Colchicine's effects on lipoprotein particle concentrations in adults with metabolic syndrome: A secondary analysis of a randomized controlled trial

Evaluation of the pharmacokinetics, chylomicron inhibition, and toxicity of colchicine in rats given low doses

Colchicine (COL) is known for its ability to inhibit the formation of intestinal chylomicrons and has been utilized as a non-surgical tool to explore drug absorption via the intestinal lymphatics. However, there is limited understanding of its pharmacokinetics and its relationship to effect and toxicity with the doses used. This study aimed to provide comprehensive COL pharmacokinetic data and correlate it with the lymphatic-blocking and toxicological effects of low-doses. Male Sprague-Dawley rats with jugular-vein cannulation (JVC) received 0.1 to 0.5 mg/kg COL via oral, 0.25 mg/kg intraperitoneal, and 0.1 mg/kg intravenous routes, followed by blood and urine sampling for LC-MS/MS analysis. Effects on lipid absorption were assessed in another eight JVC rats receiving peanut oil with and without COL, followed by blood pharmacokinetic and plasma biochemistry analysis. The results revealed that COL exhibited moderate extraction ratio and high volume of distribution, with low oral bioavailability (<8%). About 20 % was recovered in the urine after parenteral dosing. Modest but significant reductions in cholesterol absorption was observed after oral doses of 0.5 mg/kg, accompanied by signs of inflammation and increased liver enzymes persisting for a week. The effect of COL on triglycerides formation was not significant. Despite its use as a non-surgical tool in rats to investigate drug absorption via the lymphatic pathway, COL demonstrated increased levels of liver function enzymes, emphasizing the need for caution and dose optimization in its utilization.

Colchicine effects on the gut microbiome in adults with metabolic syndrome

Obesity-induced inflammation plays a substantial role in the development of insulin resistance and type 2 diabetes. The altered gut flora in obesity can also contribute to metabolic dysregulation and systemic inflammation. However, it remains unclear how dysregulation of systemic inflammation in obesity affects the gut microbiome. We hypothesized that colchicine's systemic anti-inflammatory effects in obesity would be associated with improvements in gut microbial diversity. We conducted a secondary analysis of a double-blind randomized placebo-controlled trial, in which 40 adults with obesity, high C-reactive protein (CRP) (≥2.0 mg/L), insulin resistance (homeostatic model of insulin resistance: HOMA-IR ≥2.6 mg/L), and metabolic syndrome (MetS) were randomized to three months of colchicine 0.6 mg or placebo tablets twice daily. Serum and stool samples were collected at baseline and final visit. Gut microbiota composition was characterized from stool DNA by dual-index amplification and sequencing of 16S ribosomal RNA. Pre- and post-intervention stool samples were available for 15 colchicine- and 12 placebo-treated subjects. Circulating high sensitivity CRP (hsCRP), interleukin-6, resistin, white blood count, and neutrophils were significantly decreased in the colchicine arm as compared to placebo. However, changes in stool microbiome alpha diversity, as assessed by the Chao1, Shannon, and Pielou indices, were not significant between groups. Amplicon sequence variant counts were unchanged among all examined phyla or families. Oscillibacter was the only genus to demonstrate even a nominally significant change. Among adults with obesity and MetS, colchicine significantly improved systemic inflammation. However, this anti-inflammatory effect was not associated with significant changes in the gut microbiome. Further studies are warranted to investigate this relationship.

The association between triglyceride-rich lipoproteins, circulating leukocytes, and low-grade inflammation: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND

Experimental studies have linked triglyceride-rich lipoproteins (TRLs) to inflammation, but the extent of this phenomenon in vivo has not been completely elucidated.

OBJECTIVE

We investigated the association between TRL subparticles and inflammatory markers (circulating leukocytes, plasma high-sensitivity C-reactive protein [hs-CRP], and GlycA) in the general population.

METHODS

This was a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). TRLs (number of particles per unit volume) and GlycA were measured by nuclear magnetic resonance spectroscopy. The association between TRLs and inflammatory markers was determined by multiple linear regression models adjusted for demographic data, metabolic conditions, and lifestyle factors. Standardized regression coefficients (beta) with 95% confidence intervals are reported.

RESULTS

The study population comprised 4,001 individuals (54% females, age 50 ± 9 years). TRLs, especially medium and large subparticles, were associated with GlycA (beta 0.202 [0.168, 0.235], p<0.001 for total TRLs). There was no association between TRLs and hs-CRP (beta 0.022 [-0.011, 0.056], p = 0.190). Medium, large, and very large TRLs were associated with leukocytes, with stronger connections with neutrophils and lymphocytes than monocytes. When TRL subclasses were analyzed as the proportion of the total pool of TRL particles, medium and large TRLs were positively related to leukocytes and GlycA, whereas smaller particles were inversely associated.

CONCLUSIONS

There are different patterns of association between TRL subparticles and inflammatory markers. The findings support the hypothesis that TRLs (especially medium and larger subparticles) may induce a low-grade inflammatory environment that involves leukocyte activation and is captured by GlycA, but not hs-CRP.

Immunomodulatory effects of colchicine on peripheral blood mononuclear cell subpopulations in human obesity: Data from a randomized controlled trial

OBJECTIVE

Colchicine is known to reduce inflammation and improve endothelial cell function and atherosclerosis in obesity, but there is little knowledge of the specific circulating leukocyte populations that are modulated by colchicine.

METHODS

A secondary analysis of a double-blind randomized controlled trial of colchicine 0.6 mg or placebo twice daily for 3 months on circulating leukocyte populations and regulation of the immune secretome in 35 adults with obesity was performed.

RESULTS

Colchicine altered multiple innate immune cell populations, including dendritic cells and lymphoid progenitor cells, monocytes, and natural killer cells when compared with placebo. Among all subjects and within the colchicine group, changes in natural killer cells were significantly positively associated with reductions in biomarkers of inflammation, including cyclooxygenase 2, pulmonary surfactant-associated protein D, myeloperoxidase, proteinase 3, interleukin-16, and resistin. Changes in dendritic cells were positively correlated with changes in serum heart-type fatty acid-binding protein concentrations. Additionally, colchicine treatment reduced cluster of differentiation (CD) CD4+ T effector cells and CD8+ T cytotoxic cells. Conversely, colchicine increased CD4+ and CD8+ T central memory cells and activated CD38High CD8+ T cells. Changes in CD4+ T effector cells were associated with changes in serum heart-type fatty acid-binding protein.

CONCLUSIONS

In adults with obesity, colchicine significantly affects circulating leukocyte populations involved in both innate and adaptive immune systems along with the associated inflammatory secretome.

Association between tissue human neutrophil peptide 1-3 levels and cardiovascular phenotype: a prospective, longitudinal cohort study

Objective

Inflammation is associated with atherogenesis. Although a higher neutrophil count is associated with the plaque burden, the role of neutrophil activation is unclear. Human neutrophil peptides 1–3 (HNP1–3) are a risk factor for atherogenesis in bench models and are elevated in human atheromas. This study aimed to examine the association between skin HNP1–3 deposition and the severity of coronary artery disease (CAD), including long-term outcomes.

Methods

HNP1–3 levels were immunohistochemically quantified in skin biopsies, which were prospectively taken from 599 consecutive patients before clinically indicated coronary angiography. Established cardiovascular risk factors and blood markers for atheroinflammation were obtained. CAD severity and the incidence of repeat revascularization and mortality at 48 months of follow-up were assessed in relation to HNP1–3 levels.

Results

The risk of CAD was independently associated with age and HNP1–3 in the entire cohort (F = 0.71 and F = 7.4, respectively). Additionally, HNP1–3 levels were significantly associated with myocardial necrosis (R = 0.26). At the follow-up, high HNP1–3 levels negatively affected mortality (19.54%) and recurrent revascularization (8.05%).

Conclusion

HNP1–3 tissue deposition is positively associated with the severity of CAD, myonecrosis, and long-term sequelae. HNP1–3 levels may be suppressed using colchicine.

Effects of colchicine on lipolysis and adipose tissue inflammation in adults with obesity and metabolic syndrome

OBJECTIVE

The aim of this study was to examine whether colchicine's anti-inflammatory effects would improve measures of lipolysis and distribution of leukocyte populations in subcutaneous adipose tissue (SAT).

METHODS

A secondary analysis was conducted for a double-blind, randomized, placebo-controlled pilot study in which 40 adults with obesity and metabolic syndrome (MetS) were randomized to colchicine 0.6 mg or placebo twice daily for 3 months. Non-insulin-suppressible (l₀ ), insulin-suppressible (l₂ ), and maximal (l₀ +l₂ ) lipolysis rates were calculated by minimal model analysis. Body composition was determined by dual-energy x-ray absorptiometry. SAT leukocyte populations were characterized by flow cytometry analysis from biopsied samples obtained before and after the intervention.

RESULTS

Colchicine treatment significantly decreased l₂ and l₀ +l₂ versus placebo (p < 0.05). These changes were associated with a significant reduction in markers of systemic inflammation, including high-sensitivity C-reactive protein, resistin, and circulating monocytes and neutrophils (p < 0.01). Colchicine did not significantly alter SAT leukocyte population distributions (p > 0.05).

CONCLUSIONS

In adults with obesity and MetS, colchicine appears to improve insulin regulation of lipolysis and reduce markers of systemic inflammation independent of an effect on local leukocyte distributions in SAT. Further studies are needed to better understand the mechanisms by which colchicine affects adipose tissue metabolic pathways in adults with obesity and MetS.

Analysis of hepatic transcriptome modulation exerted by γ-conglutin from lupins in a streptozotocin-induced diabetes model

Lupinus albus γ-conglutin is proposed to positively affect glucose metabolism through inhibition of hepatic glucose production and insulin-mimetic activity; however, the action mechanism is not entirely known. Besides, most studies had focused on its effect on molecular targets directly related to glucose metabolism, and few studies have investigated how γ-conglutin may affect the liver gene expression or if it plays a role in other metabolic processes. Therefore, we investigated the influence of γ-conglutin on the liver transcriptome of streptozotocin-induced diabetic rats using DNA microarrays, ontological analyses, and quantitative PCR. Of the 22,000 genes evaluated, 803 and 173 were downregulated and upregulated, respectively. The ontological analyses of the differentially expressed genes revealed that among others, the mitochondria, microtubules, cytoskeleton, and oxidoreductase activity terms were enriched, implying a possible role of γ-conglutin on autophagy. To corroborate the microarray results, we selected and quantified, by PCR, the expression of two genes associated with autophagy (Atg7 and Snx18) and found their expression augmented two and threefold, respectively; indicating a higher autophagy activity in animals treated with γ-conglutin. Although complementary studies are required, our findings indicate for the first time that the hypoglycaemic effects of γ-conglutin may involve an autophagy induction mechanism, a pivotal process for the preservation of cell physiology and glucose homeostasis.

Associations of GlycA and high-sensitivity C-reactive protein with measures of lipolysis in adults with obesity

BACKGROUND

Obesity-associated inflammation promotes metabolic dysfunction. However, it is unclear how different inflammatory biomarkers predict dysregulation in specific tissues/organs, particularly adipose tissue.

OBJECTIVE

The aim of our study was to examine whether GlycA, a nuclear magnetic resonance-measured biomarker of inflammation, is a better predictor of insulin-suppressible lipolysis and other measures of metabolic dysfunction compared with high-sensitivity C-reactive protein (hsCRP) in human obesity.

METHODS

This was a cross-sectional study of 58 nondiabetic adults with obesity (body mass index: 39.8 ± 7.0 kg/m², age 46.5 ± 12.2 years, 67.2% female) who underwent a frequently sampled intravenous glucose tolerance test in the fasted state. Noninsulin-suppressible (l₀), insulin-suppressible (l₂), and maximal (l₀+l₂) lipolysis rates, as well as insulin sensitivity and acute insulin response to glucose, were calculated by minimal model analysis. Nuclear magnetic resonance was used to measure GlycA. Body composition was determined by dual-energy X-ray absorptiometry.

RESULTS

GlycA was strongly correlated with hsCRP (r = +0.46; P < .001). GlycA and hsCRP were positively associated with l₂, l₀+l₂, and fat mass (Ps < .01). In linear regression models accounting for age, race, sex, and fat mass, GlycA remained significantly associated with l₂ and l₀+l₂ (Ps < .05), whereas hsCRP did not (Ps ≥ .20). Neither GlycA nor hsCRP was associated with l_0, insulin sensitivity, or acute insulin response to glucose.

CONCLUSIONS

GlycA was associated with elevated lipolysis, independent of adiposity, in adults with obesity. Our findings suggest that GlycA and hsCRP have distinct inflammation-mediated metabolic effects, with GlycA having a greater association with adipose tissue dysfunction. Further studies are warranted to investigate the mechanisms underlying these associations.

Colchicine's effects on metabolic and inflammatory molecules in adults with obesity and metabolic syndrome: results from a pilot randomized controlled trial

Objective

Recent clinical trials have demonstrated that colchicine may have metabolic and cardiovascular and benefits in at-risk patients; however, the mechanisms through which colchicine may improve outcomes are still unclear. We sought to examine colchicine’s effects on circulating inflammatory and metabolic molecules in adults with obesity and metabolic syndrome (MetS).

Methods

Blood samples were collected pre- and post-intervention during a double-blind randomized controlled trial in which 40 adults with obesity and MetS were randomized to colchicine 0.6 mg or placebo twice-daily for 3 months. Serum samples were analyzed for 1305 circulating factors using the SomaScan Platform. The Benjamini–Hochberg procedure was used to adjust the false discovery rate (FDR) for multiple testing.

Results

At baseline, age (48.0 ± 13.8 vs. 44.7 ± 10.3 years) and BMI (39.8 ± 6.4 vs. 41.8 ± 8.2 kg/m²) were not different between groups. After controlling for the FDR, 34 molecules were significantly changed by colchicine. Colchicine decreased concentrations of multiple inflammatory molecules, including C-reactive protein, interleukin 6, and resistin, in addition to vascular-related proteins (e.g., oxidized low-density lipoprotein receptor, phosphodiesterase 5A). Conversely, relative to placebo, colchicine significantly increased concentrations of eight molecules including secreted factors associated with metabolism and anti-thrombosis.

Conclusions

In adults with obesity, colchicine significantly affected concentrations of proteins involved in the innate immune system, endothelial function and atherosclerosis, uncovering new mechanisms behind its cardiometabolic effects. Further research is warranted to investigate whether colchicine’s IL-6 suppressive effects may be beneficial in COVID-19.

Opposing effects of HNP1 (α-defensin-1) on plasma cholesterol and atherogenesis

Atherosclerosis, the predominant cause of death in well-resourced countries, may develop in the presence of plasma lipid levels within the normal range. Inflammation may contribute to lesion development in these individuals, but the underlying mechanisms are not well understood. Transgenic mice expressing α-def-1 released from activated neutrophils develop larger lipid and macrophage-rich lesions in the proximal aortae notwithstanding hypocholesterolemia caused by accelerated clearance of α-def-1/low-density lipoprotein (LDL) complexes from the plasma. The phenotype does not develop when the release of α-def-1 is prevented with colchicine. However, ApoE-/- mice crossed with α-def-1 mice or given exogenous α-def-1 develop smaller aortic lesions associated with reduced plasma cholesterol, suggesting a protective effect of accelerated LDL clearance. Experiments were performed to address this seeming paradox and to determine if α-def-1 might provide a means to lower cholesterol and thereby attenuate atherogenesis. We confirmed that exposing ApoE-/- mice to α-def-1 lowers total plasma cholesterol and decreases lesion size. However, lesion size was larger than in mice with total plasma cholesterol lowered to the same extent by inhibiting its adsorption or by ingesting a low-fat diet. Furthermore, α-def-1 levels correlated independently with lesion size in ApoE-/- mice. These studies show that α-def-1 has competing effects on atherogenesis. Although α-def-1 accelerates LDL clearance from plasma, it also stimulates deposition and retention of LDL in the vasculature, which may contribute to development of atherosclerosis in individuals with normal or even low plasma levels of cholesterol. Inhibiting α-def-1 may attenuate the impact of chronic inflammation on atherosclerotic vascular disease.