Dawn-to-dusk dry fasting induces anti-atherosclerotic, anti-inflammatory, and anti-tumorigenic proteome in peripheral blood mononuclear cells in subjects with metabolic syndrome

Background

Metabolic syndrome characterized by abdominal obesity, high blood pressure, elevated fasting glucose and triglyceride levels and low high-density lipoprotein cholesterol level is associated with pro-inflammatory state, increased risk for atherosclerosis, and multiple cancers. Our previous results on subjects with metabolic syndrome showed that 4-week dawn-to-dusk (sunset) dry fasting resulted in significant changes in the serum proteome and improvement in several metabolic risk factors. Peripheral blood mononuclear cells (PBMC) proteomics is a powerful tool that can provide mechanistic insights into how dawn-to-dusk dry fasting affects protein expression in metabolic pathways at cellular level. In this study, we determined whether dawn-to-dusk dry fasting would induce favorable changes in PBMC proteome in subjects with metabolic syndrome, similar to the changes induced by dawn-to-dusk dry fasting in the same subjects' serum proteome.

Methods

We conducted a prospective study on subjects with metabolic syndrome and collected blood specimens before 4-week dawn-to-dusk dry fasting, at the end of 4-week dawn-to-dusk dry fasting, and one week after 4-week dawn-to-dusk dry fasting. We performed untargeted proteomics using nano ultra-high performance liquid chromatography-tandem mass spectrometry to assess the impact of 4-week dawn-to-dusk dry fasting on PBMC proteome.

Results

There were 14 subjects with metabolic syndrome with a mean age of 59 who fasted from dawn to dusk (strict dry fasting without any liquid or food intake) for more than 14 h daily for 29 days. The quantitative proteome analysis showed that apolipoprotein B (APOB) gene protein products (GP) levels were downregulated and had the most statistical significance of the observed difference at the end of 4-week dawn-to-dusk dry fasting (P = 0.008) and one week after 4-week dawn-to-dusk dry fasting (P = 0.0004) compared with the levels before 4-week dawn-to-dusk dry fasting. The comparison between GP levels before and at the end of 4-week dawn-to-dusk dry fasting showed an alteration in the expression of genes associated with lipid and atherosclerosis pathway (P = 6.014e-4) and C-type lectin receptor signaling pathway (P = 1.064e-5). The genes that were differentially expressed in the lipid and atherosclerosis pathway were APOB (P = 0.008), CD36 (P = 0.040), CALM1, CALM2, CALM3 (P = 0.015), and HSPA8 (P = 0.047). One of the differentially expressed genes in the C-type lectin receptor signaling pathway was lymphocyte-specific protein 1 (LSP1), which showed an average of 19-fold increase at the end of 4-week dawn-to-dusk dry fasting compared with the GP levels before fasting (P = 0.004). Several GPs associated with tumor-suppressor effect (TUBB4B, LSP1, ACTR3B) were upregulated, and GPs associated with tumor-promoter effect (CD36, CALM1, CALM2, CALM3, FLOT2, PPIF) were downregulated at the end of 4-week dawn-to-dusk dry fasting or one week after 4-week dawn-to-dusk dry fasting compared with the GP levels before 4-week dawn-to-dusk dry fasting.

Conclusion

Based on our results, we conclude that in subjects with metabolic syndrome, 4-week dawn-to-dusk dry fasting induced anti-atherosclerotic, anti-inflammatory, and anti-tumorigenic PMBC proteome. Randomized, controlled clinical trials are needed to further investigate the effect of dawn-to-dusk dry fasting on subjects with chronic metabolic diseases and metabolic syndrome-induced cancers.

The effect of four-week intermittent fasting from dawn to sunset on circulating brain-derived neurotrophic factor levels in subjects with metabolic syndrome and healthy subjects

Background

Brain-derived neurotrophic factor (BDNF) is a key neurotrophin that regulates food intake and energy hemostasis. BDNF also promotes neurogenesis, neuroplasticity, and neuroprotection. There are conflicting reports regarding how intermittent fasting affects circulating BDNF levels. We tested the hypothesis that 4-week intermittent fasting from dawn to sunset (4-week-IF) would decrease circulating BDNF levels in subjects with metabolic syndrome and healthy subjects.

Methods

We conducted pilot studies in subjects with metabolic syndrome and healthy subjects who fasted from dawn to sunset for more than 14 h for four consecutive weeks. We measured serum BDNF levels and metabolic parameters before 4-week-IF, at the end of 4th week during 4-week-IF, and one week after 4-week-IF.

Results

We enrolled 28 subjects, 14 with metabolic syndrome (women/men:6/8) with a mean age of 59 years and 14 healthy subjects (women/men:1/13) with a mean age of 32 years. Overall, BDNF levels decreased at the end of 4th week during 4-week-IF compared with the levels before 4-week-IF (mean paired difference = −98.5 ng/ml, P = 0.0006). When subjects with metabolic syndrome were compared with healthy subjects, subjects with metabolic syndrome had a lower mean paired reduction in BDNF levels at the end of 4th week during 4-week-IF compared with the levels before 4-week-IF (BDNF mean paired difference = −27.6 ng/ml vs. −169.5 ng/ml, P = 0.003). Multivariate linear regression analysis showed a positive correlation between the change in tumor necrosis factor-alpha and change in BDNF levels at the end of 4th week during 4-week-IF compared with the levels before 4-week-IF in subjects with metabolic syndrome (P = 0.040) and healthy subjects (P = 0.007). The change in weight and body mass index independently predicted the change in BDNF levels 1 week after 4-week-IF compared with the levels before 4-week-IF in subjects with metabolic syndrome.

Conclusion

Four-week-IF resulted in a reduction in the BDNF levels at the end of 4th week during 4-week-IF. Higher BDNF levels and a lower reduction in BDNF levels at the end of 4th week during 4-week-IF compared with the levels before 4-week-IF in subjects with metabolic syndrome than healthy subjects suggest a potential BDNF resistance similar to insulin and leptin resistance in metabolic syndrome. A positive correlation between the change in BDNF and change in tumor necrosis factor-alpha levels at the end of 4th week during 4-week-IF compared with the levels before 4-week-IF suggests that BDNF is a biomarker of inflammation and endothelial dysfunction in addition to its neurotrophic and anorexigenic features.