Double-blinded, Randomized Controlled Trial of Simvastatin Use As Adjuvant Therapy in Relapsing-Remitting Multiple Sclerosis

Multiple sclerosis (MS), the most prevalent neurological disability, is an autoimmune-mediated disorder that affects the central nervous system (CNS) and often leads to severe physical or cognitive incapacitation as well as neurological problems in young adults . Multifocal zones of inflammation due to focal T-lymphocytic and macrophage infiltrations, and oligodendrocyte death are the primary causes of myelin sheath destruction (2) that result in the formation of CNS plaques composed of inflammatory cells and their products, demyelinated and transected axons, and astrogliosis in both white and gray matter. These lesions can cross-talk with the correct transmission of nerve impulses and lead to neuronal dysfunction such as autonomic and sensorimotor defects, visual disturbances, ataxia, fatigue, difficulties in thinking, and emotional problems .

Subtypes of MS are considered important not only for prognosis but also for treatment decisions and include:

• Relapsing remitting MS (RRMS)
• Primary progressive MS (PPMS)
• Secondary progressive MS (SPMS)
• Progressive relapsing MS (PRMS). RRMS is the most common subtype (approximately 87%) which characterized by unpredictable acute attacks followed by periods of remission . During RRMS, inflammatory attacks on myelin and nerve fibers occur. Activated immune cells cause lesions in the CNS which generate symptoms of visual impairments, tingling and numbness, episodic bouts of fatigue, intestinal and urinary system disorders, spasticity, and learning and memory impairment. Approximately 10-15% of MS patients are diagnosed with PPMS which largely affect the nerves of the spinal cord. PPMS patients tend to have fewer brain lesions. Induced symptoms include problems with walking, weakness, stiffness, and trouble with balance.

Nearly 65% of patients with RRMS will subsequently develop SPMS which is considered the second phase of this disease. Many individuals experience increased weakness, intestinal and urinary system disorders, fatigue, stiffness, mental disorders, and psychological impairment. Finally, PRMS is the least common type of MS that occurs in approximately 5% of patients and is associated with symptoms such as eye pain and double vision, along with sexual, intestinal and urinary system dysfunction, dizziness, and depression. Generally MS is detected between the ages of 20 and 40 years, but less than 1% can occur in childhood and approximately 2-10% after 50 years of age .

This pathologic condition affects women more than men (sex ratio 2.5:1) and the prevalence varies by geographic area, ranging from 120 per 100,000 individuals . The etiology of MS remains unclear, however it can be considered a multifactorial disease and include a genetic predisposition combined with environmental influences .