Association between circulating leptin levels and multiple sclerosis: a systematic review and meta-analysis

Abstract

Overall, our study suggests that patients with MS have a significantly higher leptin level than in healthy controls. Further mechanism studies and longitudinal large cohort studies are still needed to further reveal the role of leptin in the pathogenesis of MS.

Investigation of blood leptin and adropin levels in patients with multiple sclerosis

“…[ 39 ] So leptin activates mTOR. Leptin was not found helpful as an MS activity biomarker in one study [ 8 ] but, in a meta-analysis, higher serum leptin levels were found in MS patients than the control group, [ 7 ] suggesting leptin as a biomarker. The role of leptin could not be demonstrated in a study conducted with naive patients with clinically isolated syndrome and RRMS.…”

Leptin levels are associated with multiple sclerosis risk

“…27 It is a well-known fact that women are more prone to develop many autoimmune diseases including MS, with sex ratios ranging from 9:1 for systemic lupus erythematosus (SLE) to a more modest 2:1 or according to more recent data 3:1 for MS, with rheumatoid arthritis (RA) having a ratio somewhere in between. 28 For both SLE and RA patients, serum levels of leptin appear to be increased 29 as is also the case with MS. 7 Since women have higher levels of leptin than men, even at the same BMI, it is attractive to propose elevated leptin as a possible explanation for the observed sex difference in disease occurrence. 30 In the present study, women had about five times higher median leptin concentrations compared to men, providing an example of a sex difference that no other known MS risk factor has shown, giving support to the notion that leptin may be of etiological importance.…”

“…Earlier case–control studies on leptin in patients with established MS have shown conflicting results, but according to a recent meta-analysis, leptin levels are higher among those with MS. 7 There are also studies indicating a role for leptin in induction of experimental autoimmune encephalomyelitis (EAE), the animal model of MS, where leptin deficient mice failed to develop EAE unless leptin was systemically administered. 24…”

“…12 Regarding risk for paediatric MS or clinically isolated syndrome, a case-control study found an increased risk among obese girls but not boys. 21 Mendelian randomization studies have also indicated a causal link between BMI and MS risk, showing that genes that elevate BMI increase the risk of MS. 22,23 Earlier case-control studies on leptin in patients with established MS have shown conflicting results, but according to a recent meta-analysis, leptin levels are higher among those with MS. 7 There are also studies indicating a role for leptin in induction of experimental autoimmune encephalomyelitis (EAE), the animal model of MS, where leptin deficient mice failed to develop EAE unless leptin was systemically administered. 24 We found that insulin and leptin levels were correlated, as has been seen in earlier studies.…”

“…In this nested case-control study, we instead measure the adipokine leptin, which is strongly correlated to both BMI and total fat mass, 5 as well as insulin, a peptide hormone associated with both obesity and type 2 diabetes. 6 Elevated levels of both leptin 7 and insulin 8 among individuals with established MS have been previously shown, but to our knowledge, no prospective studies have been performed. Since pathological processes in MS may start many years or even decades before symptom onset, an effort was made to find serum or plasma samples drawn at a young age where risk factors ought to have the largest impact on disease risk.…”