Sirtuins In Kidney Health And DiseaseⅢ

The role of sirtuins in renal homeostasis

In healthy individuals, the kidney is one of the organs with the highest resting energy consumption, and its energy needs are related to its physiological functions such as filtering blood, controlling electrolyte balance, maintaining acid-base balance, reabsorbing nutrients, and regulating blood pressure. These highly specialized functions are accomplished through more than 30 terminally differentiated cell types that perform different functions and have completely different metabolic requirements.

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The role of Sirtuins in kidney development

Without an understanding of renal embryology, a full assessment of the complexity of the intrinsic metabolism of kidney cells cannot be made. During early embryogenesis, glycolytic flux is tightly controlled and drives cell self-renewal and proliferation as the initial pool of mitochondria segregates in dividing cells. Despite the predominance of anaerobic metabolism in the embryo, mitochondrial maturation begins in mid-nephrogenesis, allowing oxidative phosphorylation to meet the increased energy demands associated with organ development. The switch from glycolysis to oxidative metabolism is key to lineage specification and the result of metabolically driven epigenetic changes that determine cell fate during embryonic differentiation.

In the kidney, the importance of this metabolic switch is illustrated by the finding that insufficient metabolic fitness affects nephron progenitor cell self-renewal and affects the final nephron number per kidney. SIRT3 is highly expressed in the embryonic kidney and is required to inhibit glycolysis and stimulate mitochondrial function to regulate the renal cell precursor pool and behavior, ultimately determining nephrogenesis and nephron empowerment processes at birth. Under conditions of maternal protein restriction, reduced SIRT3 expression is associated with low nephron number and is the main cause of increased susceptibility to renal insufficiency in the elderly. In a maternal protein-restricted mouse model, supplementation of the NAD+ precursor nicotinamide ribose restored SIRT3 expression and mitochondrial morphology and prevented oxidative stress by regulating acetylation of Opa1 and SOD2, ultimately correcting nephron empowerment. Little is known about the role of other SIRTs in kidney development. However, SIRT1 binds to the transcription factor SIX2 in vitro, suggesting a potential role for SIRT1 in controlling renal progenitor cell differentiation.

The role of Sirtuins in renal physiology

In the mature kidney, different cell types rely on different metabolic pathways to perform their specific functions. Proximal tubule cells are rich in mitochondria, which produce ATP through oxidative phosphorylation to maintain active transport of glucose, ions, and nutrients. Therefore, mitochondrial SIRTs, especially SIRT3 and SIRT5, have an important role in regulating the normal homeostasis of proximal tubular cells. Because their absence affects ATP production and induces mitochondrial fragmentation. Instead, podocytes utilize glycolysis to rapidly generate the large amounts of ATP required to regulate the filtration barrier through cytoskeletal rearrangements and modulation of the slit membrane within the foot process. Silencing SIRT6, which regulates glycolysis, has been shown to reduce the expression of slit membrane proteins.

SIRT1 is abundantly expressed in collecting duct cells and regulates sodium balance by inhibiting the transcription of the α subunit of the epithelial sodium channel (ENaC). In the distal nephron, SIRT1 cooperates with the orexigenic peptide ghrelin to regulate sodium reabsorption. SIRT7 is expressed in different renal tubule segments and regulates acid-base and renal electrolyte processing through deacetylation of K+/Cl − cotransporter 4 (KCC4). These results indicate that SIRT1 and SIRT7 play important roles in regulating water and salt balance and acidosis in the kidney, respectively.

SIRT1 also plays a major role in regulating the renal vascular compartment because it deacetylates endothelial nitric oxide synthase (eNOS) to produce nitric oxide and promote vasodilation. In addition, SIRT1 deacetylates hypoxia-inducible factor 2α (HIF2α), which is expressed in interstitial cells, endothelial cells, and glomerular cells that produce erythropoietin (EPO). This deacetylation leads to the hypoxic induction of EPO, oxygen-regulated genes, and vascular endothelial growth factor (VEGF). These results indicate an important role for SIRT1 in controlling capillary density and postnatal vascular adaptation. Compared with wild-type mice, Sirt3-deficient mice have reduced expression of VEGF and up-regulated expression of HIF1α and angiotensin-2, ultimately leading to increased endothelial damage and reduced renal capillary density. Taken together, these data indicate that SIRTs have a significant role in regulating renal homeostasis and are of great significance to the development of renal diseases.

How Does Cistanche Treat Kidney Disease?

Cistanche is a traditional Chinese herbal medicine used for centuries to treat various health conditions, including kidney disease. It is derived from the dried stems of Cistanche deserticola, a plant native to the deserts of China and Mongolia. The main active components of cistanche are phenylethanoid glycosides, echinacoside, and acteoside, which have been found to have beneficial effects on kidney health.

Kidney disease, also known as renal disease, refers to a condition in which the kidneys are not functioning properly. This can result in a buildup of waste products and toxins in the body, leading to various symptoms and complications. Cistanche may help treat kidney disease ase through several mechanisms.

Firstly, cistanche has been found to have diuretic properties, meaning it can increase urine production and help eliminate waste products from the body. This can help relieve the burden on the kidneys and prevent the buildup of toxins. By promoting diuresis, cistanche may also help Reduce high blood pressure, a common complication of kidney disease.

Moreover, cistanche has been shown to have antioxidant effects. Oxidative stress, caused by an imbalance between the production of free radicals and the body's antioxidant defenses, plays a key role in the progression of kidney disease. ies help neutralize free radicals and reduce Oxidative stress, thereby protecting the kidneys from damage. The phenylethanoid glycosides found in cistanche have been particularly effective in scavenging free radicals and inhibiting lipid peroxidation.

Additionally, cistanche has been found to have anti-inflammatory effects. Inflammation is another key factor in the development and progression of kidney disease. Cistanche's anti-inflammatory properties help reduce the production of pro-inflammatory cytokines and inhibit the activation of inflammation mandatory pathways, thus alleviating inflammation in the kidneys.

Furthermore, cistanche has been shown to have immunomodulatory effects. In kidney disease, the immune system can be dysregulated, leading to excessive inflammation and tissue damage. Cistanche helps regulate the immune response by modulating the production and activity of immune cells, such as T cells and macrophages. This immune regulation helps reduce inflammation and prevent further damage to the kidneys.

Moreover, cistanche has been found to improve renal function by promoting the regeneration of renal tubes with cells. Renal tubular epithelial cells play a crucial role in the filtration and reabsorption of waste products and electrolytes. In kidney disease, these cells can be damaged, leading to damaged renal function. Cistanche's ability to promote the regeneration of these cells helps restore proper renal function and improve overall kidney health.

In addition to these direct effects on the kidneys, cistanche has been found to have beneficial effects on other organs and systems in the body. This holistic approach to health is particularly important in kidney disease, as the condition often affects multiple organs and systems. che has been shown to have protective effects on the liver, heart, and blood vessels, which are commonly affected by kidney disease. By promoting the health of these organs, cistanche helps improve overall kidney function and prevent further complications.

In conclusion, cistanche is a traditional Chinese herbal medicine used for centuries to treat kidney disease. Its active components have diuretic, antioxidant, anti-inflammatory, immunomodulatory, and regenerative effects, which help improve renal function and protect the kidneys from further damage. , cistanche has beneficial effects on other organs and systems, making it a holistic approach to treating kidney disease.