Effects of isoflurane postconditioning on chronic phase of ischemia–reperfusion heart injury in rats

Spatio-Temporal Expression Pattern of Ki-67, pRB, MMP-9 and Bax in Human Secondary Palate Development

We analyzed the immunohistochemical expression of Ki-67, pRb, Bax, and MMP-9 during the human secondary palate formation (7th to 12th developmental weeks (DWs). The most significant proliferation was observed in the seventh DW with 32% of Ki-67-positive cells in the epithelium, while loose ectomesenchyme condensations (lec) and loose non-condensing ectomesenchyme (lnc) had only 18 and 11%, respectively (Kruskal–Wallis, p < 0.001), and diminished afterwards. Contrarily, pRb-positive cells were mostly located in the lnc (67%), with significant difference in comparison to epithelium and lec in all investigated periods (Kruskal–Wallis, p < 0.001). Ki-67- and pRb-positive cells co-expressed occasionally in all investigated periods. MMP-9 displayed a strong expression pattern with the highest number of positive cells during the seventh DW in the epithelium, with significant difference in comparison to lec and lnc (Kruskal–Wallis, p < 0.0001). The ninth DW is particularly important for the Bax expression, especially in the epithelium (84%), in comparison to lec (58%) and lnc (47%) (Kruskal–Wallis, p < 0.001). The co-expression of Bax and MMP-9 was seen only in the epithelium during seventh and ninth DWs. Our study indicates the parallel persistence of proliferation (Ki-67, pRb) and remodeling (MMP-9) that enables growth and apoptotic activity (Bax) that enable the removal of the epithelial cells at the fusion point during secondary palate formation.

GREB1L, CRELD2 and ITGA10 expression in the human developmental and postnatal kidneys: an immunohistochemical study

BACKGROUND

Aim of our study is to provide an insight into the genetic expression landscape of GREB1L, ITGA10 and CRELD2 which are important in human genitourinary tract development which might help elucidate the critical stages for the onset of kidney anomalies.

METHODS

Morphological parameters were analyzed using immunohistochemistry on human foetal (13-38 w) and postnatal (1.5 and 7.5y) human kidney samples.

RESULTS

GREB1L marker had a strong intensity and the highest rate in proximal tubules (PTC) of 1.5 years' kidney (90.25%). In the distal tubules (DCT) there were statistically significant differences in 13 w, 15 w, 16 w, 21 w, 38 w and 7.5y regarding 1.5y (Kruskal-Wallis test, p < 0.001). There was significantly more GREB1L in the glomeruli at 21 w and 38 w in regard to all other stages (Kruskal-Wallis test, p < 0.01). ITGA10 staining intensity was strongest in PCT with the highest rate in 13 w (92.75%), while the lowest rate was found in glomeruli and DCT (Kruskal-Wallis test, p < 0.001). CRELD2 had the strongest staining intensity in PCT with the highest rate in 13 w and 1.5y (92.25%) and lowest in the glomeruli of 7.5 years (24.3 %). In DCT there were statistically significant differences in CRELD2 positive cells in 13 w, 15 w, 16 w, 21 w, 38 w and 7.5y regarding 1.5y (Kruskal-Wallis test, p < 0.01). ITGA10 and CRELD2 co-localised in the postnatal period in DCT.

CONCLUSION

High kidney expressions of GREB1L, ITGA10 and CRELD2 even in the postnatal period implicate their importance not only for the onset of CAKUT in the case of their mutation but also for maintenance of kidney homeostasis.

St. Thomas and del Nido cardioplegia are superior to Custodiol cardioplegia in a rat model of donor heart

OBJECTIVES

Cardiac transplantation is an effective treatment for advanced heart disease and protection of the donor organ is directly associated with post-transplantation outcomes. Cardioplegic strategies intend to protect the donor heart against ischemic injury during transplantation procedures. In our study, the effects of three different cardioplegia solutions were evaluated in a rat heart donor model in terms of cellular base. Design. Cardioplegia solutions as St. Thomas, del Nido or Custodiol were administered to male Wistar albino rats until cardiac arrest. Arrested hearts were excised and incubated in cold cardioplegia solutions for 4 h. Organ bath experiments were performed using the right ventricular free wall strips of the heart tissues. ATP, sialic acid, TNF-α levels and MMP-9 activities were measured in heart tissues. Incubation media were also used to measure TNF-α and troponin-I levels following organ baths experiments. Results. Custodiol administration led to reduced myocardial contraction (p < .05), decreased ATP levels (p < .001) and increased both TNF-α levels (p < .05), and MMP-9 activity (p < .05). Additionally, troponin-I and TNF-α levels in media were significantly increased (p < .05), TNF-α levels were positively correlated with MMP-9 activities (r = .93, p = .007) and negatively correlated with ATP levels (r = -.91, p = .01) in the Custodiol group. Also, MMP-9 activities were negatively correlated with ATP levels (r = -.90, p = .01) Conclusion. Custodiol cardioplegia cannot prevent functional and cellular damage in donor heart tissue. St. Thomas or del Nido cardioplegia could result in superior functional and biochemical improvement during transplantation procedures. In this respect, these cardioplegic solutions may be more advantageous as cellular and functional.

NF-κB and tPA Signaling in Kidney and Other Diseases

The activation of the nuclear factor-κB (NF-κB) pathway plays a central role in the initiation and progression of inflammation, which contributes to the pathogenesis and progression of various human diseases including kidney, brain, and other diseases. Tissue plasminogen activator (tPA), a serine protease regulating homeostasis of blood coagulation, fibrinolysis, and matrix degradation, has been shown to act as a cytokine to trigger profound receptor-mediated intracellular events, modulate the NF-κB pathway, and mediate organ dysfunction and injury. In this review, we focus on the current understanding of NF-κB and tPA signaling in the development and progression of kidney disease. Their roles in the nervous and cardiovascular system are also briefly discussed.

Different Effects of Volatile and Nonvolatile Anesthetic Agents on Long-Term Survival in an Experimental Model of Hemorrhagic Shock

BACKGROUND

We investigated whether the cardioprotective, volatile gas anesthetic agent, isoflurane, could improve survival and organ function from hemorrhagic shock in an experimental rat model, compared to standard nonvolatile anesthetic agent ketamine/xylazine.

METHODS

Sprague Dawley rats (both genders) were randomized to receive either intraperitoneal ketamine/xylazine (K/X, 90 and 10 mg/kg; n = 12) or isoflurane (5% isoflurane induction and 2% maintenance in room air; n = 12) for anesthesia. Blood was withdrawn to maintain mean arterial blood pressure at 30 mm Hg for 1 hour, followed by 30 minutes of resuscitation with shed blood. Rats were allowed to recover and survive for 6 weeks.

RESULTS

During the shock phase, the total withdrawn blood volume (expressed as % of estimated total blood volume) to maintain a level of hypotension of 30 mm Hg was significantly higher in the isoflurane group (51.0% ± 1.5%) than in the K/X group (45.3% ± 1.8%; P = .023). Recovery of blood pressure during the resuscitation phase was significantly improved in the isoflurane group compared to the K/X group. The survival rate at 6 weeks was 1 (8.3%) of 12 in rats receiving K/X and 10 (83.3%) of 12 in rats receiving isoflurane (P < .001). Histology performed at 6 weeks demonstrated brain infarction in the 1 surviving rat receiving K/X; no brain infarction occurred in the 10 surviving rats that received isoflurane. No infarction was detected in heart, lung, liver, or kidneys among the surviving rats.

CONCLUSIONS

Isoflurane improved blood pressure response to resuscitation and resulted in significantly higher long-term survival rate.

Isoflurane Preconditioning Protects the Myocardium Against Ischemia and Reperfusion Injury by Upregulating GRM1 Expression

BACKGROUND

Reduction in myocardial I/R injury has become the key to the therapy of ischemic cardiovascular disease. Isoflurane (ISO) preconditioning can mimic the major potent protective mechanisms and attenuate ischemia injury. Nevertheless, the mechanisms involved in the cardioprotective effects afforded by isoflurane preconditioning have never been evaluated systematically.

METHODS

Mice were randomly divided into an ISO preconditioning group and control group. The size of the infarcted region was measured, and comparisons between ISO preconditioning and control animals were made. The metabotropic glutamate receptor type 1(GRM1) expression levels in all groups were determined by quantitative PCR. GRM1 protein expression and DNA damage relative protein γ-H2AX were measured by western blot analysis. The oxidative stress was detected by immunofluorescence after staining with the Dihydroethidium (DHE).

RESULTS

ISO preconditioning significantly reduced the IR induced infarct volumes and reversed the GRM1 protein expression level in I/R induced myocardial injury. Moreover, ISO preconditioning has a protective effect in reducing the I/R induced DNA damage and oxidative stress.

CONCLUSION

The results of the present study have demonstrated that the expression of GRM1 provides a protective role in ISO preconditioning against I/R-induced myocardial infarction by reducing the oxidative stress and DNA damage.

Immunohistochemical expression pattern of RIP5, FGFR1, FGFR2 and HIP2 in the normal human kidney development

AIM

Present study analyses the co-localisation of RIP5 with FGFR1, FGFR2 and HIP2 in the developing kidney, as RIP5 is a major determinant of urinary tract development, downstream of FGF-signaling.

METHODS

Paraffin embedded human kidney tissues of 16 conceptuses between the 6th-22th developmental week were analysed using double-immunofluorescence method with RIP5/FGFR1/FGFR2 and HIP2 markers. Quantification of positive cells were performed using Kruskal-Wallis test.

RESULTS

In the 6th week of kidney development RIP5 (89.6%) and HIP2 (39.6%) are strongly expressed in the metanephric mesenchyme. FGFR1 shows moderate/strong expression in the developing nephrons (87.3%) and collecting ducts (70.5%) (p < 0.05). RIP5/FGFR1 co-localized at the marginal zone and the ureteric bud with predominant FGFR1 expression. FGFR2 (26.1%) shows similar expression pattern as FGFR1 (70.5%) in the same kidney structures. RIP5/FGFR2 co-localized at the marginal zone and the collecting ducts (predominant expression of FGFR2). HIP2 is strongly expressed in collecting ducts (96.7%), and co-localized with RIP5. In 10th week, RIP5 expression decrease (74.2%), while the pattern of expression of RIP5 and FGFR1 in collecting ducts (33.4% and 91.9%) and developing nephrons (21.9% and 32.4%) (p < 0.05) is similar to that in the 6th developmental week. Ureter is moderately expressing RIP5 while FGFR1 is strongly expressed in the ureteric wall. FGFR2 is strongly expressed in the collecting ducts (84.3%) and ureter. HIP2 have 81.1% positive cells in the collecting duct. RIP5/FGFR1 co-localize in collecting ducts and Henley's loop.

CONCLUSIONS

The expression pattern of RIP5, FGFR1, FGFR2 and HIP2 in the human kidney development might indicate their important roles in metanephric development and ureteric muscle layer differentiation through FGF signaling pathways.

CD40-mediated HIF-1α expression underlying microangiopathy in diabetic nerve pathology

To understand the pathology and molecular signatures of microangiopathy in diabetic neuropathy, we systemically and quantitatively examined the morphometry of microvascular and nerve pathologies of sural nerves. In the endoneurium of diabetic nerves, prominent microangiopathy was observed, as evidenced by reduced capillary luminal area, increased capillary basement membrane thickness and increased proportion of fibrin(+) blood vessels. Furthermore, capillary basement membrane thickness and the proportion of fibrin(+) blood vessels were correlated with small myelinated fiber density in diabetic nerves. In diabetic nerves, there was also significant macrophage and T cell infiltration, and cluster of differentiation 40 (CD40) expression was increased. The molecular alterations observed were upregulation of hypoxia-inducible factor-1α (HIF-1α), mitogen-activated protein kinase-activated protein kinase 2 (MK2; MAPKAPK2) and phosphatase and tensin homolog (PTEN). In addition, HIF-1α was correlated with small myelinated fiber density and capillary luminal area, while both MK2 and PTEN were correlated with capillary basement membrane thickness. The molecular cascades were further demonstrated and replicated in a cell model of microangiopathy on human umbilical vein endothelial cells (HUVECs) exposed to high-glucose medium by silencing of CD40, PTEN and HIF-1α in HUVECs using shRNA. These data clarified the hierarchy of the molecular cascades, i.e. upregulation of CD40 leading to HIF-1α expression in endothelium and nerve fibers. In conclusion, this study revealed the association of microangiopathy, thrombosis and inflammatory infiltrates with nerve degeneration in diabetic nerves, demonstrating that CD40 is a key molecule for the upregulation of HIF-1α and PTEN underlying the severity of microangiopathy.

The Biological Role of Nestin(+)-Cells in Physiological and Pathological Cardiovascular Remodeling

The intermediate filament protein nestin was identified in diverse populations of cells implicated in cardiovascular remodeling. Cardiac resident neural progenitor/stem cells constitutively express nestin and following an ischemic insult migrate to the infarct region and participate in angiogenesis and neurogenesis. A modest number of normal adult ventricular fibroblasts express nestin and the intermediate filament protein is upregulated during the progression of reparative and reactive fibrosis. Nestin depletion attenuates cell cycle re-entry suggesting that increased expression of the intermediate filament protein in ventricular fibroblasts may represent an activated phenotype accelerating the biological impact during fibrosis. Nestin immunoreactivity is absent in normal adult rodent ventricular cardiomyocytes. Following ischemic damage, the intermediate filament protein is induced in a modest population of pre-existing adult ventricular cardiomyocytes bordering the peri-infarct/infarct region and nestin⁽⁺⁾-ventricular cardiomyocytes were identified in the infarcted human heart. The appearance of nestin⁽⁺⁾-ventricular cardiomyocytes post-myocardial infarction (MI) recapitulates an embryonic phenotype and depletion of the intermediate filament protein inhibits cell cycle re-entry. Recruitment of the serine/threonine kinase p38 MAPK secondary to an overt inflammatory response after an ischemic insult may represent a seminal event limiting the appearance of nestin⁽⁺⁾-ventricular cardiomyocytes and concomitantly suppressing cell cycle re-entry. Endothelial and vascular smooth muscle cells (VSMCs) express nestin and upregulation of the intermediate filament protein may directly contribute to vascular remodeling. This review will highlight the biological role of nestin⁽⁺⁾-cells during physiological and pathological remodeling of the heart and vasculature and discuss the phenotypic advantage attributed to the intermediate filament protein.

Isoflurane prevents acquired epilepsy in rat models of temporal lobe epilepsy

OBJECTIVE

Acquired epilepsy is a devastating long-term risk of various brain insults, including trauma, stroke, infections, and status epilepticus (SE). There is no preventive treatment for patients at risk. Attributable to the complex alterations involved in epileptogenesis, it is likely that multitargeted approaches are required for epilepsy prevention. We report novel preclinical findings with isoflurane, which exerts various nonanesthetic effects that may be relevant for antiepileptogenesis.

METHODS

The effects of isoflurane were investigated in two rat models of SE-induced epilepsy: intrahippocampal kainate and systemic administration of paraoxon. Isoflurane was either administered during (kainate) or after (paraoxon) induction of SE. Magnetic resonance imaging was used to assess blood-brain barrier (BBB) dysfunction. Positron emission tomography was used to visualize neuroinflammation. Long-term electrocorticographic recordings were used to monitor spontaneous recurrent seizures. Neuronal damage was assessed histologically.

RESULTS

In the absence of isoflurane, spontaneous recurrent seizures were common in the majority of rats in both models. When isoflurane was administered during kainate injection, duration and severity of SE were not affected, but only few rats developed spontaneous recurrent seizures. A similar antiepileptogenic effect was found when paraoxon-treated rats were exposed to isoflurane after SE. Moreover, in the latter model, isoflurane prevented BBB dysfunction and neurodegeneration, whereas isoflurane reduced neuroinflammation in the kainate model.

INTERPRETATION

Given that isoflurane is a widely used volatile anesthetic, and is used for inhalational long-term sedation in critically ill patients at risk to develop epilepsy, our findings hold a promising potential to be successfully translated into the clinic. Ann Neurol 2016;80:896-908.

Diabetes mellitus influences the expression of NPY and VEGF in neurons of rat trigeminal ganglion

BACKGROUND

Diabetes mellitus (DM) influences the trigeminal nerve function by changing the pain response and transduction of the orofacial sensory pathways. It affects the inflammatory response via neuropeptide Y (NPY) and vascular endothelial growth factor (VEGF), which could potentially have a relevant role in the pathophysiology of diabetic neuropathy. The aim was to investigate expression of VEGF and NPY in subpopulations of trigeminal ganglion (TG) neurons in rat models of early DM1 and DM2.

METHODS

DM1 model was induced by an intraperitoneal (i.p.) injection of streptozotocin (STZ) (55mg/kg). DM2 rats were fed with a high fat diet (HFD) for two weeks and then received 35mg/kg of STZ i.p. Two weeks and 2months after the STZ-diabetes induction, rats were sacrificed and TG was immunohistochemically analyzed for detection of VEGF and NPY expression, and also double immunofluorescence labeling with isolectin (IB4) was completed.

RESULTS

An increased percentage of NPY+ neurons was observed 2weeks after DM1 and 2months post DM2 induction. NPY immunoreactivity was restricted to IB4-negative small-diameter and IB4+ neurons. Two weeks post induction, DM1 rats showed an increased percentage of VEGF/IB4- large neurons and DM2 rats showed an increased percentage of VEGF/IB4+ neurons. Two months after DM induction, the DM1 group showed a reduced percentage of VEGF/IB4- small neurons.

CONCLUSION

The observed changes may play a critical role in the modulation of nociceptor activity and plasticity of primary sensory trigeminal neurons. The results contribute to the understanding of the basic pathophysiology of trigeminal diabetic neuropathy.

Isoflurane preconditioning inhibits the effects of tissue-type plasminogen activator on brain endothelial cell in an in vitro model of ischemic stroke

Tissue-type plasminogen activator (tPA) is the only treatment for ischemic stroke. However, tPA could induce the intracranial hemorrhage (ICH), which is the main cause of death in ischemic stroke patient after tPA treatment. At present, there is no treatment strategy to ameliorate tPA-induced brain injury after ischemia. Therefore, we investigated the effect of pre-treated isoflurane, which is a volatile anesthetic and has beneficial effects on neurological dysfunction, brain edema and infarct volume in ischemic stroke model. In this study, we used oxygen/glucose deprivation and reperfusion (OGD/R) condition to mimic an ischemic stroke in vitro. Matrix metalloproteinases (MMP) activity was measured in endothelial cell media. Also, neuronal cell culture was performed to investigate the effect of pretreated isoflurane on the neuronal cell survival after tPA-induced injury during OGD/R. Isoflurane pretreatment prevented tPA-induced MMP-2 and MMP-9 activity and suppressed tPA-triggered LRP/NF-κB/Cox-2 signaling after OGD/R. Neuronal cells, incubated with endothelial cell conditioned medium (EC-CM) after tPA + OGD/R, showed upregulation of pro-apoptotic molecules. However, neurons incubated with isoflurane-pretreated EC-CM showed increased anti-apoptotic molecules. Our findings suggest that isoflurane pretreatment could attenuate tPA-exaggerated brain ischemic injury, by reducing tPA-induced LRP/NF-κB/Cox-2 in endothelial cells, endothelial MMP-2 and MMP-9 activation, and subsequent pro-apoptotic molecule in neurons after OGD/R.

Sevoflurane mitigates shedding of hyaluronan from the coronary endothelium, also during ischemia/reperfusion: an ex vivo animal study

Glycosaminoglycan hyaluronan (HA), a major constituent of the endothelial glycocalyx, helps to maintain vascular integrity. Preconditioning the heart with volatile anesthetic agents protects against ischemia/reperfusion injury. We investigated a possible protective effect of sevoflurane on the glycocalyx, especially on HA. The effect of pre-ischemic treatment with sevoflurane (15 minutes at 2% vol/vol gas) on shedding of HA was evaluated in 28 isolated, beating guinea pig hearts, subjected to warm ischemia (20 minutes at 37°C) followed by reperfusion (40 minutes), half with and half without preconditioning by sevoflurane. HA concentration was measured in the coronary effluent. Over the last 20 minutes of reperfusion hydroxyethyl starch (1 g%) was continuously infused and the epicardial transudate collected over the last 5 minutes for measuring the colloid extravasation. Additional hearts were fixed by perfusion after the end of reperfusion for immunohistology and electron microscopy. Sevoflurane did not significantly affect post-ischemic oxidative stress, but strongly inhibited shedding of HA during the whole period, surprisingly even prior to ischemia. Immunohistology demonstrated that heparan sulfates and SDC1 of the glycocalyx were also preserved by sevoflurane. Electron microscopy revealed shedding of glycocalyx caused by ischemia and a mostly intact glycocalyx in hearts exposed to sevoflurane. Coronary vascular permeability of the colloid hydroxyethyl starch was significantly decreased by sevoflurane vs the control. We conclude that application of sevoflurane preserves the coronary endothelial glycocalyx, especially HA, sustaining the vascular barrier against ischemic damage. This may explain beneficial effects associated with clinical use of volatile anesthetics against ischemia/reperfusion injury.

Cardioprotection from emulsified isoflurane postconditioning is lost in rats with streptozotocin-induced diabetes due to the impairment of Brg1/Nrf2/STAT3 signalling

IsoPostC confers cardioprotection against myocardial IRI in non-diabetic rats but loses its effectiveness in diabetes, which may be mainly due to the impairment/reduction of Brg1/Nrf2/STAT3.