Page 20 - Contributed Paper Session (CPS) - Volume 4

CPS2106 Julio M. Singer et al.
in electrophysiological parameters have also been reported. A comparable
effect of gender is also observed in ALS patients.
Treatment of ALS with stem cells is a current research topic. Mesenchymal
stromal cells (MSC), specially those derived from adipose tissues, and pericytes
have been used in studies that focus on the reduction of the speed of the
progression of symptoms of neuro-degenerative diseases. In this context we
consider a study conducted in the Human Genome and Stem Cell Research
Center, at the Biosciences Institute, University of S˜ao Paulo, Brazil with the
objective of comparing MSC cells and pericytes injected in SOD1-G93A mice
with respect to their effects on the evolution of some symptoms of ALS. Details
may be obtained in Coatti et al. (2017).
Our objective here is to propose models for the statistical analysis of the
data.

2. The study
A set of 34 female and 21 male 8 week old SOD1-G93A mice was divided
into 3 groups Animals in the first group (12 females and 7 males) were
submitted to weekly injections of MSC cells, those in second group (11 females
and 8 males), to injection with pericytes while animals in the third group (11
females and 6 males) were submitted to the vehicle (Hank’s balanced salt
solution - HBSS). All animals were followed weekly up to their death for clinical
analysis of the progression of the disease by means of four variables, the
analysis of one of them, rotarod is considered in this study. The rotarod test
was used to evaluate motor coordination and fatigue resistance. For that
purpose, the length of time each animal could remain on the rotating cylinder
(3.5 cm) of a rotarod apparatus (IITC Life Science model 755) was recorded.
The initial speed was 1 rpm and it was increased constantly until a final speed
of 30 rpm, after 180 s. Each animal was given three tries and the longest
latency to fall was recorded. The specific objectives of the analysis are:
i) Identification of the moment when animals become symptomatic
(symptoms onset) forthe six groups defined by the combination of
treatment (HBSS, MSCs, pericytes) and sex (male, female).
ii) Estimation of the expected rate of variation in response after symptom
onset for eachgroup.
iii) Evaluation of the effects of treatment, sex and their interaction on the
expected momentof symptom onset and post onset rate of variation in
the expected response.

3. Statistical analysis
Profile plots for the response along with LOESS curves are displayed in
Figure 1.

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