TNF-alpha modulation in Alzheimer's patients
More than a decade of basic research and clinical evidence now implicates inflammatory processes in the pathogenesis of Alzheimer’s disease (AD). TNF-alpha is a pro-inflammatory cytokine, also known as the “master regulator” of the immune response, and is the key initiator of immune-related inflammation in the brain. Much evidence has linked excess TNF-alpha to the development of AD, including the demonstration of 25-fold elevated levels of TNF-alpha in the cerebrospinal fluid of AD patients and the finding that beta-amyloid (the main constituent of the amyloid plaques found in the brains of AD patients) stimulates the secretion of TNF-alpha, which in turn induces beta-amyloid production in a vicious positive-feedback loop. This beta-amyloid-induced neuroimflammation has been shown to result in neurotoxicity and to upregulate other inflammatory mediators in the brain, including interleukin (IL)-1 beta, IL-6, and nitric oxide.
To examine the effect of downregulating this inflammatory process, a group of researchers performed a 6 month pilot study in 2006 to determine the effect of modulating TNF-alpha in AD patients using the specific anti-inflammatory agent entanercept (Enbrel). Enbrel selectively inhibits the biologic activity of TNF-alpha by binding to TNF-alpha and preventing its interaction with cell-surface TNF receptors. Entanercept is already FDA approved for the treatment of such diseases as rheumatoid arthritis, psoriasis, and psoriatic arthritis.
Fifteen patients with mild to severe AD were evaluated before treatment began and once a month thereafter for six months using three standard measures of cognition: the AD Assessment Scale-Cognitive subscale (ADAS-Cog), the Severe Impairment Battery (SIB), and the Mini-Mental State Examination (MMSE). Treatment consisted of a total dose of 25 to 50 mg of Enbrel in sterile water per week via interspinous injection. This injection between two cervical vertebrae is hypothesized to improve flow of the drug to the central nervous system (CNS). All patients in this pilot study improved significantly on all assessments of cognitive ability, which is particularly amazing given the cognitive decline that would normally be expected of an AD patient over the course of six months.
As mentioned, this pilot study was approved to evaluate patients only at monthly intervals. However, during this six-month study and over the course of their clinical experience since the pilot study, the researchers noted “an unexpected and largely unprecedented clinical phenomenon… a noticeable clinical improvement within minutes of perispinal entanercept administration.” To validate these observations, the researchers performed a case study in 2008 in which a patient with severe AD was evaluated prior to, ten minutes after, two hours after, and one week after Enbrel administration.
Prior to treatment the patient had been unable to recall his birthday, his father’s occupation, or the names of any of the physicians treating him. He was not oriented to the calendar date, day of the week, year, place, city, or state. Ten minutes after receiving an injection of Enbrel, the patient correctly identified the state as California and his demeanor was observed to be calmer and more attentive. His responses to questions were less effortful, as well.
At the 2-hour post-evaluation, the patient was able to recall the name of his evaluator and was able to identify the month, day of the week, place, and name the state of California. He was slightly off on the calendar date and year, but “appeared more aware of his deficient performance.” The patient’s scores on all mental tests also improved dramatically. These improvements were maintained over the course of a week, whereupon he was evaluated again before receiving his next Enbrel dose. The patient continued to receive a weekly dose of Enbrel for a total of 5 weeks and was re-evaluated at 7 weeks (fourteen days after his last dose). His improvement in all areas of cognitive performance was marked and significant.
An important consideration when treating a patient with Enbrel, however, is that it is immunosupressive and as such leaves the patient at high risk of morbidity if they acquire an infection. This is especially important in late-stage Alzheimer’s patients, who are generally elderly, frequently visit hospitals/treatment centers, and live in community environments, making them particularly susceptible to community-acquired infection.
Following up on the publication of these unprecedented findings, the Life Extension Foundation recently published a review of both Enbrel pilot studies and the initial results of their own pilot study involving a 91-year-old female AD patient with severe cognitive deficits, who has also shown marked improvement in cognitive ability. The Life Extension Foundation is now eager to “launch an expanded study with the objective of measuring the long-term effects of weekly Enbrel injections plus nutrients that help suppress the production of excess TNF-alpha.” These trials are aimed at treating early-stage AD patients, and weekly Enbrel injections will be given in the Fort Lauderdale area.
To inquire about enrolling in this new study, contact the Life Extension Foundation.