The growth hormone-insulin-like growth factor-I axis in chronic kidney disease

Pathogenesis of Sarcopenia in Chronic Kidney Disease-The Role of Inflammation, Metabolic Dysregulation, Gut Dysbiosis, and microRNA

Chronic kidney disease (CKD) is a progressive disorder associated with a decline in kidney function. Consequently, patients with advanced stages of CKD require renal replacement therapies, such as dialysis and kidney transplantation. Various conditions lead to the development of CKD, including diabetes mellitus, hypertension, and glomerulonephritis, among others. The disease is associated with metabolic and hormonal dysregulation, including uraemia and hyperparathyroidism, as well as with low-grade systemic inflammation. Altered homeostasis increases the risk of developing severe comorbidities, such as cardiovascular diseases or sarcopenia, which increase mortality. Sarcopenia is defined as a progressive decline in muscle mass and function. However, the precise mechanisms that link CKD and the development of sarcopenia are poorly understood. Knowledge about these linking mechanisms might lead to the introduction of precise treatment strategies that could prevent muscle wasting. This review discusses inflammatory mediators, metabolic and hormonal dysregulation, gut microbiota dysbiosis, and non-coding RNA alterations that could link CKD and sarcopenia.

[Growth hormone - 30 years of clinical practice: past, present, future]

The recombinant technologies era, which began in the second half of the XX century, made it possible to produce recombinant growth hormone (rGH) necessary for the treatment of stunting of various genesis. The time of practically unlimited possibilities of rGH production has come, which served as a stimulus for studying the efficacy and safety of rGH application, searching for optimal ways of its use and dosing regimes. Many years of experience in the use of somatropin in clinical practice allowed us to obtain data on its effectiveness primarily in somatotropic insufficiency in children, to study its effect on the functional state of various organs and systems, and to expand the indications for the use of RGR.

Low-Plasma Insulin-Like Growth Factor-1 Associates With Increased Mortality in Chronic Kidney Disease Patients With Reduced Muscle Strength

OBJECTIVES

Chronic kidney disease (CKD) leads to metabolic and nutritional abnormalities including resistance to insulin-like growth factor-1 (IGF-1) action, and reduced muscle mass and strength. Low IGF-1 as well as low hand-grip muscle strength (HGS) are independent predictors of increased mortality in CKD patients.

METHODS

In 685 patients (CKD Stage 3-5, median age 58 years; 62% men), baseline measurements of IGF-1, HGS, subjective global assessment (SGA), lean body mass index (LBMI), and metabolic and inflammatory biomarkers potentially linked to IGF-1 were analyzed in relation to mortality during 5 years of follow-up. We compared survival in 4 groups with high or low (cut-offs defined by receiver operating characteristic curve analysis) levels of IGF-1 and HGS.

RESULTS

Patients with low IGF-1 were older; had lower BMI, HGS, and LBMI, were more likely to have diabetes, cardiovascular disease (CVD), and malnutrition (SGA >1); and had high-sensitivity C-reactive protein levels. During 5 years of follow-up, 208 patients died. The mortality rate was highest among patients with Low IGF-1 + Low HGS. In competing-risk regression analysis, Low IGF-1 + Low HGS was independently associated with 2.8 times higher all-cause mortality risk than Low IGF-1 + High HGS, after adjusting for Framingham's CVD risk score, presence of CVD, SGA, dialysis status, high-sensitivity C-reactive protein, albumin, LBMI, and sample time in freezer.

CONCLUSION

Low IGF-1 was associated with increased all-cause mortality in patients who also had low HGS but not in those with high HGS, suggesting that the association of IGF-1 with survival in CKD patients depends on nutritional status.

SIRPα Mediates IGF1 Receptor in Cardiomyopathy Induced by Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is characterized by increased myocardial mass despite near-normal blood pressure, suggesting the presence of a separate trigger. A potential driver is SIRPα (signal regulatory protein alpha)-a mediator impairing insulin signaling. The objective of this study is to assess the role of circulating SIRPα in CKD-induced adverse cardiac remodeling.

METHODS

SIRPα expression was evaluated in mouse models and patients with CKD. Specifically, mutant, muscle-specific, or cardiac muscle-specific SIRPα KO (knockout) mice were examined after subtotal nephrectomy. Cardiac function was assessed by echocardiography. Metabolic responses were confirmed in cultured muscle cells or cardiomyocytes.

RESULTS

We demonstrate that SIRPα regulates myocardial insulin/IGF1R (insulin growth factor-1 receptor) signaling in CKD. First, in the serum of both mice and patients, SIRPα was robustly secreted in response to CKD. Second, cardiac muscle upregulation of SIRPα was associated with impaired insulin/IGF1R signaling, myocardial dysfunction, and fibrosis. However, both global and cardiac muscle-specific SIRPα KO mice displayed improved cardiac function when compared with control mice with CKD. Third, both muscle-specific or cardiac muscle-specific SIRPα KO mice did not significantly activate fetal genes and maintained insulin/IGF1R signaling with suppressed fibrosis despite the presence of CKD. Importantly, SIRPα directly interacted with IGF1R. Next, rSIRPα (recombinant SIRPα) protein was introduced into muscle-specific SIRPα KO mice reestablishing the insulin/IGF1R signaling activity. Additionally, overexpression of SIRPα in myoblasts and cardiomyocytes impaired pAKT (phosphorylation of AKT) and insulin/IGF1R signaling. Furthermore, myotubes and cardiomyocytes, but not adipocytes treated with high glucose or cardiomyocytes treated with uremic toxins, stimulated secretion of SIRPα in culture media, suggesting these cells are the origin of circulating SIRPα in CKD. Both intracellular and extracellular SIRPα exert biologically synergistic effects impairing intracellular myocardial insulin/IGF1R signaling.

CONCLUSIONS

Myokine SIRPα expression impairs insulin/IGF1R functions in cardiac muscle, affecting cardiometabolic signaling pathways. Circulating SIRPα constitutes an important readout of insulin resistance in CKD-induced cardiomyopathy.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

IGF-1 and IGFBP-3 in Inflammatory Cachexia

Inflammation induces a wide response of the neuroendocrine system, which leads to modifications in all the endocrine axes. The hypothalamic–growth hormone (GH)–insulin-like growth factor-1 (IGF-1) axis is deeply affected by inflammation, its response being characterized by GH resistance and a decrease in circulating levels of IGF-1. The endocrine and metabolic responses to inflammation allow the organism to survive. However, in chronic inflammatory conditions, the inhibition of the hypothalamic–GH–IGF-1 axis contributes to the catabolic process, with skeletal muscle atrophy and cachexia. Here, we review the changes in pituitary GH secretion, IGF-1, and IGF-1 binding protein-3 (IGFBP-3), as well as the mechanism that mediated those responses. The contribution of GH and IGF-1 to muscle wasting during inflammation has also been analyzed.

The Role of Growth Hormone in Chronic Kidney Disease

Growth hormone (GH) has become a critical therapy for treating growth delay and failure in pediatric chronic kidney disease. Recombinant human GH treatment is safe and significantly improves height and height velocity in these growing patients and improved growth outcomes are associated with decreased morbidity and mortality as well as improved quality of life. However, the utility of recombinant human GH in adults with chronic kidney disease and end-stage renal disease for optimization of body habitus and reducing frailty remains uncertain. Semin Nephrol 41:x-xx © 2021 Elsevier Inc. All rights reserved.

Short adult height increases the risk of end-stage renal disease in type 2 diabetes

OBJECTIVE

Although short adult height has been associated with an increasing variety of diseases and all-cause death, no reliable data exist on the association between adult height and end-stage renal disease (ESRD) in diabetic patients. We investigated the relationship between short adult height, development of ESRD, and mortality in type 2 diabetes mellitus (DM).

METHODS

This nationwide population-based cohort study analyzed clinical data from a total of 2,621,907 subjects aged ≥30 years with type 2 DM between January 1, 2009 and December 31, 2012, using the National Health Insurance Database in Korea.

RESULTS

During a 6.9-year follow-up period, 220,457 subjects (8.4%) died, and 28,704 subjects (1.1%) started dialysis. Short adult height significantly increased the incidence of ESRD and all-cause mortality in the overall cohort analysis. In multivariable Cox models, hazard ratios (HR) for the development of ESRD comparing the highest and lowest quartiles of adult height were 0.86 (95% CI 0.83-0.89). All-cause mortality also decreased with the highest height compared to patients with the lowest height, after fully adjusting for confounding variables (HR 0.79, 95% CI 0.78-0.81). Adult height had an inverse relationship to newly diagnosed ESRD (male: HR 0.86, 95% CI 0.83-0.90, female: HR 0.84, 95% CI 0.79-0.90) and all-cause mortality (male: HR 0.81, 95% CI 0.79-0.82, female: HR 0.80, 95% CI 0.78-0.82).

CONCLUSIONS

Short adult height is strongly associated with the increased risk of ESRD development and all-cause mortality in type 2 DM.

SOCS2 Silencing Improves Somatic Growth without Worsening Kidney Function in CKD

BACKGROUND

Growth hormone (GH) resistance in CKD is partly due to increased expression of SOCS2, a GH signaling negative regulator. In SOCS2 absence, body growth is exaggerated. However, GH overexpression in mice causes glomerulosclerosis. Accordingly, we tested whether lack of SOCS2 improves body growth, but accelerates kidney damage in CKD.

METHODS

Eight-week-old mutant SOCS2-deficient high growth (HG) and normal wild-type mice (N) underwent 5/6 nephrectomy (CKD) or sham operation (C) and were sacrificed after 12 weeks, generating 4 groups: C-N, C-HG, CKD-N, CKD-HG.

RESULTS

Somatic growth, inhibited in CKD-N, increased significantly in CKD-HG. Liver p-STAT5, a key intracellular signal of GH receptor (GHR) activation, was decreased in CKD-N but not in CKD-HG. Serum Cr as well as histopathological scores of renal fibrosis were similar in both CKD groups. Kidney fibrogenic (TGF-β and collagen type IV mRNA) and inflammatory precursors (IL6, STAT3, and SOCS3 mRNA) were similarly increased in C-HG, CKD-HG, and CKD-N versus C-N. Renal GHR mRNA was decreased in C-HG, CKD-HG, and CKD-N versus C-N. Kidney p-STAT5 was decreased in CKD-N but not elevated in CKD-HG.

CONCLUSIONS

CKD-related growth retardation is overcome by SOCS2 silencing, in association with increased hepatic STAT5 phosphorylation. Renal insufficiency is not worsened by SOCS2 absence, as kidney GHR and STAT5 are not upregulated. This may be due to elevated kidney proinflammatory cytokines and their mediators, phospho-STAT3 and SOCS3, which may counteract for the absence in SOCS2 and explain the renal safety of prolonged GH therapy in CKD.

Influence of exogenous growth hormone administration on circulating concentrations of α-klotho in healthy and chronic kidney disease subjects: a prospective, single-center open case-control pilot study

BACKGROUND

The CKD-associated decline in soluble α-Klotho (α-Klotho) levels is considered detrimental. Some studies suggest a direct induction of α-Klotho concentrations by growth hormone (GH). In the present study, the effect of exogenous GH administration on α-Klotho concentrations in a clinical cohort with mild chronic kidney disease (CKD) and healthy subjects was studied.

METHODS

A prospective, single-center open case-control pilot study was performed involving 8 patients with mild CKD and 8 healthy controls matched for age and sex. All participants received subcutaneous GH injections (Genotropin®, 20 mcg/kg/day) for 7 consecutive days. α-Klotho concentrations were measured at baseline, after 7 days of therapy and 1 week after the intervention was stopped.

RESULTS

α-Klotho concentrations were not different between CKD-patients and healthy controls at baseline (554 (388-659) vs. 547 (421-711) pg/mL, P = 0.38). Overall, GH therapy increased α-Klotho concentrations from 554 (405-659) to 645 (516-754) pg/mL, P < 0.05). This was accompanied by an increase of IGF-1 concentrations from 26.8 ± 5.0 nmol/L to 61.7 ± 17.7 nmol/L (P < 0.05). GH therapy induced a trend toward increased α-Klotho concentrations both in the CKD group (554 (388-659) to 591 (358-742) pg/mL (P = 0.19)) and the healthy controls (547 (421-711) pg/mL to 654 (538-754) pg/mL (P = 0.13)). The change in α-Klotho concentration was not different for both groups (P for interaction = 0.71). α-Klotho concentrations returned to baseline levels within one week after the treatment (P < 0.05).

CONCLUSIONS

GH therapy increases α-Klotho concentrations in subjects with normal renal function or stage 3 CKD. A larger follow-up study is needed to determine whether the effect size is different between both groups or in patients with more severe CKD.

TRIAL REGISTRATION

This trial is registered in EudraCT ( 2013-003354-24 ).

Evaluation of serum insulin-like growth factor-1 and 26S proteasome concentrations in healthy dogs and dogs with chronic diseases depending on body condition score

In patients suffering from chronic diseases, the objective assessment of metabolic states could be of interest for disease prognosis and therapeutic options. Therefore, the aim of this study was to assess insulin-like growth factor-1 (IGF-1) and 26S proteasome (26SP) in healthy dogs and dogs suffering from chronic diseases depending on their body condition score (BCS) and to examine their potential for objective assessment of anabolic and catabolic states. Serum concentrations of IGF-1, an anabolic hormone, and 26SP, a multiprotein complex which is part of the ubiquitin-proteasome pathway, by which the majority of endogenous proteins including the muscle proteins are degraded, were measured in 21 healthy dogs and 20 dogs with chronic diseases by canine ELISA. The concentrations of IGF-1, 26SP and their ratio (IGF-1/26SP) were set in relationship to the BCS of the dogs. When examining healthy and chronically diseased dogs separately, a positive correlation between IGF-1 and the BCS was observed in the healthy group and a negative correlation between 26SP and the BCS was noted in dogs with chronic diseases. Further, dogs suffering from chronic diseases showed higher 26SP concentrations and lower values for IGF-1/26SP than the healthy dogs. Overall, we detected a negative correlation between 26SP and the BCS and a positive correlation between IGF-1/26SP and the BCS. The results of our study indicate usability of IGF-1 for description of anabolic states, while 26SP could be useful for detection and description of catabolic states. Finally, the ratio IGF-1/26SP seems to be promising for assessment of metabolic states.

Growth and Nutrition in Pediatric Chronic Kidney Disease

Children with chronic kidney disease (CKD) feature significant challenges to the maintenance of adequate nutrition and linear growth. Moreover, the impaired nutritional state contributes directly to poor growth. Therefore, it is necessary to consider nutritional status in the assessment of etiology and treatment of sub-optimal linear growth. The major causes of poor linear growth including dysregulation of the growth hormone/insulin-like growth factor-I (IGF-I) axis, nutritional deficiency, metabolic acidosis, anemia, renal osteodystrophy/bone mineral disease, and inflammation. This review summarizes the causes and assessment tools of growth and nutrition while providing a summary of state of the art therapies for these co-morbidities of pediatric CKD.

Growth hormone (GH)-transgenic insulin-like growth factor 1 (IGF1)-deficient mice allow dissociation of excess GH and IGF1 effects on glomerular and tubular growth

Growth hormone (GH)‐transgenic mice with permanently elevated systemic levels of GH and insulin‐like growth factor 1 (IGF1) reproducibly develop renal and glomerular hypertrophy and subsequent progressive glomerulosclerosis, finally leading to terminal renal failure. To dissociate IGF1‐dependent and ‐independent effects of GH excess on renal growth and lesion development in vivo, the kidneys of 75 days old IGF1‐deficient (I^−/−) and of IGF1‐deficient GH‐transgenic mice (I^−/−/G), as well as of GH‐transgenic (G) and nontransgenic wild‐type control mice (I^+/+) were examined by quantitative stereological and functional analyses. Both G and I^−/−/G mice developed glomerular hypertrophy, hyperplasia of glomerular mesangial and endothelial cells, podocyte hypertrophy and foot process effacement, albuminuria, and glomerulosclerosis. However, I^−/−/G mice exhibited less severe glomerular alterations, as compared to G mice. Compared to I^+/+ mice, G mice exhibited renal hypertrophy with a significant increase in the number without a change in the size of proximal tubular epithelial (PTE) cells. In contrast, I^−/−/G mice did not display significant PTE cell hyperplasia, as compared to I^−/− mice. These findings indicate that GH excess stimulates glomerular growth and induces lesions progressing to glomerulosclerosis in the absence of IGF1. In contrast, IGF1 represents an important mediator of GH‐dependent proximal tubular growth in GH‐transgenic mice.

Regulation of Long Bone Growth in Vertebrates; It Is Time to Catch Up

The regulation of organ size is essential to human health and has fascinated biologists for centuries. Key to the growth process is the ability of most organs to integrate organ-extrinsic cues (eg, nutritional status, inflammatory processes) with organ-intrinsic information (eg, genetic programs, local signals) into a growth response that adapts to changing environmental conditions and ensures that the size of an organ is coordinated with the rest of the body. Paired organs such as the vertebrate limbs and the long bones within them are excellent models for studying this type of regulation because it is possible to manipulate one member of the pair and leave the other as an internal control. During development, growth plates at the end of each long bone produce a transient cartilage model that is progressively replaced by bone. Here, we review how proliferation and differentiation of cells within each growth plate are tightly controlled mainly by growth plate-intrinsic mechanisms that are additionally modulated by extrinsic signals. We also discuss the involvement of several signaling hubs in the integration and modulation of growth-related signals and how they could confer remarkable plasticity to the growth plate. Indeed, long bones have a significant ability for "catch-up growth" to attain normal size after a transient growth delay. We propose that the characterization of catch-up growth, in light of recent advances in physiology and cell biology, will provide long sought clues into the molecular mechanisms that underlie organ growth regulation. Importantly, catch-up growth early in life is commonly associated with metabolic disorders in adulthood, and this association is not completely understood. Further elucidation of the molecules and cellular interactions that influence organ size coordination should allow development of novel therapies for human growth disorders that are noninvasive and have minimal side effects.

Urinary creatinine excretion, bioelectrical impedance analysis, and clinical outcomes in patients with CKD: the CRIC study

BACKGROUND AND OBJECTIVES

Previous studies in chronic disease states have demonstrated an association between lower urinary creatinine excretion (UCr) and increased mortality, a finding presumed to reflect the effect of low muscle mass on clinical outcomes. Little is known about the relationship between UCr and other measures of body composition in terms of the ability to predict outcomes of interest.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using data from the Chronic Renal Insufficiency Cohort (CRIC), the relationship between UCr, fat free mass (FFM) as estimated by bioelectrical impedance analysis, and (in a subpopulation) whole-body dual-energy x-ray absorptiometry assessment of appendicular lean mass were characterized. The associations of UCr and FFM with mortality and ESRD were compared using Cox proportional hazards models.

RESULTS

A total of 3604 CRIC participants (91% of the full CRIC cohort) with both a baseline UCr and FFM measurement were included; of these, 232 had contemporaneous dual-energy x-ray absorptiometry measurements. Participants were recruited between July 2003 and March 2007. UCr and FFM were modestly correlated (rho=0.50; P<0.001), while FFM and appendicular lean mass were highly correlated (rho=0.91; P<0.001). Higher urinary urea nitrogen, black race, younger age, and lower serum cystatin C level were all significantly associated with higher UCr. Over a median (interquartile range) of 4.2 (3.1-5.0) years of follow-up, 336 (9.3%) participants died and 510 (14.2%) reached ESRD. Lower UCr was associated with death and ESRD even after adjustment for FFM (adjusted hazard ratio for death per 1 SD higher level of UCr, 0.63 [95% confidence interval, 0.56 to 0.72]; adjusted hazard ratio for ESRD per 1 SD higher level of UCr, 0.70 [95% confidence interval, 0.63 to 0.75]).

CONCLUSIONS

Among a cohort of individuals with CKD, lower UCr is associated with death and ESRD independent of FFM as assessed by bioelectrical impedance analysis.

Anabolic exercise in haemodialysis patients: a randomised controlled pilot study

BACKGROUND

The anabolic response to progressive resistance exercise training (PRET) in haemodialysis patients is unclear. This pilot efficacy study aimed to determine whether high-intensity intradialytic PRET could reverse atrophy and consequently improve strength and physical function in haemodialysis patients. A second aim was to compare any anabolic response to that of healthy participants completing the same program.

METHODS

In a single blind controlled study, 23 haemodialysis patients and 9 healthy individuals were randomly allocated to PRET or an attention control (SHAM) group. PRET completed high-intensity exercise leg extensions using novel equipment. SHAM completed low-intensity lower body stretching activities using ultra light resistance bands. Exercises were completed thrice weekly for 12 weeks, during dialysis in the haemodialysis patients. Outcomes included knee extensor muscle volume by magnetic resonance imaging, knee extensor strength by isometric dynamometer and lower body tests of physical function. Data were analysed by a per protocol method using between-group comparisons.

RESULTS

PRET elicited a statistically and clinically significant anabolic response in haemodialysis patients (PRET-SHAM, mean difference [95 % CI]: 193[63 to 324] cm(3)) that was very similar to the response in healthy participants (PRET-SHAM, 169[-41 to 379] cm(3)). PRET increased strength in both haemodialysis patients and healthy participants. In contrast, PRET only enhanced lower body functional capacity in the healthy participants.

CONCLUSIONS

Intradialytic PRET elicited a normal anabolic and strength response in haemodialysis patients. The lack of a change in functional capacity was surprising and warrants further investigation.

Insulin-like growth factors and kidney disease

Insulin-like growth factors (IGF-1 and IGF-2) are necessary for normal growth and development. They are related structurally to proinsulin and promote cell proliferation, differentiation, and survival, as well as insulin-like metabolic effects, in most cell types and tissues. In particular, IGFs are important for normal pre- and postnatal kidney development. IGF-1 mediates many growth hormone actions, and both growth hormone excess and deficiency are associated with perturbed kidney function. IGFs affect renal hemodynamics both directly and indirectly by interacting with the renin-angiotensin system. In addition to the IGF ligands, the IGF system includes receptors for IGF-1, IGF-2/mannose-6-phosphate, and insulin, and a family of 6 high-affinity IGF-binding proteins that modulate IGF action. Disordered regulation of the IGF system has been implicated in a number of kidney diseases. IGF activity is enhanced in early diabetic nephropathy and polycystic kidneys, whereas IGF resistance is found in chronic kidney failure. IGFs have a potential role in enhancing stem cell repair of kidney injury. Most IGF actions are mediated by the tyrosine kinase IGF-1 receptor, and inhibitors recently have been developed. Further studies are needed to determine the optimal role of IGF-based therapies in kidney disease.

Nutrition assessment of children with advanced stages of chronic kidney disease-A single center study

BACKGROUND

Malnutrition is a major problem among children with Chronic Kidney Disease (CKD) and it is essential to be recognized as early as possible. Aim of our study was to assess the nutrition status of children with CKD.

METHODS

Nutrition status of 30 children (1-16 years) with CKD stages IIIV and on peritoneal dialysis was evaluated. Malnutrition risk was assessed by Pediatric Digital Scaled MAlnutrition Risk screening Tool (PeDiSMART) score software.Anthropometry was expressed as Z-scores for age and sex. Phase angle (PhA) and body cell mass were assessed by bioelectrical impedance analysis (BIA). Three-day food intake was recorded and analyzed. Biochemical indexes were assessed.

RESULTS

Depending on the marker used for assessment 20-40% of our patients were malnourished. Intake/requirements ratio (median) was 86.5% for actual energy intake and 127% for actual protein intake. Multiple regression analysis has shown that the most determinant factor for Mid Upper Arm Circumference (MUAMC) was actual protein intake, Glomerular Filtration Rate (GFR) and age at diagnosis. PhA was mainly affected by GFR and energy intake. Statistically significant inverse correlation was found between PeDiSMART score and PhA (p=0.001), MUAMC (p=0.008) as well as protein intake (p=0.016).

CONCLUSIONS

A considerable proportion of children with advanced CKD are undernourished. Regular dietitian evaluation based on novel tools as PeDiSMART score and PhA may identify earlier patients at risk for malnutrition. Hippokratia 2014; 18 (3): 212-216.

Growth in children with chronic kidney disease: 13 years follow up study

BACKGROUND

Growth retardation is one of the most visible comorbid conditions of chronic kidney disease (CKD) in children. To our knowledge, published data on longitudinal follow-up of growth in pediatric patients with CKD is lacking from the region of South-East Europe. Herein we report the results from the Serbian Pediatric Registry of Chronic Kidney Disease.

METHODS

The data reported in the present prospective analysis were collected between 2000 and 2012. A total of 324 children with CKD were enrolled in the registry.

RESULTS

Prevalence of growth failure at registry entry was 29.3 %. Mean height standard deviation scores (HtSDS) in children with stunting and those with normal stature were -3.00 [95 % confidence interval (CI) -3.21 to -2.79] and -0.08 (95 % CI -0.22 to 0.05) (p < 0.001), respectively. Children with hereditary nephropathy had worse growth at registration (-1.51; 95 % CI -1.97 to -1.04, p = 0.008). Those with CKD stages 4 and 5 before registration had more chance to have short stature at registration than those with CKD stages 2 and 3 [odds ratio (OR) = 0.458, CI 0.268-0.782, p = 0.004]. Dialysis was an independent negative predictor for maintaining optimal stature during the follow-up period (OR = 0.324, CI = 0.199-0.529, p < 0.001), while transplantation was an independent positive predictor for improvement of small stature during follow-up (OR = 3.706, CI = 1.785-7.696, p < 0.001).

CONCLUSION

Growth failure remains a significant problem in children with CKD, being worst in patients with hereditary renal disease. Growth is not improved by standard dialysis, but transplantation has a positive impact on growth in children.

Growth in children with chronic kidney disease: role of nutrition, growth hormone, dialysis, and steroids

PURPOSE OF REVIEW

Children with chronic kidney disease (CKD) have impaired growth that leads to short stature in adulthood. The problem persists even with successful transplantation and steroid withdrawal protocols. The aim of this review is to provide an overview of the pressing issues related to growth failure in children with CKD both before and after transplantation.

RECENT FINDINGS

Although great strides have been made in dialysis and transplantation, the incidence of abnormal adult height in children growing up with CKD remains as high as 45-60%. The lack of catch-up growth and resultant short stature is a critical issue for self-esteem and quality of life in many children with CKD. Aggressive daily dialysis, improved nutrition, treatment of metabolic bone disease, and the use of recombinant human growth hormone provide some hope for catch-up growth in select patients.

SUMMARY

The causes of growth failure in the setting of CKD are multifactorial. Attention to all the details by optimizing nutritional, bone and mineral metabolism, correcting metabolic acidosis and anemia, achieving excellent blood pressure control, reversing cardiovascular complications such as left ventricular hypertrophy, and minimizing the use of corticosteroids is the current standard of care. Aggressive daily dialysis can reverse many of the uremic derangements. For patients not yet on dialysis or for those after renal transplant, early institution of recombinant human growth hormone can promote growth. Improved understanding of the mechanisms of hormone resistance may offer novel targets or measurements of treatment effectiveness.

IGF-1 and survival in ESRD

BACKGROUND AND OBJECTIVES

IGF-1 deficiency links to malnutrition in CKD patients; however, it is not clear to what extent it associates with survival among these patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Serum IGF-1 and other biochemical, clinical (subjective global assessment), and densitometric (dual energy x-ray absorptiometry) markers of nutritional status and mineral and bone metabolism were measured in a cohort of 365 Swedish clinically stable CKD stage 5 patients (median age of 53 years) initiating dialysis between 1994 and 2009; in 207 patients, measurements were also taken after 1 year of dialysis. Deaths were registered during a median follow-up of 5 years. Associations of mortality with baseline IGF-1 and changes of IGF-1 after 1 year of dialysis were evaluated by Cox models.

RESULTS

At baseline, IGF-1 concentrations associated negatively with age, diabetes mellitus, cardiovascular disease, poor nutritional status, IL-6, and osteoprotegerin and positively with body fat mass, bone mineral density, serum phosphate, calcium, and fibroblast growth factor-23. At 1 year, IGF-1 had increased by 33%. In multivariate regression, low age, diabetes mellitus, and high serum phosphate and calcium associated with IGF-1 at baseline, and in a mixed model, these factors, together with high fat body mass, associated with changes of IGF-1 during the first 1 year of dialysis. Adjusting for calendar year of inclusion, age, sex, diabetes mellitus, cardiovascular disease, IL-6, and poor nutritional status, a 1 SD higher level of IGF-1 at baseline associated with lower mortality risk (hazard ratio, 0.57; 95% confidence interval, 0.32 to 0.98). Persistently low or decreasing IGF-1 levels during the first 1 year on dialysis predicted worse survival (adjusted hazard ratio, 2.19; 95% confidence interval, 1.06 to 4.50).

CONCLUSION

In incident dialysis patients, low serum IGF-1 associates with body composition and markers of mineral and bone metabolism, and it predicts increased mortality risk.

Insulin-like growth factor-I (IGF-I) and clinical nutrition

IGF-I (insulin-like growth factor-I) is a peptide hormone, produced predominantly by the liver in response to pituitary GH (growth hormone), which is involved in a wide variety of physiological processes. It acts in an endocrine, paracrine and autocrine manner to promote growth. The production of IGF-I signals the availability of nutrients needed for its anabolic actions. Recently, there has been growing interest in its role in health and disease. IGF-I has long been known to be regulated by nutrition and dysregulated in states of under- and over-nutrition, its serum concentrations falling in malnutrition and responding promptly to refeeding. This has led to interest in its utility as a nutritional biomarker. A considerable evidence base supports utility for measurement of IGF-I in nutritional contexts. Its concentration may be valuable in providing information on nutritional status, prognosis and in monitoring nutritional support. However, it is insufficiently specific for use as a screening test for under nutrition as its serum concentration is influenced by many factors other than nutritional status, notably the APR (acute-phase response) and endocrine conditions. Concentrations should be interpreted along with clinical findings and the results of other investigations such as CRP (C-reactive protein). More recently, there has been interest in free IGF-I which holds promise as a nutritional marker. The present review covers nutritional regulation of IGF-I and its dysregulation in disease, then goes on to review recent studies supporting its utility as a nutritional marker in clinical contexts. Although not currently recommended by clinical guidelines, it is likely that, in time, measurement of IGF-I will become a routine part of nutritional assessment in a number of these contexts.

Protective role of growth hormone against hyperhomocysteinemia-induced glomerular injury

The present study investigated the protective role of growth hormone (GH) against hyperhomocysteinemia (hHcys)-induced activations of reactive oxygen species/hypoxia-inducible factor (HIF)-1α, epithelial-mesenchymal transition (EMT), and consequent glomerular injury. A hHcys model was induced by folate free diet in mice. The urine protein excretion significantly increased while plasma GH levels dramatically decreased in hHcys. Real-time reverse transcription polymerase chain reaction showed that GH receptor (GHR) level increased in the cortex of hHcys mice, which mainly occurred in podocytes as shown by confocal microscopy. Recombinant mouse growth hormone (rmGH) treatment (0.02 mg/kg, once a day for 6 weeks) significantly restored the plasma GH, inhibited GHR upregulation and attenuated proteinuria. Correspondingly, rmGH treatment also blocked hHcys-induced decrease in the expression of podocin, a podocyte slit diaphragm molecule, and inhibited the increases in the expression of desmin, a podocyte injury marker. It was also demonstrated that in hHcys the expression of epithelial markers, p-cadherin and ZO-1, decreased, while the expression of mesenchymal markers, antifibroblast-specific protein 1 (FSP-1) and α-SMA, increased in podocytes, which together suggest the activation of EMT in podocytes. Nicotinamide adenine dinucleotide phosphate oxidase (Nox)-dependent superoxide anion (O2 (.-)) and hypoxia-inducible factor-1α (HIF-1α) level in the hHcys mice cortex was markedly enhanced. These hHcys-induced EMT enhancement and Nox-dependent O2 (.-)/HIF-1α activation were significantly attenuated by rmGH treatment. HIF-1α level increased in Hcys-treated cultured podocytes, which were blocked by rmGH treatment. Meanwhile, homocysteine (Hcys)-induced EMT in cultured podocytes was significantly reversed by HIF-1α siRNA. All these results support the view that GH ameliorates hHcys-induced glomerular injury by reducing Nox-dependent O2 (.-)/HIF-1α signal pathway and EMT.

Mechanism of earthquake simulation as a prenatal stressor retarding rat offspring development and chinese medicine correcting the retardation: hormones and gene-expression alteration

We aimed to investigate the mechanism of shaking as a prenatal stressor impacting the development of the offspring and Chinese medicines correcting the alterations. Pregnant rats were randomized into earthquake simulation group (ESG), herbal group (HG) which received herbal supplements in feed after shaking, and control group (CG). Findings revealed body weight and open field test (OFT) score of ESG offspring were statistically inferior to the CG and HG offspring. The corticosterone levels of ESG were higher than those of CG but not than HG. The dopamine level of ESG was slightly lower than that of the CG and of HG was higher than that of ESG. The 5-HT of ESG was higher than CG and HG. The growth hormone level of the ESG was significantly lower than ESG but not than CG. Gene expression profile showed 81 genes upregulated and 39 genes downregulated in ESG versus CG, and 60 genes upregulated and 28 genes downregulated in ESG versus HG. Eighty-four genes were found differentially expressed in ESG versus CG comparison and were normalized in ESG versus HG. We conclude that maternal shaking negatively affected physical and nervous system development, with specific alterations in neurohormones and gene expression. Chinese herbal medicine reduced these negative outcomes.

Melanocortin antagonism ameliorates muscle wasting and inflammation in chronic kidney disease

Aberrant melanocortin signaling has been implicated in the pathogenesis of wasting in chronic kidney disease (CKD). Previously, we demonstrated that agouti-related peptide (AgRP), a melenocortin-4 receptor antagonist, reduced CKD-associated cachexia in CKD mice. Our previous studies with AgRP utilized dual energy X-ray (DXA) densitometry to assess the body composition in mice (Cheung W, Kuo HJ, Markison S, Chen C, Foster AC, Marks DL, Mak RH. J Am Soc Nephrol 18: 2517-2524, 2007; Cheung W, Yu PX, Little BM, Cone RD, Marks DL, Mak RH. J Clin Invest 115: 1659-1665, 2005). DXA is unable to differentiate water content in mice, and fluid retention in CKD may lead to an overestimate of lean mass. In this study, we employed quantitative magnetic resonance technique to evaluate body composition change following central administration of AgRP in a CKD mouse model. AgRP treatment improved energy expenditure, total body mass, fat mass, and lean body mass in CKD mouse. We also investigated the effect of CKD-associated cachexia on the signaling pathways leading to wasting in skeletal muscle, as well as whether these changes can be ameliorated by central administration of AgRP. AgRP treatment caused an overall decrease in proinflammatory cytokines, which may be one important mechanism of its effects. Muscle wasting in CKD may be due to the activation of proteolytic pathways as well as inhibition of myogenesis and muscle regeneration processes. Our results suggest that these aberrant pathological pathways leading to muscle wasting in CKD mice were ameliorated by central administration of AgRP.

Exploring metabolic dysfunction in chronic kidney disease

Impaired kidney function and chronic kidney disease (CKD) leading to kidney failure and end-stage renal disease (ESRD) is a serious medical condition associated with increased morbidity, mortality, and in particular cardiovascular disease (CVD) risk. CKD is associated with multiple physiological and metabolic disturbances, including hypertension, dyslipidemia and the anorexia-cachexia syndrome which are linked to poor outcomes. Specific hormonal, inflammatory, and nutritional-metabolic factors may play key roles in CKD development and pathogenesis. These include raised proinflammatory cytokines, such as interleukin-1 and −6, tumor necrosis factor, altered hepatic acute phase proteins, including reduced albumin, increased C-reactive protein, and perturbations in normal anabolic hormone responses with reduced growth hormone-insulin-like growth factor-1 axis activity. Others include hyperactivation of the renin-angiotensin aldosterone system (RAAS), with angiotensin II and aldosterone implicated in hypertension and the promotion of insulin resistance, and subsequent pharmacological blockade shown to improve blood pressure, metabolic control and offer reno-protective effects. Abnormal adipocytokine levels including leptin and adiponectin may further promote the insulin resistant, and proinflammatory state in CKD. Ghrelin may be also implicated and controversial studies suggest activities may be reduced in human CKD, and may provide a rationale for administration of acyl-ghrelin. Poor vitamin D status has also been associated with patient outcome and CVD risk and may indicate a role for supplementation. Glucocorticoid activities traditionally known for their involvement in the pathogenesis of a number of disease states are increased and may be implicated in CKD-associated hypertension, insulin resistance, diabetes risk and cachexia, both directly and indirectly through effects on other systems including activation of the mineralcorticoid receptor. Insight into the multiple factors altered in CKD may provide useful information on disease pathogenesis, clinical assessment and treatment rationale such as potential pharmacological, nutritional and exercise therapies.

Cachexia and protein-energy wasting in children with chronic kidney disease

Children with chronic kidney disease (CKD) are at risk for "cachexia" or "protein-energy wasting" (PEW). These terms describe a pathophysiologic process resulting in the loss of muscle, with or without loss of fat, and involving maladaptive responses, including anorexia and elevated metabolic rate. PEW has been defined specifically in relation to CKD. We review the diagnostic criteria for cachexia and PEW in CKD and consider the limitations and applicability of these criteria to children with CKD. In addition, we present an overview of the manifestations and mechanisms of cachexia and PEW. A host of pathogenetic factors are considered, including systemic inflammation, endocrine perturbations, and abnormal neuropeptide signaling, as well as poor nutritional intake. Mortality risk, which is 100- to 200-fold higher in patients with end-stage renal disease than in the general population, is strongly correlated with the components of cachexia/PEW. Further research into the causes and consequences of wasting and growth retardation is needed in order to improve the survival and quality of life for children with CKD.

Molecular mechanisms of cachexia in chronic disease

Cachexia is a metabolic syndrome that manifests with excessive weight loss and disproportionate muscle wasting. It is related to many different chronic diseases, such as cancer, infections, liver disease, inflammatory bowel disease, cardiac disease, chronic obstructive pulmonary disease, chronic renal failure and rheumatoid arthritis. Cachexia is linked with poor outcome for the patients. In this article, we explore the role of the hypothalamus, liver, muscle tissue and adipose tissue in the pathogenesis of this syndrome, particularly concentrating on the role of cytokines, hormones and cell energy-controlling pathways (such as AMPK, PI3K/Akt and mTOR). We also look at possible future directions for therapeutic strategies.

Association of chronic kidney disease with muscle deficits in children

The effect of chronic kidney disease (CKD) on muscle mass in children, independent of poor growth and delayed maturation, is not well understood. We sought to characterize whole body and regional lean mass (LM) and fat mass (FM) in children and adolescents with CKD and to identify correlates of LM deficits in CKD. We estimated LM and FM from dual energy x-ray absorptiometry scans in 143 children with CKD and 958 controls at two pediatric centers. We expressed whole body, trunk, and leg values of LM and FM as Z-scores relative to height, sitting height, and leg length, respectively, using the controls as the reference. We used multivariable regression models to compare Z-scores in CKD and controls, adjusted for age and maturation, and to identify correlates of LM Z-scores in CKD. Greater CKD severity associated with greater leg LM deficits. Compared with controls, leg LM Z-scores were similar in CKD stages 2 to 3 (difference: 0.02 [95% CI: -0.20, 0.24]; P = 0.8), but were lower in CKD stages 4 to 5 (-0.41 [-0.66, -0.15]; P = 0.002) and dialysis (-1.03 [-1.33, -0.74]; P < 0.0001). Among CKD participants, growth hormone therapy associated with greater leg LM Z-score (0.58 [0.03, 1.13]; P = 0.04), adjusted for CKD severity. Serum albumin, bicarbonate, and markers of inflammation did not associate with LM Z-scores. CKD associated with greater trunk LM and FM, variable whole body LM, and normal leg FM, compared with controls. In conclusion, advanced CKD associates with significant deficits in leg lean mass, indicating skeletal muscle wasting. These data call for prospective studies of interventions to improve muscle mass among children with CKD.

The effect of corrective surgery on serum IGF-1, IGFBP-3 levels and growth in children with congenital heart disease

The aim of this study is to evaluate growth and insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels in infants with congenital heart disease (CHD) pre- and postoperatively over a period of a year. Anthropometric values and serum levels of IGF-1 and IGFBP-3 of 40 infants with CHD (20 cyanotic and 20 acyanotic) were compared with 32 healthy controls. Acyanotic infants and infants with pulmonary hypertension (PH) presented significantly more growth failure. Preoperatively, serum IGF-1 and IGFBP-3 levels were lower in the acyanotic group than the cyanotic and the control groups (p = 0.22; p < 0.01). The upward trend in IGF-1 and IGFBP-3 levels in this year-long study demonstrated that the values in the third month and the first year were higher than the preoperative values (p < 0.05). The parallel increase of weight gain and IGF-1, IGFBP-3 levels were the best evidence that these parameters are good nutritional indicators. Timing the corrective surgery before chronic malnutrition or PH develops is an important issue to maintain a normal growth for children with CHD.

Uremia attenuates growth hormone-stimulated insulin-like growth factor-1 expression, a process worsened by inflammation

Growth hormone (GH) resistance is common in uremia and together with resistance to insulin-like growth factor-1 (IGF-1) contributes to uremic growth retardation and muscle wasting. Previously, we found decreased GH-stimulated janus-kinase 2-signal transducers and activators of transcription 5 (STAT5) phosphorylation and nuclear translocation in uremia; however, it is unclear whether there are more distal defects. Therefore, we tested whether the binding of phosphorylated STAT5b to DNA is intact in uremia. Using uremic rats we found that in addition to impaired hepatic STAT5b phosphorylation, the binding of available phospho-STAT5b to DNA is decreased thus contributing to impaired IGF-1 gene expression. As sepsis-induced inflammation causes a loss of body protein and as Gram-negative infections are relatively common in uremia, we also characterized mechanisms in which acute inflammation might contribute to GH resistance in uremia. Endotoxin-induced inflammation markedly increased the resistance to GH-mediated STAT5b signaling, and further decreased STAT5b binding to DNA and IGF-1 gene expression. These perturbations appear to be related to increased cytokine expression. Thus, our findings indicate that hepatic resistance to GH-induced IGF-1 expression in uremia arises due to defects in STAT5b phosphorylation and its impaired binding to DNA, processes further aggravated by inflammation.

Etiology and treatment of growth retardation in children with chronic kidney disease and end-stage renal disease: a historical perspective

Dramatic changes have occurred in our understanding of the etiology of the growth retardation associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD) during the past 50 years. Significant interest has been focused on preventing and/or correcting the growth retardation because of the emergence of the dual therapeutic modalities of dialysis and renal transplantation to prolong the lives of infants, children, and adolescents afflicted with CKD and ESRD. These efforts have resulted in a significant improvement in the height Z-score over the past two decades of children with CKD and ESRD. This has had a salutary impact on the final adult height of such children which should hopefully lead to an enhanced quality of life in the future. This report addresses the progress that has been made in the management of growth retardation in the pediatric population with CKD and ESRD.

A review of the effects of growth hormone changes on symptoms of frailty in the elderly with chronic kidney disease

The incidence and prevalence of chronic kidney disease (CKD) is increasing worldwide, especially in the elderly. Recently, functional impairment and frailty have been recognized as factors affecting the quality of life, and outcomes in elderly patients with CKD and therapeutic interventions to improve function and reduce frailty are therefore being considered. Growth hormone (GH) levels decrease with age and GH actions are impaired in CKD patients. GH stimulates protein synthesis, bone, and glucose metabolism, and affects body composition by reducing body fat and increasing lean body mass. An increase in lean body mass may reduce frailty and thus avoid functional impairment. Thus, providing GH to elderly CKD patients could potentially improve outcomes and quality of life by lowering the risk of frailty and associated functional impairment. There are few studies assessing the long-term effects of GH administration on symptoms of frailty in elderly patients with CKD. In this review we will try to shed some light on the trials assessing the administration of GH to elderly subjects and to patients with CKD and focus on the possible role GH administration may play to improve frailty and quality of life in those patients.

A powerful new agonist: flooding the system with growth hormone

Niemczyk et al. treated predialysis chronic kidney disease patients with a new growth hormone-releasing hormone agonist, AKL-0707, and noted important changes in body composition characterized by an increase in fat-free mass, a modest rise in bone mineral content, and a reduction in fat mass. These changes were accompanied by a reduction in both serum urea nitrogen and normalized protein nitrogen appearance rate, while dietary protein intake was unchanged. Importantly, there were no serious adverse events.

Progression of glomerular and tubular disease in pediatrics

Chronic kidney disease may be stimulated by many different etiologies, but its progression involves a common, yet complex, series of events that lead to the replacement of normal tissue with scar. These events include altered physiology within the kidney leading to abnormal hemodynamics, chronic hypoxia, inflammation, cellular dysfunction, and activation of fibrogenic biochemical pathways. The end result is the replacement of normal structures with extracellular matrix. Treatments presently are focused on delaying or preventing such progression, and are largely nonspecific. In pediatrics, such therapy is complicated further by pathophysiological issues that render children a unique population.

The C-terminal cytoplasmic domain of human proEGF is a negative modulator of body and organ weights in transgenic mice

We generated transgenic mice to study the in vivo role of the cytoplasmic domain of human proEGF (proEGFcyt). Post-pubertal proEGFcyt transgenic (tg) mice displayed an up to 15% reduction in body weight, including smaller kidney and brain weights as compared to control littermates. Renal histology, gene expression profiles, and functional parameters were normal. In both sexes, serum levels of IGFBP-3 were reduced. Circulating IGF-I/IGF-II levels were unchanged. Histomorphological analysis revealed isolated foci of liver necrosis specific to proEGFcyt tg mice. In conclusion, we identified proEGF cytoplasmic domain as a novel modulator of whole body and organ-specific growth in mice.

Metabolic abnormalities in chronic kidney disease that contribute to cardiovascular disease, and nutritional initiatives that may diminish the risk

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with a wide range of severe metabolic and nutritional disturbances that directly or indirectly contribute to left ventricular hypertrophy, ischemic heart disease, vascular calcification, heart failure and other manifestations of cardiovascular disease (CVD). The CVD mortality rate in CKD patients is far higher than in the general population, and CKD is today recognized as one of the most important risk factors for CVD. In this review, we discuss the links between metabolic abnormalities and CVD in CKD patients and nutritional initiatives that may reduce this risk.

RECENT FINDINGS

Certain nontraditional risk factors, such as protein-energy wasting, inflammation, and biomarkers reflecting bone and mineral disorders, are strong predictors of CVD mortality in CKD patients. Although several small nutritional intervention studies have been performed and nutritional guidelines have been introduced in order to minimize metabolic disorders and improve nutritional status, they have so far not been proven to reduce morbidity nor mortality.

SUMMARY

Although the pathophysiological mechanisms involved in the markedly increased CVD risk of CKD patients are becoming more evident, still few nutritional randomized controlled studies have been conducted in this high-risk patient group.

Gene therapy by electroporation for the treatment of chronic renal failure in companion animals

Background

Growth hormone-releasing hormone (GHRH) plasmid-based therapy for the treatment of chronic renal failure and its complications was examined. Companion dogs (13.1 ± 0.8 years, 29.4 ± 5.01 kg) and cats (13.2 ± 0.9 years, 8.5 ± 0.37 kg) received a single 0.4 mg or 0.1 mg species-specific plasmid injection, respectively, intramuscularly followed by electroporation, and analyzed up to 75 days post-treatment; controls underwent electroporation without plasmid administration.

Results

Plasmid-treated animals showed an increase in body weight (dogs 22.5% and cats 3.2%) compared to control animals, and displayed improved quality of life parameters including significant increases in appetite, activity, mentation and exercise tolerance levels. Insulin-like growth factor I (IGF-I, the downstream effector of GHRH) levels were increased in the plasmid treated animals. Hematological parameters were also significantly improved. Protein metabolism changes were observed suggesting a shift from a catabolic to an anabolic state in the treated animals. Blood urea nitrogen and creatinine did not show any significant changes suggesting maintenance of kidney function whereas the control animal's renal function deteriorated. Treated animals survived longer than control animals with 70% of dogs and 80% of cats surviving until study day 75. Only 17% and 40% of the control dogs and cats, respectively, survived to day 75.

Conclusion

Improved quality of life, survival and general well-being indicate that further investigation is warranted, and show the potential of a plasmid-based therapy by electroporation in preventing and managing complications of renal insufficiency.