Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Knowledge, attitude and practice on standard precautions for prevention of HIV infection among clinical year medical students

BACKGROUND

Human Immunodeficiency Virus (HIV) can be transmitted through blood, vaginal secretion, infected semen, breast milk as well as blood containing saliva, vomitus and urine. Health care workers (HCWs) are at risk of HIV infection; and standard precautions is a guideline to be followed by HCWs to prevent it.

OBJECTIVE

This study was aimed to evaluate the level of knowledge, attitude and practice on standard precautions for prevention of HIV infection; and its associated factors.

MATERIALS AND METHODS

This cross-sectional study was conducted among 200 clinical year medical students from a public university in Malaysia. The clinical year medical students were arranged into strata according to year of study and were randomly selected via stratified random sampling. Each respondent were provided a selfadministered questionnaire. There were four sections in the questionnaire to obtain information on socio-demographic characteristics, knowledge, attitude and practice on standard precautions. Both descriptive and analytical analyses such as Chi-squared test were performed.

RESULTS

A total of 162 respondents participated in this study, contributed to the response rate of 81%. The study demonstrated that there was no significant association between level of practice with socio-demographic characteristics such as gender, ethnicity, age, religion, year of study and total family income. However, there was a significant association between level of practice with level of knowledge and attitude (p<0.05). For every one year increase in age, the respondents were 1.7 times (p=0.001) and 1.5 times (p=0.012) more likely to have knowledge score between 50th and 75th percentile and above 75th percentile compared to below 50th percentile, respectively.

CONCLUSION

It could be interpreted from the findings, that there is a need for further improvement in the knowledge and attitude level among the respondents; which will eventually improve their practice.

Sequence analysis of E/NS1 gene junction of Dengue Type-1 viruses isolated in Klang Valley 2010 to 2012

Dengue is a mosquito-borne viral disease caused by four serotypes of dengue virus, affecting the human population for decades in many tropical and subtropical regions of the world. In Malaysia, all four dengue serotypes co-circulates in a dengue season even though any one of the serotypes can predominate. In this study, serum samples were collected from dengue fever and severe dengue fever patients within Klang Valley from 2010-2012 to determine the prevailing dengue serotypes. In addition, sequencing of the envelope/nonstructural 1 (E/NS1) gene junction of the virus isolated was performed to identify the presence of any mutations that are suggestive of increased virulence in the virus. The results showed that Dengue-1 (DEN-1) was the predominant circulating serotype. The E/NS1 gene sequences of the isolates were analysed to trace the evolutionary knowledge of the strains. All sequences of the isolates were compared with DEN-1 prototype Hawaii strain as the reference sequence. The E/NS1 sequences of other dengue strains from neighbouring regions as well as other parts of the world obtained from the GenBank database were also included in the phylogenetic tree analysis. Analyses showed that there was 97% to 100% similarity among the ten isolates at the nucleotide level. Similarly, the amino acid analogue also showed 98% to 100% homology. However, all five non-severe dengue isolates showed variation at position 780, resulting in an amino acid change from valine to alanine as compared to severe dengue isolates. A rooted phylogenetic tree was performed using neighbour-joining method with DEN-2 and DEN-3 as the outgroups. Results showed that all ten isolates were classified as genotype I. In addition, the five isolates from severe dengue patients were found to be clustered together with JN697057 and JN697058, Malaysian DEN-1 strains from the 2005 outbreak.

Strain-dependent host transcriptional responses to Toxoplasma infection are largely conserved in mammalian and avian hosts

Toxoplasma gondii has a remarkable ability to infect an enormous variety of mammalian and avian species. Given this, it is surprising that three strains (Types I/II/III) account for the majority of isolates from Europe/North America. The selective pressures that have driven the emergence of these particular strains, however, remain enigmatic. We hypothesized that strain selection might be partially driven by adaptation of strains for mammalian versus avian hosts. To test this, we examine in vitro, strain-dependent host responses in fibroblasts of a representative avian host, the chicken (Gallus gallus). Using gene expression profiling of infected chicken embryonic fibroblasts and pathway analysis to assess host response, we show here that chicken cells respond with distinct transcriptional profiles upon infection with Type II versus III strains that are reminiscent of profiles observed in mammalian cells. To identify the parasite drivers of these differences, chicken fibroblasts were infected with individual F1 progeny of a Type II x III cross and host gene expression was assessed for each by microarray. QTL mapping of transcriptional differences suggested, and deletion strains confirmed, that, as in mammalian cells, the polymorphic rhoptry kinase ROP16 is the major driver of strain-specific responses. We originally hypothesized that comparing avian versus mammalian host response might reveal an inversion in parasite strain-dependent phenotypes; specifically, for polymorphic effectors like ROP16, we hypothesized that the allele with most activity in mammalian cells might be less active in avian cells. Instead, we found that activity of ROP16 alleles appears to be conserved across host species; moreover, additional parasite loci that were previously mapped for strain-specific effects on mammalian response showed similar strain-specific effects in chicken cells. These results indicate that if different hosts select for different parasite genotypes, the selection operates downstream of the signaling occurring during the beginning of the host's immune response.

Toxoplasma polymorphic effectors determine macrophage polarization and intestinal inflammation

European and North American strains of the parasite Toxoplasma gondii belong to three distinct clonal lineages, type I, type II, and type III, which differ in virulence. Understanding the basis of Toxoplasma strain differences and how secreted effectors work to achieve chronic infection is a major goal of current research. Here we show that type I and III infected macrophages, a cell type required for host immunity to Toxoplasma, are alternatively activated, while type II infected macrophages are classically activated. The Toxoplasma rhoptry kinase ROP16, which activates STAT6, is responsible for alternative activation. The Toxoplasma dense granule protein GRA15, which activates NF-κB, promotes classical activation by type II parasites. These effectors antagonistically regulate many of the same genes, and mice infected with type II parasites expressing type I ROP16 are protected against Toxoplasma-induced ileitis. Thus, polymorphisms in determinants that modulate macrophage activation influence the ability of Toxoplasma to establish a chronic infection.

Toxoplasma rhoptry protein 16 (ROP16) subverts host function by direct tyrosine phosphorylation of STAT6

The obligate intracellular parasite, Toxoplasma gondii, modulates host immunity in a variety of highly specific ways. Previous work revealed a polymorphic, injected parasite factor, ROP16, to be a key virulence determinant and regulator of host cell transcription. These properties were shown to be partially mediated by dysregulation of the host transcription factors STAT3 and STAT6, but the molecular mechanisms underlying this phenotype were unclear. Here, we use a Type I Toxoplasma strain deficient in ROP16 to show that ROP16 induces not only sustained activation but also an extremely rapid (within 1 min) initial activation of STAT6. Using recombinant wild-type and kinase-deficient ROP16, we demonstrate in vitro that ROP16 has intrinsic tyrosine kinase activity and is capable of directly phosphorylating the key tyrosine residue for STAT6 activation, Tyr(641). Furthermore, ROP16 co-immunoprecipitates with STAT6 from infected cells. Taken together, these data strongly suggest that STAT6 is a direct substrate for ROP16 in vivo.

Coordinated loading of IRG resistance GTPases on to the Toxoplasma gondii parasitophorous vacuole

The immunity-related GTPases (IRGs) constitute an interferon-induced intracellular resistance mechanism in mice against Toxoplasma gondii. IRG proteins accumulate on the parasitophorous vacuole membrane (PVM), leading to its disruption and to death of the parasite. How IRGs target the PVM is unknown. We show that accumulation of IRGs on the PVM begins minutes after parasite invasion and increases for about 1 h. Targeting occurs independently of several signalling pathways and the microtubule network, suggesting that IRG transport is diffusion-driven. The intensity of IRG accumulation on the PVM, however, is reduced in absence of the autophagy regulator, Atg5. In wild-type cells IRG proteins accumulate cooperatively on PVMs in a definite order reflecting a temporal hierarchy, with Irgb6 and Irgb10 apparently acting as pioneers. Loading of IRG proteins onto the vacuoles of virulent Toxoplasma strains is attenuated and the two pioneer IRGs are the most affected. The polymorphic rhoptry kinases, ROP16, ROP18 and the catalytically inactive proteins, ROP5A–D, are not individually responsible for this effect. Thus IRG proteins protect mice against avirulent strains of Toxoplasma but fail against virulent strains. The complex cooperative behaviour of IRG proteins in resisting Toxoplasma may hint at undiscovered complexity also in virulence mechanisms.

Directed evolution of ligand dependence: small-molecule-activated protein splicing

Artificial molecular switches that modulate protein activities in response to synthetic small molecules would serve as tools for exerting temporal and dose-dependent control over protein function. Self-splicing protein elements (inteins) are attractive starting points for the creation of such switches, because their insertion into a protein blocks the target protein's function until splicing occurs. Natural inteins, however, are not known to be regulated by small molecules. We evolved an intein-based molecular switch that transduces binding of a small molecule into the activation of an arbitrary protein of interest. Simple insertion of a natural ligand-binding domain into a minimal intein destroys splicing activity. To restore activity in a ligand-dependent manner, we linked protein splicing to cell survival or fluorescence in Saccharomyces cerevisiae. Iterated cycles of mutagenesis and selection yielded inteins with strong splicing activities that highly depend on 4-hydroxytamoxifen. Insertion of an evolved intein into four unrelated proteins in living cells revealed that ligand-dependent activation of protein function is general, fairly rapid, dose-dependent, and posttranslational. Our directed-evolution approach therefore evolved small-molecule dependence in a protein and also created a general tool for modulating the function of arbitrary proteins in living cells with a single cell-permeable, synthetic small molecule.

Androgen receptor mutations causing human androgen insensitivity syndromes show a key role of residue M807 in Helix 8-Helix 10 interactions and in receptor ligand-binding domain stability

Transactivation activity of the androgen receptor (AR) is induced by the binding of an androgen to its ligand-binding domain (LBD). The tertiary architecture of the AR LBD, in common with other steroid/nuclear receptors, is a sandwich of 12 alpha-helices (H). We have encountered a missense substitution, M807T, which was associated with partially defective androgen binding in a 46,XY infant with ambiguous genitalia. In contrast, two other substitutions in the same residue 807 to valine and arginine, resulted in almost total abrogation of androgen-binding and complete androgen insensitivity syndrome in two unrelated individuals. We recreated these substitutions in residue 807 and observed that disruption of ligand-binding and transactivation activities was total for M807R and partial for M807V, while the least-affected was M807T. Modelling of the AR LBD indicate that van der Waal interactions between residue 807 (H8) to H9 and H10 were severely disrupted for the arginine mutant, but relatively preserved for the threonine and valine mutants. However, there was a subtle difference between these two variants in that M807T, but not M807V, improved van der Waal contacts with another residue L859 in H10, suggesting the importance of interactions between M807 and L859 for LBD stability. Atomic distances of M807 (H8) to L859 (H10) in corresponding residues of the distantly related ER alpha, RXR alpha, PPAR gamma and VDR LBD are highly conserved and almost invariant, suggesting that H8/H10 interactions are critical for LBD stability in other members of the steroid/nuclear receptor superfamily.

Androgen receptor polymorphisms and mutations in male infertility

Normal spermatogenesis depends on a sequential cascade of genetic events triggered by factors encoded by sex chromosomes. To determine the contribution of genetic aberrations to male infertility, the X-linked androgen receptor (AR) gene was examined for mutations and polymorphisms in a large cohort of infertile men. Genetic screening of over 400 patients and controls showed that defects in the AR gene lead to the production of dysfunctional receptor protein in up to 10% of males with abnormally low sperm production and male infertility. The dozens of mutations and polymorphisms uncovered were associated with subtly reduced intrinsic AR activity, and are of two main categories: polymorphic changes in length of a trinucleotide CAG tract in the N-terminal transactivation domain, and missense mutations in the C-terminal ligand-binding domain. These polymorphisms and mutations are associated with reduced AR function due to defective intermolecular protein-protein interactions with coactivator molecules. Genetic screening for AR mutations and polymorphism should be offered to severely oligospermic and azoospermic patients. These traits can be transmitted to progeny, and counseling can be offered to affected families. Clarification of the molecular mechanisms of pathogenesis has led to rational hormonal therapy.

Genetics of male infertility: role of androgen receptor mutations and Y-microdeletions

INTRODUCTION

Although infertility affects about 5% of the male population, its cause in most cases is uncertain. Normal spermatogenesis depends on a sequential cascade of genetic events triggered by factors encoded by the sex chromosomes. To determine the contribution of genetic aberrations to male infertility, the X-linked androgen receptor gene and the Y-chromosome were examined for mutations in a large cohort of infertile men.

METHODS

Screening of the androgen receptor (AR) gene for single-stranded conformation polymorphisms, confirmation by DNA sequencing, structure-function studies with androgen-responsive reporter genes and chimeric-protein constructs were performed. Y-chromosome microdeletions screening was done with multiplex polymerase chain reaction (PCR) analyses.

RESULTS

Genetic screening of over 400 patients and controls showed that defects in the androgen receptor gene lead to the production of dysfunctional receptor protein in 15% of males with abnormally low sperm production. The dozens of mutations and polymorphisms uncovered were associated with reduced intrinsic androgen receptor activity and involve principally two regions of the androgen receptor. Gene-transfer experiments implicated defective intermolecular protein-protein interactions with coactivator molecules as the cause of reduced receptor function. Submicroscopic deletions of the Y-chromosome were also been detected in about 6% of patients with severely reduced spermatogenesis. The deleted segments encoded RNA-binding proteins of unknown function and are not linked to defects in the androgen receptor.

CONCLUSIONS

Mutations and polymorphisms of the AR, and Y-microdeletions cause defective sperm production and male infertility in about 20% of subfertile men. These traits can be transmitted to progeny, and counselling can be offered to affected families. Clarification of the molecular mechanisms of pathogenesis has led to rational hormonal therapy.

Panax (ginseng)--panacea or placebo? Molecular and cellular basis of its pharmacological activity

INTRODUCTION

The use of ethnobotanical drugs amongst Asians as complementary medicine is prevalent and is also gaining increasing popularity in the West. The most well-known herb traditionally used as a drug is the root of the ginseng species. There are many traditional and anecdotal claims to the therapeutic properties of ginseng. In recent years, there have been systematic efforts to analyse the bioactivities of ginseng saponins.

METHODS

A comprehensive review of published literature covering molecular and cellular research as well as animal and human studies on ginseng and its derivatives.

RESULTS AND CONCLUSION

Current published data would serve as a framework to understand the pharmacology of ginseng in its entirety, from its molecular action to actual therapeutic effects observed in human use. A new paradigm is emerging whereby the pharmacological effects of traditional herbs such as ginseng can be understood in the light of their polyvalent actions as demonstrated by ginseng saponins with their positive anti-mutagenic, anti-cancer, anti-inflammatory, anti-diabetes and neurovascular effects. With increasing understanding, evidence-based incorporation of traditional herbs as complementary medicine into mainstream medical science can be achieved in the near future.

Directed pharmacological therapy of ambiguous genitalia due to an androgen receptor gene mutation

We report a 46,XY infant with an M807T mutation in his androgen receptor that abrogated cellular responses to testosterone, but not to dihydrotestosterone (DHT), resulting in ambiguous genitalia. Treatment with a topical DHT gel restored male genital development allowing the infant to be reared in accordance with his chromosomal sex.