Providing environmentally sustainable nephrology care: focus in low- and middle-income countries

Health care on a global scale significantly contributes to carbon emissions, with high-income countries being the primary culprits. Within health care, dialysis plays a significant role as a major source of emissions. Low- and middle-income countries have a high burden of kidney disease and are facing an increasing demand for dialysis. This reality presents multiple opportunities to plan for environmentally sustainable and quality kidney care. By placing a stronger emphasis on primary and secondary prevention of kidney disease and its progression, within the framework of universal health coverage, as well as empowering patients to enhance self-care, we can significantly reduce the need for costly and environmentally detrimental kidney replacement therapy. Mandating the adoption of lean and innovative low-carbon dialysis practices while also promoting the growth of kidney transplantation would enable low- and middle-income countries to take the lead in implementing environmentally friendly nephrology practices and reducing costs, thus optimizing sustainability and the well-being of individuals living with kidney disease.

Inequities in kidney health and kidney care

Health inequity refers to the existence of unnecessary and unfair differences in the ability of an individual or community to achieve optimal health and access appropriate care. Kidney diseases, including acute kidney injury and chronic kidney disease, are the epitome of health inequity. Kidney disease risk and outcomes are strongly associated with inequities that occur across the entire clinical course of disease. Insufficient investment across the spectrum of kidney health and kidney care is a fundamental source of inequity. In addition, social and structural inequities, including inequities in access to primary health care, education and preventative strategies, are major risk factors for, and contribute to, poorer outcomes for individuals living with kidney diseases. Access to affordable kidney care is also highly inequitable, resulting in financial hardship and catastrophic health expenditure for the most vulnerable. Solutions to these injustices require leadership and political will. The nephrology community has an important role in advocacy and in identifying and implementing solutions to dismantle inequities that affect kidney health.

Increased resting energy expenditure in children with attention-deficit-hyperactivity disorder

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most frequently reported neuropsychiatric disorders in childhood. However, there is limited data on the biological basis for this disorder. Disturbances in neurotransmitters have been suggested to play a pathophysiologic role. Phenotypically an increased prevalence of obesity has been reported.

OBJECTIVE

To investigate resting energy expenditure (REE) and diet-induced thermogenesis in stimulant medication-naïve children with ADHD.

DESIGN

Case control study of 12 pre-pubertal boys with ADHD of the hyperactive-impulsive type and 12 control boys without ADHD. Anthropometric testing and indirect calorimetry were performed before and after a standardized meal. REE and thermogenesis were measured in each subject at 2 time points. In an independent group of 60 boys with ADHD, BMI standard deviation scores (BMI-SDS) were compared to age-adapted reference values.

RESULTS

REE was on average 6.5 kcal/kg fat free mass/day higher in the ADHD compared to the control group (p<0.01). In contrast, the thermogenic effect of food was not different between the two groups (average increase by 16%, p=n.s.). The repeat measurements, an average of 5±1 months apart, were highly reproducible in all subjects. Age and restlessness did not explain the differences in REE. Boys with ADHD had similar BMI-SDS values (mean BMI-SDS -0.10±0.98) as reference groups.

CONCLUSIONS

REE, in contrast to diet-induced thermogenesis, is higher in medication-naïve boys with ADHD. The normal BMI levels suggest increased energy intake in these children.

When the earth trembles in the Americas: the experience of Haiti and Chile 2010

The response of the nephrological community to the Haiti and Chile earthquakes which occurred in the first months of 2010 is described. In Haiti, renal support was organized by the Renal Disaster Relief Task Force (RDRTF) of the International Society of Nephrology (ISN) in close collaboration with Médecins Sans Frontières (MSF), and covered both patients with acute kidney injury (AKI) and patients with chronic kidney disease (CKD). The majority of AKI patients (19/27) suffered from crush syndrome and recovered their kidney function. The remaining 8 patients with AKI showed acute-to-chronic renal failure with very low recovery rates. The intervention of the RDRTF-ISN involved 25 volunteers of 9 nationalities, lasted exactly 2 months, and was characterized by major organizational difficulties and problems to create awareness among other rescue teams regarding the availability of dialysis possibilities. Part of the Haitian patients with AKI reached the Dominican Republic (DR) and received their therapy there. The nephrological community in the DR was able to cope with this extra patient load. In both Haiti and the DR, dialysis treatment was able to be prevented in at least 40 patients by screening and adequate fluid administration. Since laboratory facilities were destroyed in Port-au-Prince and were thus lacking during the first weeks of the intervention, the use from the very beginning on of a point-of-care device (i-STAT®) was very efficient for the detection of aberrant kidney function and electrolyte parameters. In Chile, nephrological problems were essentially related to difficulties delivering dialysis treatment to CKD patients, due to the damage to several units. This necessitated the reallocation of patients and the adaptation of their schedules. The problems could be handled by the local nephrologists. These observations illustrate that local and international preparedness might be life-saving if renal problems occur in earthquake circumstances.

Adverse effects associated with the use of South African traditional folk remedies

Although the toxicity of traditional folk remedies is well known in Africa, it is a subject which is surrounded by secrecy and has not been comprehensively studied.

OBJECTIVES

The aims of this study are to describe the clinical features of patients admitted to hospital with a confirmed history of using folk remedies, and to gather data on their toxicity in a systematic fashion.

DESIGN

Prospective case series.

SETTING

Paediatric and adult wards of academic hospitals in Johannesburg, South Africa.

SUBJECTS

The study population included 103 patients ranging from one day to 75 years of age, all of whom had recent folk remedy use.

MAIN OUTCOME MEASURES

All available clinical data were analysed. Primary outcomes were the presence of renal and liver dysfunction, death or discharge from hospital.

RESULTS

The most common clinical features on presentation were dehydration (51%), vomiting (46%), jaundice (40%), diarrhoea (39%), altered mental status (37%) and oligoanuria (30%). Renal dysfunction was present in 76% of patients and liver dysfunction in 48%. The overall mortality was 34%. The odds ratio of death was 5.1 (95% CI 1.41 to 18.5) in patients with renal dysfunction (p = 0.0077) and 5.35 (95% CI 1.99 to 14.4) in patients with liver dysfunction (p = 0.0006).

CONCLUSION

Renal and liver dysfunction are frequently associated with use of folk remedies, and mortality in these patients is high. In view of the large numbers of African individuals living in the United States and Europe, it is important for physicians elsewhere to be aware of the potential toxicity of African folk remedies, and to inquire about their use.

Molecular cloning and characterization of an intracellular chloride channel in the proximal tubule cell line, LLC-PK1

CLC5 is an intracellular chloride channel of unknown function, expressed in the renal proximal tubule. The subcellular localization and function of CLC5 were investigated in the LLC-PK1 porcine proximal tubule cell line. We cloned a cDNA for the porcine CLC5 ortholog (pCLC5) that is predicted to encode an 83-kDa protein with 97% amino acid sequence identity to rat and human CLC5. By immunofluorescence, pCLC5 was localized to early endosomes of the apical membrane fluid-phase endocytotic pathway and to the Golgi complex. Xenopus oocytes injected with pCLC5 cRNA exhibited outwardly rectifying whole cell currents with a relative conductance profile (nitrate Cl(-) approximately Br(-) > I(-) > acetate > gluconate) different from that of control oocytes. Acidification of the extracellular medium reversibly inhibited this outward current with a pK(a) of 6.0 and a Hill coefficient of 1. Overexpression of CLC5 in LLC-PK1 cells resulted in morphological changes, including loss of cell-cell contacts and the appearance of multiple prominent vesicles. These findings are consistent with a potential role for CLC5 in the acidification of membrane compartments of both the endocytic and the exocytic pathway and suggest that its function may be important for normal intercellular adhesion and vesicular trafficking.

Diet-dependent hypercalciuria in transgenic mice with reduced CLC5 chloride channel expression

Dent's disease is an X-linked inherited disorder characterized by hypercalciuria, nephrocalcinosis, nephrolithiasis, low molecular weight proteinuria, Fanconi's syndrome, and renal failure. It is caused by inactivating mutations in CLC5, a member of the CLC voltage-gated chloride channel family. CLC5 is known to be expressed in the endosomal compartment of the renal proximal tubule, where it may be required for endosomal acidification and trafficking. Although the Fanconi's syndrome and low molecular weight proteinuria in Dent's disease can be explained by disruption of endosomal function in this nephron segment, the pathogenesis of the hypercalciuria in this disease is unknown. We have generated transgenic mice (RZ) with reduced CLC5 expression by introduction of an antisense ribozyme targeted against CLC5. RZ mice are markedly hypercalciuric compared with nontransgenic control mice, at a time when their serum electrolytes and renal function are otherwise normal. This suggests that hypercalciuria in Dent's disease is a direct consequence of CLC5 hypofunction and is not attributable to a gain of function by mutant CLC5, an effect of modifier genes, or a secondary result of nonspecific renal injury. Surprisingly, hypercalciuria in RZ mice is abolished by dietary calcium deprivation, suggesting that the hypercalciuria may be attributable to gastrointestinal hyperabsorption of calcium rather than a renal calcium leak.

Renin-angiotensin blockade lowers MCP-1 expression in diabetic rats

BACKGROUND

Glomerular macrophage accumulation in diabetes implicates monocyte recruitment mechanisms in the pathogenesis of diabetic nephropathy. To test the hypothesis that overexpression of monocyte chemoattractant protein-1 (MCP-1), a monocyte chemoattractant, is attenuated by renin-angiotensin system (RAS) inhibition, we assessed expression of genes regulating monocyte transmigration in the glomeruli of diabetic rats.

METHODS

Competitive reverse transcription-polymerase chain reaction (RT-PCR) was used to semiquantitate mRNA expression in glomeruli harvested by sieving at serial intervals after the induction of diabetes by streptozotocin in Munich-Wistar rats. Although subject to limitations, competitive RT-PCR provides an objective measure suited to the minute quantities of RNA extractable from glomerular isolates.

RESULTS

Time-dependent elevation of MCP-1 expression was dramatically suppressed by treatment with the angiotensin-converting enzyme inhibitor enalapril or the AT1 receptor antagonist candesartan, and was closely associated with effects on proteinuria and glomerular macrophage number. By contrast, no sustained suppression of the cell adhesion molecules intercellular adhesion molecule-1 or vascular cell adhesion molecule-1 or the classic MCP-1 stimulators tumor necrosis factor-alpha or interleukin-1beta followed RAS inhibition, and suppression of transforming growth factor-beta1 expression was transient.

CONCLUSION

These data suggest that glomerular macrophage recruitment in experimental diabetes is largely determined by angiotensin-stimulated MCP-1 expression. We conclude that the RAS is an important regulator of local MCP-1 expression, either directly or through glomerular hemodynamic effects, and that our data strongly implicate macrophage recruitment and activation in the pathogenesis of early diabetic glomerular injury.

Intrarenal and subcellular localization of rat CLC5

Dent's disease, an inherited disorder characterized by hypercalciuria, nephrolithiasis, nephrocalcinosis, rickets, low-molecular-weight proteinuria, Fanconi's syndrome, and renal failure, is caused by mutations in the renal chloride channel, CLC5. The normal role of CLC5 is unknown. We have investigated the intrarenal and subcellular localization of CLC5 in rat kidney by in situ hybridization and immunohistochemistry. By in situ hybridization, CLC5 mRNA was detected predominantly in cortical medullary ray and outer medullary tubule epithelial cells. Polyclonal antiserum was generated against a CLC5 fusion protein, affinity purified, and immunoadsorbed against CLC3 and CLC4 to yield a CLC5 isoform-specific antiserum. By immunohistochemistry, CLC5 protein was localized to the intracellular domain of tubular epithelial cells in the S3 segment of the proximal tubule and the medullary thick ascending limb. By subcellular membrane fractionation and flow cytometry, CLC5 expression was found in outer medullary endosomes. These findings are consistent with a model in which CLC5 encodes an endosomal chloride channel that facilitates acidification and trafficking of renal epithelial endosomes.