Cardiopulmonary determinants of reduced exercise tolerance in Fabry disease.

Fabry disease (FD), also known as Anderson-Fabry disease, is a hereditary disorder of glycosphingolipid metabolism, caused by a deficiency of the lysosomal alpha-galactosidase A enzyme. This causes a progressive accumulation of glycosphingolipids in tissues and organs which represents the main pathogenetic mechanism of FD. The disease is progressive and multisystemic and is characterized by early symptoms and late complications (renal, cardiac and neurological dysfunction). Fatigue and exercise intolerance are early common symptoms in FD patients but the specific causes are still to be defined. In this narrative review, we deal with the contribution of cardiac and pulmonary dysfunctions in determining fatigue and exercise intolerance in FD patients.

Exploring Adiponectin in Autosomal Dominant Kidney Disease: Insight and Implications.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common monogenic disorder characterized by renal cysts and progressive renal failure. In kidney diseases, adipose tissue undergoes functional changes that have been associated with increased inflammation and insulin resistance mediated by release of adipokines. Adiponectin is involved in various cellular processes, such as energy and inflammatory and oxidative processes. However, it remains to be determined whether adiponectin is involved in the concomitant metabolic dysfunctions present in PKD. In this scenario, we aimed to analyze: (a) PPARγ, ADIPOQ, ADIPOR1 and ADIPOR2 gene variations in 92 ADPKD patients through PCR-Sanger sequencing; and (b) adiponectin levels and its oligomerization state by ELISA and Western Blot. Our results indicated that: (a) 14 patients carried the PPARγ SNP, 29 patients carried the ADIPOQ SNP rs1501299, and 25 patients carried the analyzed ADIPOR1 SNPs. Finally, 82 patients carried ADIPOR2 SNPs; and (b) Adiponectin is statistically lower in ADPKD patients compared to controls, and further statistically lower in ESRD than in non-ESRD patients. An inverse relationship between adiponectin and albumin and between adiponectin and creatinine and a direct relationship between adiponectin and eGFR were found. Interestingly, significantly lower levels of adiponectin were found in patients bearing the ADIPOQ rs1501299 SNP and associated with low levels of eGFR. In conclusion, adiponectin levels and the presence of ADIPOQ rs1501299 genotype are significantly associated with a worse ADPKD phenotype, indicating that both could potentially provide important insights into the disease. Further studies are warranted to understand the pathophysiological role of adiponectin in ADPKD patients.

Diet and Physical Activity in Fabry Disease: A Narrative Review.

Fabry disease (FD) is caused by mutations in the galactosidase alpha (GLA) gene which lead to the accumulation of globotriaosylceramide (Gb-3). Enzyme replacement therapy (ERT) and oral chaperone therapy are the current pharmacological treatments for this condition. However, in the literature, there is a growing emphasis on exploring non-pharmacological therapeutic strategies to improve the quality of life of patients with FD. In particular, the nutritional approach to FD has been marginally addressed in the scientific literature, although specific dietary interventions may be useful for the management of nephropathy and gastrointestinal complications, which are often present in patients with FD. Especially in cases of confirmed diagnosis of irritable bowel syndrome (IBS), a low-FODMAP diet can represent an effective approach to improving intestinal manifestations. Furthermore, it is known that some food components, such as polyphenols, may be able to modulate some pathogenetic mechanisms underlying the disease, such as inflammation and oxidative stress. Therefore, the use of healthy dietary patterns should be encouraged in this patient group. Sports practice can be useful for patients with multi-organ involvement, particularly in cardiovascular, renal, and neurological aspects. Therefore, the aim of this review is to summarize current knowledge on the role of nutrition and physical activity in FD patients.

Residents' satisfaction and suggestions to improve nephrology residency in Italy, and comparison with the organization in other European countries.

BACKGROUND: In Italy, nephrology residency is available in twenty-one nephrology schools, each with its own strengths and weaknesses. The present study is aimed at exploring the residents' satisfaction with their training programs. METHODS: Between April 20th and May 19th, 2021, a questionnaire on residency satisfaction consisting of 49 items was sent to 586 residents and 175 recently certified specialists (qualified to practice as nephrologists in 2019 and 2020), with a response rate of 81% and 51%, respectively. The teaching organization was contextualized with a survey involving 13 European nephrology schools. RESULTS: Most residency fellowship programs received a good rating with regard to "satisfaction", in particular for the following items: number of hospitalizations followed-up, chronic hemodialysis training, follow-up of transplanted patients, diagnosis and treatment of glomerulonephritis. The teachings that were identified as being of lower quality or insufficient intensity included vascular access management, ultrasound diagnostics and renal nutrition. The need for improvement in formal teaching programs was underlined. Young nephrologists were rather satisfied with their salary and with the quality of the work they were doing, but only few were interested in an academic career since it was generally held that it is "too difficult" to obtain a university position. Many young nephrologists who filled in the questionnaire felt that lack of experience in peritoneal dialysis and vascular access management was a barrier to finding an ideal job. Compared to other European training programs, the Italian program differs with regard to longer exposure to nephrology (as compared to internal medicine), and greater flexibility for internships in different settings, including abroad. CONCLUSIONS: This first nationwide survey on the satisfaction of residents in nephrology indicates that, despite rather good overall satisfaction, there is room for improvement to make nephrology a more appealing choice and to fulfill the needs of a growing number of renal disease patients.

[Type I Hyperprolinemia - What about the Kidney?]

Hyperprolinemia is a rare genetic condition due to mutations in proline metabolic pathway. Type I Hyperprolinemia (HPI) typically causes neuropsychiatric disorders, and diagnosis is usually confirmed in pediatric population with suggestive neuropsychiatric involvement by elevated serum proline levels and elevated urinary proline, hydroxyproline, and glycine levels. The possible coexistence of nephropathy in patients with HPI, often specified as malformative urinary disease, is often mentioned. However, reports of HPI diagnosis due to kidney impairment do not exist in scientific literature yet. Here we present the case of a patient presenting with chronic kidney disease secondary to obstructive nephropathy who received a HPI diagnosis in adulthood. Interestingly, the family study showed the same 22q11.21 deletion and elevated blood proline levels in the father, who had no clinical anomalies. We therefore suggest, in light of the high frequency of mutations involving 22q11 and PRODH in the general population, to consider these rare alterations in patients with congenital urinary malformations, even in the presence of nuanced neurological symptoms and negative family history.

Molecular Diagnosis and Identification of Novel Pathogenic Variants in a Large Cohort of Italian Patients Affected by Polycystic Kidney Diseases.

Polycystic Kidney Diseases (PKDs) consist of a genetically and phenotypically heterogeneous group of inherited disorders characterized by numerous renal cysts. PKDs include autosomal dominant ADPKD, autosomal recessive ARPKD and atypical forms. Here, we analyzed 255 Italian patients using an NGS panel of 63 genes, plus Sanger sequencing of exon 1 of the PKD1 gene and MPLA (PKD1, PKD2 and PKHD1) analysis. Overall, 167 patients bore pathogenic/likely pathogenic variants in dominant genes, and 5 patients in recessive genes. Four patients were carriers of one pathogenic/likely pathogenic recessive variant. A total of 24 patients had a VUS variant in dominant genes, 8 patients in recessive genes and 15 patients were carriers of one VUS variant in recessive genes. Finally, in 32 patients we could not reveal any variant. Regarding the global diagnostic status, 69% of total patients bore pathogenic/likely pathogenic variants, 18.4% VUS variants and in 12.6% of patients we could not find any. PKD1 and PKD2 resulted to be the most mutated genes; additional genes were UMOD and GANAB. Among recessive genes, PKHD1 was the most mutated gene. An analysis of eGFR values showed that patients with truncating variants had a more severe phenotype. In conclusion, our study confirmed the high degree of genetic complexity at the basis of PKDs and highlighted the crucial role of molecular characterization in patients with suspicious clinical diagnosis. An accurate and early molecular diagnosis is essential to adopt the appropriate therapeutic protocol and represents a predictive factor for family members.

Home-based exercise in patients on maintenance dialysis: a systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The impact of home-based exercise on physical performance and quality of life (QoL) in patients on maintenance dialysis has not yet been fully established. METHODS: We searched four large electronic databases to identify randomized controlled trials (RCTs) reporting the impact of home-based exercise interventions vs. usual care or intradialytic exercise interventions, on physical performance and QoL in patients on dialysis. The meta-analysis was performed using fixed effects modeling. RESULTS: We included 12 unique RCTs involving 791 patients of various ages on maintenance dialysis. Home-based exercise interventions were associated with an improvement of walking speed at the 6 Minutes Walking Test [6MWT; nine RCTs; pooled weighted mean differences (WMD): 33.7 m, 95% confidence interval (CI) 22.8-44.5; P < 0.001; I2 = 0%) and in aerobic capacity as assessed by the peak oxygen consumption (VO2 peak; 3 RCTs; pooled WMD: 2.04 ml/kg/min, 95% CI 0.25-3.83; P = 0.03; I2 = 0%). They were also associated with improved QoL, as assessed by the Short Form (36) Health (SF-36) score. Stratifying the RCTs by control groups, no significant difference was found between home-based exercise and intradialytic exercise interventions. Funnel plots did not reveal any significant publication bias. CONCLUSIONS: Our systematic review and meta-analysis showed that home-based exercise interventions for 3-6 months were associated with significant improvements in physical performance in patients on maintenance dialysis. However, further RCTs with a longer follow-up should be conducted to assess the safety, adherence, feasibility, and effects on QoL of home-based exercise programs in dialysis patients.

Familial polycystic kidneys with no genetic confirmation: Are we sure it is ADPKD?

Autosomal dominant polycystic kidney disease (ADPKD) is the most common heritable multifocal cystic disease encountered in clinical practice, and it is usually diagnosed in patients with family history by the evidence of markedly enlarged kidneys with multiple bilateral cysts at ultrasound (U.S.), computed tomography (CT) scan, or magnetic resonance imaging (MRI). In most cases, genetic testing is not required. Though ADPKD diagnosis is often straightforward, misdiagnosis is possible. Here we present a case of ADPKD misdiagnosis, followed by a review of the most important kidney heritable multifocal cystic diseases. Our case report demonstrates that ADPKD can be erroneously diagnosed when other kidney heritable multifocal cystic diseases occur without their distinguishing manifestations and when there is no genetic characterization among the relatives. A proper diagnosis of heritable diseases is crucial, as it allows an appropriate management of family members who carry disease allele, apart from patient management. Therefore, we suggest a careful differential diagnosis with possible molecular genetic analysis in presentations with familial cystic kidneys and suspicious clinical and radiological features.

RAAS Inhibitor Prescription and Hyperkalemia Event in Patients With Chronic Kidney Disease: A Single-Center Retrospective Study.

Hyperkalemia is common in patients treated with renin-angiotensin-aldosterone system inhibitors (RAASis), and it represents the main cause of the large gap reported between guideline recommendations and real-world practice in chronic kidney disease (CKD). We conducted a CKD-population-based restrospective study to determine the prevalence of patients with CKD treated with RAASis, incidence of hyperkalemia in patients with CKD treated with RAASis, and proportion of patients with RAASi medication change after experiencing incident hyperkalemia. Among 809 patients with CKD analyzed, 556 (68.7%) were treated with RAASis, and RAASi prescription was greater in stages 2-4 of CKD. Hyperkalemia occurred in 9.2% of RAASi-treated patients, and the adjusted rate of hyperkalemia among patients with stage 4-5 CKD was 3-fold higher compared with patients with eGFR > 60 ml/min/1.73 m2. RAASi treatment was discontinued in 55.3% of the patients after hyperkalemia event (74.2% discontinued therapy, 3.2% received a reduced dose, and 22.6% reduced the number of RAASi drugs). This study shows that the incidence of hyperkalemia is frequently observed in patients with CKD patients with RAASis, and that rates increase with deteriorating levels of kidney function from stages 1 to 3. RAASi medication change following an episode of hyperkalemia occurred in almost half of the patients after experiencing hyperkalemia.

Therapeutic advances in ADPKD: the future awaits.

Autosomal dominant polycystic kidney disease (ADPKD) is a heterogeneous genetic disorder included in ciliopathies, representing the fourth cause of end stage renal disease (ESRD), with an estimated prevalence between 1:1000 and 1:2500. It is mainly caused by mutations in the PKD1 and PKD2 genes encoding for polycystin 1 (PC1) and polycystin 2 (PC2), which regulate differentiation, proliferation, survival, apoptosis, and autophagy. The advances in the knowledge of multiple molecular pathways involved in the pathophysiology of ADPKD led to the development of several treatments which are currently under investigation. Recently, the widespread approval of tolvaptan and, in Italy, of long-acting release octreotide (octreotide-LAR), represents but the beginning of the new therapeutic management of ADPKD patients. Encouraging results are expected from ongoing randomized controlled trials (RCTs), which are investigating not only drugs acting on the calcium/cyclic adenosin monoposphate (cAMP) pathway, the most studied target so far, but also molecules targeting specific pathophysiological pathways (e.g. epidermal growth factor (EGF) receptor, AMP-activated protein kinase (AMPK) and KEAP1-Nrf2) and sphingolipids. Moreover, studies on animal models and cultured cells have also provided further promising therapeutic strategies based on the role of intracellular calcium, cell cycle regulation, MAPK pathway, epigenetic DNA, interstitial inflammation, and cell therapy. Thus, in a near future, tailored therapy could be the key to changing the natural history of ADPKD thanks to the vigorous efforts that are being made to implement clinical and preclinical studies in this field. Our review aimed to summarize the spectrum of drugs that are available in the clinical practice and the most promising molecules undergoing clinical, animal, and cultured cell studies.

Stepwise shortening of agalsidase beta infusion duration in Fabry disease: Clinical experience with infusion rate escalation protocol.

BACKGROUND: Although enzyme replacement therapy with agalsidase beta resulted in a variety of clinical benefits, life-long biweekly intravenous infusion may impact on patients' quality of life. Moreover, regular infusions are time-consuming: although a stepwise shortening of infusion duration is allowed up to a minimum of 1.5 hr, in most centers it remains ≥3 hr, and no data exists about the safety and tolerability of agalsidase beta administration at maximum tolerated infusion rate. METHODS: In this study, we reported our experience with a stepwise infusion rate escalation protocol developed in our center in a cohort of 53 Fabry patients (both already receiving and treatment-naΪve), and explored factors predictive for the infusion rate increase tolerability. RESULTS: Fifty-two patients (98%) reduced infusion duration ≤3 hr; of these, 38 (72%) even reached a duration ≤2 hr. We found a significant difference between the mean duration reached by already treated and naΪve patients (p < .01). More severely affected patients (male patients and those with lower enzyme activity) received longer infusions for higher risk of infusion-associated reactions (IARs). A significant correlation between anti-agalsidase antibodies and IARs was found. CONCLUSION: Our infusion rate escalation protocol is safe and could improve patient compliance, satisfaction and quality of life.

[Tolvaptan in ADPKD: a turning point or an unsustainable therapy? One year of "real life" experience].

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent monogenic kidney disease, alone responsible for over 10% of patients with end-stage renal disease, and with an important impact on public health. Tolvaptan (TOLV) has recently been approved in many European countries for its ability to slow disease progression in patients that are eligible for treatment. Nevertheless, the doctor's choice to prescribe the drug and the patient's compliance are strongly influenced by the aquaretic effect complications. In a cohort of patients pertaining to the Nephrology clinic of the AOU Federico II of Naples and treated with TOLV, we assessed not only the adherence to the treatment and the safety of the drug, but also the real feasibility of this therapy through specific questionnaires on sleep quality, abdominal-renal pain, quality of life and patients' general satisfaction. Within the limits of preliminary data and on the basis of the responses of our population, followed for a period of at least one year and administered the maximum titration dosage, it can be asserted that the doubts regarding the real compliance of the patients can be overcome.

Plasma p-cresol lowering effect of sevelamer in non-dialysis CKD patients: evidence from a randomized controlled trial.

BACKGROUND: The accumulation of p-cresol, a metabolic product of aromatic amino acids generated by intestinal microbiome, increases the cardiovascular risk in chronic kidney disease (CKD) patients. Therefore, therapeutic strategies to reduce plasma p-cresol levels are highly demanded. It has been reported that the phosphate binder sevelamer (SEV) sequesters p-cresol in vitro, while in vivo studies on dialysis patients showed controversial results. Aim of our study was to evaluate the effect of SEV on p-cresol levels in non-dialysis CKD patients. METHODS: This was a single-blind, randomized placebo-controlled trial (Registration number NCT02199444) carried on 69 CKD patients (stage 3-5, not on dialysis), randomly assigned (1:1) to receive either SEV or placebo for 3 months. Total p-cresol serum levels were evaluated at baseline (T0), and 1 (T1) and 3 months (T3) after treatment start. The primary end-point was to evaluate the effect of SEV on p-cresol levels. RESULTS: Compared to baseline (T0, 7.4 ± 2.7 mg/mL), p-cresol mean concentration was significantly reduced in SEV patients after one (- 2.06 mg/mL, 95% CI - 2.62 to - 1.50 mg/mL; p < 0.001) and 3 months of treatment (- 3.97 mg/mL, 95% CI - 4.53 to - 3.41 mg/mL; p < 0.001); no change of plasma p-cresol concentration was recorded in placebo-treated patients. Moreover, P and LDL values were reduced after 3 months of treatment by SEV but not placebo. CONCLUSIONS: In conclusion, our study represents the first evidence that SEV is effective in reducing p-cresol levels in CKD patients in conservative treatment, and confirms its beneficial effects on inflammation and lipid pattern.