Skeletal muscles contain resident immune cell populations and their abundance and type is altered in inflammatory myopathies, endotoxemia or different types of muscle injury/insult. Within tissues, ...monocytes differentiate into macrophages and polarize to acquire pro- or anti-inflammatory phenotypes. Skeletal muscle macrophages play a fundamental role in repair and pathogen clearance. These events require a precisely regulated cross-talk between myofibers and immune cells, involving paracrine/autocrine and contact interactions. Skeletal muscle also undergoes continuous repair as a result of contractile activity that involves participation of myokines and anti-inflammatory input. Finally, skeletal muscle is the major site of dietary glucose disposal; therefore, muscle insulin resistance is essential to the development of whole body insulin resistance. Notably, muscle inflammation is emerging as a potential contributor to insulin resistance. Recent reports show that inflammatory macrophage numbers within muscle are elevated during obesity and that muscle cells in vitro can mount autonomous inflammatory responses under metabolic challenge. Here, we review the nature of skeletal muscle inflammation associated with muscle exercise, damage, and regeneration, endotoxin presence, and myopathies, as well as the new evidence of local inflammation arising with obesity that potentially contributes to insulin resistance.
Chronic kidney disease (CKD) leads to uremia. CKD is characterized by a gradual increase in kidney fibrosis and loss of kidney function, which is associated with a progressive increase in risk of ...atherosclerosis and cardiovascular death. To prevent progression of both kidney fibrosis and atherosclerosis in uremic settings, insight into new treatment options with effects on both parameters is warranted. The GLP-1 analogue liraglutide improves glucose homeostasis, and is approved for treatment of type 2 diabetes. Animal studies suggest that GLP-1 also dampens inflammation and atherosclerosis. Our aim was to examine effects of liraglutide on kidney fibrosis and atherosclerosis in a mouse model of moderate uremia (5/6 nephrectomy (NX)). Uremic (n = 29) and sham-operated (n = 14) atherosclerosis-prone low density lipoprotein receptor knockout mice were treated with liraglutide (1000 μg/kg, s.c. once daily) or vehicle for 13 weeks. As expected, uremia increased aortic atherosclerosis. In the remnant kidneys from NX mice, flow cytometry revealed an increase in the number of monocyte-like cells (CD68+F4/80-), CD4+, and CD8+ T-cells, suggesting that moderate uremia induced kidney inflammation. Furthermore, markers of fibrosis (i.e. Col1a1 and Col3a1) were upregulated, and histological examinations showed increased glomerular diameter in NX mice. Importantly, liraglutide treatment attenuated atherosclerosis (~40%, p < 0.05) and reduced kidney inflammation in NX mice. There was no effect of liraglutide on expression of fibrosis markers and/or kidney histology. This study suggests that liraglutide has beneficial effects in a mouse model of moderate uremia by reducing atherosclerosis and attenuating kidney inflammation.
•Diabetic kidney disease (DKD) is a disease of high unmet therapeutic need.•Several drugs are in clinical development for treatment of DKD.•Rodent models of DKD show variable human ...translatability.•Selection of a preclinical rodent model of DKD should be based on drug target.•Rodent models of advanced DKD improve the ability to predict clinical outcomes.
Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD). Except for SGLT2 inhibitors and GLP-1R agonists, there have been few changes in DKD treatment over the past 25 years, when multifactorial intervention was introduced in patients with type 2 diabetes mellitus (T2DM). The unmet clinical need is partly due to the lack of animal models that replicate clinical features of human DKD, which has raised concern about the utility of these models in preclinical drug discovery. In this review, we performed a comprehensive analysis of rodent models of DKD to compare treatment efficacy from preclinical testing with outcome from clinical trials. We also investigated whether rodent models are predictive for clinical outcomes of therapeutic agents in human DKD.
Objective
In obesity, immune cells infiltrate adipose tissue. Skeletal muscle is the major tissue of insulin‐dependent glucose disposal, and indices of muscle inflammation arise during obesity, but ...whether and which immune cells increase in muscle remain unclear.
Methods
Immune cell presence in quadriceps muscle of wild type mice fed high‐fat diet (HFD) was studied for 3 days to 10 weeks, in CCL2‐KO mice fed HFD for 1 week, and in human muscle. Leukocyte presence was assessed by gene expression of lineage markers, cyto/chemokines and receptors; immunohistochemistry; and flow cytometry.
Results
After 1 week HFD, concomitantly with glucose intolerance, muscle gene expression of Ly6b, Emr1 (F4/80), Tnf, Ccl2, and Ccr2 rose, as did pro‐ and anti‐inflammatory markers Itgax (CD11c) and Mgl2. CD11c+ proinflammatory macrophages in muscle increased by 76%. After 10 weeks HFD, macrophages in muscle increased by 47%. Quadriceps from CCL2‐KO mice on HFD did not gain macrophages and maintained insulin sensitivity. Muscle of obese, glucose‐intolerant humans showed elevated CD68 (macrophage marker) and ITGAX, correlating with poor glucose disposal and adiposity.
Conclusion
Mouse and human skeletal muscles gain a distinct population of inflammatory macrophages upon HFD or obesity, linked to insulin resistance in humans and CCL2 availability in mice.
IntroductionDiabetic kidney disease is a severe complication of diabetes. The diagnosis is based on clinical characteristics such as persistently elevated albuminuria, hypertension and decline in ...kidney function, although this definition is not specific to kidney disease caused by diabetes. The only way to establish an accurate diagnosis—diabetic nephropathy—is by performing a kidney biopsy. The histological presentation of diabetic nephropathy can be associated with a heterogeneous range of histological features with many pathophysiological factors involved demonstrating the complexity of the condition. Current treatment strategies aim to slow disease progression and are not specific to the underlying pathological processes.This study will investigate the prevalence of diabetic nephropathy in individuals with type 2 diabetes (T2D) and severely elevated albuminuria. The deep molecular characterisation of the kidney biopsy and biological specimens may pave the way for improved diagnostic accuracy and a better understanding of the pathological processes involved and may also reveal new targets for individualised treatment.Methods and analysisIn the PRecIsion MEdicine based on kidney TIssue Molecular interrogation in diabetic nEphropathy 2 study, research kidney biopsies will be performed in 300 participants with T2D, urine albumin/creatinine ratio ≥700 mg/g and estimated glomerular filtration ratio >30 mL/min/1.73 m2. Cutting-edge molecular technologies will be applied to the kidney, blood, urine, faeces and saliva samples for comprehensive multi-omics profiling. The associated disease course and clinical outcomes will be assessed by annual follow-up for 20 years.Ethics and disseminationThe Danish Regional Committee on Health Research Ethics and the Knowledge Center on Data Protection (in the Capital Region of Denmark) have granted approval for the study. The results will be published in peer-reviewed journals.Trial registration numberNCT04916132.
Introduction: Emerging treatments of diabetic kidney disease (DKD) include SGLT2 inhibitors and GLP-1 receptor agonists that are nephroprotective beyond their blood glucose lowering effects. To ...confirm the translatability of a mouse model for drug discovery in DKD, we tested the efficacy of an ACE inhibitor and a SGLT2 inhibitor in the reninAAV UNx db/db mouse model.
Methods: Female db/db mice were injected with a renin-encoding adeno-associated virus construct (reninAAV) to induce hypertension and uninephrectomized (UNx). At 12 weeks of age, dosing with vehicle, lisinopril, empagliflozin, or the combination (combo) was initiated. Plasma and urine markers were measured after 12 weeks of dosing and terminal kidney samples were collected for 3D light sheet microscopy and 2D histology.
Results: In reninAAV UNx db/db mice, treatment with empagliflozin and combo reduced fed BG and HbA1c compared to vehicle. Treatment with lisinopril and combo reduced urine ACR and KIM1-to-creatinine compared to vehicle, while treatment with empagliflozin alone worsened urine ACR. Glomerular hypertrophy as assessed by 3D imaging was reduced in combo treated reninAAV UNx db/db mice compared to vehicle, while treatment with empagliflozin alone worsened glomerular hypertrophy. The total number of glomeruli per kidney was unaffected by treatments. Compared to vehicle treatment, lisinopril and combo treatment reduced the fraction of score 3+4 glomeruli, and glomerulosclerosis index (GSI) was reduced by with lisinopril and combo treatment. Treatment with empagliflozin alone worsened GSI. Morphometric analyses showed that lisinopril and combo treatment reduced kidney CD11b and KIM1 load.
Conclusion: Responses to the combination treatment with lisinopril and empagliflozin showed improvement of urine and histological markers of DKD. Together, these data confirm the translatability of the reninAAV UNx db/db mouse model of DKD.
Disclosure
M. V. Østergaard: None. M. Christensen: None. T. Secher: Employee; Self; Gubra, Employee; Spouse/Partner; Novo Nordisk, Stock/Shareholder; Self; Gubra, Stock/Shareholder; Spouse/Partner; Novo Nordisk. J. L. Skytte: None. U. Roostalu: Employee; Self; Gubra. C. G. Salinas: Employee; Self; Gubra, Employee; Spouse/Partner; Novo Nordisk, Stock/Shareholder; Spouse/Partner; Novo Nordisk. F. E. Sembach: None. L. N. Fink: Employee; Self; Gubra, Stock/Shareholder; Self; Novo Nordisk A/S. N. Vrang: Board Member; Self; Gubra, Employee; Self; Gubra, Stock/Shareholder; Self; Gubra.
Preterm neonates are susceptible to gastrointestinal disorders such as necrotizing enterocolitis (NEC). Maternal milk and colostrum protects against NEC via growth promoting, immunomodulatory, and ...antimicrobial factors. The fetal enteral diet amniotic fluid (AF), contains similar components, and we hypothesized that postnatal AF administration reduces inflammatory responses and NEC in preterm neonates. Preterm pigs (92% gestation) were delivered by caesarean section and fed parental nutrition (2 days) followed by enteral (2 days) porcine colostrum (COLOS, n = 7), infant formula (FORM, n = 13), or AF supplied before and after introduction of formula (AF, n = 10) in experiment 1, and supplied only during the enteral feeding period in experiment 2 (FORM, n = 16; AF, n = 14). The NEC score was reduced in both AF and COLOS pigs, relative to FORM, when AF was provided prior to full enteral feeding (9.9 and 7.7 compared with 17.3, P < 0.05). There was no effect of AF when provided only during enteral feeding. AF pigs showed decreased bacterial abundance in colon and intestinal inflammation-related genes (e.g., TNF-α, IL-1α, IL-6, NOS) were downregulated, relative to FORM pigs with NEC. Anti-inflammatory properties of AF were supported by delayed maturation and decreased TNF-α production in murine dendritic cells, as well as increased proliferation and migration, and downregulation of IL-6 expression in intestinal cells (IEC-6, IPEC-J2). Like colostrum, AF may reduce NEC development in preterm neonates by suppressing the proinflammatory responses to enteral formula feeding and gut colonization when provided before the onset of NEC.
Lactic acid bacteria (LAB) are abundant in the gastrointestinal tract where they continuously regulate the immune system. NK cells are potently activated by dendritic cells (DCs) matured by ...inflammatory stimuli, and NK cells are present in the gut epithelium and in mesenteric lymph nodes, but it is not known how NK–DC interactions are affected by the predominantly non-pathogenic LAB. We demonstrate that human DCs exposed to different strains of gut-derived LAB consistently induce proliferation, cytotoxicity and activation markers in autologous NK cells. On the contrary, strains of LAB differ greatly in their ability to induce DC-dependent IFN-γ production by NK cells. This suggests that DCs stimulated by gut LAB may expand the pool of NK cells and increase their cytotoxic potential. Specific LAB, inducing high levels of IL-12 in DCs, may promote amplification of a type-1 response via potent stimulation of IFN-γ production in NK cells. Combining IFN-γ-inducing and non-inducing LAB completely abrogates DC-mediated IFN-γ production by NK cells, and therefore LAB modulating IFN-γ production in NK cells may be important regulators of the immune response.
The current understanding of molecular mechanisms driving diabetic kidney disease (DKD) is limited, partly due to the complex structure of the kidney. To identify genes and signalling pathways ...involved in the progression of DKD, we compared kidney cortical versus glomerular transcriptome profiles in uninephrectomized (UNx) db/db mouse models of early-stage (UNx only) and advanced UNxplus adeno-associated virus-mediated renin-1 overexpression (UNx-Renin) DKD using RNAseq. Compared to normoglycemic db/m mice, db/db UNx and db/db UNx-Renin mice showed marked changes in their kidney cortical and glomerular gene expression profiles. UNx-Renin mice displayed more marked perturbations in gene components associated with the activation of the immune system and enhanced extracellular matrix remodelling, supporting histological hallmarks of progressive DKD in this model. Single-nucleus RNAseq enabled the linking of transcriptome profiles to specific kidney cell types. In conclusion, integration of RNAseq at the cortical, glomerular and single-nucleus level provides an enhanced resolution of molecular signalling pathways associated with disease progression in preclinical models of DKD, and may thus be advantageous for identifying novel therapeutic targets in DKD.
A glucose responsive insulin (GRI) that responds to changes in blood glucose concentrations has remained an elusive goal. Here we describe the development of glucose cleavable linkers based on ...hydrazone and thiazolidine structures. We developed linkers with low levels of spontaneous hydrolysis but increased level of hydrolysis with rising concentrations of glucose, which demonstrated their glucose responsiveness in vitro. Lipidated hydrazones and thiazolidines were conjugated to the LysB29 side‐chain of HI by pH‐controlled acylations providing GRIs with glucose responsiveness confirmed in vitro for thiazolidines. Clamp studies showed increased glucose infusion at hyperglycemic conditions for one GRI indicative of a true glucose response. The glucose responsive cleavable linker in these GRIs allow changes in glucose levels to drive the release of active insulin from a circulating depot. We have demonstrated an unprecedented, chemically responsive linker concept for biopharmaceuticals.
463 Million people live with diabetes of which approximately 10 % have type 1 diabetes. A glucose responsive insulin that responds to fluctuations in blood glucose concentrations has remained an elusive goal for decades. Here we describe the chemical development of hydrazones and thiazolidines that are cleavable in glucose concentration dependent manner. These were used to construct unprecedented glucose responsive insulins.
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