A Diet Mimicking Fasting Promotes Regeneration and Reduces Autoimmunity and Multiple Sclerosis Symptoms

Summary
Dietary interventions have not been effective in the treatment of multiple sclerosis (MS). Here we show that periodic 3 day cycles of a fasting mimicking diet (FMD) are effective in ameliorating demyelination and symptoms in a murine experimental autoimmune encephalomyelitis (EAE) model. The FMD reduced clinical severity in all mice, and completely reversed symptoms in 20% of the animals. These improvements were associated with increased corticosterone levels and Treg cell number, reduced levels of pro-inflammatory cytokines, TH1 and TH17 cells, and antigen presenting cells (APCs). Moreover, the FMD promoted oligodendrocyte precursor cell regeneration and remyelination in axons in response to both EAE and cuprizone MS models, supporting its effects on both suppression of autoimmunity and remyelination. We also report preliminary data suggesting that a FMD or a chronic ketogenic diet are safe, feasible and potentially effective in the treatment of relapsing remitting multiple sclerosis (RRMS) patients (NCT01538355).

Introduction
Multiple sclerosis (MS) is an autoimmune disorder characterized by T cell-mediated demyelination and neurodegeneration in the central nervous system (CNS) (Friese and Fugger, 2005; Pender and Greer, 2007; Rasmussen et al., 2007; Sospedra and Martin, 2005). In experimental autoimmune encephalomyelitis (EAE), an animal model for MS, activated myelin-specific TH1 and TH17 cells cross the blood brain barrier and migrate into the CNS, where they are activated by local antigen presenting cells (APCs) and promote inflammation (Dhib-Jalbut, 2007; Fletcher et al., 2010; Goverman, 2009; Hemmer et al., 2002). This inflammatory process leads to oligodendrocyte death, demyelination and axonal damage, which eventually cause neurological damage (Lucchinetti et al., 1999; Raine and Wu, 1993). Although oligodendrocyte precursor cells (OPCs) can migrate to the sites of MS lesions, they often fail to differentiate into functional oligodendrocytes (Chang et al., 2002; Wolswijk, 1998). Several MS treatment drugs have been effective in reducing immune responses, but their impact on long-term disease progression, accrual of irreversible neurological disability, and the function of the immune system remains largely unclear, underlining the need for novel therapeutic strategies (Wingerchuk and Carter, 2014). Therefore, effective treatments for MS may require not only the mitigation of autoimmunity, but also the stimulation of oligodendrocyte regeneration and the restoration of a functional myelin sheath. Periodic cycles of prolonged fasting (PF) or of a fasting mimicking diet (FMD) lasting 2 or more days can increase protection of multiple systems against a variety of chemotherapy drugs in mice and possibly humans. Moreover, PF or FMD reverse the immunosuppression or immunosenescence of either chemotherapy or aging through hematopoietic stem cell-based regeneration (Brandhorst et al., 2015; Cheng et al., 2014; Fontana et al., 2010; Guevara-Aguirre et al., 2011; Lee et al., 2010; Longo and Mattson, 2014). Chronic caloric restriction, a ketogenic diet (KD), and intermittent fasting have been shown to prevent EAE by reducing inflammation and enhance neuroprotection when administered prior to disease induction or signs (Esquifino et al., 2007; Kafami et al., 2010; Kim do et al., 2012; Piccio et al., 2008) but dietary interventions have not been reported as a therapy for EAE or MS or to promote myelin regeneration.

Here we report on the effects of low calorie and low protein FMD cycles as a treatment of MS mouse models, and investigate the mechanisms involved. Furthermore, we report preliminary results on the safety and feasibility of a FMD and a KD in patients with relapsing-remitting MS (RRMS).

Results
The FMD cycles reduce disease severity in the MOG35-55-induced EAE model
We examined the effects of periodic cycles of a very low calorie and low protein fasting mimicking diet (FMD) lasting 3 days every 7 days (3 cycles) or a ketogenic diet (KD) continued throughout the 30 days on EAE model induced with active immunization with myelin oligodendrocyte glycoprotein 35-55 (MOG35-55) (Fig. 1a). Groups of mice were treated both semi-therapeutically -EAE FMD (S); in which FMD treatment started after 10% of the immunized population showed EAE signs- or therapeutically -EAE FMD (T), in which FMD treatment started after all of the immunized population showed EAE signs. FMD and KD treatment decreased the disease severity compared to the control (Fig. 1b); however, the FMD reduced the mean severity score to approximately 1, whereas the KD group reduced the severity score to approximately 2 at the later stages (Fig. 1b). In the EAE FMD (S) group, FMD treatment not only delayed the onset of disease but also lowered the incidence rate (100% vs. 45.6%; Fig. 1c). In the EAE FMD (T) group, FMD cycles completely reversed the severity score to 0 in 21.7% of the cohort (no observable signs; Fig. 1d), and reduced the severity score to below 0.5 in over 50% of the mice (12 out of 23 mice; Fig. 1e). To address whether the FMD cycles also have beneficial effects on the chronic EAE models that have established disease, we initiated FMD treatment two weeks after initial EAE signs (EAE CTRL-FMD). Prior to the treatment, both the EAE CTRL and EAE CTRL-FMD cohorts had similar severity scores (3.19 ± 0.52 vs. 3.30 ± 0.27; Day 24). After three FMD cycles, we observed a significant reduction of severity score in the EAE CTRL-FMD cohort compared to the EAE CTRL cohort (3.3 ± 0.57 vs. 2.1 ± 0.89; Day 42; p < 0.05; Fig. 1f). As infiltration of immune cells and demyelination are histopathological hallmarks of EAE and MS, spinal cord sections were stained with hematoxylin and eosin to visualize infiltrating immune cells (H&E; Fig. 1g) or solochrome cyanine to visualize myelin (Fig. 1 h). To assess demyelination and axonal damage, immunohistochemistry was performed using antibodies against myelin basic protein (MBP) or dephosphorylated neurofilaments (SMI-32; Fig. 1i). At D3, the level of infiltrating immune cells and demyelination were similar in the EAE CTRL and EAE FMD groups (Fig. 1j; Supplemental Fig. 1h). At D14, sections of EAE CTRL mice displayed severe immune cell infiltration corresponding with demyelinated lesions, reduced MBP expression and increased SMI-32 expression (Fig. 1j–m). By contrast, sections of EAE FMD mice at D14 displayed significantly reduced immune cell infiltration and demyelination (Fig. 1j–m). Although MBP staining showed no significant difference between EAE CTRL and EAE FMD at D14 (Fig. 1l), neurofilament dephosphorylation in the EAE FMD mice was reduced compared to the EAE CTRL group (Fig. 1m). Overall, these results suggest that FMD cycles reduce EAE disease severity in part by reducing inflammation, and preventing demyelination and axonal damage.

Full Text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4899145/