[Edaily Reporter YU JIN-HEE ] The kidneys are often called the “silent organ” because once damaged, they are difficult to restore. For patients with chronic kidney disease (CKD), whose kidney function gradually declines, the most feared enemy is “uremic toxins,” which accumulate in the body and damage blood vessels and other organs. While existing treatments have been limited to “post-hoc symptomatic therapy”—which involves using charcoal (spherical activated carbon) to absorb and expel toxins already present in the body—a new paradigm is emerging that alters the gut microbiome itself to block the root cause of toxin production. At the heart of this innovation is “K-probiotics,” developed using indigenous South Korean technology.

The story began at Zvezdara University Hospital in Serbia, Eastern Europe. A clinical trial was conducted in which 34 patients with stage 3–4 chronic kidney disease (CKD), who were on the verge of requiring dialysis, were administered “CBT Lactobacillus,” a patented strain from the Korean company CELL BIOTECH CO ., LTD(049960).

The results were astonishing. The glomerular filtration rate (GFR)—a key indicator of kidney function—improved by 12.5% in patients who took the probiotics. Furthermore, “indoxyl sulfate” (IS), a major uremic toxin that circulates in the body and damages the kidneys, decreased by 21.5%, and the inflammation marker (hsCRP) plummeted by nearly 40%. The medical community was flooded with questions such as, “How can probiotics in the gut help the kidneys, which are located behind the back?”

To answer this question, CELL BIOTECH CO ., LTD’s R&D Center embarked on an in-depth study. To elucidate the “Gut-Kidney Axis” theory—which posits that the gut and kidneys exchange signals closely—the team conducted follow-up studies using in vitro and in vivo models, and the results were published in *Life Sciences* (IF: 6.4), a leading journal in the field of pharmacology.

The research team tracked the capabilities of Duolac’s three core patented strains (CBT-LA1, CBT-LC5, CBT-BL3) in a step-by-step process. In the first phase—in vitro experiments—the CBT lactic acid bacteria broke down and reduced intestinal indole, the “raw material” for uremic toxins, by up to 87.7%. This effectively prevented toxins from forming in the first place.

Subsequently, a dramatic turnaround was observed in mouse experiments where acute kidney injury was induced by the anticancer drug cisplatin. Upon administration of CBT lactic acid bacteria, blood levels of indole sulfate (IS) decreased by 82.7%, and levels of p-cresyl sulfate (pCS)—another lethal uremic toxin—decreased by as much as 92.7%. As the toxins cleared, the kidney damage marker (KIM-1) decreased by 73.3% and blood urea nitrogen (BUN) by 71.5%, indicating that the damaged kidney tissue had clearly stabilized.

A particularly noteworthy aspect of this study is the comparative analysis with “spherical activated carbon (AST-120),” a standard medication currently widely used for patients with kidney disease.

Spherical activated carbon adsorbs uremic toxins like a sponge and excretes them, but it does not alter the intestinal environment itself. In contrast, CBT probiotics not only reduced uremic toxins but also restored the devastated gut microbiota to a “healthy, normal state.” Beneficial gut bacteria, such as Bifidobacterium and Lactobacillus, have begun to thrive again, enabling the gut itself to develop an “autogenous defense barrier” that suppresses toxins.

An official from CELL BIOTECH CO ., LTD’s R&D Center explained the significance of the research, stating, “We have scientifically proven that by normalizing the gut microbiome—rather than merely reducing toxin levels—we can break the vicious cycle of kidney damage.”

CELL BIOTECH CO ., LTD is a leading Korean probiotics company that has maintained its position as the nation’s top probiotics exporter for 13 consecutive years, based on its proprietary, globally patented “Dual Coating” technology. Having expanded its reach beyond the gut into the field of microbiome-based biopharmaceuticals—including the development of new drugs for colorectal cancer—CELL BIOTECH CO ., LTD has set another major milestone with this research: “improving kidney disease.”

The day is not far off when a single probiotic capsule, taken daily, will serve as a reliable shield to protect the kidney health of patients suffering from chronic diseases.