Complement activation in obesity, insulin resistance, and type 2 diabetes mellitus

Plasma-based proteomics analysis of molecular pathways in canine diabetes mellitus after astaxanthin supplementation

The hyperglycemic state in diabetes mellitus induces oxidative stress and inflammation, contributing to diabetic tissue damage and associated complications. Astaxanthin, a potent antioxidant carotenoid, has been investigated for its potential to prevent and manage diabetes across various species; however, its effect on client-owned dogs remains poorly studied. This study explored the impact of astaxanthin supplementation on canine diabetes mellitus using a proteomics approach. A total of 18 client-owned dogs were enrolled: 6 dogs with diabetes mellitus and 12 clinically healthy dogs. The diabetic dogs received their standard treatment regimen along with daily oral supplementation of 12 mg of astaxanthin (1.5-2.4 mg/kg) for 90 days. Plasma samples were collected at the beginning and end of the study period for proteomics analysis. After astaxanthin supplementation, significant alterations in the expression of proteins associated with the complement system, coagulation cascade, JAK-STAT signaling, and protein kinase C signaling (all of which contribute to inflammation and oxidative stress) were observed. Astaxanthin exhibited potential for reducing diabetes-associated complications, such as insulin resistance, vascular dysfunction, nephropathy, and cardiac issues, even though it did not affect clinical parameters (hematology, plasma biochemistry, blood glucose, and serum fructosamine). These findings suggest that astaxanthin may be a valuable complementary therapy for managing diabetes-related complications in canines.

Convergence of plant sterols and host eukaryotic cell-derived defensive lipids at the infectious pathogen-host interface

Plant sterols (PSs) exhibit intrinsic functions such as antibacterial effects. Their effects simultaneously on both host-mediated and bacteria-mediated pathogenesis are not yet fully understood. We hypothesized that when absorptive cells, defensive cells and detoxer cells are cultured together, their convergent response to an infectious pathogen depends on the molecular mimicry between the ingested sterols and their own defensive lipids. A human triple cell co-culture model incorporating colonocytes, macrophages, and hepatocytes was established. Cocultures were stimulated with Klebsiella pneumoniae 52145 (Kp52145) in the presence of pure plant sterol (β-sitosterol, PS) for 6 h. Changes in the structural health markers of the stimulated cocultured cells and their immune response and biochemical markers of pathogenicity were determined. PS significantly inhibited the secretion of cytokines induced by Kp52145. Cell viability was higher in the Kp52145 + PS group compared to the Kp52145 alone group. PS decreased Kp52145-induced marker of pathogenicity (SOD), accompanied by reduced levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), mannose binding lectin (MBL), and pentraxin 3 (PTX3) which are the mediators and enzymes associated with the inflammatory response to an infectious-inflamed milieu. PS recovered Kp52145-decreased peroxidase (POX), catalase (CAT), complement component 3 (C3), and high-density lipoprotein cholesterol (HDL-C) values. Convergence of ingested plant sterols and host eukaryotic cell-derived defensive lipids mitigates the disruptive effects of bacterial toxic effector molecules. Structural or immunological similarities (molecular mimicry) between ingested plant sterols and host defensive lipids play an important role in modulating bacterial signalling that occurs at the pathogen-host interface and in the mitigation of infection- and inflammation-driven pathological processes.

Plasma complement system markers and their association with cardiometabolic risk factors: an ethnic comparison of White European and Black African men

Populations of Black African (BA) ancestry are disproportionately affected by cardiometabolic diseases, possibly due to dysregulation of the complement system. This study aimed to determine relationships between fasting complement markers and cardiometabolic risk in BA and White European (WE) men, and whether postprandial complement response differs by ethnicity. Eighty-eight BA and 97 WE men [age = 44.4 (42.0-47.6) yr, body mass index (BMI) = 29.2 ± 4.5 kg·m-2] were assessed for fasting plasma complement markers and cardiometabolic risk factors. A second cohort (n = 20 men, 10 BA) [age = 31.0 ± 1.1 yr, BMI = 27.1 (26.0-28.6) kg·m-2] men underwent a moderate-to-high-fat feeding protocol to measure postprandial plasma complement, serum insulin, plasma glucose, triacylglycerol (TAG), and nonesterified fatty acids. C4 and Factor D were lower, and iC3b was higher in BA compared with WE men. C3 and C4 were strongly associated with all adiposity markers in both ethnicities, but the WE cohort showed stronger associations between C3 and subcutaneous adipose tissue, C5 and WC, and iC3b and visceral adipose tissue compared with BA. C3 was associated with all cardiometabolic risk factors in both ethnicities. Associations between C5 and cholesterol, C4 and TAG, and terminal complement complex and (both total and LDL)-cholesterol were only observed in the WE cohort. There was a trend toward ethnic differences in postprandial Factor D (P = 0.097) and iC3b (P = 0.085). The weaker associations between the complement system markers with adiposity and lipid profiles in BA compared with WE men suggest ethnic differences in the determinants of complement production and activation, whereby adipose tissue may play a less important role in BA men.NEW & NOTEWORTHY The present study found that markers of the complement system were less strongly associated with adiposity and lipid profiles in Black African men compared with White European men, suggesting ethnic differences in the determinants of complement production and activation. In Black African men, adipose tissue may play a less important role in complement production and activation and also in the link with traditional cardiometabolic risk factors.

Immune cell dysfunction: A critical player in development of diabetes complications

Diabetes mellitus, a global health challenge, influences millions worldwide by leading to severe complications and premature death. A key factor in its pathogenesis is immune cell dysfunction, which aggravates both type 1 and type 2 diabetes. The important role that immune cell dysregulation plays in the emergence of diabetes complications is investigated in this research. It highlights the manner in which diabetes compromises the immune system's adaptive as well as innate responses. Key defects in innate immunity include impaired pathogen recognition, and dysfunctional behavior of macrophages, neutrophils, and natural killer (NK) cells. Additionally, the complement system is dysregulated, and cytokine production is altered, affecting overall immune signaling. The study investigates the dysfunction of several T and B cell subsets, such as CD4+ T cells, CD8+ T cells, regulatory T cells, and B cells, in relation to adaptive immunity. These dysfunctions collectively contribute to chronic inflammation, reduced pathogen clearance, and increased susceptibility to infections, ultimately exacerbating diabetes complications. Developing targeted therapies to reduce diabetes complications and enhance patient outcomes requires an understanding of these mechanisms.

Association of Complement Proteins with C Reactive Protein in Non-Obese Women with and Without Polycystic Ovary Syndrome

Complement proteins are increased in polycystic ovary syndrome (PCOS), as are markers of inflammation, such as the C-reactive protein (CRP); however, both may be increased in obesity. We hypothesised that body mass index (BMI)-driven CRP would comparably associate with an increase in complement proteins when obesity was accounted for in non-obese women with and without PCOS. In a non-obese, non-insulin-resistant population without inflammation (24 with PCOS and 24 control women), plasma CRP was measured by immunoassay. Slow Off-rate Modified Aptamer (SOMA)-scan plasma proteomic analysis of the classical, lectin, and alternative pathway complement proteins was undertaken. BMI, insulin resistance, and CRP did not differ (p < 0.05) between the cohorts. The alternative pathway of the complement protein system was overexpressed in PCOS (p < 0.05). CRP correlated positively (p < 0.05) with alternate pathway parameters in women with and without PCOS for C3a, iC3b, Factor B, Factor H, and Factor I; in PCOS alone for C3, C3adesArg, and C3d; and in women without PCOS, for properdin. CRP did not correlate with lectin pathway C2 or MBL (p > 0.05). CRP correlated positively (p < 0.05) with C4 of the classical pathways in women with PCOS alone. Hyperandrogenemia did not correlate with CRP or complement in non-obese PCOS. BMI correlated positively with C3, C3adesArg, C3a, iC3b, Factor B, Factor H, and properdin: classical pathway proteins; C1q, C4, C5 and C5a in PCOS women; BMI only correlated negatively with C1q in non-PCOS women. Upregulation of complement proteins occur in non-obese PCOS, and CRP is positively associated with complement protein changes in both women with and without PCOS. This indicates that BMI induces changes in CRP that lead to changes in the complement pathways, particularly the alternate pathway, with increases in CRP (though still within the reference laboratory normal range) leading to upregulation of complement proteins in PCOS. This suggests an enhanced set point for CRP-induced complement protein dysregulation in PCOS.

Plasma Proteomic Signatures of Adiposity Are Associated With Cardiovascular Risk Factors and Type 2 Diabetes Risk in a Multiethnic Asian Population

The biomarkers connecting obesity and cardiometabolic diseases are not fully understood. We aimed to 1) evaluate the associations between BMI, waist circumference (WC), and ∼5,000 plasma proteins (SomaScan V4), 2) identify protein signatures of BMI and WC, and 3) evaluate the associations between the protein signatures and cardiometabolic health, including metabolically unhealthy obesity and type 2 diabetes incidence in the Singapore Multi-Ethnic Cohort Phase 1 (MEC1). Among 410 BMI-associated and 385 WC-associated proteins, we identified protein signatures of BMI and WC and validated them in an independent data set across two time points and externally in the Atherosclerosis Risk in Communities (ARIC) study. The BMI and WC protein signatures were highly correlated with total and visceral body fat, respectively. Furthermore, the protein signatures were significantly associated with cardiometabolic risk factors and metabolically unhealthy obesity. In prospective analyses, the protein signatures were strongly associated with type 2 diabetes risk in MEC1 (odds ratio per SD increment in WC protein signature 2.84; 95% CI 2.47-3.25) and ARIC (hazard ratio 1.98; 95% CI 1.88-2.08). Our protein signatures have potential uses in the monitoring of metabolically unhealthy obesity.

ARTICLE HIGHLIGHTS

We evaluated the associations between ∼5,000 plasma proteins and BMI and waist circumference (WC) in a multiethnic Asian population. We identified 410 proteins associated with BMI and 385 proteins associated with WC and derived protein signatures of BMI and WC, which we validated externally in a U.S. cohort. Both the BMI and WC protein signatures were strongly associated with cardiometabolic risk factors, metabolically unhealthy obesity, and risk of obesity, metabolic syndrome, and type 2 diabetes. Our protein signatures have potential uses in monitoring metabolically unhealthy obesity.

Microglia aggregates define distinct immune and neurodegenerative niches in Alzheimer's disease hippocampus

In Alzheimer's disease (AD), microglia form distinct cellular aggregates that play critical roles in disease progression, including Aβ plaque-associated microglia (PaM) and the newly identified coffin-like microglia (CoM). PaM are closely associated with amyloid-β (Aβ) plaques, while CoM are enriched in the pyramidal layer of the CA2/CA1 hippocampal subfields, where they frequently engulf neurons and associate with tau-positive tangles and phosphorylated α-synuclein. To elucidate the role of these microglial subtypes, we employed high-content neuropathology, integrating Deep Spatial Profiling (DSP), multiplex chromogenic immunohistochemistry and confocal microscopy, to comprehensively map and characterise their morphological and molecular signatures, as well as their neuropathological and astrocytic microenvironments, in AD and control post-mortem samples. PaM and PaM-associated astrocytes exhibited signatures related to complement system pathways, ErbB signalling, and metabolic and neurodegenerative processes. In contrast, CoM displayed markers associated with protein degradation and immune signalling pathways, including STING, TGF-β, and NF-κB. While no direct association between CD8 + T cells and either microglial type was observed, CD163 + perivascular macrophages were frequently incorporated into PaM. These findings provide novel insights into the heterogeneity of microglial responses, in particular their distinct interactions with astrocytes and infiltrating immune cells, and shed light on specific neurodegenerative hotspots and their implications for hippocampal deterioration in AD.

Canine obesity, overweight, and adipokine serum concentration are associated with hematological, biochemical, hormonal, and cardiovascular markers

Background

Canine obesity is an increasingly concerning issue that negatively impacts dogs' health, quality of life, and lifespan.

Aim

This study aimed to evaluate the adipokine profiles of overweight (OW) and obese (OB) dogs and their associations with various hematological, biochemical, hormonal, and cardiovascular markers.

Methods

A total of 84 dogs were classified according to their body condition scores as normal weight (NW), OW, or OB, and were subsequently subjected to blood pressure measurement, blood testing, and urine sampling.

Results

The findings revealed that OB dogs had higher serum concentrations of leptin and resistin while exhibiting lower levels of adiponectin when compared to NW dogs. Additionally, they showed higher systolic blood pressure. Serum creatinine levels were lower in OB dogs, and urinary specific gravity was reduced in both OW and OB dogs compared to their NW counterparts. Furthermore, total leukocyte counts and neutrophil counts were elevated in OW and OB dogs. The study also found that serum insulin levels were positively correlated with triglycerides, cholesterol, and C-reactive protein.

Conclusion

Canine obesity is reflected in altered adipokine concentrations and is associated with insulin resistance, as well as changes in renal function, protein metabolism, and hematological markers.

Immune Regulatory Crosstalk in Adipose Tissue Thermogenesis

Brown adipose tissue (BAT) and thermogenic beige fat within white adipose tissue (WAT), collectively known as adaptive thermogenic fat, dissipate energy as heat, offering promising therapeutic potential to combat obesity and metabolic disorders. The specific biological functions of these fat depots are determined by their unique interaction with the microenvironments, composed of immune cells, endothelial cells, pericytes, and nerve fibers. Immune cells residing in these depots play a key role in regulating energy expenditure and systemic energy homeostasis. The dynamic microenvironment of thermogenic fat depots is essential for maintaining tissue health and function. Immune cells infiltrate both BAT and beige WAT, contributing to their homeostasis and activation through intricate cellular communications. Emerging evidence underscores the importance of various immune cell populations in regulating thermogenic adipose tissue, though many remain undercharacterized. This review provides a comprehensive overview of the immune cells that regulate adaptive thermogenesis and their complex interactions within the adipose niche, highlighting their potential to influence metabolic health and contribute to therapeutic interventions for obesity and metabolic syndrome.

Circulating proteomic profiles in women with morbid obesity compared to normal-weight women

In this study, we aimed to evaluate circulating proteomic levels in women with morbid obesity (MO) compared to normal-weight (NW) women. Moreover, we have compared the proteomic profile between women with metabolically healthy (MH) MO and those with type 2 diabetes mellitus (T2DM). The study included 66 normal-weight (NW) women and 129 women with MO (54 MH and 75 with T2DM). Blood samples were processed for proteomics, involving protein extraction, quantification, digestion with peptide labelling and Nano (liquid chromatography (LC)-(Orbitrap) coupled to mass/mass spectrometry (MS/MS) analysis. Statistical analyses were performed. We identified 257 proteins. Women with MO showed significantly increased levels of 35 proteins and decreased levels of 45 proteins compared to NW women. Enrichment analysis of metabolic pathways revealed significant findings. Women with MO have an altered proteomic profile compared to normal-weight women, involving proteins significantly related to chylomicron assembly, complement cascade, clotting pathways and the insulin growth factor system. Regarding women with MO and T2DM compared to MHMO women, the proteomic profile shows alterations in mostly the same pathways associated with obesity. These findings confirmed in previous reports can help us better understand the pathophysiology of obesity and associated diseases. SIGNIFICANCE: Women with morbid obesity (MO) exhibit substantial proteomic alterations compared to normal-weight (NW) women, involving 80 proteins. These alterations are linked to significant metabolic pathways, including chylomicron assembly, complement cascade, clotting pathways and the insulin growth factor system. Additionally, women with MO and type 2 diabetes mellitus (T2DM) compared to metabolically healthy MO women share similar proteomic changes than the first comparison. These findings enhance our understanding of the pathophysiology of obesity and associated diseases, offering potential targets for therapeutic intervention.

Urine exosome biomarkers of obesity after Lekhana Basti treatment - Report of a pilot study

BACKGROUND

Obesity is a rising risk factor for various diseases including cardiovascular diseases and Cancer. The limitations of targeted obesity-treatment approaches employed in the clinic presently underscore the importance of developing integrative management strategies for identification of specific biomarkers of obesity.

OBJECTIVES

Given the specificity of exosome/extracellular vesicle (EV) biomarkers, we aimed here to identify the EV biomarkers of Ayurveda treatment - Lekhana Basti - for Obesity.

METHODOLOGY

A total of eighteen 24-h urine samples from 6 participants with BMI>30 kg/m2 were used in this study, collected over 3 time-points during the Lekhana basti (medicated enema for obesity) treatment. Urine EV were isolated using Polyethylene Glycol (PEG). The proteins were resolved by 1-d gel electrophoresis and identified using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and quantified by label-free methods. Significant Protein-Protein Interactions, KEGG pathway analysis and enrichment, functional gene ontology (GO) annotation were identified and shortlisted in comparison to Obesity reference genes from DisGeNET.

RESULTS

With UniProt as a reference subsequent to LC-MS/MS-identification, a total of 210 exosome proteins were identified. Seventy-three proteins were overexpressed in pathway enrichment analysis. Further, GO functional annotation identified 15 common proteins involved. Finally, the 8 hub proteins associated with obesity were identified and their differential expression profile compared between three different time-points during Lekhana Basti treatment. Six protein markers overexpressed during obesity were downregulated post Lekhana Basti treatment, while 2 markers increased in abundance post-treatment.

CONCLUSION

To our knowledge, this is the first study to isolate and identify urine EV protein abundance profiles from obese female participants of India. The study results indicate significant changes in the differential expression profile of 8 hub proteins involved in obesity, after Lekhana Basti treatment. The biomarker signature of the pilot study indicates the role of Ayurveda treatment and the possible pathways involved in the treatment of Obesity. Further, this study underlines the specificity of urine exosomes/EV as diagnostic markers as well as the potential of Ayurveda treatment in effective management of obesity.

The dose-effect response of combined red and infrared photobiomodulation on insulin resistance in skeletal muscle cells

Obesity is a major public health problem and is a major contributor to the development of insulin resistance. In previous studies we observed that single-wavelength red or infrared photobiomodulation (PBM) improved insulin signaling in adipocytes and skeletal muscle of mice fed a high-fat diet, but information about the combination of different wavelengths, as well as the effect of different light doses (J/cm2) is lacking. Therefore, the aim of this study was to investigate the effects of different doses of dual-wavelength PBM on insulin signaling in muscle cell, and explore potential mechanisms involved. Mouse myoblasts (C2C12) were differentiated into myotubes and cultured in palmitic acid, sodium oleate and l-carnitine (PAL) to induce insulin resistance high or in glucose medium (CTRL). Then, they received SHAM treatment (lights off, 0 J/cm2) or PBM (660 + 850 nm; 2, 4 or 8 J/cm2). PAL induced insulin resistance (assessed by Akt phosphorylation at ser473), attenuated maximal citrate synthase activity, and increased the phosphorylation of c-Jun NH(2) terminal kinase (JNK) (T183/Y185). PBM at doses of 4 or 8 J/cm2 reversed these PAL-induced responses. Furthermore, at doses of 2, 4 or 8 J/cm2, PBM reversed the increase in mitofusin-2 content induced by PAL. In conclusion, the combination of dual-wavelength red and infrared PBM at doses of 4 and 8 J/cm2 improved intracellular insulin signaling in musculoskeletal cells, and this effect appears to involve the modulation of mitochondrial function and the attenuation of the activation of stress kinases.

Circulating mannose-binding lectin in diabetic patients and risk of vascular complications: a systematic review and meta-analysis

Objectives

Recent studies have confirmed the involvement of mannose-binding lectin (MBL) in the pathogenesis of vascular complications in individuals with diabetes. Due to the discrepancy between the results of studies, a meta-analysis was conducted to evaluate MBL levels in patients with diabetes and its vascular complications.

Methods

We reviewed all observational studies published in PubMed/Medline, Scopus, EMBASE, and Web of Science Core Collection databases to identify relevant studies up to 1 April 2024. To account for describing heterogeneity among the studies, I2 and χ2 statistics were utilized. Also, a random-effects model was employed to combine the studies. The Newcastle Ottawa Scale (NOS) checklist was applied for quality assessment of each study.

Results

Twenty-eight papers were encompassed in this meta-analysis. The mean difference in MBL levels between patients with diabetic nephropathy and diabetic retinopathy differed significantly compared with the healthy control group and the diabetic group without vascular complications (P-value < 0.05). Moreover, the pooled results revealed a significant relationship between MBL levels and the incidence of vascular complications (pooled HR = 1.44, 95% CI: 1.07-1.95, P-value < 0.05) and disease-related mortality (pooled HR = 1.52, 95% CI: 1.07-2.16, P-value < 0.05) among diabetic patients. Also, there was a direct association between incidence of nephropathy in diabetics and higher levels of MBL (pooled HR = 2.16, 95% CI: 1.52-3.08, P-value < 0.05).

Conclusion

Diabetic patients with elevated MBL levels are potentially at increased risk of vascular complications such as nephropathy and retinopathy. Therefore, by determining MBL status in diabetic patients, it is possible to predict the progress and possible consequences of the disease.

Complement C3 promotes islet β-cell dedifferentiation by activating Wnt/β-catenin pathway

Islet β-cell dedifferentiation is a key step in the progression of diabetes, and complement C3 enhances secretion of several inflammatory mediators and cytokines in type 2 diabetes mellitus (T2DM). Here, we identified the underlying mechanisms of complement C3 in islet β-cell dedifferentiation. The protein level of C3 is increased in blood of T2DM patients and mice, as well as in T2DM islet β cells. Insulin, gliclazide, and metformin decreased complement C3, Nga3, and Oct4 levels but increased Pdx1 and MafA expressions; these treatments inhibit islet β-cell dedifferentiation in in vitro and in vivo models. We also observed that C3 promoted islet β-cell dedifferentiation, whereas C3 knockdown inhibited β-cell dedifferentiation. Moreover, C3 activates Wnt/β-catenin pathway by upregulating p-β-catenin levels, Wnt/β-catenin inhibitors significantly blocked C3-induced upregulation of islet β-cell dedifferentiation. In conclusion, C3 promoted islet β-cell dedifferentiation by activation of Wnt/β-catenin in T2DM. Targeting C3 might be a potential therapeutic strategy for T2DM treatment.

Circulating Factors as Potential Biomarkers of Cardiovascular Damage Progression Associated with Type 2 Diabetes

Background: Diabetes, particularly type 2 diabetes (T2D), is linked with an increased risk of developing coronary heart disease (CHD). The present study aimed to evaluate potential circulating biomarkers of CHD by adopting a targeted proteomic approach based on proximity extension assays (PEA). Methods: The study was based on 30 patients with both T2D and CHD (group DC), 30 patients with T2D without CHD (group DN) and 29 patients without diabetes but with a diagnosis of CHD (group NC). Plasma samples were analyzed using PEA, with an Olink Target 96 cardiometabolic panel expressed as normalized protein expression (NPX) units. Results: Lysosomal Pro-X carboxypeptidase (PRCP), Liver carboxylesterase 1 (CES1), Complement C2 (C2), and Intercellular adhesion molecule 3 (ICAM3) were lower in the DC and NC groups compared with the DN groups. Lithostathine-1-alpha (REG1A) and Immunoglobulin lambda constant 2 (IGLC2) were found higher in the DC group compared to DN and NC groups. ROC analysis suggested a significant ability of the six proteins to distinguish among the three groups (whole model test p < 0.0001, AUC 0.83-0.88), with a satisfactory discriminating performance in terms of sensitivity (77-90%) and specificity (70-90%). A possible role of IGLC2, PRCP, and REG1A in indicating kidney impairment was found, with a sensitivity of 92% and specificity of 83%. Conclusions: The identified panel of six plasma proteins, using a targeted proteomic approach, provided evidence that these parameters could be considered in the chronic evolution of T2D and its complications.

Complement Factor C1q Mediates Vascular Endothelial Dysfunction in STZ-Induced Diabetic Mice

Diabetes is a significant global public health issue with implications for vascular endothelial cells (ECs) dysfunction and the subsequent development and advancement of diabetes complications. This study aims to compare the cellular and molecular properties of the aorta in normal and streptozotocin (STZ)-induced diabetic mice, with a focus on elucidating potential mechanism underlying EC dysfunction. Here, we performed a single-cell RNA sequencing survey of 32,573 cells from the aorta of normal and STZ-induced diabetic mice. We found a compendium of 10 distinct cell types, mainly ECs, smooth muscle cells, fibroblast, pericyte, immune cells, and stromal cells. As the diabetes condition progressed, we observed a subpopulation of aortic ECs that exhibited significantly elevated expression of complement (C) molecule C1qa compared with their healthy counterparts. This increased expression of C1qa was found to induce reactive oxygen species (ROS) production, facilitate EC migration and increased permeability, and impair the vasodilation within the aortic segment of mice. Furthermore, AAV-Tie2-shRNA-C1qa was administered into diabetic mice by tail vein injection, showing that inhibition of C1qa in the endothelium led to a reduction in ROS production, decreased vascular permeability, and improved vasodilation. Collectively, these findings highlight the crucial involvement of C1qa in endothelial dysfunction associated with diabetes.

ARTICLE HIGHLIGHTS

A Systematic Review of Proteomics in Obesity: Unpacking the Molecular Puzzle

PURPOSE OF REVIEW

The present study aims to review the existing literature to identify pathophysiological proteins in obesity by conducting a systematic review of proteomics studies. Proteomics may reveal the mechanisms of obesity development and clarify the links between obesity and related diseases, improving our comprehension of obesity and its clinical implications.

RECENT FINDINGS

Most of the molecular events implicated in obesity development remain incomplete. Proteomics stands as a powerful tool for elucidating the intricate interactions among proteins in the context of obesity. This methodology has the potential to identify proteins involved in pathological processes and to evaluate changes in protein abundance during obesity development, contributing to the identification of early disease predisposition, monitoring the effectiveness of interventions and improving disease management overall. Despite many non-targeted proteomic studies exploring obesity, a comprehensive and up-to-date systematic review of the molecular events implicated in obesity development is lacking. The lack of such a review presents a significant challenge for researchers trying to interpret the existing literature. This systematic review was conducted following the PRISMA guidelines and included sixteen human proteomic studies, each of which delineated proteins exhibiting significant alterations in obesity. A total of 41 proteins were reported to be altered in obesity by at least two or more studies. These proteins were involved in metabolic pathways, oxidative stress responses, inflammatory processes, protein folding, coagulation, as well as structure/cytoskeleton. Many of the identified proteomic biomarkers of obesity have also been reported to be dysregulated in obesity-related disease. Among them, seven proteins, which belong to metabolic pathways (aldehyde dehydrogenase and apolipoprotein A1), the chaperone family (albumin, heat shock protein beta 1, protein disulfide-isomerase A3) and oxidative stress and inflammation proteins (catalase and complement C3), could potentially serve as biomarkers for the progression of obesity and the development of comorbidities, contributing to personalized medicine in the field of obesity. Our systematic review in proteomics represents a substantial step forward in unravelling the complexities of protein alterations associated with obesity. It provides valuable insights into the pathophysiological mechanisms underlying obesity, thereby opening avenues for the discovery of potential biomarkers and the development of personalized medicine in obesity.

Yoga Therapy Attenuates the Progression of Diabetes - Insights from Proteomics and Metabolomics Analysis

Objective

Diabetes management remains challenging despite advancements in therapeutics, with many subjects developing complications. Yoga has been shown to aid diabetes management. This study investigates the impact of yoga therapy on diabetes progression, utilizing proteomics and metabolomics analyses to explore underlying molecular mechanisms.

Methodology

A 3-month longitudinal study involving healthy subjects with prediabetes and diabetes was conducted. Blood glucose, glycated hemoglobin (HbA1c), lipid profile, and malondialdehyde (MDA) levels were measured before and after the yoga intervention.

Results and Conclusion

Healthy subjects showed no significant changes in blood glucose, lipid profile, HbA1c, or MDA levels. However, subjects with prediabetes and diabetes experienced positive changes, with decreases in HbA1c and MDA levels. Proteomics and metabolomics analyses provided insights into the molecular mechanisms by which yoga attenuates diabetes progression in subjects with prediabetes and diabetes. This study is a pioneering effort to understand the molecular basis of yoga's beneficial effects on diabetes management.

Proteome profiling reveals opportunities to investigate biomarkers of oxidative stress and immune responses in blubber biopsies from free-ranging baleen whales

Over 25% of cetacean species worldwide are listed as critically endangered, endangered or vulnerable by the International Union for Conservation of Nature. Objective and widely applicable tools to assess cetacean health are therefore vital for population monitoring and to inform conservation initiatives. Novel blubber biomarkers of physiological state are examples of such tools that could be used to assess overall health. Proteins extracted from blubber likely originate from both the circulation and various cell types within the tissue itself, and their expression is responsive to signals originating from other organs and the nervous system. Blubber proteins can therefore capture information on physiological stressors experienced by individuals at the time of sampling. For the first time, we assess the feasibility of applying shotgun proteomics to blubber biopsy samples collected from free-ranging baleen whales. Samples were collected from minke whales (Balaenoptera acutorostrata) (n = 10) in the Gulf of St Lawrence, Canada. Total protein was extracted using a RIPA cell lysis and extraction buffer-based protocol. Extracted proteins were separated and identified using nanoflow Liquid Chromatography Electrospray Ionization in tandem with Mass Spectrometry. We mapped proteins to known biological pathways and determined whether they were significantly enriched based on the proteome profile. A pathway enrichment map was created to visualize overlap in tissue-level biological processes. Amongst the most significantly enriched biological pathways were those involved in immune system function: inflammatory responses, leukocyte-mediated immunity and the humoral immune response. Pathways associated with responses to oxidative stress were also enriched. Using a suite of such protein biomarkers has the potential to better assess the overall health and physiological state of live individuals through remote biopsy sampling. This information is vital for population health assessments to predict population trajectories, and ultimately guide and monitor conservation priorities and initiatives.

BAFF neutralization impairs the autoantibody-mediated clearance of dead adipocytes and aggravates obesity-induced insulin resistance

B cell-activating factor (BAFF) is a critical TNF-family cytokine that regulates homeostasis and peripheral tolerance of B2 cells. BAFF overproduction promotes autoantibody generation and autoimmune diseases. During obesity, BAFF is predominantly produced by white adipose tissue (WAT), and IgG autoantibodies against adipocytes are identified in the WAT of obese humans. However, it remains to be determined if the autoantibodies formed during obesity affect WAT remodeling and systemic insulin resistance. Here, we show that IgG autoantibodies are generated in high-fat diet (HFD)-induced obese mice that bind to apoptotic adipocytes and promote their phagocytosis by macrophages. Next, using murine models of obesity in which the gonadal WAT undergoes remodeling, we found that BAFF neutralization depleted IgG autoantibodies, increased the number of dead adipocytes, and exacerbated WAT inflammation and insulin resistance. RNA sequencing of the stromal vascular fraction from the WAT revealed decreased expression of immunoglobulin light-chain and heavy-chain variable genes suggesting a decreased repertoire of B cells after BAFF neutralization. Further, the B cell activation and the phagocytosis pathways were impaired in the WAT of BAFF-neutralized mice. In vitro, plasma IgG fractions from BAFF-neutralized mice reduced the phagocytic clearance of apoptotic adipocytes. Altogether, our study suggests that IgG autoantibodies developed during obesity, at least in part, dampens exacerbated WAT inflammation and systemic insulin resistance.

Exploring protein relative relations in skeletal muscle proteomic analysis for insights into insulin resistance and type 2 diabetes

The escalating prevalence of insulin resistance (IR) and type 2 diabetes mellitus (T2D) underscores the urgent need for improved early detection techniques and effective treatment strategies. In this context, our study presents a proteomic analysis of post-exercise skeletal muscle biopsies from individuals across a spectrum of glucose metabolism states: normal, prediabetes, and T2D. This enabled the identification of significant protein relationships indicative of each specific glycemic condition. Our investigation primarily leveraged the machine learning approach, employing the white-box algorithm relative evolutionary hierarchical analysis (REHA), to explore the impact of regulated, mixed mode exercise on skeletal muscle proteome in subjects with diverse glycemic status. This method aimed to advance the diagnosis of IR and T2D and elucidate the molecular pathways involved in its development and the response to exercise. Additionally, we used proteomics-specific statistical analysis to provide a comparative perspective, highlighting the nuanced differences identified by REHA. Validation of the REHA model with a comparable external dataset further demonstrated its efficacy in distinguishing between diverse proteomic profiles. Key metrics such as accuracy and the area under the ROC curve confirmed REHA's capability to uncover novel molecular pathways and significant protein interactions, offering fresh insights into the effects of exercise on IR and T2D pathophysiology of skeletal muscle. The visualizations not only underscored significant proteins and their interactions but also showcased decision trees that effectively differentiate between various glycemic states, thereby enhancing our understanding of the biomolecular landscape of T2D.

Adipsin and adipocyte-derived C3aR1 regulate thermogenic fat in a sex-dependent fashion

Thermogenesis in beige/brown adipose tissues can be leveraged to combat metabolic disorders such as type 2 diabetes and obesity. The complement system plays pleiotropic roles in metabolic homeostasis and organismal energy balance with canonical effects on immune cells and noncanonical effects on nonimmune cells. The adipsin/C3a/C3a receptor 1 (C3aR1) pathway stimulates insulin secretion and sustains pancreatic β cell mass. However, its role in adipose thermogenesis has not been defined. Here, we show that male Adipsin/Cfd-knockout mice exhibited increased energy expenditure and white adipose tissue (WAT) browning. In addition, male adipocyte-specific C3aR1-knockout mice exhibited enhanced WAT thermogenesis and increased respiration. In stark contrast, female adipocyte-specific C3aR1-knockout mice displayed decreased brown fat thermogenesis and were cold intolerant. Female mice expressed lower levels of Adipsin in thermogenic adipocytes and adipose tissues than males. C3aR1 was also lower in female subcutaneous adipose tissue than in males. Collectively, these results reveal sexual dimorphism in the adipsin/C3a/C3aR1 axis in regulating adipose thermogenesis and defense against cold stress. Our findings establish a potentially new role of the alternative complement pathway in adaptive thermogenesis and highlight sex-specific considerations in potential therapeutic targets for metabolic diseases.

Viral infection and host immune response in diabetes

Diabetes, a chronic metabolic disorder disrupting blood sugar regulation, has emerged as a prominent silent pandemic. Uncontrolled diabetes predisposes an individual to develop fatal complications like cardiovascular disorders, kidney damage, and neuropathies and aggravates the severity of treatable infections. Escalating cases of Type 1 and Type 2 diabetes correlate with a global upswing in diabetes-linked mortality. As a growing global concern with limited preventive interventions, diabetes necessitates extensive research to mitigate its healthcare burden and assist ailing patients. An altered immune system exacerbated by chronic hyperinflammation heightens the susceptibility of diabetic individuals to microbial infections, including notable viruses like SARS-CoV-2, dengue, and influenza. Given such a scenario, we scrutinized the literature and compiled molecular pathways and signaling cascades related to immune compartments in diabetics that escalate the severity associated with the above-mentioned viral infections in them as compared to healthy individuals. The pathogenesis of these viral infections that trigger diabetes compromises both innate and adaptive immune functions and pre-existing diabetes also leads to heightened disease severity. Lastly, this review succinctly outlines available treatments for diabetics, which may hold promise as preventive or supportive measures to effectively combat these viral infections in the former.

Multiomics Picture of Obesity in Young Adults

Obesity is a socially significant disease that is characterized by a disproportionate accumulation of fat. It is also associated with chronic inflammation, cancer, diabetes, and other comorbidities. Investigating biomarkers and pathological processes linked to obesity is especially vital for young individuals, given their increased potential for lifestyle modifications. By comparing the genetic, proteomic, and metabolomic profiles of individuals categorized as underweight, normal, overweight, and obese, we aimed to determine which omics layer most accurately reflects the phenotypic changes in an organism that result from obesity. We profiled blood plasma samples by employing three omics methodologies. The untargeted GC×GC-MS metabolomics approach identified 313 metabolites. To augment the metabolomic dataset, we integrated a label-free HPLC-MS/MS proteomics method, leading to the identification of 708 proteins. The genomic layer encompassed the genotyping of 647,250 SNPs. Utilizing omics data, we trained sparse Partial Least Squares models to predict body mass index. Molecular features exhibiting frequently non-zero coefficients were selected as potential biomarkers, and we further explored enriched biological pathways. Proteomics was the most effective in single-omics analyses, with a median absolute error (MAE) of 5.44 ± 0.31 kg/m2, incorporating an average of 24 proteins per model. Metabolomics showed slightly lower performance (MAE = 6.06 ± 0.33 kg/m2), followed by genomics (MAE = 6.20 ± 0.34 kg/m2). As expected, multiomic models demonstrated better accuracy, particularly the combination of proteomics and metabolomics (MAE = 4.77 ± 0.33 kg/m2), while including genomics data did not enhance the results. This manuscript is the first multiomics study of obesity in a gender-balanced cohort of young adults profiled by genomic, proteomic, and metabolomic methods. The comprehensive approach provides novel insights into the molecular mechanisms of obesity, opening avenues for more targeted interventions.

Oxidative Stress: A Culprit in the Progression of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the principal culprit behind chronic kidney disease (CKD), ultimately developing end-stage renal disease (ESRD) and necessitating costly dialysis or kidney transplantation. The limited therapeutic efficiency among individuals with DKD is a result of our finite understanding of its pathogenesis. DKD is the result of complex interactions between various factors. Oxidative stress is a fundamental factor that can establish a link between hyperglycemia and the vascular complications frequently encountered in diabetes, particularly DKD. It is crucial to recognize the essential and integral role of oxidative stress in the development of diabetic vascular complications, particularly DKD. Hyperglycemia is the primary culprit that can trigger an upsurge in the production of reactive oxygen species (ROS), ultimately sparking oxidative stress. The main endogenous sources of ROS include mitochondrial ROS production, NADPH oxidases (Nox), uncoupled endothelial nitric oxide synthase (eNOS), xanthine oxidase (XO), cytochrome P450 (CYP450), and lipoxygenase. Under persistent high glucose levels, immune cells, the complement system, advanced glycation end products (AGEs), protein kinase C (PKC), polyol pathway, and the hexosamine pathway are activated. Consequently, the oxidant-antioxidant balance within the body is disrupted, which triggers a series of reactions in various downstream pathways, including phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), transforming growth factor beta/p38-mitogen-activated protein kinase (TGF-β/p38-MAPK), nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase (AMPK), and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. The disease might persist even if strict glucose control is achieved, which can be attributed to epigenetic modifications. The treatment of DKD remains an unresolved issue. Therefore, reducing ROS is an intriguing therapeutic target. The clinical trials have shown that bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, blood glucose-lowering drugs, such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can effectively slow down the progression of DKD by reducing oxidative stress. Other antioxidants, including vitamins, lipoic acid, Nox inhibitors, epigenetic regulators, and complement inhibitors, present a promising therapeutic option for the treatment of DKD. In this review, we conduct a thorough assessment of both preclinical studies and current findings from clinical studies that focus on targeted interventions aimed at manipulating these pathways. We aim to provide a comprehensive overview of the current state of research in this area and identify key areas for future exploration.

Impact of diabetes mellitus on osteoarthritis: a scoping review on biomarkers

Osteoarthritis (OA) commonly affects the knee and hip joints and accounts for 19.3% of disability-adjusted life years and years lived with disability worldwide (Refs , ). Early management is important in order to avoid disability uphold quality of life (Ref. ). However, a lack of awareness of subclinical and early symptomatic stages of OA often hampers early management (Ref. ). Moreover, late diagnosis of OA among those with severe disease, at a stage when OA management becomes more complicated is common (Refs , , , ). Established risk factors for the development and progression of OA include increasing age, female, history of trauma and obesity (Ref. ). Recent studies have also drawn a link between OA and metabolic syndrome, which is characterized by insulin resistance, dyslipidaemia and hypertension (Refs , ).

Impact of Strongyloides stercoralis infection on complement activation in Type 2 diabetes mellitus: Insights from a clinical and anthelmintic intervention study

BACKGROUND

Numerous studies indicate a potential protective role of helminths in diabetes mellitus (DM) progression. The complement system, vital for host defense, plays a crucial role in tissue homeostasis and immune surveillance. Dysregulated complement activation is implicated in diabetic complications. We aimed to investigate the influence of the helminth, Strongyloides stercoralis (Ss) on complement activation in individuals with type 2 DM (T2D).

METHODOLOGY

We assessed circulating levels of complement proteins (C1q, C2, C3, C4, C4b, C5, C5a, and MBL (Lectin)) and their regulatory components (Factor B, Factor D, Factor H, and Factor I) in individuals with T2D with (n = 60) or without concomitant Ss infection (n = 58). Additionally, we evaluated the impact of anthelmintic therapy on these parameters after 6 months in Ss-infected individuals (n = 60).

RESULTS

Ss+DM+ individuals demonstrated reduced levels of complement proteins (C1q, C4b, MBL (Lectin), C3, C5a, and C3b/iC3b) and complement regulatory proteins (Factor B and Factor D) compared to Ss-DM+ individuals. Following anthelmintic therapy, there was a partial reversal of these levels in Ss+DM+ individuals.

CONCLUSION

Our findings indicate that Ss infection reduces complement activation, potentially mitigating inflammatory processes in individuals with T2D. The study underscores the complex interplay between helminth infections, complement regulation, and diabetes mellitus, offering insights into potential therapeutic avenues.

The complement system as a key modulator of the oral microbiome in health and disease

In this review, we address the interplay between the complement system and host microbiomes in health and disease, focussing on oral bacteria known to contribute to homeostasis or to promote dysbiosis associated with dental caries and periodontal diseases. Host proteins modulating complement activities in the oral environment and expression profiles of complement proteins in oral tissues were described. In addition, we highlight a sub-set of bacterial proteins involved in complement evasion and/or dysregulation previously characterized in pathogenic species (or strains), but further conserved among prototypical commensal species of the oral microbiome. Potential roles of these proteins in host-microbiome homeostasis and in the emergence of commensal strain lineages with increased virulence were also addressed. Finally, we provide examples of how commensal bacteria might exploit the complement system in competitive or cooperative interactions within the complex microbial communities of oral biofilms. These issues highlight the need for studies investigating the effects of the complement system on bacterial behaviour and competitiveness during their complex interactions within oral and extra-oral host sites.

Adipose Tissue Inflammation: Linking Physiological Stressors to Disease Susceptibility

The study of adipose tissue (AT) is enjoying a renaissance. White, brown, and beige adipocytes are being investigated in adult animals, and the critical roles of small depots like perivascular AT are becoming clear. But the most profound revision of the AT dogma has been its cellular composition and regulation. Single-cell transcriptomic studies revealed that adipocytes comprise well under 50% of the cells in white AT, and a substantial portion of the rest are immune cells. Altering the function of AT resident leukocytes can induce or correct metabolic syndrome and, more surprisingly, alter adaptive immune responses to infection. Although the field is dominated by obesity research, conditions such as rapid lipolysis, infection, and heat stress impact AT immune dynamics as well. Recent findings in rodents lead to critical questions that should be explored in domestic livestock as potential avenues for improved animal resilience to stressors, particularly as animals age.

Characteristics of changes in plasma proteome profiling after sleeve gastrectomy

Bariatric surgery (BS), recognized as the most effective intervention for morbid obesity and associated metabolic comorbidities, encompasses both weight loss-dependent and weight loss-independent mechanisms to exert its metabolic benefits. In this study, we employed plasma proteomics technology, a recently developed mass spectrometric approach, to quantitatively assess 632 circulating proteins in a longitudinal cohort of 9 individuals who underwent sleeve gastrectomy (SG). Through time series clustering and Gene Ontology (GO) enrichment analysis, we observed that complement activation, proteolysis, and negative regulation of triglyceride catabolic process were the primary biological processes enriched in down-regulated proteins. Conversely, up-regulated differentially expressed proteins (DEPs) were significantly associated with negative regulation of peptidase activity, fibrinolysis, keratinocyte migration, and acute-phase response. Notably, we identified seven proteins (ApoD, BCHE, CNDP1, AFM, ITIH3, SERPINF1, FCN3) that demonstrated significant alterations at 1-, 3-, and 6-month intervals post SG, compared to baseline. These proteins play essential roles in metabolism, immune and inflammatory responses, as well as oxidative stress. Consequently, they hold promising potential as therapeutic targets for combating obesity and its associated comorbidities.

Advances in oxidative stress in pathogenesis of diabetic kidney disease and efficacy of TCM intervention

Diabetic kidney disease (DKD) is a common complication of diabetes and has become the leading cause of end-stage kidney disease. The pathogenesis of DKD is complicated, and oxidative stress is considered as a core of DKD onset. High glucose can lead to increased production of reactive oxygen species (ROS) via the polyol, PKC, AGE/RAGE and hexosamine pathways, resulting in enhanced oxidative stress response. In this way, pathways such as PI3K/Akt, TGF-β1/p38-MAPK and NF-κB are activated, inducing endothelial cell apoptosis, inflammation, autophagy and fibrosis that cause histologic and functional abnormalities of the kidney and finally result in kidney injury. Presently, the treatment for DKD remains an unresolved issue. Traditional Chinese medicine (TCM) has unique advantages for DKD prevention and treatment attributed to its multi-target, multi-component, and multi-pathway characteristics. Numerous studies have proved that Chinese herbs (e.g., Golden Thread, Kudzuvine Root, Tripterygium glycosides, and Ginseng) and patent medicines (e.g., Shenshuaining Tablet, Compound Rhizoma Coptidis Capsule, and Zishen Tongluo Granule) are effective for DKD treatment. The present review described the role of oxidative stress in DKD pathogenesis and the effect of TCM intervention for DKD prevention and treatment, in an attempt to provide evidence for clinical practice.

Cardiometabolic disease in Black African and Caribbean populations: an ethnic divergence in pathophysiology?

In the UK, populations of Black African and Caribbean (BAC) ethnicity suffer higher rates of cardiometabolic disease than White Europeans (WE). Obesity, leading to increased visceral adipose tissue (VAT) and intrahepatic lipid (IHL), has long been associated with cardiometabolic risk, driving insulin resistance and defective fatty acid/lipoprotein metabolism. These defects are compounded by a state of chronic low-grade inflammation, driven by dysfunctional adipose tissue. Emerging evidence has highlighted associations between central complement system components and adipose tissue, fatty acid metabolism and inflammation; it may therefore sit at the intersection of various cardiometabolic disease risk factors. However, increasing evidence suggests an ethnic divergence in pathophysiology, whereby current theories fail to explain the high rates of cardiometabolic disease in BAC populations. Lower fasting and postprandial TAG has been reported in BAC, alongside lower VAT and IHL deposition, which are paradoxical to the high rates of cardiometabolic disease exhibited by this ethnic group. Furthermore, BAC have been shown to exhibit a more anti-inflammatory profile, with lower TNF-α and greater IL-10. In contrast, recent evidence has revealed greater complement activation in BAC compared to WE, suggesting its dysregulation may play a greater role in the high rates of cardiometabolic disease experienced by this population. This review outlines the current theories of how obesity is proposed to drive cardiometabolic disease, before discussing evidence for ethnic differences in disease pathophysiology between BAC and WE populations.

Flavonols as a Potential Pharmacological Intervention for Alleviating Cognitive Decline in Diabetes: Evidence from Preclinical Studies

Diabetes mellitus is a complex metabolic disease associated with reduced synaptic plasticity, atrophy of the hippocampus, and cognitive decline. Cognitive impairment results from several pathological mechanisms, including increased levels of advanced glycation end products (AGEs) and their receptors, prolonged oxidative stress and impaired activity of endogenous mechanisms of antioxidant defense, neuroinflammation driven by the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), decreased expression of brain-derived neurotrophic factor (BDNF), and disturbance of signaling pathways involved in neuronal survival and cognitive functioning. There is increasing evidence that dietary interventions can reduce the risk of various diabetic complications. In this context, flavonols, a highly abundant class of flavonoids in the human diet, are appreciated as a potential pharmacological intervention against cognitive decline in diabetes. In preclinical studies, flavonols have shown neuroprotective, antioxidative, anti-inflammatory, and memory-enhancing properties based on their ability to regulate glucose levels, attenuate oxidative stress and inflammation, promote the expression of neurotrophic factors, and regulate signaling pathways. The present review gives an overview of the molecular mechanisms involved in diabetes-induced cognitive dysfunctions and the results of preclinical studies showing that flavonols have the ability to alleviate cognitive impairment. Although the results from animal studies are promising, clinical and epidemiological studies are still needed to advance our knowledge on the potential of flavonols to improve cognitive decline in diabetic patients.

Precision pharmacological reversal of strain-specific diet-induced metabolic syndrome in mice informed by epigenetic and transcriptional regulation

Diet-related metabolic syndrome is the largest contributor to adverse health in the United States. However, the study of gene-environment interactions and their epigenomic and transcriptomic integration is complicated by the lack of environmental and genetic control in humans that is possible in mouse models. Here we exposed three mouse strains, C57BL/6J (BL6), A/J, and NOD/ShiLtJ (NOD), to a high-fat, high-carbohydrate diet, leading to varying degrees of metabolic syndrome. We then performed transcriptomic and genome-wide DNA methylation analyses for each strain and found overlapping but also highly divergent changes in gene expression and methylation upstream of the discordant metabolic phenotypes. Strain-specific pathway analysis of dietary effects revealed a dysregulation of cholesterol biosynthesis common to all three strains but distinct regulatory networks driving this dysregulation. This suggests a strategy for strain-specific targeted pharmacologic intervention of these upstream regulators informed by epigenetic and transcriptional regulation. As a pilot study, we administered the drug GW4064 to target one of these genotype-dependent networks, the farnesoid X receptor pathway, and found that GW4064 exerts strain-specific protection against dietary effects in BL6, as predicted by our transcriptomic analysis. Furthermore, GW4064 treatment induced inflammatory-related gene expression changes in NOD, indicating a strain-specific effect in its associated toxicities as well as its therapeutic efficacy. This pilot study demonstrates the potential efficacy of precision therapeutics for genotype-informed dietary metabolic intervention and a mouse platform for guiding this approach.

Obesity and recurrent miscarriage: The interconnections between adipose tissue and the immune system

Currently, obesity is considered a global public health problem. It is the main risk factor for noncommunicable diseases and reproductive complications, such as recurrent miscarriage (RM). RM affects approximately 1% of couples of reproductive age, and recent studies suggest that its prevalence is increasing. Immunological abnormalities may be responsible for a significant number of cases of unexplained RM. Obesity is recognized as a chronic low-grade inflammatory condition. The accumulation of fat in obese adipose tissue promotes changes in the local and systemic immune response. Adipokines, exosomes, micro-RNAs, lipids, and other factors released or secreted by adipose tissue are responsible for the interconnection between obesity and the immune system. Obesity-induced dysregulation of the innate and acquired immune response is also involved in the immunopathology of pregnancy loss in patients with unexplained RM. Therefore, understanding the communication pathways between maternal adipose tissue and the immune response in women living with obesity and RM is an important objective. Thus, diagnostic tools and new immunomodulatory therapies may be proposed for the management of patients with concurrent obesity and RM.

Ldlr-/-.Leiden mice develop neurodegeneration, age-dependent astrogliosis and obesity-induced changes in microglia immunophenotype which are partly reversed by complement component 5 neutralizing antibody

Introduction

Obesity has been linked to vascular dysfunction, cognitive impairment and neurodegenerative diseases. However, experimental models that recapitulate brain pathology in relation to obesity and vascular dysfunction are still lacking.

Methods

In this study we performed the histological and histochemical characterization of brains from Ldlr-/-.Leiden mice, an established model for obesity and associated vascular disease. First, HFD-fed 18 week-old and 50 week-old Ldlr-/-.Leiden male mice were compared with age-matched C57BL/6J mice. We then assessed the effect of high-fat diet (HFD)-induced obesity on brain pathology in Ldlr-/-.Leiden mice and tested whether a treatment with an anti-complement component 5 antibody, a terminal complement pathway inhibitor recently shown to reduce vascular disease, can attenuate neurodegeneration and neuroinflammation. Histological analyses were complemented with Next Generation Sequencing (NGS) analyses of the hippocampus to unravel molecular pathways underlying brain histopathology.

Results

We show that chow-fed Ldlr-/-.Leiden mice have more severe neurodegeneration and show an age-dependent astrogliosis that is not observed in age-matched C57BL/6J controls. This was substantiated by pathway enrichment analysis using the NGS data which showed that oxidative phosphorylation, EIF2 signaling and mitochondrial dysfunction pathways, all associated with neurodegeneration, were significantly altered in the hippocampus of Ldlr-/-.Leiden mice compared with C57BL/6J controls. Obesity-inducing HFD-feeding did not aggravate neurodegeneration and astrogliosis in Ldlr-/-.Leiden mice. However, brains from HFD-fed Ldlr-/-.Leiden mice showed reduced IBA-1 immunoreactivity and increased CD68 immunoreactivity compared with chow-fed Ldlr-/-.Leiden mice, indicating alteration of microglial immunophenotype by HFD feeding. The systemic administration of an anti-C5 treatment partially restored the HFD effect on microglial immunophenotype. In addition, NGS data of hippocampi from Ldlr-/-.Leiden mice showed that HFD feeding affected multiple molecular pathways relative to chow-fed controls: HFD notably inactivated synaptogenesis and activated neuroinflammation pathways. The anti-C5 treatment restored the HFD-induced effect on molecular pathways to a large extent.

Conclusion

This study shows that the Ldlr-/-.Leiden mouse model is suitable to study brain histopathology and associated biological processes in a context of obesity and provides evidence of the potential therapeutic value of anti-complement therapy against obesity-induced neuroinflammation.

Precision pharmacological reversal of genotype-specific diet-induced metabolic syndrome in mice informed by transcriptional regulation

Diet-related metabolic syndrome is the largest contributor to adverse health in the United States. However, the study of gene-environment interactions and their epigenomic and transcriptomic integration is complicated by the lack of environmental and genetic control in humans that is possible in mouse models. Here we exposed three mouse strains, C57BL/6J (BL6), A/J, and NOD/ShiLtJ (NOD), to a high-fat high-carbohydrate diet, leading to varying degrees of metabolic syndrome. We then performed transcriptomic and genomic DNA methylation analyses and found overlapping but also highly divergent changes in gene expression and methylation upstream of the discordant metabolic phenotypes. Strain-specific pathway analysis of dietary effects reveals a dysregulation of cholesterol biosynthesis common to all three strains but distinct regulatory networks driving this dysregulation. This suggests a strategy for strain-specific targeted pharmacologic intervention of these upstream regulators informed by transcriptional regulation. As a pilot study, we administered the drug GW4064 to target one of these genotype-dependent networks, the Farnesoid X receptor pathway, and found that GW4064 exerts genotype-specific protection against dietary effects in BL6, as predicted by our transcriptomic analysis, as well as increased inflammatory-related gene expression changes in NOD. This pilot study demonstrates the potential efficacy of precision therapeutics for genotype-informed dietary metabolic intervention, and a mouse platform for guiding this approach.

Ethnic differences in complement system biomarkers and their association with metabolic health in men of Black African and White European ethnicity

Inflammation plays a fundamental role in the development of several metabolic diseases, including obesity and type 2 diabetes (T2D); the complement system has been implicated in their development. People of Black African (BA) ethnicity are disproportionately affected by T2D and other metabolic diseases but the impact of ethnicity on the complement system has not been explored. We investigated ethnic differences in complement biomarkers and activation status between men of BA and White European (WE) ethnicity and explored their association with parameters of metabolic health. We measured a panel of 15 complement components, regulators, and activation products in fasting plasma from 89 BA and 96 WE men. Ethnic differences were statistically validated. Association of complement biomarkers with metabolic health indices (BMI, waist circumference, insulin resistance, and HbA1c) were assessed in the groups. Plasma levels of the key complement components C3 and C4, the regulators clusterin and properdin and the activation marker iC3b were significantly higher in BA compared to WE men after age adjustment, while FD levels were significantly lower. C3 and C4 levels positively correlated with some or all markers of metabolic dysfunction in both ethnic groups while FD was inversely associated with HbA1c in both groups, and clusterin and properdin were inversely associated with some markers of metabolic dysfunction only in the WE group. Our findings of increased levels of complement components and activation products in BA compared to WE men suggest differences in complement regulation that may impact susceptibility to poor metabolic health.

Association of Complement C3 With Incident Type 2 Diabetes and the Mediating Role of BMI: A 10-Year Follow-Up Study

CONTEXT

Impairment of immune and inflammatory homeostasis is reported to be one of the causal factors of diabetes. However, the association of complement C3 levels with incident diabetes in humans remains unclear.

OBJECTIVE

This study aimed to examine the association between C3 levels and incident type 2 diabetes mellitus (T2DM), and further explore the potential mediating role of body mass index (BMI) in C3-T2DM associations.

METHODS

We determined serum C3 levels of 2662 nondiabetic middle-aged and elderly (64.62 ± 7.25 years) individuals from the Dongfeng-Tongji cohort at baseline. Cox regression was employed to examine the incidence of T2DM in relationship to C3 levels during 10 years of follow-up. Mediation analysis was further applied to assess potential effect of BMI on the C3-T2DM associations.

RESULTS

Overall, 711 (26.7%) participants developed T2DM during 23 067 person-years of follow-up. Higher serum C3 was significantly associated with higher risk of incident T2DM after full adjustment (HR [95% CI] = 1.16 [1.05, 1.27]; per SD higher). Compared with the first quartile of C3 levels, the HR in the fourth quartile was 1.52 (95% CI = [1.14, 2.02]; Ptrend = 0.029). Robust significant linear dose-response relationship was observed between C3 levels and BMI (Poverall < 0.001, Pnonlinear = 0.96). Mediation analyses indicated that BMI might mediate 41.0% of the associations between C3 and T2DM.

CONCLUSION

The present prospective study revealed that C3 could be an early biomarker for incident T2DM, and that BMI might play a potential mediating role in the C3-T2DM associations, which provided clues for the pathogenesis of diabetes.

Prognostic nutritional index as a risk factor for diabetic kidney disease and mortality in patients with type 2 diabetes mellitus

AIMS

Microinflammation and malnutrition are common in individuals with type 2 diabetes mellitus (T2DM). We aimed to validate whether prognostic nutritional index (PNI) may increase the risk of diabetic kidney disease (DKD) and all-cause mortality in T2DM patients.

METHODS

This retrospective cohort study was based on the National Health and Nutrition Examination Survey (NHANES) and National Death Index (NDI) 2013-2018 database. A total of 14,349 eligible subjects were included, and 2720 of them were with T2DM. PNI was assessed by the 5 × lymphocyte count (10⁹/L) + serum albumin (g/L). The Logistic and Cox regression analyses were conducted to investigate the risk factors of DKD and mortality in T2DM patients.

RESULTS

For 14,349 participants represented 224.7 million noninstitutionalized residents of the United State, the average PNI was 53.72 ± 0.12, and the prevalence of T2DM was 14.89%. T2DM patients had a lower level of PNI and dietary protein intake, a higher risk of mortality, kidney injury, anemia, arterial hypertension and hyperuricemia, compared with non-T2DM subjects. DKD occurred in 35.06% of diabetic participants and a higher PNI was independently related with a lower risk of DKD (OR 0.64, 95% CI 0.459-0.892, p = 0.01) in T2DM after multivariate adjustment. During a median follow-up of 46 person-months (29-66 months), a total of 233 T2DM individuals died from all causes (mortality rate = 8.17%). Subjects with T2DM who had a higher PNI showed a lower risk of all-cause mortality (HR 0.60, 95% CI 0.37-0.97, p = 0.036).

CONCLUSIONS

PNI, as a marker of immunonutrition, correlated with the incidence of DKD, and was an independent predictor for all-cause mortality in participants with T2DM. Thus, PNI may conduce to the risk stratification and timely intervention of T2DM patients.

Comparison of Plasma Exosome Proteomes Between Obese and Non-Obese Patients with Type 2 Diabetes Mellitus

PURPOSE

Obesity is considered a promoter of type 2 diabetes mellitus (T2DM). However, the underlying mechanism remains unclear. This study aimed to identify plasma exosome differentially expressed proteins (DEPs) that are potentially involved in the development of obesity-related T2DM.

METHODS

Exosomes were isolated from the plasma of obese and non-obese T2DM patients (n = 10 for each group). A label-free quantitative mass spectrometry analysis was applied to identify plasma exosome DEPs in obese patients compared with non-obese patients, followed by bioinformatics analysis including GO annotation, KEGG analysis, subcellular localization prediction, transcription factor analysis, and protein-protein interaction (PPI) prediction.

RESULTS

We identified 2 significantly upregulated proteins (C9 and PON1) and 5 significantly downregulated proteins (HPX, A1BG, CFHR1, ANG, and CALM) in obese patients compared with those in non-obese patients. KEGG analysis demonstrated that the insulin signaling pathway was one of the pathways that significantly correlated with the DEPs. The DEPs were primarily localized in the extracellular space (5 out of 7). HMG-box and NF-Y beta might regulate the transcription of the DEPs. C9, PON1, HPX, and CFHR1 were present in the PPI network.

CONCLUSION

The plasma exosome DEPs are potentially responsible for the development of obesity-related T2DM possibly through the insulin signaling pathway and the interaction with other proteins. Our study may guide future research direction toward the pathogenesis of obesity-related T2DM.

Association between overweight/obesity and multidrug-resistant tuberculosis

OBJECTIVE.

To evaluate the association between overweight/obesity and multidrug resistance in patients with and without a history of tuberculosis treatment.

MATERIALS AND METHODS.

Cross-sectional study of secondary data from a tuberculosis cohort, which included anthropometric and drug-sensitivity testing data at the baseline visit of patients with and without previous tuberculosis treatment.

RESULTS.

We evaluated 3,734 new cases and 766 with a history of having received treatment for tuberculosis. Overweight/obesity was not associated with multidrug resistance in patients with a history of tuberculosis treatment, with a prevalence ratio of 0.97 and a 95% confidence interval of 0.68-1.38.

CONCLUSIONS.

Overweight/obesity is not associated with multidrug resistance in tuberculosis. Overweight/obesity is a dynamic process that may influence the relationship between the immune system and the metabolic system.

Immunoregulatory Sertoli Cell Allografts Engineered to Express Human Insulin Survive Humoral-Mediated Rejection

An effective treatment and possible cure for type 1 diabetes is transplantation of pancreatic islets. Unfortunately, transplanted islets are rejected by the immune system with humoral-mediated responses being an important part of rejection. Sertoli cells (SC), an immune regulatory cell shown to survive as allografts long-term without immunosuppressants, have the potential to be used as a cell-based gene therapy vehicle to deliver endogenous insulin-a possible alternative to islets. Previously, we transduced a mouse SC line to produce human insulin. After transplantation into diabetic mice, these cells consistently produced low levels of insulin with graft survival of 75% at 50 days post-transplantation. The object of this study was to assess humoral immune regulation by these engineered SC. Both nontransduced and transduced SC survived exposure to human serum with complement in vitro. Analysis of allografts in vivo at 20 and 50 days post-transplantation revealed that despite IgG antibody detection, complement factor deposition was low and grafts survived through 50 days post-transplantation. Furthermore, the transduced SC secreted elevated levels of the complement inhibitor C1q binding protein. Overall, this suggests SC genetically engineered to express insulin maintain their ability to prevent complement-mediated killing. Since inhibiting complement-mediated rejection is important for graft survival, further studies of how SC modifies the immune response could be utilized to advance the use of genetically engineered SC or to prolong islet allograft survival to improve the treatment of diabetes.

Complement C3 as a potential NAFLD predictor in an Egyptian cohort with diabetes and/or obesity

Complement system is becoming increasingly recognized as being intimately tied to obesity and other various metabolic abnormalities linked to it and may be involved in NAFLD. The goal of this study was to see if complement C3 might be used as a diagnostic and prognostic marker in NAFLD patients. Forty-one NAFLD patients and fourteen age- and gender-matched control individuals were enrolled in this study. All subjects were subjected to abdominal ultrasound examination and clinical assessment with special emphasis on the liver function enzymes, blood glucose levels, lipid profile, and kidney function tests. Non-invasive assessment of hepatic steatosis and fibrosis has evolved using serology-based scoring systems such as the Fibrosis-4 score and NAFLD Fibrosis Score (NFS). Additionally, serum levels of complement C3 were determined by the ELISA method. In this study, BMI, cholesterol, triglyceride levels, and NFS were all substantially higher in NAFLD patients compared to healthy controls. Moreover, complement C3 was considerably higher in NAFLD cases (1.52±0.29 g/L) vs. healthy controls (0.93±0.289 g/L) (p<0.001). Compared to lean people (0.93±0.29 g/L), the mean complement C3 levels were significantly higher in obese diabetes (1.69±0.29 g/L), obese non-diabetic (1.48±0.174 g/L), and diabetic non-obese patients (1.36±0.28 g/L). Using a cutoff for complement C3 1.135 (g/L) for distinguishing NAFLD patients from healthy controls has a sensitivity of 90.2% and specificity of 78.6%. In conclusion, serum complement C3 may be useful in the identification of fibrosis in non-alcoholic fatty liver disease. Moreover, complement C3 may be a promising tool for predicting the worsening of liver inflammation.

Metabolic and proteomic signatures of type 2 diabetes subtypes in an Arab population

Type 2 diabetes (T2D) has a heterogeneous etiology influencing its progression, treatment, and complications. A data driven cluster analysis in European individuals with T2D previously identified four subtypes: severe insulin deficient (SIDD), severe insulin resistant (SIRD), mild obesity-related (MOD), and mild age-related (MARD) diabetes. Here, the clustering approach was applied to individuals with T2D from the Qatar Biobank and validated in an independent set. Cluster-specific signatures of circulating metabolites and proteins were established, revealing subtype-specific molecular mechanisms, including activation of the complement system with features of autoimmune diabetes and reduced 1,5-anhydroglucitol in SIDD, impaired insulin signaling in SIRD, and elevated leptin and fatty acid binding protein levels in MOD. The MARD cluster was the healthiest with metabolomic and proteomic profiles most similar to the controls. We have translated the T2D subtypes to an Arab population and identified distinct molecular signatures to further our understanding of the etiology of these subtypes.

Pitfalls in complement analysis: A systematic literature review of assessing complement activation

Background

The complement system is an essential component of our innate defense and plays a vital role in the pathogenesis of many diseases. Assessment of complement activation is critical in monitoring both disease progression and response to therapy. Complement analysis requires accurate and standardized sampling and assay procedures, which has proven to be challenging.

Objective

We performed a systematic analysis of the current methods used to assess complement components and reviewed whether the identified studies performed their complement measurements according to the recommended practice regarding pre-analytical sample handling and assay technique. Results are supplemented with own data regarding the assessment of key complement biomarkers to illustrate the importance of accurate sampling and measuring of complement components.

Methods

A literature search using the Pubmed/MEDLINE database was performed focusing on studies measuring the key complement components C3, C5 and/or their split products and/or the soluble variant of the terminal C5b-9 complement complex (sTCC) in human blood samples that were published between February 2017 and February 2022. The identified studies were reviewed whether they had used the correct sample type and techniques for their analyses.

Results

A total of 92 out of 376 studies were selected for full-text analysis. Forty-five studies (49%) were identified as using the correct sample type and techniques for their complement analyses, while 25 studies (27%) did not use the correct sample type or technique. For 22 studies (24%), it was not specified which sample type was used.

Conclusion

A substantial part of the reviewed studies did not use the appropriate sample type for assessing complement activation or did not mention which sample type was used. This deviation from the standardized procedure can lead to misinterpretation of complement biomarker levels and hampers proper comparison of complement measurements between studies. Therefore, this study underlines the necessity of general guidelines for accurate and standardized complement analysis

Apolipoprotein C3 and circulating mediators of preadipocyte proliferation in states of lipodystrophy

Adipogenesis is a complex process controlled by intrinsic and extrinsic factors that regulate preadipocyte proliferation, adipogenic capacity and maturation of metabolic function. Here we show that insulin and IGF-1 receptors are essential for mature adipocyte survival and that deletion of both IR and IGF1R specifically in fat using a tamoxifen inducible-AdipoQ-Cre (Ai-DKO) leads to rapid and severe loss of adipocytes in all depots, associated with a metabolic syndrome characterized by hypertriglyceridemia, hyperglycemia, hyperinsulinemia, fatty liver, and pancreatic beta cell proliferation. In this model, this pathological phenotype reverses over a few weeks, in large part, due to preadipocyte proliferation and adipose tissue regeneration. Incubation of preadipocytes with serum from the Ai-DKO mice in vitro stimulates cell proliferation, and this effect can be mimicked by conditioned media from liver slices of Ai-DKO mice, but not by media of cultured Ai-DKO adipocytes, indicating a hepatic origin of the growth factor. Proteomic analysis of serum reveals apolipoprotein C3 (APOC3), a protein secreted by liver, as one of the most upregulated proteins in the Ai-DKO mice. In vitro, purified and delipidated APOC3 stimulates preadipocyte proliferation, however, knockdown of hepatic APOC3 in vivo in Ai-DKO mice is not sufficient to block adipose regeneration. Thus, lipodystrophy is associated with presence of increased preadipocyte-stimulating growth factors in serum. Our study indicates that APOC3 is one contributing factor to preadipocyte proliferation, however, other still-unidentified circulating growth factors are also likely present in Ai-DKO mice. Identification of these factors may provide a new approach to regulation of adipose mass in health and disease.

Tuberculosis in an Aging World

Tuberculosis (TB) is one of the leading causes of death due to its being an infectious disease, caused by the airborne pathogen Mycobacterium tuberculosis (M.tb). Approximately one-fourth of the world’s population is infected with latent M.tb, and TB is considered a global threat killing over 4000 people every day. The risk of TB susceptibility and mortality is significantly increased in individuals aged 65 and older, confirming that the elderly represent one of the largest reservoirs for M.tb infection. The elderly population faces many challenges that increase their risk of developing respiratory diseases, including TB. The challenges the elderly face in this regard include the following: decreased lung function, immuno-senescence, inflammaging, adverse drug effects, low tolerance to anti-TB drugs, lack of suitable diagnoses/interventions, and age-associated comorbidities. In order to find new therapeutic strategies to maintain lung homeostasis and resistance to respiratory infections as we age, it is necessary to understand the molecular and cellular mechanisms behind natural lung aging. This review focuses primarily on why the elderly are more susceptible to TB disease and death, with a focus on pulmonary function and comorbidities.

The Association of Acute Phase Proteins in Stress and Inflammation-Induced T2D

Acute phase proteins (APPs), such as plasminogen activator inhibitor-1 (PAI-1), serum amyloid A (SAA), and C-reactive protein (CRP), are elevated in type-2 diabetes (T2D) and are routinely used as biomarkers for this disease. These APPs are regulated by the peripheral mediators of stress (i.e., endogenous glucocorticoids (GCs)) and inflammation (i.e., pro-inflammatory cytokines), with both implicated in the development of insulin resistance, the main risk factor for the development of T2D. In this review we propose that APPs, PAI-1, SAA, and CRP, could be the causative rather than only a correlative link between the physiological elements of risk (stress and inflammation) and the development of insulin resistance.