CMPH Journal

Introduction

In recent years, autism spectrum disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have become a problem. These disorders affect communication skills, making it difficult for people to adapt to society. ASD and ADHD are classified as neurodevelopmental disorders [1], and symptoms include poor communication skills and difficulty responding when spoken to [2]. For this reason, ASD and ADHD are diagnostic names that encompass a continuum (spectrum) of various conditions, such as stereotypic behavior [3]. The diagnostic criteria for ASD are set out in the DSM-5 as meeting two criteria: “social communication disorder” and “restricted interests [4]. At the same time, ADHD is a neurodevelopmental disorder (developmental disorder) or behavioral disorder characterized by symptoms such as hyperactivity, impulsivity, and inattention [5]. Although these are classified as developmental disorders, the symptoms of developmental disorders vary widely, so it is necessary to provide various types of support tailored to each individual and appropriate environmental adjustment [6]. It is considered effective to provide comprehensive support that combines environmental adjustment, psychosocial support, and drug therapy in collaboration with various support organizations according to the individual’s condition [7]. In this context, one area of research that has been attracting attention in recent years is the causal relationship between intestinal flora and developmental disorders [8]. As the term braingut correlation suggests, intestinal flora also influences the central nervous system [9]. There have been reports of intestinal flora disorders in patients with developmental disorders [10]. There have also been reports of autism symptoms being alleviated by improving intestinal flora [11].

Approximately 1000 types of enterobacteria, totalling approximately 100 trillion bacteria, reside in the intestines and form the intestinal flora [12]. Disturbance in the balance of the intestinal flora is called dysbiosis, and it causes inflammation and abnormal insulin resistance through cell metabolism regulators such as AMPK and NF-κB [11]. It is believed that these abnormalities lead to a vicious cycle in which developmental disorders progress [13]. Enterococcus faecalis Kawai strain lactic acid bacteria (Enterococcus faecalis Kawai strain) was discovered among the lactic acid bacteria living in healthy humans by Dr. Yasuo Kawai while he was searching for lactic acid bacteria that are considered to be most effective in preventing the three major lifestyle-related diseases of cancer, heart disease, and cerebrovascular disease, and is a lactic acid bacterium that has been proven to be particularly effective in treating arteriosclerosis [14]. It is suggested that Enterococcus faecalis Kawai strain lactic acid bacteria may also be highly effective in improving the intestinal environment and preventing developmental disorders.

It is said that there is a close relationship between the intestinal flora and the immune system [15]. If the balance of the intestinal flora is not maintained, the immune system will be weakened, causing fungi to proliferate, resulting in inflammation, and allowing undigested proteins that should not be absorbed to enter the body through the intestinal wall. This is known as “leaky gut syndrome” [16]. Therefore, improving the intestinal flora is thought to not only improve the immune system, but also be an approach to developmental disorders.

In humans, cells are constantly dividing according to the cell cycle, and senescent cells also appear as a result. Senescent cells may increase in the body because it becomes difficult to remove them due to a decline in the immune system in the body [17]. Therefore, developmental disorders can also be seen as a problem with immune function [18]. Various immune cells act to remove senescent cells, but this effect may be weakened by a decline in immune function, which is correlated with the intestinal flora [19]. Therefore, this study was planned with the aim of elucidating the disease prevention effect of Lactobacillus faecalis Kawai strain against developmental disorders. We believe that this study will contribute to the construction of a new treatment strategy for the prevention and improvement of developmental disorders from the perspective of suppressing the progression of developmental disorders by improving the intestinal environment.

In recent years, the concept of fasting has become popular in Japan. Fasting means to fast, but it means to restrict the intake of solid food. There are types of regular fasting that are applied worldwide based on traditional, cultural, or religious backgrounds. In ancient medicine, fasting has been an established treatment since Hippocrates. Since then, it has been recommended by most old European medical schools for the treatment of acute and chronic diseases [20]. The frequency of food intake in modern people tends to have a long period of energy intake and a short fasting period, and high-calorie diets and sedentary lifestyles affect the body’s metabolism and increase the incidence of obesity, diabetes, cardiovascular disease, stroke, and dementia year by year [21]. At the same time, it is said that fasting changes the balance of the intestinal flora, so it may be useful for preventing lifestyle-related diseases such as strengthening the immune system [22]. However, since the subjects with developmental disorders studied in this study were young people, fasting was not possible. Therefore, this time, the purpose of this study was to analyze changes in the intestinal flora of young people with developmental disorders using Enterococcus faecalis Kawai strain lactobacillus.

Materials and Methods

This study received ethical approval from the International Society for Geriatrics and Gerontology Ethics Committee (ISGN＿NI10032023).

Type of study: Single-blind functional evaluation

Intervention method

The subjects were aged 10 years or younger. Each subject orally ingested Lactobacillus faecalis Kawai strain for 12 months according to the dosage (※1) determined based on the subject’s weight. All nine subjects were diagnosed with developmental disorders using the Social Responsiveness Scale Second Edition (SRS-2) before and after ingestion. Two of the subjects dropped out, leaving only seven in the final sample. Stool samples were collected from the seven subjects, and intestinal flora tests were performed. In addition, the balance of intestinal flora was scored for statistical purposes and divided into five groups: A, A’, B, B’, C, C’, and D, with A: 90, A’: 80, B: 70, B’: 60, C: 50, C’: 40, and D: 30, with the minimum and maximum scores set at 30 and 90, respectively. Since the n number for these five groups was 7, a non-parametric test was performed. Based on the obtained results, the statistical analysis software IBM SPSS Statistics version 25 was used, and because there was a pairing, a Wilcoxon signed rank test was used to perform a significance test at a significance level of 5%.

(※1) Dosage and Administration

Weight 10-19 kg: 1 packet (295 mg)

Weight 20-29 kg: 2 packets (590 mg)

Weight 30-39 kg: 3 packets (885 mg)

Weight 40-49 kg: 4 packets (1180 mg)

Results

Changes in intestinal flora

As shown in Table 1 and Table 2, subjects with developmental disorders have poor intestinal flora balance. However, when the test substance was administered, the intestinal flora improved. Furthermore, when the scores were statistically processed, the result was P=0.026, which satisfied P<0.05, and a significant difference was confirmed (Figure 1).

Table 1: Changes in intestinal flora before and after administration of test substance (score).

Table 2: Intestinal flora average and SD.

Figure 1: Intestinal flora average and SD (P<0.05).

Changes in the intestinal flora of each subject The target balance of intestinal flora is shown in Figures 2-9.

Figure 2: Target Balance.

Figure 3: Changes in the intestinal flora of subject 1.

Figure 4: Changes in the intestinal flora of subject 2.

Figure 5: Changes in the intestinal flora of subject 3.

Figure 6: Changes in the intestinal flora of subject 4.

Figure 7: Changes in the intestinal flora of subject 5.

Figure 8: Changes in the intestinal flora of subject 6.

Figure 9: Changes in the intestinal flora of subject 7.