A randomized, open-label, clinical trial examined the effects of canagliflozin on albuminuria and eGFR decline using an individual pre-intervention eGFR slope.

Demonstrating drug efficacy in slowing kidney disease progression requires large clinical trials when targeting participants with an early stage of chronic kidney disease (CKD). In this randomized, parallel-group, open-labeled trial (CANPIONE study), we assessed the effect of the sodium-glucose cotransporter 2 (SGLT2) inhibitor canagliflozin using the individual's change in estimated glomerular filtration rate (eGFR) slope before (pre-intervention slope) and during treatment (chronic slope). We randomly assigned (1:1) participants with type 2 diabetes, urinary albumin-to-creatinine ratio (UACR) of 50 to under 300 mg/g, and an eGFR of at least 45 ml/min/1.73m2 to receive canagliflozin or guideline-recommended treatment except for SGLT2 inhibitors (control). The first and second primary outcomes were the geometric mean percentage change from baseline in UACR and the change in eGFR slope, respectively. Of 98 randomized participants, 96 received at least one study treatment. The least-squares mean change from baseline in log-transformed geometric mean UACR was significantly greater in the canagliflozin group than the control group (between group-difference, -30.8% (95% confidence interval -42.6 to -16.8). The between-group difference (canagliflozin group - control group) of change in eGFR slope (chronic - pre-intervention) was 4.4 (1.6 to 7.3) ml/min/1.73 m2 per year, which was more pronounced in participants with faster eGFR decline. In summary, canagliflozin reduced albuminuria and the participant-specific natural course of eGFR decline in participants with type 2 diabetes and microalbuminuria. Thus, the CANPIONE study suggests that the within-individual change in eGFR slope may be a novel approach to determine the kidney protective potential of new therapies in early stages of CKD.

Rationale, design and baseline characteristics of the effect of canagliflozin in patients with type 2 diabetes and microalbuminuria in the Japanese population: The CANPIONE study.

AIM: To evaluate the effect of canagliflozin, a sodium-glucose co-transporter-2 (SGLT2) inhibitor, on albuminuria and the decline of estimated glomerular filtration rate (eGFR) in participants with type 2 diabetes and microalbuminuria. METHODS: The CANPIONE study is a multicentre, randomized, parallel-group and open-labelled study consisting of a unique 24-week preintervention period, during which the rate of eGFR decline before intervention is estimated, followed by a 52-week intervention and a 4-week washout period. Participants with a geometric mean urinary albumin-to-creatinine ratio (UACR) of 50 and higher and less than 300 mg/g in two consecutive first-morning voids at two different time points, and an eGFR of 45 ml/min/1.73m2 or higher, are randomly assigned to receive canagliflozin 100 mg daily or to continue guideline-recommended treatment, except for SGLT2 inhibitors. The first primary outcome is the change in UACR, and the second primary outcome is the change in eGFR slope. RESULTS: A total of 258 participants were screened and 98 were randomized at 21 sites in Japan from August 2018 to May 2021. The mean baseline age was 61.4 years and 25.8% were female. The mean HbA1c was 7.9%, mean eGFR was 74.1 ml/min/1.73m2 and median UACR was 104.2 mg/g. CONCLUSIONS: The CANPIONE study will determine whether the SGLT2 inhibitor canagliflozin can reduce albuminuria and slow eGFR decline in participants with type 2 diabetes and microalbuminuria.

Human PTRF mutations cause secondary deficiency of caveolins resulting in muscular dystrophy with generalized lipodystrophy.

Caveolae are invaginations of the plasma membrane involved in many cellular processes, including clathrin-independent endocytosis, cholesterol transport, and signal transduction. They are characterized by the presence of caveolin proteins. Mutations that cause deficiency in caveolin-3, which is expressed exclusively in skeletal and cardiac muscle, have been linked to muscular dystrophy. Polymerase I and transcript release factor (PTRF; also known as cavin) is a caveolar-associated protein suggested to play an essential role in the formation of caveolae and the stabilization of caveolins. Here, we identified PTRF mutations in 5 nonconsanguineous patients who presented with both generalized lipodystrophy and muscular dystrophy. Muscle hypertrophy, muscle mounding, mild metabolic complications, and elevated serum creatine kinase levels were observed in these patients. Skeletal muscle biopsies revealed chronic dystrophic changes, deficiency and mislocalization of all 3 caveolin family members, and reduction of caveolae structure. We generated expression constructs recapitulating the human mutations; upon overexpression in myoblasts, these mutations resulted in PTRF mislocalization and disrupted physical interaction with caveolins. Our data confirm that PTRF is essential for formation of caveolae and proper localization of caveolins in human cells and suggest that clinical features observed in the patients with PTRF mutations are associated with a secondary deficiency of caveolins.