Prediabetes is an intermediate metabolic state between normoglycemia and diabetes marked by insulin resistance, metabolic dysfunction, and low‑grade inflammation. These disturbances can produce early renal alterations—such as glomerular hyperfiltration, increased urinary protein excretion, and subclinical tubular injury—that are often underrecognized. The authors investigated whether Modified Huanglian Wendan Decoction (MHWD), a traditional formulation previously shown to modulate glucose and lipid metabolism, can prevent or attenuate renal injury during prediabetes and through which molecular mechanisms.
The decoction’s main active compounds were profiled using UPLC‑MS. Analysis identified 15 principal chemical constituents of MHWD. The specific compound identities and quantities were reported in the source article but are not detailed in this PubMed abstract.
The investigators induced a prediabetic state in rats by combining a high‑fat diet with low‑dose streptozotocin (STZ). This model produced metabolic abnormalities and early markers of renal injury suitable for testing MHWD’s effects. Complementary in vitro studies were performed in HK‑2 human proximal tubular epithelial cells exposed to high glucose to mimic hyperglycemic stress on renal tubular cells.
Metformin, an established AMPK activator, was used as a positive control to compare effects on autophagy and inflammation. Pharmacologic inhibitors—chloroquine to block autophagy and Compound C to inhibit AMPK—were used to probe pathway dependence.
Treatment with MHWD improved multiple systemic metabolic parameters in prediabetic rats. Reported effects included reductions in hyperglycemia, improvements in insulin sensitivity, correction of dyslipidemia, and attenuation of excessive weight gain. These metabolic benefits accompanied the renal protective findings described below.
MHWD attenuated indicators of renal injury in the prediabetic animals and reduced both systemic and renal inflammation. The authors report decreases in inflammatory markers in kidney tissue and systemically, although the abstract does not list specific cytokine names or concentrations. Structural and ultrastructural renal assessments supported improved renal status following MHWD treatment.
Transcriptome and proteome analyses of kidney tissue implicated three central processes mediating MHWD’s effects: metabolic regulation, restoration of autophagy, and anti‑inflammatory actions. These omics data guided targeted validation experiments focused on autophagy machinery and the AMPK/ULK1 signaling axis.
Morphologic and molecular assays confirmed that MHWD restored autophagic activity in kidney tissue. Transmission electron microscopy demonstrated autophagic structures, while immunofluorescence and Western blot analyses showed changes in autophagy‑related protein expression consistent with restored autophagy. These readouts were linked to activation of the AMPK/ULK1 pathway, supporting a mechanistic chain in which MHWD activates AMPK, which in turn engages ULK1 to initiate autophagy and thereby reduce inflammation and cellular stress in the kidney.
In HK‑2 cells exposed to high glucose, MHWD reproduced the renal protective phenotype observed in vivo: restoration of autophagy‑related markers and suppression of inflammatory cytokine expression. The cellular results paralleled those seen with metformin, reinforcing a role for AMPK activation in MHWD’s mechanism of action.
To test dependence on autophagy and AMPK signaling, the investigators used chloroquine (which impairs autophagosome–lysosome fusion) and Compound C (an AMPK inhibitor). Both inhibitors attenuated or eliminated MHWD’s protective effects in vivo and in vitro, indicating that MHWD’s renal and anti‑inflammatory benefits are mediated at least in part via AMPK/ULK1‑dependent autophagy.
MHWD produced effects on autophagy activation, metabolic correction, and inflammation suppression that the authors report as comparable to those of metformin in the experimental settings used. Based on these data, MHWD is proposed as a candidate for early kidney protection in prediabetes through restoration of autophagic homeostasis, enhancement of energy metabolism, and anti‑inflammatory actions. The abstract frames these findings as providing a mechanistic basis for potential clinical application, while full translational steps and safety considerations would require further study.
The authors conclude that MHWD ameliorates metabolic disorders and preserves renal function in prediabetes by restoring autophagy, improving energy metabolism, and suppressing inflammation via the AMPK/ULK1 pathway. This provides mechanistic support for early kidney protection strategies in prediabetes. The PubMed abstract does not provide detailed quantitative results, compound identities from the UPLC‑MS beyond a count of 15 principal constituents, nor exhaustive safety or dosing data; those specifics are reported in the full text of the article.