Heart Failure Etiologies and Challenges to Care in the Developing World: An Observational Study in the Democratic Republic of Congo.

BACKGROUND: Limited data are available regarding causes and outcomes of heart failure as well as organization of care in the developing world. METHODS AND RESULTS: We included consecutive patients diagnosed with heart failure from November 2014 to September 2016 in a university and private hospital of Lubumbashi, Democratic Republic Congo. Baseline data, including echocardiography, were analyzed to determine factors associated with mortality. Cost of hospitalization as well as challenges for care regarding follow-up were determined. A total of 231 patients (56 ± 17 years, 47% men, left ventricular ejection fraction 29 ± 15%, 20% atrial fibrillation) were diagnosed, more during heart failure hospitalizations (69%) than as outpatients (31%). Main risk factors for heart failure included hypertension (59%), chronic kidney disease (51%), alcohol abuse (38%), and obesity (32%). Dilated cardiomyopathy was the most prevalent etiology (48%), with ischemic cardiomyopathy being present in only 4%. In-hospital mortality rate was 19% and associated with an estimated glomerular filtration rate of <60 mL·min-1·1.73 m-2 (P < .01) and atrial fibrillation (P = .02). One hundred six patients (46%) were lost to follow-up, which was mainly related to lack of organization of care, poverty, and poor health literacy. Of the remaining 95 subjects, another 33 (35%) died within 1 year after presentation. The average cost of care for a 10-day hospitalization was higher in a private than in a university hospital (885 vs 409 USD). CONCLUSIONS: Patients admitted for heart failure in DRC have a high incidence of nonischemic cardiomyopathy and present late during their disease, with limited resources being available accounting for a high mortality rate and very high loss to follow-up.

Mesenchymal stem cells or cardiac progenitors for cardiac repair? A comparative study.

In the past, clinical trials transplanting bone marrow-derived mononuclear cells reported a limited improvement in cardiac function. Therefore, the search for stem cells leading to more successful stem cell therapies continues. Good candidates are the so-called cardiac stem cells (CSCs). To date, there is no clear evidence to show if these cells are intrinsic stem cells from the heart or mobilized cells from bone marrow. In this study we performed a comparative study between human mesenchymal stem cells (hMSCs), purified c-kit(+) CSCs, and cardiosphere-derived cells (CDCs). Our results showed that hMSCs can be discriminated from CSCs by their differentiation capacity towards adipocytes and osteocytes and the expression of CD140b. On the other hand, cardiac progenitors display a greater cardiomyogenic differentiation capacity. Despite a different isolation protocol, no distinction could be made between c-kit(+) CSCs and CDCs, indicating that they probably derive from the same precursor or even are the same cells.

Glycine enhances microglial intracellular calcium signaling. A role for sodium-coupled neutral amino acid transporters.

The inhibitory neurotransmitter glycine is known to enhance microglial nitric oxide production. However, up to now, the mechanism is undocumented. Since calcium is an important second messenger in both immune and glial cells, we studied the effects of glycine on intracellular calcium signaling. We found that millimolar concentrations of glycine enhance microglial intracellular calcium transients induced by 100 µM ATP or by 500 nM thapsigargin. This modulation was unaffected by the glycine receptor antagonist strychnine and could not be mimicked by glycine receptor agonists such as taurine or ß-alanine, indicating glycine receptor independency. The modulation of calcium responses could be mimicked by several structurally related amino acids (e.g., serine, alanine, or glutamine) and was inhibited in the presence of the neutral amino acid transporter substrate α-aminoisobutyric acid (AIB). We correlated these findings to immunofluorescence glycine uptake experiments which showed a clear glycine uptake which was inhibited by AIB. Furthermore, all amino acids that were shown to modulate calcium responses also evoked AIB-sensitive inward currents, mainly carried by sodium, as demonstrated by patch clamp experiments. Based on these findings, we propose that sodium-coupled neutral amino acid transporters are responsible for the observed glycine modulation of intracellular calcium responses.

Simvastatin interferes with process outgrowth and branching of oligodendrocytes.

Statins have attracted interest as a treatment option for multiple sclerosis (MS) because of their pleiotropic antiinflammatory and immunomodulatory effects. However, contradictory results have been described when they are applied to oligodendrocytes (OLGs), the cell type predominantly affected in MS. In this study we focus on the in vitro effect of statins on process outgrowth in OLN-93 cells, a well-characterized OLG-derived cell line, and primary cultures of neonatal rat OLGs. Application of the lipophilic simvastatin, as low as 0.1-1 µM, disturbs process formation of both cell types, leading to less ramified cells. We show that both protein isoprenylation and cholesterol synthesis are required for the normal differentiation of OLGs. It is further demonstrated that the expression of 2',3'-cyclic-nucleotide-3' phosphodiesterase (CNP) and tubulin is lowered, concomitant with a reduction of membrane-bound CNP as well as tubulin. Therefore, we propose that lack of isoprenylation of CNP could help to explain the altered morphological and biochemical differentiation state of treated OLGs. Moreover, expression of specific myelin markers, such as myelin basic protein, myelin-associated glycoprotein, and myelin oligodendrocyte glycoprotein, was compromised after treatment. We conclude that simvastatin treatment has detrimental effects on OLG process outgrowth, the prior step in (re)myelination, thereby mortgaging long-term healing of MS lesions.

Human bone marrow stem cells co-cultured with neonatal rat cardiomyocytes display limited cardiomyogenic plasticity.

BACKGROUND AIMS: This study investigated whether neonatal rat cardiomyocytes (NRCM), when co-cultured, can induce transdifferentiation of either human mesenchymal stromal cells (MSC) or hematopoietic stem cells (HSC) into cardiomyocytes. Stem cells were obtained from patients with ischemic heart disease. METHODS: Ex vivo-expanded MSC or freshly isolated HSC were used to set-up a co-culture system between NRCM and MSC or HSC. 5-azacytidin (5-aza) or dimethylsulfoxide (DMSO) was used as differentiation-inducing factor. Co-cultured stem cells were separated from NRCM by flow sorting, and cardiac gene expression was analyzed by reverse transcriptase-polymerase chain reaction. Cellular morphology was analyzed by immunofluorescence and transmission electron microscopy (TEM). RESULTS: Co-culturing MSC induced expression of troponin T and GATA-4. However, no expression of alpha-actinin, myosin heavy chain or troponin I was detected. In the case of HSC, only expression of troponin T could be induced. Immunofluorescence and TEM confirmed the absence of sarcomeric organization in co-cultured MSC and HSC. Adding 5-aza or DMSO to the co-cultures did not influence differentiation. CONCLUSIONS: This in vitro co-culture study obtained no convincing evidence of transdifferentiation of either MSC or HSC into functional cardiomyocytes. Nevertheless, induction of troponin T was observed in MSC and HSC, and GATA-4 in MSC. However, no morphologic changes could be detected by immunofluorescence or by TEM. These data could explain why only limited functional improvement was reported in clinical stem cell trials.

Recovery of regional but not global contractile function by the direct intramyocardial autologous bone marrow transplantation: results from a randomized controlled clinical trial.

BACKGROUND: Recent trials have shown that intracoronary infusion of bone marrow cells (BMCs) improves functional recovery after acute myocardial infarction. However, whether this treatment is effective in heart failure as a consequence of remodeling after organized infarcts remains unclear. In this randomized trial, we assessed the hypothesis that direct intramyocardial injection of autologous mononuclear bone marrow cells during coronary artery bypass graft (CABG) could improve global and regional left ventricular ejection fraction (LVEF) at 4-month follow-up. METHODS AND RESULTS: Twenty patients (age 64.8+/-8.7; 17 male, 3 female) with a postinfarction nonviable scar, as assessed by thallium (Tl) scintigraphy and cardiac magnetic resonance imaging (MRI), scheduled for elective CABG, were included. They were randomized to a control group (n =10, CABG only) or a BMC group (CABG and injection of 60.10(6)+/-31.10(6) BMC). Primary end points were global LVEF change and wall thickening changes in the infarct area from baseline to 4-month follow-up, as measured by MRI. Changes in metabolic activity were measured by Tl scintigraphy and expressed as a score with a range from 0 to 4, corresponding to percent of maximal myocardial Tl uptake (4 indicates <50%, nonviable scar; 3, 50% to 60%; 2, 60% to 70%; 1, 70% to 80%; 0>80%). Global LVEF at baseline was 39.5+/-5.5% in controls and 42.9+/-10.3% in the BMC group (P=0.38). At 4 months, LVEF had increased to 43.1+/-10.9% in the control group and to 48.9+/-9.5% in the BMC group (P=0.23). Systolic thickening had improved from -0.6+/-1.3 mm at baseline to 1.8+/-2.6 mm at 4 months in the cell-implanted scars, whereas nontreated scars remained largely akinetic (-0.5+/-2.0 mm at baseline compared with 0.4+/-1.7 mm at 4 months, P=0.007 control versus BMC-treated group at 4 months). Defect score decreased from 4 to 3.3+/-0.9 in the BMC group and to 3.7+/-0.4 in the control group (P=0.18). CONCLUSIONS: At 4 months, there was no significant difference in global LVEF between both groups, but a recovery of regional contractile function in previously nonviable scar was observed in the BMC group.

Investigation of the Ba2+-sensitive NH4+ transport pathways in the apical cell membrane of primary cultured rabbit MTAL cells.

BACKGROUND: Several apical ammonium (NH(4)(+)/NH(3)) transport pathways have been described in medullary thick ascending limb (MTAL) cells. The exact nature and importance of some of these pathways remain controversial. METHODS: Ammonium transport in primary cultured rabbit MTAL cells was investigated by measuring intracellular pH (pH(i)). RESULTS: To create physiological conditions, experiments were performed in the symmetrical presence of NH(4)Cl, which acidified the cells to pH(i) 6.89. When blockers of apical NH(4)(+) transport were used, the cells alkalinized due to a decreased NH(4)(+) loading. The following values (pH units) were observed: bumetanide, +0.05; verapamil, +0.04; Ba(2+) and Cs(+), +0.19; tertiapin, +0.09. Tetraethylammonium had no effect. Depolarizing the cells by increasing the K(+) concentration alkalinized the cells by 0.16 pH units. Because NH(4)(+) might enter through nonspecific channels, ammonium pulse experiments were performed: an NH(4)Cl pulse acidified controls as well as depolarized cells. In contrast, when Ba(2+), Cs(+) or tertiapin were present, an NH(4)Cl pulse alkalinized the cells. The pharmacological profile of this apical NH(4)(+) transport pathway correlates with the renal outer medullary K(+) (ROMK) channel. Indirect immunofluorescence showed the presence of the ROMK protein. CONCLUSION: In these MTAL cells the Ba(2+)-sensitive component of NH(4)(+) transport is predominant and consists of permeation of NH(4)(+) through an apical ROMK-related channel.

From Bone Marrow to Cardiac Atrial Appendage Stem Cells for Cardiac Repair: A Review.

Traditionally the heart is considered a terminally differentiated organ. However, at the beginning of this century increased mitotic activity was reported in ischemic and idiopathic dilated cardiomyopathy hearts, compared to healthy controls, underscoring the potential of regeneration after injury. Due to the presence of adult stem cells in bone marrow and their purported ability to differentiate into other cell lineages, this cell population was soon estimated to be the most suited candidate for cardiac regeneration. Clinical trials with autologous bone marrow-derived mononuclear cells, using either an intracoronary or direct intramyocardial injection approach consistently showed only minor improvement in global left ventricular ejection fraction. This was explained by their limited cardiomyogenic differentiation potential. To obtain more convincing improvement in cardiac function, based on true myocardial regeneration, the focus of research has shifted towards resident cardiac progenitor cells. Several isolation procedures have been described: the c-kit surface marker was the first to be used, however experimental research has clearly shown that c-kit+ cells only marginally contribute to regeneration post myocardial infarction. Sphere formation was used to isolate the so-called cardiosphere derived cells (CDC), and also in this cell population cardiomyogenic differentiation is a rare event. Recently a new type of stem cells derived from atrial tissue (cardiac atrial stem cells - CASCs) was identified, based on the presence of the enzyme aldehyde dehydrogenase (ALDH). Those cells significantly improve both regional and global LV ejection fraction, based on substantial engraftment and consistent differentiation into mature cardiomyocytes (98%).

Immune-mediated oligodendrocyte injury in multiple sclerosis: molecular mechanisms and therapeutic interventions.

In this review, new insights into the immunopathogenesis of multiple sclerosis (MS) are discussed, with special focus on the potential mechanisms leading to neuroinflammation in MS--that is, the role of autoreactive T cells, infections, and neurodegenerative events. Oligodendrocytes are considered to be the target of autoimmune inflammation in the CNS of MS patients. Some important features of oligodendrocyte biology are discussed, together with the molecular mechanisms that are potentially involved in oligodendrocyte injury. These include injury mechanisms that might be executed by the adaptive and innate immune system, via cytokines and/or oligodendrocyte receptors, or as a consequence of nitrative and oxidative stress, and excitotoxicity. The mode of cell death of oligodendrocytes in MS is discussed, in addition to the mechanisms of axonal injury as observed in pathology- and imaging-based studies. Finally, recent progress in therapeutic strategies that may interfere with these pathological processes are reviewed, with a focus on repair strategies, such as gene therapy, antibody-mediated remyelination, and stem cell therapy.

Diffusion of sphingomyelin and myelin oligodendrocyte glycoprotein in the membrane of OLN-93 oligodendroglial cells studied by fluorescence correlation spectroscopy.

Evidence has been accumulated that the plasma membrane of various mammalian cell types is heterogeneous in structure and may contain lipid microdomains (lipid rafts). This study focuses on the membrane organization of living oligodendrocytes, which are the myelin-producing cells of the central nervous system. Fluorescence correlation spectroscopy (FCS) was used to monitor the lateral diffusion of a lipid and of a protein in the oligodendroglial cell line OLN-93. The lipid was fluorescently labelled sphingomyelin (Bodipy FL-C5 SM). The protein was the myelin oligodendrocyte glycoprotein (MOG). In order to monitor the lateral diffusion of MOG, OLN-93 cells were transfected with a MOG-EGFP (enhanced green fluorescent protein) fusion plasmid. The measurements were performed at room temperature. FCS data were analyzed for two-dimensional (2D) diffusion according to three models which all included a triplet fraction: (a) 2D 1 component (2D1C), (b) 2D anomalous diffusion (2D1Calpha), and (c) 2D 2 components (2D2C). Preliminary results indicate that for the lipid case, the best fits are obtained with 2D2C. In the case of MOG-EGFP, 2D2C and 2D1Calpha give fits of similar quality. The parameter estimates obtained with 2D1Calpha, however, have a lower standard deviation. The anomaly parameter for MOG-EGFP is 0.59+/-0.01.

Hyponatremia in acute decompensated heart failure: depletion versus dilution.

Hyponatremia frequently poses a therapeutic challenge in acute decompensated heart failure (ADHF). Treating physicians should differentiate between depletional versus dilutional hyponatremia. The former is caused by diuretic agents, which enhance sodium excretion, often with concomitant potassium/magnesium losses. This can be treated with isotonic saline, whereas potassium/magnesium administration may be helpful if plasma concentrations are low. In contrast, as impaired water excretion, rather than sodium deficiency, is the culprit in dilutional hyponatremia, isotonic saline administration may further depress the serum sodium concentration. Because free water excretion is achieved by continuous sodium reabsorption in distal nephron segments with low water permeability, diuretic agents that impair this mechanism (e.g., thiazide-type diuretic agents and mineralocorticoid receptor antagonists) should be avoided, and proximally acting agents (e.g., acetazolamide and loop diuretic agents) are preferred. Vasopressin antagonists, which promote low water permeability in the collecting ducts and, hence, free water excretion, remain under investigation for dilutional hyponatremia in ADHF.

The pathophysiological role of interstitial sodium in heart failure.

The current understanding of heart failure (HF) does not fully explain the spectrum of HF symptoms. Most HF hospitalizations are related to sodium (Na(+)) and fluid retention resulting from neurohumoral up-regulation. Recent insights suggest that Na(+) is not distributed in the body solely as a free cation, but that it is also bound to large interstitial glycosaminoglycan (GAG) networks in different tissues, which have an important regulatory function. In HF, high Na(+) intake and neurohumoral alterations disrupt GAG structure, leading to loss of the interstitial buffer capacity and disproportionate interstitial fluid accumulation. Moreover, a diminished endothelial GAG network (the endothelial glycocalyx) results in increased vascular resistance and disturbed endothelial nitric oxide production. New imaging modalities can help evaluate interstitial Na(+) and endothelial glycocalyx integrity. Furthermore, several therapies have been proven to stabilize interstitial GAG networks. Hence, a better appreciation of this new Na(+) "compartment" might improve current management of HF.

Interferon-gamma-induced calcium influx in T lymphocytes of multiple sclerosis and rheumatoid arthritis patients: a complementary mechanism for T cell activation?

Autoreactive T lymphocytes are considered to play a crucial role in orchestrating a chronic inflammation in the central nervous system (CNS) of multiple sclerosis (MS) patients and in the joints of rheumatoid arthritis (RA) patients. However, it has been suggested that the majority of T cells in the immune infiltrate are nonspecifically recruited into the CNS and into the inflamed joint. In addition, several lines of evidence suggest an important role for interferon-gamma (IFN-gamma) in the pathogenesis of MS and RA. We have studied whether peripheral blood T cells from patients with autoimmune diseases are more susceptible to activation in the presence of IFN-gamma. The results indicate that IFN-gamma mediates a sustained elevated [Ca(2+)](i) in T cells of (active) MS and RA patients as compared to healthy controls and patients with common viral infections. No [Ca(2+)](i) increase was observed in Ca(2+)-free medium, excluding an effect of IFN-gamma on Ca(2+)-release from intracellular stores. Although the IFN-gamma-activated Ca(2+)-influx is insufficient to induce T cell proliferation in vitro, our data indicate a significantly augmented proliferation in response to suboptimal doses of PHA in the presence of IFN-gamma. This study suggests that the IFN-gamma-induced Ca(2+)-influx can act as a complementary mechanism in the activation of blood T lymphocytes from MS and RA patients.

Bartter's and Gitelman's syndromes: from gene to clinic.

Bartter's and Gitelman's syndromes are characterized by hypokalemia, normal to low blood pressure and hypochloremic metabolic alkalosis. Recently, investigators have been able to demonstrate mutations of six genes encoding several renal tubular transporters and ion channels that can be held responsible for Bartter's and Gitelman's syndromes. Neonatal Bartter's syndrome is caused by mutations of NKCC2 or ROMK, classic Bartter's syndrome by mutations of ClC-Kb, Bartter's syndrome associated with sensorineural deafness is due to mutations of BSND, Gitelman's syndrome to mutations of NCCT and Bartter's syndrome associated with autosomal dominant hypocalcemia is linked to mutations of CASR. We review the pathophysiology of these syndromes in relation to their clinical presentation.

The kidney in congestive heart failure: 'are natriuresis, sodium, and diuretics really the good, the bad and the ugly?'.

This review discusses renal sodium handling in heart failure. Increased sodium avidity and tendency to extracellular volume overload, i.e. congestion, are hallmark features of the heart failure syndrome. Particularly in the case of concomitant renal dysfunction, the kidneys often fail to elicit potent natriuresis. Yet, assessment of renal function is generally performed by measuring serum creatinine, which has inherent limitations as a biomarker for the glomerular filtration rate (GFR). Moreover, glomerular filtration only represents part of the nephron's function. Alterations in the fractional reabsorptive rate of sodium are at least equally important in emerging therapy-refractory congestion. Indeed, renal blood flow decreases before the GFR is affected in congestive heart failure. The resulting increased filtration fraction changes Starling forces in peritubular capillaries, which drive sodium reabsorption in the proximal tubules. Congestion further stimulates this process by augmenting renal lymph flow. Consequently, fractional sodium reabsorption in the proximal tubules is significantly increased, limiting sodium delivery to the distal nephron. Orthosympathetic activation probably plays a pivotal role in those deranged intrarenal haemodynamics, which ultimately enhance diuretic resistance, stimulate neurohumoral activation with aldosterone breakthrough, and compromise the counter-regulatory function of natriuretic peptides. Recent evidence even suggests that intrinsic renal derangements might impair natriuresis early on, before clinical congestion or neurohumoral activation are evident. This represents a paradigm shift in heart failure pathophysiology, as it suggests that renal dysfunction-although not by conventional GFR measurements-is driving disease progression. In this respect, a better understanding of renal sodium handling in congestive heart failure is crucial to achieve more tailored decongestive therapy, while preserving renal function.

Abdominal contributions to cardiorenal dysfunction in congestive heart failure.

Current pathophysiological models of congestive heart failure unsatisfactorily explain the detrimental link between congestion and cardiorenal function. Abdominal congestion (i.e., splanchnic venous and interstitial congestion) manifests in a substantial number of patients with advanced congestive heart failure, yet is poorly defined. Compromised capacitance function of the splanchnic vasculature and deficient abdominal lymph flow resulting in interstitial edema might both be implied in the occurrence of increased cardiac filling pressures and renal dysfunction. Indeed, increased intra-abdominal pressure, as an extreme marker of abdominal congestion, is correlated with renal dysfunction in advanced congestive heart failure. Intriguing findings provide preliminary evidence that alterations in the liver and spleen contribute to systemic congestion in heart failure. Finally, gut-derived hormones might influence sodium homeostasis, whereas entrance of bowel toxins into the circulatory system, as a result of impaired intestinal barrier function secondary to congestion, might further depress cardiac as well as renal function. Those toxins are mainly produced by micro-organisms in the gut lumen, with presumably important alterations in advanced heart failure, especially when renal function is depressed. Therefore, in this state-of-the-art review, we explore the crosstalk between the abdomen, heart, and kidneys in congestive heart failure. This might offer new diagnostic opportunities as well as treatment strategies to achieve decongestion in heart failure, especially when abdominal congestion is present. Among those currently under investigation are paracentesis, ultrafiltration, peritoneal dialysis, oral sodium binders, vasodilator therapy, renal sympathetic denervation and agents targeting the gut microbiota.

The cardiac atrial appendage stem cell: a new and promising candidate for myocardial repair.

AIMS: Considerable shortcomings in the treatment of myocardial infarction (MI) still exist and therefore mortality remains high. Cardiac stem cell (CSC) therapy is a promising approach for myocardial repair. However, identification and isolation of candidate CSCs is mainly based on the presence or absence of certain cell surface markers, which suffers from some drawbacks. In order to find a more specific and reliable identification and isolation method, we investigated whether CSCs can be isolated based on the high expression of aldehyde dehydrogenase (ALDH). METHODS AND RESULTS: An ALDH(+) stem cell population, the cardiac atrial appendage stem cells (CASCs), was isolated from human atrial appendages. CASCs possess a unique phenotype that is clearly different from c-kit(+) CSCs but that seems more related to the recently described cardiac colony-forming-unit fibroblasts. Based on immunophenotype and in vitro differentiation studies, we suggest that CASCs are an intrinsic stem cell population and are not mobilized from bone marrow or peripheral blood. Indeed, they possess a clonogenicity of 16% and express pluripotency-associated genes. Furthermore, compared with cardiosphere-derived cells, CASCs possess an enhanced cardiac differentiation capacity. Indeed, differentiated cells express the most important cardiac-specific genes, produce troponin T proteins, and have an electrophysiological behaviour similar to that of adult cardiomyocytes (CMs). Transplanting CASCs in the minipig MI model resulted in extensive cardiomyogenic differentiation without teratoma formation. CONCLUSION: We have identified a new human CSC population able to differentiate into functional CMs. This opens interesting perspectives for cell therapy in patients with ischaemic heart disease.

Mannitol Reduces the Hydrostatic Pressure in the Proximal Tubule of the Isolated Blood-Perfused Rabbit Kidney during Hypoxic Stress and Improves Its Function.

BACKGROUND/AIMS: Hypoxia may play a role in the development of renal failure in donated kidneys. In the present study, the effects of hypoxia on isolated blood-perfused rabbit kidneys were investigated and the effects of mannitol were explored, giving special attention to intratubular pressure. METHODS: Kidneys were perfused with their autologous blood during four 30-min periods (P1-P4). P1 was considered baseline function. In P2, hypoxia was induced either alone or with an infusion of mannitol (15 mg/min) during P2-P4. Reoxygenation was applied after P2. Proximal intratubular pressure was measured in all conditions. RESULTS: During hypoxia, renal blood flow doubled and restored immediately in P3. Urine flow stopped in P2, except in the series with mannitol, but gradually resumed in P3 and P4. Likewise, creatinine clearance recovered slightly (<25%) in P4, except for the series with mannitol, where it still could be measured in P2 and reached a value >50% of P1. Proximal intratubular pressure (mean ± SD) increased from 12 ± 5 in P1 to 24 ± 11 mm Hg during hypoxia and returned to 10 ± 6 mm Hg in P3. This increase was not observed with mannitol. CONCLUSION: Cellular swelling might be responsible for the suppressed filtration during hypoxia and can be prevented by mannitol.

Analysis of mitochondrial pH and ion concentrations.

Detailed practical information is provided with emphasis on mapping cytosolic and mitochondrial pH, mitochondrial Na(+), and briefly also aspects related to mitochondrial Ca(2+) measurements in living cells, as grown on (un)coated glass coverslips. This chapter lists (laser scanning confocal) microscope instrumentation and setup requirements for proper imaging conditions, cell holders, and an easy-to-use incubator stage. For the daily routine of preparing buffer and calibration solutions, extensive annotated protocols are provided. In addition, detailed measurement and image analysis protocols are given to routinely obtain optimum results with confidence, while avoiding a number of typical pitfalls.

Glycine and glycine receptor signalling in non-neuronal cells.

Glycine is an inhibitory neurotransmitter acting mainly in the caudal part of the central nervous system. Besides this neurotransmitter function, glycine has cytoprotective and modulatory effects in different non-neuronal cell types. Modulatory effects were mainly described in immune cells, endothelial cells and macroglial cells, where glycine modulates proliferation, differentiation, migration and cytokine production. Activation of glycine receptors (GlyRs) causes membrane potential changes that in turn modulate calcium flux and downstream effects in these cells. Cytoprotective effects were mainly described in renal cells, hepatocytes and endothelial cells, where glycine protects cells from ischemic cell death. In these cell types, glycine has been suggested to stabilize porous defects that develop in the plasma membranes of ischemic cells, leading to leakage of macromolecules and subsequent cell death. Although there is some evidence linking these effects to the activation of GlyRs, they seem to operate in an entirely different mode from classical neuronal subtypes.