Page 701 - Small Animal Clinical Nutrition 5th Edition

726 Small Animal Clinical Nutrition

years of EE, the enrichment alone was sufficient to detect (Milgram et al, 1993; Knoll, 1998). Selegiline may also con-
VetBooks.ir improved performance on the intensity discrimination and tribute to a decrease in ROS in the brain by decreasing produc-
tion of free radicals, scavenging oxygen free radicals and
reversal tasks. On both of these tasks, the investigators found
that combined antioxidant dietary and EE intervention were
enhancing the scavenging action of enzymes such as catalase
more effective than either treatment alone. The authors con- and superoxide dismutase (Carillo et al, 1994; Heinonen and
cluded that a prolonged period of EE has substantial effects on Lammintausta, 1991). Selegiline is given at a dose of 0.5 to 1
cognitive performance in older beagles, and like the antioxidant mg/kg per os each morning. Although selegiline can be used
food, appears to slow development of age-related cognitive concurrently with most veterinary therapeutic foods and sup-
decline in old dogs (Milgram et al, 2004, 2005). plements, it should not be combined with narcotics, antidepres-
sants or monoamine oxidase inhibitors. Therefore, it should
Supplements probably not be used with supplements containing tryptophan,
A number of complementary therapies are marketed as treat- St. John’s wort or Ginkgo biloba.
ments for cognitive dysfunction. These products may contain Propentofylline and nicergoline, which may enhance cere-
mixtures of herbal extracts, vitamins, phospholipids, fatty acids, brovascular transmission, are licensed in some European coun-
antioxidants and mitochondrial cofactors believed to act in a tries and Australia for signs of brain aging in senior pets
synergistic or potentiating manner to slow the progression of or (Penaliggon, 1991; Kapl and Rudolphi, 1998). The efficacy of
improve clinical signs associated with brain aging. Although nicergoline has been demonstrated in at least one clinical trial
there is little evidence to support the efficacy of most of these (Penaliggon, 1991). It was recently determined that senior dogs
products, three clinical trials have recently reported improve- display a greater sensitivity to the memory impairment effects
ments in clinical signs of CDS in pets given dietary supple- of scopolamine (an anticholinergic drug) than younger dogs
ments containing phosphatidylserine (Osella et al, 2007; Cena and show a positive response to experimental cholinomimetics
et al, 2005; Heath et al, 2007). Phosphatidylserine, Gingko bilo- (Araujo et al, 2005a). A major focus of drug therapy for
ba, pyridoxine and vitamin E are distributed in Italy as a neu- Alzheimer’s disease in people is to enhance cholinergic trans-
b
roprotective dietary supplement for senior dogs and cats. In a mission. Therefore, drugs that act to augment cholinergic
preliminary laboratory evaluation, dogs were tested after transmission might have application for clinical use in dogs
administration of a placebo or the product for 60 days, in a with cognitive decline; however, no available drugs have been
crossover design using spatial memory assessments (Araujo et sufficiently investigated (Araujo et al, 2005a). This may, how-
al, 2006). Performance accuracy was significantly improved in ever, explain why some of the natural supplements (e.g., those
the treated group compared to the baseline group. In addition, containing phosphatidylserine) are effective by enhancing
dogs receiving the supplement in the first portion of the study cholinergic transmission or helping protect cholinergic neurons
maintained their improved performance (Araujo et al, 2006). (Vannucchi et al, 1990; Gelbann and Mullet, 1992).
This product was recently reformulated and now contains In addition to preventive therapy, it may be necessary to con-
resveratrol. sider medications to treat specific signs such as anxiety, restless-
Other commercially available supplements contain docosa- ness, night waking and agitation. Selection of the appropriate
hexaenoic acid, eicosapentaenoic acid and acetylcysteine, which medication should consider the pet’s health and any concurrent
is a primary precursor to glutathione and coenzyme Q10. Fatty medications. In general, anxiolytics that are less likely to cause
acids and glutathione may be beneficial in slowing brain aging hepatic complications (e.g., clonazepam, oxazepam, lorazepam
in people (Horrocks and Yeo, 1999; Pocernich et al, 2000). or buspirone), natural products such as DAP, and antidepres-
Preliminary work also showed an improvement in memory and sants that have little or no anticholinergic effects, such as fluox-
health status in dogs receiving a docosahexaenoic acid supple- etine might be the most appropriate options.
ment (Araujo et al, 2005). S-adenosyl-methionine (SAMe)
may be useful in elderly pets because it has been shown to be
helpful for treating cognitive dysfunction in people. REASSESSMENT
Furthermore, in a preliminary open label clinical trial, SAMe
improved activity levels, sleep-wake cycles, playfulness and fecal Improvements in abnormal behavior associated with brain
elimination disorders in elderly depressed or confused pets c aging may be noted within six to 12 weeks after making a
(Arnold, 2005). dietary change. If improvements are not noted with 12 weeks,
then it is unlikely that nutritional management alone will result
Drug Therapy in significant improvement. Therapy with supplements and
Selegiline is licensed for treatment of cognitive dysfunction in drugs appears to be safe to use in conjunction with nutritional
d
dogs in North America. Selegiline is a selective and irre- management. Reassessment of behavioral changes can also
versible inhibitor of MOA-B in dogs (Milgram et al, 1993). It occur during routine health maintenance protocols established
increases 2-phenylethylamine in the canine brain. This drug is for mature or geriatric pets in each hospital.
a neuromodulator; therefore, the primary mode of action may As mentioned above, in 2005, the American Animal Hos-
be to enhance dopamine and catecholamine function in the pital Association senior care task force published guidelines
cortex and hippocampus to improve cognitive function that recommended yearly wellness screening for healthy mid-