rat pups aged 4-10 days. The antioxidants cysteine and mannitol were included to prevent accumulation of NAPQI. In addition, animals were exposed to a cassette of common stress factors: an inflammatory diet, psychological stress, antibiotics, and mock infections using killed bacteria. At age 37-49 days, observation during introduction to a novel conspecific revealed increased rearing behavior, an asocial activity, in animals treated with acetaminophen plus antioxidants, regardless of their exposure to oxidative stress factors (2-way ANOVA; P < 0.0001). This observation would suggest that the initial hypothesis is incorrect, and that oxidative stress mediators do not entirely eliminate the effects of acetaminophen on neurodevelopment. This study provides additional cause for caution when considering the use of acetaminophen in the pediatric population, and provides evidence that the effects of acetaminophen on neurodevelopment need to be considered both in the presence and in the absence of oxidative stress.

The Antiedematous Effect of Exogenous Lactate Therapy in Traumatic Brain Injury: A Physiological and Mechanistic Approach

Background

Sodium lactate (SL) has been described as an efficient therapy in treating raised intracranial pressure (ICP). However, the precise mechanism by which SL reduces intracranial hypertension is not well defined. An antiedematous effect has been proposed but never demonstrated. In this context, the involvement of chloride channels, aquaporins, or K–Cl cotransporters has also been suggested, but these mechanisms have never been assessed when using SL.

Methods

In a rat model of traumatic brain injury (TBI), we compared the effect of SL versus mannitol 20% on ICP, cerebral tissue oxygen pressure, and brain water content. We attempted to clarify the involvement of chloride channels in the antiedematous effects associated with lactate therapy in TBI.

Results

An equimolar single bolus of SL and mannitol significantly reduced brain water content and ICP and improved cerebral tissue oxygen pressure 4 h after severe TBI. The effect of SL on brain water content was much longer than that of mannitol and persisted at 24 h post TBI. Western blot and immunofluorescence staining analyses performed 24 h after TBI revealed that SL infusion is associated with an upregulation of aquaporin 4 and K–Cl cotransporter 2.

Conclusions

SL is an effective therapy for treating brain edema after TBI. This study suggests, for the first time, the potential role of chloride channels in the antiedematous effect induced by exogenous SL.

Deuterium oxide as a contrast medium for real-time MRI-guided endovascular neurointervention

Rationale: Endovascular intervention plays an important role in the treatment of various diseases, in which MRI-guidance can potentially improve precision. However, the clinical applications of currently available contrast media, including Gadolinium-based contrast agents and superparamagnetic iron oxide particles (SPIO), are hindered by safety concerns. In the present study, we sought to develop D2O as a novel contrast agent for guiding endovascular neurointervention. Methods: Animal studies were approved by institutional ACUC and conducted using an 11.7 T Bruker Biospec system and a 3T Siemens Trio clinical scanner for rodent and canine imaging, respectively. The locally selective blood brain barrier opening (BBBO) in rat brains was obtained by intraarterial (IA) injection of mannitol. The dynamic T2w* EPI MRI sequence was used to study the trans-catheter perfusion territory by IA administered SPIO before mannitol administration, whereas a dynamic T1w FLASH sequence was used to acquire Gd contrast-enhanced MRI for assessing BBBO after injection of mannitol. The contrast generated by D2O assessed by either EPI or FLASH methods was compared with the corresponding results assessed by SPIO or Gd. The utility of D2O MRI was also demonstrated to guide drug delivery to glioma in a mouse model. Finally, the clinical utility of D2O-MRI was demonstrated in a canine model. Results: Our study has shown that the contrast generated by D2O can be used to precisely delineate trans-catheter perfusion territory in both small and large animals. The perfusion territories determined by D2O-MRI show moderate correlation with those by SPIO-MRI (Spearman coefficient r = 0.5234, P < 0.001). Moreover, our results show that the perfusion territory determined by D2O-MRI can successfully predict the areas with BBBO after mannitol treatment similar to that assessed by Gd-MRI (Spearman coefficient r = 0.6923, P < 0.001). Using D2O-MRI as imaging guidance, the optimal infusion rate in the mouse brain was determined to be 150 µL/min to maximize the delivery efficacy to the tumor without serious off-target delivery to the brain parenchyma. The enhanced drug delivery of antibodies to the brain tumor was confirmed by fluorescence imaging. Conclusion: Our study demonstrated that D2O can be used as a negative MRI contrast medium to guide endovascular neurointervention. The established D2O -MRI method is safe and quantitative, without the concern of contrast accumulation. These qualities make it an attempting approach for a variety of endovascular procedures.

D-Mannitol Induces a Brown Fat-like Phenotype via a β3-Adrenergic Receptor-Dependent Mechanism

The presence of brown adipocytes within white adipose tissue is associated with phenotypes that exhibit improved metabolism and proper body weight maintenance. Therefore, a variety of dietary agents that facilitate the browning of white adipocytes have been investigated. In this study, we screened a natural product library comprising 133 compounds with the potential to promote the browning of white adipocytes, and found that D-mannitol induces the browning of 3T3-L1 adipocytes by enhancing the expression of brown fat-specific genes and proteins, and upregulating lipid metabolism markers. D-mannitol also increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase 1 (ACC), suggesting a possible role in lipolysis and fat oxidation. Moreover, an increase in the expression of genes associated with D-mannitol-induced browning was strongly correlated with the activation of the β3-adrenergic receptor as well as AMPK, protein kinase A (PKA), and PPARγ coactivator 1α (PGC1α). D-mannitol effectively reduced the body weight of mice fed a high-fat diet, and increased the expression of β1-oxidation and energy expenditure markers, such as Cidea, carnitine palmityl transferase 1 (CPT1), uncoupling protein 1 (UCP1), PGC1α, and acyl-coenzyme A oxidase (ACOX1) in the inguinal white adipose tissue. Our findings suggest that D-mannitol plays a dual regulatory role by inducing the generation of a brown fat-like phenotype and enhancing lipid metabolism. These results indicate that D-mannitol can function as an anti-obesity supplement.

High Glucose Treatment Limits Drosha Protein Expression and Alters AngiomiR Maturation in Microvascular Primary Endothelial Cells via an Mdm2-dependent Mechanism

Diabetes promotes an angiostatic phenotype in the microvascular endothelium of skeletal muscle and skin. Angiogenesis-related microRNAs (angiomiRs) regulate angiogenesis through the translational repression of pro- and anti-angiogenic genes. The maturation of micro-RNA (miRs), including angiomiRs, requires the action of DROSHA and DICER proteins. While hyperglycemia modifies the expression of angiomiRs, it is unknown whether high glucose conditions alter the maturation process of angiomiRs in dermal and skeletal muscle microvascular endothelial cells (MECs). Compared to 5 mM of glucose, high glucose condition (30 mM, 6-24 h) decreased DROSHA protein expression, without changing DROSHA mRNA, DICER mRNA, or DICER protein in primary dermal MECs. Despite DROSHA decreasing, high glucose enhanced the maturation and expression of one angiomiR, miR-15a, and downregulated an miR-15a target: Vascular Endothelial Growth Factor-A (VEGF-A). The high glucose condition increased Murine Double Minute-2 (MDM2) expression and MDM2-binding to DROSHA. Inhibition of MDM2 prevented the effects evoked by high glucose on DROSHA protein and miR-15a maturation in dermal MECs. In db/db mice, blood glucose was negatively correlated with the expression of skeletal muscle DROSHA protein, and high glucose decreased DROSHA protein in skeletal muscle MECs. Altogether, our results suggest that high glucose reduces DROSHA protein and enhances the maturation of the angiostatic miR-15a through a mechanism that requires MDM2 activity.

Cardioprotective Properties of Mannitol-Involvement of Mitochondrial Potassium Channels

Cardiac preconditioning (PC) and postconditioning (PoC) are powerful measures against the consequences of myocardial ischemia and reperfusion (I/R) injury. Mannitol-a hyperosmolar solution-is clinically used for treatment of intracranial and intraocular pressure or promotion of diuresis in renal failure. Next to these clinical indications, different organ-protective properties-e.g., perioperative neuroprotection-are described. However, whether Mannitol also confers cardioprotection via a pre- and/or postconditioning stimulus, possibly reducing consequences of I/R injury, remains to be seen. Therefore, in the present study we investigated whether (1) Mannitol-induced pre- and/or postconditioning induces myocardial infarct size reduction and (2) activation of mitochondrial ATP-sensitive potassium (mKATP) channels is involved in cardioprotection by Mannitol. Experiments were performed on isolated hearts of male Wistar rats via a pressure controlled Langendorff system, randomized into 7 groups. Each heart underwent 33 min of global ischemia and 60 min of reperfusion. Control hearts (Con) received Krebs-Henseleit buffer as vehicle only. Pre- and postconditioning was achieved by administration of 11 mmol/L Mannitol for 10 min before ischemia (Man-PC) or immediately at the onset of reperfusion (Man-PoC), respectively. In further groups, the mKATP channel blocker 5HD, was applied with and without Mannitol, to determine the potential underlying cardioprotective mechanisms. Primary endpoint was infarct size, determined by triphenyltetrazolium chloride staining. Mannitol significantly reduced infarct size both as a pre- (Man-PC) and postconditioning (Man-PoC) stimulus compared to control hearts (Man-PC: 31 ± 4%; Man-PoC: 35 ± 6%, each p < 0.05 vs. Con: 57 ± 9%). The mKATP channel inhibitor completely abrogated the cardioprotective effect of Mannitol-induced pre- (5HD-PC-Man-PC: 59 ± 8%, p < 0.05 vs. Man-PC) and postconditioning (5HD-PoC-Man-PoC: 59 ± 10% vs. p < 0.05 Man-PoC). Infarct size was not influenced by 5HD itself (5HD-PC: 60 ± 14%; 5HD-PoC: 54 ± 14%, each ns vs. Con). This study demonstrates that Mannitol (1) induces myocardial pre- and postconditioning and (2) confers cardioprotection via activation of mKATP channels.

Quercetin alleviates seed germination and growth inhibition in Apocynum venetum and Apocynum pictum under mannitol-induced osmotic stress

Quercetin is one of the main flavonoids in the human diet and mainly found in different plant tissues, including seeds, flowers, leaves, stems, and roots. However, its biological function in plant tissues, especially in seeds, is unknown. In this study, the seed germination and subsequent seedling growth of Apocynum pictum and A. venetum under osmotic stress (400 mmol L^-1 mannitol) supplemented with 5 μmol L^-1 quercetin were evaluated after 7, 14, and 21 days of germination. Results showed that quercetin improved the germination percentage and seed vigor, as indicated by the higher germination energy, shoot length, root length, dry weight, fresh weight, and chlorophyll content in A. pictum and A. venetum seedlings under the mannitol compared with those under the mannitol alone. Quercetin decreased H₂O₂ and O₂^- production and cell membrane damage, and mostly increased the gene expression of superoxide dismutase, peroxidase, catalase, chalcone synthase and flavonol synthase in A. pictum and A. venetum seedlings under the mannitol compared with those under the mannitol alone. In addition, the germination energy of A. pictum was 21.57% higher than that of A. venetum, and the gene expression of key enzymes in quercetin biosynthesis in A. pictum was mostly higher than that in A. venetum after 1 and 7 days of germination. These results indicated that quercetin was an effective anti-osmotic agent that alleviated the adverse effect of mannitol-induced osmotic stress on seed germination and seed vigor, and A. pictum seeds were more osmotic resistant than A. venetum seeds.

A moso bamboo transcription factor, Phehdz1, positively regulates the drought stress response of transgenic rice

78 HD-Zip family genes in Phyllostachys edulis were analyzed. Overexpression of Phehdz1 can improve the drought tolerance of transgenic rice and affect its secondary metabolism. Many studies suggested homeodomain-leucine zipper (HD-Zip) transcription factors are important regulators of plant growth and development, signal transduction, and responses to environmental stresses. In this study, 78 moso bamboo (Phyllostachys edulis) HD-Zip genes were investigated and classified into four subfamilies (HD-Zip I-IV). Additionally, Phehdz1 (HD-Zip I gene) was isolated and confirmed to be highly expressed in the roots. A quantitative real-time PCR analysis indicated Phehdz1 expression was significantly induced by drought, high salinity, and abscisic acid (ABA). A transient expression assay proved that Phehdz1 was localized in the nucleus of tobacco cells. Moreover, it could bind to the core region encoded by the H-box sequence (CAATAATTG) in yeast. In response to mannitol treatments, the Phehdz1-overexpressing transgenic rice had a higher germination rate and longer shoots than the wild-type controls. Moreover, Phehdz1-overexpressing rice plants had a higher survival rate as well as higher relative water and proline contents, but a lower malondialdehyde content, than the WT plants after a 30% polyethylene glycol 6000 treatment. Accordingly, the overexpression of Phehdz1 enhances the drought tolerance of transgenic rice. Many of the differentially expressed genes identified by a transcriptome analysis are involved in MAPK signal transduction and the biosynthesis of secondary metabolites. Thus, the overexpression of Phehdz1 enhances the drought stress tolerance of transgenic rice, while also potentially modulating the expression of metabolism-related genes.

ScAOC1, an allene oxide cyclase gene, confers defense response to biotic and abiotic stresses in sugarcane

KEY MESSAGE

An allene oxide cyclase gene which is involved in defense against biotic and abiotic stresses was cloned and characterized in sugarcane. Allene oxide cyclase (AOC), a key enzyme in jasmonate acid (JA) biosynthesis, affects the stereoisomerism and biological activity of JA molecules, and plays an important role in plant stress resistance. In this study, four SsAOC alleles (SsAOC1-SsAOC4), which shared similar gene structure and were located on Chr1A, Chr1B, Chr1C, and Chr1D, respectively, were mined from sugarcane wild species Saccharum spontaneum, and a homologous gene ScAOC1 (GenBank Accession Number: MK674849) was cloned from sugarcane hybrid variety Yacheng05-179 inoculated with Sporisorium scitamineum for 48 h. ScAOC1 and SsAOC1-SsAOC4 were alkaline, unstable, hydrophilic, and non-secretory proteins, which possess the same set of conserved motifs and were clustered into one group in the phylogenetic analysis. ScAOC1 was expressed in all sugarcane tissues, but with different levels. After infection by S. scitamineum, the transcripts of ScAOC1 were increased significantly both in the smut-susceptible (ROC22) and resistant (Yacheng05-179) varieties, but its transcripts were more accumulated and lasted for a longer period in the smut-resistant variety than in the smut-susceptible one. ScAOC1 was down-regulated under MeJA and NaCl treatments, but up-regulated under SA, ABA, PEG, and cold stresses. Transiently overexpressing ScAOC1 gene into Nicotiana benthamiana leaves regulated the responses of N. benthamiana to two pathogens Ralstonia solanacearum and Fusarium solani var. coeruleum. Furthermore, prokaryotic expression analysis showed overexpression of ScAOC1 in Escherichia coli BL21 could enhance its tolerance to NaCl, mannitol, and cold stimuli. These results indicated that ScAOC1 may play an active role in response to biotic and abiotic stresses in sugarcane.

Preventing neuronal edema increases network excitability after traumatic brain injury

Edema is an important target for clinical intervention after traumatic brain injury (TBI). We used in vivo cellular resolution imaging and electrophysiological recording to examine the ionic mechanisms underlying neuronal edema and their effects on neuronal and network excitability after controlled cortical impact (CCI) in mice. Unexpectedly, we found that neuronal edema 48 hours after CCI was associated with reduced cellular and network excitability, concurrent with an increase in the expression ratio of the cation-chloride cotransporters (CCCs) NKCC1 and KCC2. Treatment with the CCC blocker bumetanide prevented neuronal swelling via a reversal in the NKCC1/KCC2 expression ratio, identifying altered chloride flux as the mechanism of neuronal edema. Importantly, bumetanide treatment was associated with increased neuronal and network excitability after injury, including increased susceptibility to spreading depolarizations (SDs) and seizures, known agents of clinical worsening after TBI. Treatment with mannitol, a first-line edema treatment in clinical practice, was also associated with increased susceptibility to SDs and seizures after CCI, showing that neuronal volume reduction, regardless of mechanism, was associated with an excitability increase. Finally, we observed an increase in excitability when neuronal edema normalized by 1 week after CCI. We conclude that neuronal swelling may exert protective effects against damaging excitability in the aftermath of TBI and that treatment of edema has the potential to reverse these effects.

Rg1 in combination with mannitol protects neurons against glutamate-induced ER stress via the PERK-eIF2 α-ATF4 signaling pathway

AIMS

Ginseng and ginsenosides are known for their remarkable effects on the central nervous system. However, pharmacokinetic studies have suggested that the Ginsenoside Rg1 (Rg1) cannot be efficiently transported through the blood-brain barrier. To investigate the effects of Rg1 in combination with mannitol protects neurons against glutamate-induced ER stress via the PERK-eIF2 -ATF4 signaling pathway.

MAIN METHODS

Rg1, along with the BBB permeabilizer mannitol, exhibited a potent neuroprotective effect by significantly reducing the neurological scores and infarct volume in rats exposed to middle cerebral artery occlusion. We evaluated the effect of Rg1 on neuroprotection after MCAO, and also explored its potential mechanism of action.

KEY FINDINGS

Our results show that Rg1 reduced the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive neurons. This neuroprotection may be dependent, at least in part, on the preservation of the endoplasmic reticulum and mitochondrial function. Ischemia-induced brain injury is largely caused by the excessive release of glutamate, which results in excitotoxicity and cell death. Neurons were pretreated with Rg1 before inducing endoplasmic reticulum stress with glutamate. A reduction in the expression of Bax and a concomitant increase in Bcl2 expression prevented the induction of apoptosis. Furthermore, Rg1 downregulated the expression of endoplasmic reticulum stress genes.

SIGNIFICANCE

Our results indicate that Rg1 modulation of stress-responsive genes helps prevent glutamate-induced endoplasmic reticulum stress in neurons through the PERK-eIF2-α-ATF4 signaling pathway.

Adenosine A2a Receptor Stimulation Attenuates Ischemia-Reperfusion Injury and Improves Survival in A Porcine Model of DCD Liver Transplantation

Orthotopic liver transplantation (OLT) using allografts from donation after circulatory death (DCD) is potentially associated with compromised clinical outcomes due to ischemia-reperfusion injury (IRI)-induced organ damage and graft-related complications. The aim of this study was to provide in vivo data on the effects of adenosine A2a receptor stimulation in a clinically relevant large animal model of DCD liver transplantation. Cardiac arrest was induced in German Landrace pigs (n = 10; 20-25 kg). After 30 min of warm ischemia, the donor liver was retrieved following a cold flush with 3 L of histidine-tryptophan-ketoglutarate-HTK solution. Animals of the treatment group (n = 5/group) received a standard dose of the selective adenosine receptor agonist CGS 21680 added to the cold flush. All grafts were stored for 4.5 h at 4 °C in HTK-solution before OLT. Hepatocellular injury, apoptosis, protein kinase A-PKA activity, graft microcirculation, liver function, and animal survival were assessed. Compared to untreated livers, adenosine A2a receptor stimulation resulted in improved tissue microcirculation (103% ± 5% vs. 38% ± 4% compared to baseline; p < 0.05), accelerated functional recovery of the graft (indocyanine green-plasma disappearance rate (ICG-PDR) of 75% ± 18% vs. 40% ± 30% after 3 h), increased PKA activity ratio (56% ± 3% vs. 32% ± 3%; p < 0.001 after 1 h), and consequently reduced tissue necrosis and apoptosis. The potent protective effects were clinically manifested in significantly improved survival in the treatment group after 72 h (100% vs. 40%; p = 0.04). The ex vivo administration of adenosine A2a receptor agonist during the back-table flush mitigates IRI-mediated tissue damage and improves functional graft recovery and survival in a large animal model of DCD liver transplantation.

Hypertonic saline and mannitol in patients with traumatic brain injury: A systematic and meta-analysis

BACKGROUND

To compare the effects of 3% hypertonic saline solution and 20% mannitol solution on intracranial hypertension.

METHODS

WAN-FANGDATA, CNKI, and CQVIP databases were searched, and relevant literatures of randomized controlled trials comparing 3% hypertonic saline solution with mannitol in reducing intracranial hypertension from 2010 to October 2019 were collected. Meta-analysis was performed using RevMan software.

RESULTS

As a result, 10 articles that met the inclusion criteria were finally included. A total of 544 patients were enrolled in the study, 270 in the hypertonic saline group and 274 in the mannitol group. There was no significant difference in the decrease of intracranial pressure and the onset time of drug between the 2 groups after intervention (all P > .05). There was a statistically significant difference between the hypertonic saline group and the mannitol group in terms of duration of effect in reducing intracranial pressure (95% confidence interval: 0.64-1.05, Z = 8.09, P < .00001) and cerebral perfusion pressure after intervention (95% confidence interval: 0.15-0.92, Z = 2.72, P = .007).

CONCLUSION

Both 3% hypertonic saline and mannitol can effectively reduce intracranial pressure, but 3% hypertonic saline has a more sustained effect on intracranial pressure and can effectively increase cerebral perfusion pressure.

Effectiveness of Brain Protection With Histidine-Tryptophan-Ketoglutarate Solutions

BACKGROUND

Tissue-protective solutions increase resistance of cells to ischemic conditions. Especially in carotid and aortic arch surgeries where the brain perfusion is at risk, these solutions may be beneficial to prevent ischemic brain damage. This study was designed to demonstrate the effectiveness of histidine-tryptophan-ketoglutarate (HTK) solution in increasing resistance of brain tissue to ischemic conditions.

METHODS

Three separate randomized groups were created, each consisting of eight rabbits. The groups were called the ischemia, HTK and sham groups, respectively. In the ischemia group, temporary brain ischemia was created for 15 minutes by placing clamps on the bilateral subclavian and common carotid arteries. Then the clamps were removed, and the brain was reperfused for 30 minutes. In the HTK group, HTK solution was sent to the brain through the internal carotid artery before the same ischemia-reperfusion protocol was applied. Histopathological analyses using a visual scoring system to assess the degree of ischemic changes and the apoptotic cell index by TUNEL test were performed in all brain tissue samples.

RESULTS

Apoptotic cell indices of the HTK (20.6%) and sham (17.8%) groups were lower than the ischemia group (56.8%) (P < .05). Statistically significant differences were detected between all groups in categorical scores (P < .05).

CONCLUSIONS

It was shown that less ischemic damage occurs in the brain tissue with the use of HTK solution, and it may be a candidate approach to prevent the brain from ischemic insults during cerebrovascular surgery. Further studies are required to demonstrate its exact effectiveness, in terms of dose, duration, and temperature.

Cloning and functional analysis of AmDUF1517 promoter from Ammopiptanthus mongolicus

Domains of unknown function protein family 1517 (DUF1517) in Ammopiptanthus mongolicus, could be induced by abiotic stresses, whose upstream regulatory sequence might be an ideal source of abiotic-induced promoter. In this study, a 1026-bp promoter of AmDUF1517 from A. mongolicus was cloned. Five deletion fragments (Full, Q1-Q4) of different length of the AmDUF1517 promoter were fused with the β-glucuronidase (GUS) reporter and transformed into Arabidopsis thaliana. The deletion analysis showed that sequences Full, Q1 and Q3 responded well to mannitol, NaCl and 4 °C stresses, while Q2 and Q4 segments did not. The Q3 fragment (280 bp; -280 to -1 bp) showed the highest promoter activity under normal and mannitol, NaCl and 4 °C conditions. The result suggested that Q3 in the AmDUF1517 gene promoter could be a new source of induced promoters for abiotic resistance breeding in plant genetic engineering.

"The Secret Life of Human Donor Hearts": An Examination of Transcriptomic Events During Cold Storage

BACKGROUND

Ischemic tolerance of donor hearts has a major impact on the efficiency in utilization and clinical outcomes. Molecular events during storage may influence the severity of ischemic injury.

METHODS

RNA sequencing was used to study the transcriptional profile of the human left ventricle (LV, n=4) and right ventricle (RV, n=4) after 0, 4, and 8 hours of cold storage in histidine-tryptophan-ketoglutarate preservation solution. Gene set enrichment analysis and gene ontology analysis was used to examine transcriptomic changes with cold storage. Terminal deoxynucleotidyl transferase 2´-Deoxyuridine, 5´-Triphosphate nick end labeling and p65 staining was used to examine for cell death and NFκB activation, respectively.

RESULTS

The LV showed activation of genes related to inflammation and allograft rejection but downregulation of oxidative phosphorylation and fatty acid metabolism pathway genes. In contrast, inflammation-related genes were down-regulated in the RV and while oxidative phosphorylation genes were activated. These transcriptomic changes were most significant at the 8 hours with much lower differences observed between 0 and 4 hours. RNA velocity estimates corroborated the finding that immune-related genes were activated in the LV but not in the RV during storage. With increasing preservation duration, the LV showed an increase in nuclear translocation of NFκB (p65), whereas the RV showed increased cell death close to the endocardium especially at 8 hours.

CONCLUSIONS

Our results demonstrated that the LV and RV of human donor hearts have distinct responses to cold ischemic storage. Transcriptomic changes related to inflammation, oxidative phosphorylation, and fatty acid metabolism pathways as well as cell death and NFκB activation were most pronounced after 8 hours of storage.

Histidine-Tryptophan-Ketoglutarate Solution for Donor Heart Preservation Is Safe for Transplantation

BACKGROUND

Various solutions are used for donor heart preservation. We examined the outcomes in our heart transplant population where histidine-tryptophan-ketoglutarate (HTK) solution has been used for heart preservation since 2004.

METHODS

This was a retrospective review of the United Network for Organ Sharing (UNOS) database (2004-2016) comparing our heart transplant outcomes with other national centers. Propensity matching in a 1:3 ratio was performed to adjust for preoperative recipient variables.

RESULTS

After propensity matching comparing UNOS outcomes (n = 1080) with our institutional data (n = 360), there was no difference in matched preoperative variables. Donor hearts were similar for donor age, sex, donor-to-recipient size ratio, LVEF, and ischemic time. Our HTK cohort had a larger proportion with donor cardiac arrest (26.3% vs 6.1%, P < .001) and longer cardiac arrest duration (22.1 ± 16.0 vs 17.2 ± 14.0 minutes, P = .052). Our primary graft dysfunction (PGD) rate requiring mechanical support was 4.2% (n = 1). Postoperative mechanical support use for PGD included extracorporeal membrane oxygenation in 9 (60.0%), intraaortic balloon pump in 4 (26.7%), right ventricular assist device in 3 (20%), and biventricular assist device in 3 (20%). Overall survival at our institution was similar to the national average (P = .649). Survival at 1, 5, and 10 years with HTK was 92.2%, 81.3%, and 70.8%, and for the UNOS population was 91.6%, 80.3%, and 62.0%, respectively.

CONCLUSIONS

Use of HTK solution for donor hearts was associated with a low rate of severe PGD. Overall survival was not significantly different from other institutions using a variety of preservation solutions in the UNOS database during the same period. HTK solution is efficacious for preservation of donor hearts.

Effects of Osmotic Therapy on Pupil Reactivity: Quantification Using Pupillometry in Critically Ill Neurologic Patients

BACKGROUND

Osmotic therapy is a critical component of medical management for cerebral edema. While up to 90% of neurointensivists report using these treatments, few quantitative clinical measurements guide optimal timing, dose, or administration frequency. Its use is frequently triggered by a qualitative assessment of neurologic deterioration and/or pupil size, and anecdotally appears to improve pupil asymmetry suggestive of uncal herniation. However, subjective pupil assessment has poor reliability, making it difficult to detect or track subtle changes. We hypothesized that osmotic therapy reproducibly improves quantitative pupil metrics.

METHODS

We included patients at two centers who had recorded quantitative pupil measurements within 2 h before and after either 20% mannitol or 23.4% hypertonic saline in the neurosciences intensive care unit. The primary outcome was the Neurologic Pupil Index (NPi), a composite metric ranging from 0 to 5 in which > 3 is considered normal. Secondary outcomes included pupil size, percent change, constriction and dilation velocity, and latency. Results were analyzed with Wilcoxon signed-rank tests, Chi-square and multi-level linear regression to control for other edema-reducing interventions.

RESULTS

Out of 72 admissions (403 paired pupil observations), NPi significantly differed within 2 h of osmotic therapy when controlling for other commonly used interventions in our whole cohort (β = 0.08, p = 0.0168). The effect was most pronounced (β = 0.57) in patients with abnormal NPi prior to intervention (p = 0.0235).

CONCLUSIONS

Pupil reactivity significantly improves after osmotic therapy in a heterogenous critically ill population when controlling for various other interventions. Future work is necessary to determine dose-dependent effects and clinical utility.

Myocardial protection in the arterial switch operation: Custodiol versus cold blood cardioplegia

OBJECTIVES

The optimal myocardial protective solution in the neonatal arterial switch operation remains controversial. The aim of this study was to demonstrate that Bretschneider's histidine-tryptophan-ketoglutarate crystalloid solution (Custodiol) offers protection at least similar to that of cold blood cardioplegia.

METHODS

Patients who underwent the neonatal arterial switch operation with Custodiol between January 2016 and December 2018 (n = 23) were compared with an historical cohort from August 2010 to December 2015 in which cold blood cardioplegia was used (n = 41). A linear mixed-effect model for repeated measures was performed to test the recovery of myocardial function based on inotropic and vasoactive inotropic scores, cardiac enzyme release and left ventricular ejection fraction.

RESULTS

Patients in the cold blood cardioplegia group had higher inotropic scores in the first 24 h (0 h, P = 0.001 and 24 h, P = 0.006) and higher vasoactive inotropic scores in the first 72 h (0 h, 24 h and 48 h, P < 0.001; 72 h, P = 0.012). Cardiac troponin-I concentrations were higher in the cold blood cardioplegia group at postoperative hours 1-72 (1 h, 6 h, 12 h and 24 h, P < 0.001; 48 h, P = 0.001 and 72 h, P = 0.003). Creatinine-kinase-MB concentrations were higher in the cold blood cardioplegia group at postoperative hours 1-24 (1 h, 6 h and 12 h, P < 0.001; 24 h, P = 0.042). The left ventricular ejection fraction was higher in the Custodiol group just after the operation (P = 0.005), at 24 h (P = 0.001) and on the first day without inotropic support (P = 0.011).

CONCLUSIONS

Neonatal myocardium protected with Custodiol during the arterial switch operation presented optimal ventricular function recovery with less inotropic support and less myocardial damage compared with cold blood cardioplegia.

Metabolic responses of wheat seedlings to osmotic stress induced by various osmolytes under iso-osmotic conditions

Many environmental stresses cause osmotic stress which induces several metabolic changes in plants. These changes often vary depending on the genotype, type and intensity of stress or the environmental conditions. In the current experiments, metabolic responses of wheat to osmotic stress induced by different kinds of osmolytes were studied under iso-osmotic stress conditions. A single wheat genotypes was treated with PEG-6000, mannitol, sorbitol or NaCl at such concentrations which reduce the osmotic potential of the culture media to the same level (-0.8MPa). The metabolic changes, including the accumulation of proline, glycine betaine (GB) and sugar metabolites (glucose, fructose, galactose, maltose and sucrose) were studied both in the leaves and roots together with monitoring the plant growth, changes in the photosynthetic activity and chlorophyll content of the leaves. In addition, the polyamine metabolism was also investigated. Although all osmolytes inhibited growth similarly, they induced different physiological and metabolic responses: the CO2 assimilation capacity, RWC content and the osmotic potential (ψπ) of the leaves decreased intensively, especially after mannitol and sorbitol treatments, followed by NaCl treatment, while PEG caused only a slight modification in these parameters. In the roots, the most pronounced decrease of ψπ was found after salt-treatments, followed by PEG treatment. Osmotic stress induced the accumulation of proline, glycine betaine and soluble sugars, such as fructose, glucose, sucrose and galactose in both the root and leaf sap. Specific metabolic response of roots and leaves under PEG included accumulation of glucose, fructose and GB (in the roots); sucrose, galactose and proline synthesis were dominant under NaCl stress while exposure to mannitol and sorbitol triggered polyamine metabolism and overproduction of maltose. The amount of those metabolites was time-dependent in the manner that longer exposure to iso-osmotic stress conditions stimulated the sugar metabolic routes. Our results showed that the various osmolytes activated different metabolic processes even under iso-osmotic stress conditions and these changes also differed in the leaves and roots.