Tier 3 — preclinical

Alpha-Ketoglutarate as a Molecule with Pleiotropic Activity: Well-Known and Novel Possibilities of Therapeutic Use

Barbara Zdzisińska, Aleksandra Żurek, Martyna Kandefer-Szerszeń
Archivum Immunologiae et Therapiae Experimentalis 2017 Volume 65, issue 1, pages 21–36

Bibliography

PubMed
PMID 27326424
PubMed Central
PMC5274648
DOI
10.1007/s00005-016-0406-x
Funding
This work was supported by research Grant No 2013/11/B/NZ4/04557 from State Funds for Scientific Research National Science Centre (NCN), Poland.
Competing interests
Not stated. The published article contains no formal competing interests declaration section. Published open access under Creative Commons Attribution 4.0 International License.

Study snapshot

DesignNarrative review
ModelHuman clinical populations (post-surgical, burns, hemodialysis, osteopenia); rodent, poultry and porcine models; in vitro cell culture (fibroblasts, thymocytes, tumour cell lines)
SampleNot applicable — narrative review synthesising the AKG therapeutic literature to 2015
InterventionOrnithine α-ketoglutarate (OKG), calcium α-ketoglutarate, sodium α-ketoglutarate, and cell-permeable AKG esters (octyl-AKG, 1-trifluoromethyl benzyl-AKG) delivered orally, enterally, parenterally, or in vitro at study-specific doses
DurationNot applicable
EndpointsProtein and nitrogen metabolism in catabolic states; Antioxidant activity and cyanide antagonism; Immunomodulatory effects on phagocyte and lymphocyte function; Bone anabolic effects (density, collagen synthesis, prolidase activity); Anticancer activity via HIF-1α destabilisation and epigenetic modulation

What the study showed, in plain terms

Alpha-ketoglutarate (AKG) is a central metabolic intermediate with roles in the TCA cycle, nitrogen/amino-acid metabolism and 2-oxoglutarate-dependent enzymes. This 2017 review surveys AKG biology across protein turnover, oxidative stress, immune function, bone and cancer-related pathways.

The article also summarizes older clinical and translational literature using different AKG salts and formulations in settings such as postoperative care, catabolic illness and bone metabolism. Those studies are heterogeneous and are not equivalent to modern calcium-AKG longevity supplementation.

For the postmenopausal bone study, this review describes an AKG sodium salt plus calcium intervention and reports lower CTX and higher lumbar-spine BMD versus calcium carbonate alone; the separately catalogued primary Filip paper reports the intervention as an AKG calcium salt. When citing that trial, the primary paper should determine the formulation.

Overall this is a mechanistic and translational narrative review, not a systematic evidence synthesis or direct proof that oral Ca-AKG slows human aging.

Key findings

  • AKG occupies a central position in TCA-cycle metabolism and links carbon metabolism with amino-acid and nitrogen handling.
  • AKG is a co-substrate for 2-oxoglutarate-dependent dioxygenases, connecting metabolic state with oxygen sensing and epigenetic regulation.
  • The review describes preclinical evidence involving antioxidant defenses, immune signaling, tissue metabolism and cancer-related pathways.
  • The review summarizes a 24-week postmenopausal bone study as AKG sodium salt plus calcium, reporting roughly 37% lower serum CTX and higher lumbar-spine BMD versus calcium carbonate alone; the separately catalogued primary Filip paper reports the AKG intervention as a calcium salt.
  • Older clinical literature reviewed used multiple AKG salts and combination products in catabolic or postoperative settings, so formulation and indication matter for interpretation.
  • The review notes extensive intestinal metabolism and short circulating persistence of AKG, which complicate extrapolation from experimental exposure to oral supplement dosing.

What this study can and cannot tell us

This is a narrative review rather than a systematic review or meta-analysis. Study selection, quality assessment and quantitative synthesis are limited relative to modern evidence-review standards.

The evidence base spans cell culture, animal models and heterogeneous human studies using different salts, routes, doses and clinical populations. These data cannot be pooled into a single estimate of benefit for modern oral Ca-AKG supplementation.

The review's description of the Filip 2007 bone intervention as an AKG sodium salt conflicts with the separately verified primary report, which describes an AKG calcium salt. This illustrates why primary papers should be used for formulation-specific claims.

The review itself notes substantial intestinal metabolism and short blood persistence of AKG. Those pharmacokinetic constraints make dose and formulation important and limit direct translation from experimental systems.

Citation network

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Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology