Medium-chain acyl-CoA dehydrogenase deficiency in gene-targeted mice

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common inherited disorder of mitochondrial fatty acid β-oxidation in humans. To better understand the pathogenesis of this disease, we developed a mouse model for MCAD deficiency (MCAD-/-) by gene targeting in embryonic stem (ES) cells. The MCAD-/- mice developed an organic aciduria and fatty liver, and showed profound cold intolerance at 4 °C with prior fasting. The sporadic cardiac lesions seen in MCAD-/- mice have not been reported in human MCAD patients. There was significant neonatal mortality of MCAD -/- pups demonstrating similarities to patterns of clinical episodes and mortality in MCAD-deficient patients. The MCAD-deficient mouse reproduced important aspects of human MCAD deficiency and is a valuable model for further analysis of the roles of fatty acid oxidation and pathogenesis of human diseases involving fatty acid oxidation. © 2005 Tolwani et al

Magnesium lactate in the treatment of Gitelman syndrome: patient-reported outcomes.

BACKGROUND: Gitelman syndrome (GS) is a rare recessively inherited renal tubulopathy associated with renal potassium (K) and magnesium (Mg) loss. It requires lifelong K and Mg supplementation at high doses that are at best unpalatable and at worst, intolerable. In particular, gastrointestinal side effects often limit full therapeutic usage. METHODS: We report here the analysis of a cohort of 28 adult patients with genetically proven GS who attend our specialist tubular disorders clinic, in whom we initiated the use of a modified-release Mg preparation (slow-release Mg lactate) and who were surveyed by questionnaire. RESULTS: Twenty-five patients (89%) preferred the new treatment regimen. Of these 25, 17 (68%) regarded their symptom burden as improved and seven reported no worsening. Of the 25 who were not Mg-treatment naïve, 13 (59%) patients reported fewer side effects, 7 (32%) described them as the same and only 2 (9%) considered side effects to be worse. Five were able to increase their dose without ill-effect. Overall, biochemistry improved in 91% of the 23 patients switched from therapy with other preparations who chose to continue the modified-release Mg preparation. Eleven (48%) improved both their Mg and K mean levels, 3 (13%) improved Mg levels only and in 7 cases (30%), K levels alone rose. CONCLUSIONS: Patient-reported and biochemical outcomes using modified-release Mg supplements were very favourable, and patient choice should play a large part in choosing Mg supplements with GS patients.This work was supported by the Wellcome Trust and the NIHR Cambridge Biomedical Research Centre, and contains data that were presented in abstract form at ASN Kidney week 2014.This is the final version of the article. It first appeared from Oxford University Press via https://doi.org/10.1093/ndt/gfw01

Nomenclature for renal replacement therapy and blood purification techniques in critically ill patients: practical applications

This article reports the conclusions of the second part of a consensus expert conference on the nomenclature of renal replacement therapy (RRT) techniques currently utilized to manage acute kidney injury and other organ dysfunction syndromes in critically ill patients. A multidisciplinary approach was taken to achieve harmonization of definitions, components, techniques, and operations of the extracorporeal therapies. The article describes the RRT techniques in detail with the relevant technology, procedures, and phases of treatment and key aspects of volume management/fluid balance in critically ill patients. In addition, the article describes recent developments in other extracorporeal therapies, including therapeutic plasma exchange, multiple organ support therapy, liver support, lung support, and blood purification in sepsis. This is a consensus report on nomenclature harmonization in extracorporeal blood purification therapies, such as hemofiltration, plasma exchange, multiple organ support therapies, and blood purification in sepsis

Long-Term Follow-Up of Patients after Acute Kidney Injury: Patterns of Renal Functional Recovery

Background and Objectives: Patients who survive acute kidney injury (AKI), especially those with partial renal recovery, present a higher long-term mortality risk. However, there is no consensus on the best time to assess renal function after an episode of acute kidney injury or agreement on the definition of renal recovery. In addition, only limited data regarding predictors of recovery are available. Design, Setting, Participants, & Measurements: From 1984 to 2009, 84 adult survivors of acute kidney injury were followed by the same nephrologist (RCRMA) for a median time of 4.1 years. Patients were seen at least once each year after discharge until end stage renal disease (ESRD) or death. In each consultation serum creatinine was measured and glomerular filtration rate estimated. Renal recovery was defined as a glomerular filtration rate value $60 mL/min/1.73 m2. A multiple logistic regression was performed to evaluate factors independently associated with renal recovery. Results: The median length of follow-up was 50 months (30–90 months). All patients had stabilized their glomerular filtration rates by 18 months and 83 % of them stabilized earlier: up to 12 months. Renal recovery occurred in 16 patients (19%) at discharge and in 54 (64%) by 18 months. Six patients died and four patients progressed to ESRD during the follow up period. Age (OR 1.09, p,0.0001) and serum creatinine at hospital discharge (OR 2.48, p = 0.007) were independent factors associated with non renal recovery. The acute kidney injury severity, evaluated by peak serum creatinine and nee

Publisher Correction:COVID-19-associated acute kidney injury: consensus report of the 25^th Acute Disease Quality Initiative (ADQI) Workgroup (Nature Reviews Nephrology, (2020), 10.1038/s41581-020-00356-5)

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Continuous venovenous hemodiafiltration with a low citrate dose regional anticoagulation protocol and a phosphate-containing solution: effects on acid–base status and phosphate supplementation needs

BACKGROUND: Recent guidelines suggest the adoption of regional citrate anticoagulation (RCA) as first choice CRRT anticoagulation modality in patients without contraindications for citrate. Regardless of the anticoagulation protocol, hypophosphatemia represents a potential drawback of CRRT which could be prevented by the adoption of phosphate-containing CRRT solutions. The aim was to evaluate the effects on acid--base status and phosphate supplementation needs of a new RCA protocol for Continuous Venovenous Hemodiafiltration (CVVHDF) combining the use of citrate with a phosphate-containing CRRT solution. METHODS: To refine our routine RCA-CVVH protocol (12 mmol/l citrate, HCO3- 32 mmol/l replacement fluid) (protocol A) and to prevent CRRT-related hypophosphatemia, we introduced a new RCA-CVVHDF protocol (protocol B) combining an 18 mmol/l citrate solution with a phosphate-containing dialysate/replacement fluid (HCO3- 30 mmol/l, Phosphate 1.2). A low citrate dose (2.5--3 mmol/l) and a higher than usual target circuit-Ca2+ (<=0.5 mmol/l) have been adopted. RESULTS: Two historical groups of heart surgery patients (n = 40) underwent RCA-CRRT with protocol A (n = 20, 102 circuits, total running time 5283 hours) or protocol B (n = 20, 138 circuits, total running time 7308 hours). Despite higher circuit-Ca2+ in protocol B (0.37 vs 0.42 mmol/l, p < 0.001), circuit life was comparable (51.8 +/- 36.5 vs 53 +/- 32.6 hours). Protocol A required additional bicarbonate supplementation (6 +/- 6.4 mmol/h) in 90% of patients while protocol B ensured appropriate acid--base balance without additional interventions: pH 7.43 (7.40--7.46), Bicarbonate 25.3 (23.8--26.6) mmol/l, BE 0.9 (-0.8 to +2.4); median (IQR). No episodes of clinically relevant metabolic alkalosis, requiring modifications of RCA-CRRT settings, were observed. Phosphate supplementation was needed in all group A patients (3.4 +/- 2.4 g/day) and in only 30% of group B patients (0.5 +/- 1.5 g/day). Hypophosphatemia developed in 75% and 30% of group A and group B patients, respectively. Serum phosphate was significantly higher in protocol B patients (P < 0.001) and, differently to protocol A, appeared to be steadily maintained in near normal range (0.97--1.45 mmol/l, IQR)

Mitochondrial 2,4-dienoyl-CoA Reductase Deficiency in Mice Results in Severe Hypoglycemia with Stress Intolerance and Unimpaired Ketogenesis

The mitochondrial β-oxidation system is one of the central metabolic pathways of energy metabolism in mammals. Enzyme defects in this pathway cause fatty acid oxidation disorders. To elucidate the role of 2,4-dienoyl-CoA reductase (DECR) as an auxiliary enzyme in the mitochondrial β-oxidation of unsaturated fatty acids, we created a DECR–deficient mouse line. In Decr−/− mice, the mitochondrial β-oxidation of unsaturated fatty acids with double bonds is expected to halt at the level of trans-2, cis/trans-4-dienoyl-CoA intermediates. In line with this expectation, fasted Decr−/− mice displayed increased serum acylcarnitines, especially decadienoylcarnitine, a product of the incomplete oxidation of linoleic acid (C18:2), urinary excretion of unsaturated dicarboxylic acids, and hepatic steatosis, wherein unsaturated fatty acids accumulate in liver triacylglycerols. Metabolically challenged Decr−/− mice turned on ketogenesis, but unexpectedly developed hypoglycemia. Induced expression of peroxisomal β-oxidation and microsomal ω-oxidation enzymes reflect the increased lipid load, whereas reduced mRNA levels of PGC-1α and CREB, as well as enzymes in the gluconeogenetic pathway, can contribute to stress-induced hypoglycemia. Furthermore, the thermogenic response was perturbed, as demonstrated by intolerance to acute cold exposure. This study highlights the necessity of DECR and the breakdown of unsaturated fatty acids in the transition of intermediary metabolism from the fed to the fasted state

Renal replacement therapy in acute kidney injury: controversy and consensus

Renal replacement therapies (RRTs) represent a cornerstone in the management of severe acute kidney injury. This area of intensive care and nephrology has undergone significant improvement and evolution in recent years. Continuous RRTs have been a major focus of new technological and treatment strategies. RRT is being used increasingly in the intensive care unit, not only for renal indications but also for other organ-supportive strategies. Several aspects related to RRT are now well established, but others remain controversial. In this review, we review the available RRT modalities, covering technical and clinical aspects. We discuss several controversial issues, provide some practical recommendations, and where possible suggest a research agenda for the future

Long-Term Gene Therapy Causes Transgene-Specific Changes in the Morphology of Regenerating Retinal Ganglion Cells

Recombinant adeno-associated viral (rAAV) vectors can be used to introduce neurotrophic genes into injured CNS neurons, promoting survival and axonal regeneration. Gene therapy holds much promise for the treatment of neurotrauma and neurodegenerative diseases; however, neurotrophic factors are known to alter dendritic architecture, and thus we set out to determine whether such transgenes also change the morphology of transduced neurons. We compared changes in dendritic morphology of regenerating adult rat retinal ganglion cells (RGCs) after long-term transduction with rAAV2 encoding: (i) green fluorescent protein (GFP), or (ii) bi-cistronic vectors encoding GFP and ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF) or growth-associated protein-43 (GAP43). To enhance regeneration, rats received an autologous peripheral nerve graft onto the cut optic nerve of each rAAV2 injected eye. After 5–8 months, RGCs with regenerated axons were retrogradely labeled with fluorogold (FG). Live retinal wholemounts were prepared and GFP positive (transduced) or GFP negative (non-transduced) RGCs injected iontophoretically with 2% lucifer yellow. Dendritic morphology was analyzed using Neurolucida software. Significant changes in dendritic architecture were found, in both transduced and non-transduced populations. Multivariate analysis revealed that transgenic BDNF increased dendritic field area whereas GAP43 increased dendritic complexity. CNTF decreased complexity but only in a subset of RGCs. Sholl analysis showed changes in dendritic branching in rAAV2-BDNF-GFP and rAAV2-CNTF-GFP groups and the proportion of FG positive RGCs with aberrant morphology tripled in these groups compared to controls. RGCs in all transgene groups displayed abnormal stratification. Thus in addition to promoting cell survival and axonal regeneration, vector-mediated expression of neurotrophic factors has measurable, gene-specific effects on the morphology of injured adult neurons. Such changes will likely alter the functional properties of neurons and may need to be considered when designing vector-based protocols for the treatment of neurotrauma and neurodegeneration

Dietary levels of pure flavonoids improve spatial memory performance and increase hippocampal brain-derived neurotrophic factor.

Evidence suggests that flavonoid-rich foods are capable of inducing improvements in memory and cognition in animals and humans. However, there is a lack of clarity concerning whether flavonoids are the causal agents in inducing such behavioral responses. Here we show that supplementation with pure anthocyanins or pure flavanols for 6 weeks, at levels similar to that found in blueberry (2% w/w), results in an enhancement of spatial memory in 18 month old rats. Pure flavanols and pure anthocyanins were observed to induce significant improvements in spatial working memory (p = 0.002 and p = 0.006 respectively), to a similar extent to that following blueberry supplementation (p = 0.002). These behavioral changes were paralleled by increases in hippocampal brain-derived neurotrophic factor (R = 0.46, p<0.01), suggesting a common mechanism for the enhancement of memory. However, unlike protein levels of BDNF, the regional enhancement of BDNF mRNA expression in the hippocampus appeared to be predominantly enhanced by anthocyanins. Our data support the claim that flavonoids are likely causal agents in mediating the cognitive effects of flavonoid-rich foods