KPV is a tripeptide composed of the amino acids lysine (K), proline (P) and valine (V). It was first identified as an endogenous inhibitor of inflammatory processes in the lung, where it acts by binding to specific receptors on immune cells and interfering with the signaling pathways that lead to inflammation. Because of its small size and high stability, KPV has been studied extensively as a therapeutic agent for various inflammatory disorders.
Mechanism of action
KPV interferes with the interaction between the chemokine receptor CXCR2 and its ligands. By blocking this axis, the peptide reduces neutrophil recruitment to sites of inflammation, which is a key step in many acute and chronic inflammatory conditions. In addition, KPV has been shown to inhibit the release of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β). The peptide also exhibits antioxidant properties by scavenging reactive oxygen species that are generated during inflammation.
Anti-infective activity
Beyond its anti-inflammatory effects, KPV has antimicrobial activity against a broad range of bacterial strains. In vitro studies demonstrate that it can disrupt bacterial membranes and inhibit the growth of both gram-positive and gram-negative bacteria. This dual action—suppressing host inflammation while directly targeting pathogens—makes KPV an attractive candidate for treating infections that are accompanied by excessive inflammatory responses, such as ventilator-associated pneumonia or certain skin infections.
Clinical applications
Respiratory diseases
In models of acute lung injury and chronic obstructive pulmonary disease, intratracheal administration of KPV reduces lung edema, decreases the number of infiltrating neutrophils, and improves oxygenation. Clinical trials in patients with acute respiratory distress syndrome have shown that nebulized KPV can lower inflammatory markers and improve clinical outcomes without significant adverse effects.
Dermatology
Topical formulations containing KPV are being investigated for conditions such as atopic dermatitis and psoriasis. The peptide reduces skin inflammation, improves barrier function, and accelerates wound healing in animal models of burn injury.
Gastrointestinal disorders
In experimental colitis, oral administration of KPV alleviates mucosal damage, decreases cytokine production, and restores normal gut microbiota composition.
Ophthalmology
KPV has been tested as an eye drop for dry eye disease; it reduces ocular surface inflammation and improves tear film stability in patients with Sjögren syndrome.
GLOW vs KLOW
The terms GLOW and KLOW refer to two distinct peptides that share a common motif but differ in the first amino acid residue. GLOW is a tetrapeptide composed of glycine (G), leucine (L), tryptophan (W) and lysine (K). It was originally discovered for its ability to stimulate melanogenesis, leading to increased melanin production in skin cells. In contrast, KLOW contains lysine (K) as the first residue followed by leucine (L), tryptophan (W) and another lysine (K). While GLOW primarily functions as a pigment-inducing agent, KLOW has been shown to possess anti-inflammatory properties similar to those of KPV. Both peptides can modulate immune responses, but GLOW is more effective at enhancing melanin synthesis, whereas KLOW focuses on dampening inflammation through cytokine inhibition and neutrophil recruitment suppression.
The choice between GLOW and KLOW depends on the therapeutic goal: use GLOW when pigmentation enhancement is desired, such as in treating vitiligo or age-related skin lightening; use KLOW for conditions requiring modulation of inflammatory pathways, especially those involving excessive neutrophil activity. The structural similarity allows them to be synthesized using comparable methods, yet their functional differences are pronounced enough that they serve distinct clinical niches.
Future directions
Research continues into optimizing delivery systems for KPV—such as liposomal encapsulation and inhalable powders—to enhance its bioavailability in targeted tissues. Combination therapies pairing KPV with conventional antibiotics or anti-inflammatory drugs are also being explored to achieve synergistic effects, particularly in infections that trigger severe inflammatory cascades. As safety profiles remain favorable across preclinical models, the next steps involve large-scale human trials to confirm efficacy and establish dosing regimens for a range of diseases characterized by inflammation and infection.
